OGS improvements in 2012 in running the Northeastern Italy Seismic Network: the Ferrara VBB borehole seismic station

Science.gov (United States)

Pesaresi, Damiano; Romanelli, Marco; Barnaba, Carla; Bragato, Pier Luigi; Durì, Giorgio

2013-04-01

The Centro di Ricerche Sismologiche (CRS, Seismological Research Center) of the Istituto Nazionale di Oceanografia e di Geofisica Sperimentale (OGS, Italian National Institute for Oceanography and Experimental Geophysics) in Udine (Italy) after the strong earthquake of magnitude M=6.4 occurred in 1976 in the Italian Friuli-Venezia Giulia region, started to operate the Northeastern Italy Seismic Network: it currently consists of 17 very sensitive broad band and 18 simpler short period seismic stations, all telemetered to and acquired in real time at the OGS-CRS data center in Udine. Real time data exchange agreements in place with other Italian, Slovenian, Austrian and Swiss seismological institutes lead to a total number of about 100 seismic stations acquired in real time, which makes the OGS the reference institute for seismic monitoring of Northeastern Italy. The southwestern edge of the OGS seismic network stands on the Po alluvial basin: earthquake localization and characterization in this area is affected by the presence of soft alluvial deposits. OGS ha already experience in running a local seismic network in high noise conditions making use of borehole installations in the case of the micro-seismicity monitoring of a local gas storage site for a private company. Following the ML=5.9 earthquake that struck the Emilia region around Ferrara in Northern Italy on May 20, 2012 at 02:03:53 UTC, a cooperation of Istituto Nazionale di Geofisica e Vulcanologia, OGS, the Comune di Ferrara and the University of Ferrara lead to the reinstallation of a previously existing very broad band (VBB) borehole seismic station in Ferrara. The aim of the OGS intervention was on one hand to extend its real time seismic monitoring capabilities toward South-West, including Ferrara and its surroundings, and on the other hand to evaluate the seismic response at the site. We will describe improvements in running the Northeastern Italy Seismic Network, including details of the Ferrara VBB

The measurement of the vertical component of hydraulic conductivity in single cased and uncased boreholes

International Nuclear Information System (INIS)

Black, J.H.; Noy, D.J.; Brightman, M.A.

1986-11-01

The project summarised in the paper aimed to assess the different existing methods of measuring vertical hydraulic conductivity in single boreholes by carrying out some actual field testing. The measurements are relevant to the disposal of radioactive waste into argillaceous rocks, where the primary geological barrier to potential leachate migration is the mudrock. Also the prime parameter of interest in the assessment of mudrocks is the vertical component of hydraulic conductivity. A description of the methods of test analysis and interpretation is given. The experimental programme for open borehole testing and cased borehole testing is described, along with the practical and theoretical considerations. (U.K.)

Characterizing fractures and shear zones in crystalline rock using seismic and GPR methods

Science.gov (United States)

Doetsch, Joseph; Jordi, Claudio; Laaksonlaita, Niko; Gischig, Valentin; Schmelzbach, Cedric; Maurer, Hansruedi

2016-04-01

Understanding the natural or artificially created hydraulic conductivity of a rock mass is critical for the successful exploitation of enhanced geothermal systems (EGS). The hydraulic response of fractured crystalline rock is largely governed by the spatial organization of permeable fractures. Defining the 3D geometry of these fractures and their connectivity is extremely challenging, because fractures can only be observed directly at their intersections with tunnels or boreholes. Borehole-based and tunnel-based ground-penetrating radar (GPR) and seismic measurements have the potential to image fractures and other heterogeneities between and around boreholes and tunnels, and to monitor subtle time-lapse changes in great detail. We present the analysis of data acquired in the Grimsel rock laboratory as part of the In-situ Stimulation and Circulation (ISC) experiment, in which a series of stimulation experiments have been and will be performed. The experiments in the granitic rock range from hydraulic fracturing to controlled fault-slip experiments. The aim is to obtain a better understanding of coupled seismo-hydro-mechanical processes associated with high-pressure fluid injections in crystalline rocks and their impact on permeability creation and enhancement. GPR and seismic data have been recorded to improve the geological model and characterize permeable fractures and shear zones. The acquired and processed data include reflection GPR profiles measured from tunnel walls, single-borehole GPR images, and borehole-to-borehole and tunnel-to-tunnel seismic and GPR tomograms. The reflection GPR data reveal the geometry of shear zones up to a distance of 30 m from the tunnels and boreholes, but the interpretation is complicated by the geometrical ambiguity around tunnels and boreholes and by spurious reflections from man-made structures such as boreholes. The GPR and seismic traveltime tomography results reveal brittle fractured rock between two ductile shear zones. The

OGS improvements in 2012 in running the North-eastern Italy Seismic Network: the Ferrara VBB borehole seismic station

Science.gov (United States)

Pesaresi, D.; Romanelli, M.; Barnaba, C.; Bragato, P. L.; Durì, G.

2014-07-01

The Centro di Ricerche Sismologiche (CRS, Seismological Research Centre) of the Istituto Nazionale di Oceanografia e di Geofisica Sperimentale (OGS, Italian National Institute for Oceanography and Experimental Geophysics) in Udine (Italy) after the strong earthquake of magnitude M=6.4 occurred in 1976 in the Italian Friuli-Venezia Giulia region, started to operate the North-eastern Italy Seismic Network: it currently consists of 17 very sensitive broad band and 18 simpler short period seismic stations, all telemetered to and acquired in real time at the OGS-CRS data centre in Udine. Real time data exchange agreements in place with other Italian, Slovenian, Austrian and Swiss seismological institutes lead to a total number of about 100 seismic stations acquired in real time, which makes the OGS the reference institute for seismic monitoring of North-eastern Italy. The south-western edge of the OGS seismic network (Fig. 1) stands on the Po alluvial basin: earthquake localization and characterization in this area is affected by the presence of soft alluvial deposits. OGS ha already experience in running a local seismic network in high noise conditions making use of borehole installations in the case of the micro-seismicity monitoring of a local gas storage site for a private company. Following the ML = 5.9 earthquake that struck the Emilia region around Ferrara in Northern Italy on 20 May 2012 at 02:03:53 UTC, a cooperation of Istituto Nazionale di Geofisica e Vulcanologia, OGS, the Comune di Ferrara and the University of Ferrara lead to the reinstallation of a previously existing very broad band (VBB) borehole seismic station in Ferrara. The aim of the OGS intervention was on one hand to extend its real time seismic monitoring capabilities toward South-West, including Ferrara and its surroundings, and on the other hand to evaluate the seismic response at the site. We will describe improvements in running the North-eastern Italy Seismic Network, including details of

A Hydraulic Stress Measurement System for Investigations at Depth in Slim Boreholes

Science.gov (United States)

Ask, M. V. S.; Ask, D.; Cornet, F. H.; Nilsson, T.; Talib, M.; Sundberg, J.

2017-12-01

Knowledge of the state of stress is essential to most underground work in rock mechanics as it provides means to analyze the mechanical behavior of a rock mass, serve as boundary condition in rock engineering problems, and help understand rock mass stability and groundwater flow. Luleå University of Technology (LTU) has developed and built a wire-line system for hydraulic rock stress measurements in slim boreholes together with the University of Strasbourg and Geosigma AB. The system consists of a downhole- and a surface unit. The downhole unit consists of hydraulic fracturing equipment (straddle packers and downhole imaging tool) and their associated data acquisition systems. The surface unit comprises of a 40-foot container permanently mounted on a trailer, which is equipped with a tripod, wire-line winches, water hydraulics, and a generator. The surface unit serves as a climate-independent on-site operations center, as well as a self-supporting transport vessel for the entire system. Three hydraulic stress testing methods can be applied: hydraulic fracturing, sleeve fracturing and hydraulic testing of pre-existing fractures. The three-dimensional stress tensor and its variation with depth within a continuous rock mass can be determined in a scientific unambiguously way by integrating results from the three test methods. The testing system is state of the art in several aspects including: (1) Large depth range (3 km), (2) Ability to test three borehole dimensions, (3) Resistivity imager maps the orientation of tested fracture (which is highlighted); (4) Highly stiff and resistive to corrosion downhole testing equipment; and (5) Very detailed control on the injection flow rate and cumulative volume is obtained by a hydraulic injection pump with variable piston rate, and a highly sensitive flow-meter. These aspects highly reduce measurement-related uncertainties of stress determination. Commissioning testing and initial field tests are scheduled to occur in a 1200

Aespoe Hard Rock Laboratory. Backfill and Plug test. Hydraulic testing of core drilled boreholes in the ZEDEX drift

Energy Technology Data Exchange (ETDEWEB)

Ludvigson, Jan-Erik; Nordqvist, Rune; Ekman, Lennart; Hansson, Kent (GEOSIGMA AB, Uppsala (Sweden))

2009-07-01

The present report documents the performance and results of hydraulic testing in selected core boreholes in the Zedex drift. The holes will be used as rock instrumentation boreholes during the Backfill and Plug Test at Aespoe HRL. The testing involves both 1 m long boreholes with 56 mm diameter as well as longer boreholes c. 5 m, 8 m and 25 m long with 56 mm or 76 mm diameter. Only single-hole tests were performed. The tests were carried out as short-time constant head injection tests since all boreholes tested (except one) were non-flowing before tests. The injection phase was followed by a pressure recovery phase. Furthermore, the tests were carried out as single-packer tests. A specially designed test system was used for the tests. The main evaluation of the tests was performed on data from the recovery phase by a new approach based on a non-linear regression technique combined with a flow simulation model (SUTRA). The tests in the 1 m-holes (testing the interval c. 0.3-0.7 m in the rock perpendicular to the tunnel face) show that the hydraulic conductivity of the superficial rock around the Zedex drift in general is low. However, during testing in some boreholes, visible leakage in the rock occurred through superficial fractures into the tunnel. These fractures were mainly located in the floor of the Zedex drift and are probably blast-induced. These fractures have a high hydraulic conductivity. The tests in the longer boreholes show that the hydraulic conductivity further into the rock in general is below c. 1x10-10 m/s. Increased hydraulic conductivity (c.1.5x10-8 m/s) was only observed in the flowing borehole KXZSD8HL.

Deep Downhole Seismic Testing at the Waste Treatment Plant Site, Hanford, WA. Volume V S-Wave Measurements in Borehole C4996 Seismic Records, Wave-Arrival Identifications and Interpreted S-Wave Velocity Profile.

Energy Technology Data Exchange (ETDEWEB)

Stokoe, Kenneth H.; Li, Song Cheng; Cox, Brady R.; Menq, Farn-Yuh

2007-06-06

Velocity measurements in shallow sediments from ground surface to approximately 370 to 400 feet bgs were collected by Redpath Geophysics using impulsive S- and P-wave seismic sources (Redpath 2007). Measurements below this depth within basalt and sedimentary interbeds were made by UTA between October and December 2006 using the T-Rex vibratory seismic source in each of the three boreholes. Results of these measurements including seismic records, wave-arrival identifications and interpreted velocity profiles are presented in the following six volumes: I. P-Wave Measurements in Borehole C4993 II. P-Wave Measurements in Borehole C4996 III. P-Wave Measurements in Borehole C4997 IV. S-Wave Measurements in Borehole C4993 V. S-Wave Measurements in Borehole C4996 VI. S-Wave Measurements in Borehole C4997 In this volume (V), all S-wave measurements are presented that were performed in Borehole C4996 at the WTP with T-Rex as the seismic source and the Lawrence Berkeley National Laboratory (LBNL) 3-D wireline geophone as the at-depth borehole receiver.

Deep Downhole Seismic Testing at the Waste Treatment Plant Site, Hanford, WA. Volume VI S-Wave Measurements in Borehole C4997 Seismic Records, Wave-Arrival Identifications and Interpreted S-Wave Velocity Profile.

Energy Technology Data Exchange (ETDEWEB)

Stokoe, Kenneth H.; Li, Song Cheng; Cox, Brady R.; Menq, Farn-Yuh

2007-06-06

Velocity measurements in shallow sediments from ground surface to approximately 370 to 400 feet bgs were collected by Redpath Geophysics using impulsive S- and P-wave seismic sources (Redpath 2007). Measurements below this depth within basalt and sedimentary interbeds were made by UTA between October and December 2006 using the T-Rex vibratory seismic source in each of the three boreholes. Results of these measurements including seismic records, wave-arrival identifications and interpreted velocity profiles are presented in the following six volumes: I. P-Wave Measurements in Borehole C4993 II. P-Wave Measurements in Borehole C4996 III. P-Wave Measurements in Borehole C4997 IV. S-Wave Measurements in Borehole C4993 V. S-Wave Measurements in Borehole C4996 VI. S-Wave Measurements in Borehole C4997 In this volume (VI), all S-wave measurements are presented that were performed in Borehole C4997 at the WTP with T-Rex as the seismic source and the Lawrence Berkeley National Laboratory (LBNL) 3-D wireline geophone as the at-depth borehole receiver.

Investigation on the real-time prediction of ground motions using seismic records observed in deep boreholes

Science.gov (United States)

Miyakoshi, H.; Tsuno, S.

2013-12-01

The present method of the EEW system installed in the railway field of Japan predicts seismic ground motions based on the estimated earthquake information about epicentral distances and magnitudes using initial P-waves observed on the surface. In the case of local earthquakes beneath the Tokyo Metropolitan Area, however, a method to directly predict seismic ground motions using P-waves observed in deep boreholes could issue EEWs more simply and surely. Besides, a method to predict seismic ground motions, using S-waves observed in deep boreholes and S-wave velocity structures beneath seismic stations, could show planar distributions of ground motions for train operation control areas in the aftermath of earthquakes. This information is available to decide areas in which the emergency inspection of railway structures should be performed. To develop those two methods, we investigated relationships between peak amplitudes on the surface and those in deep boreholes, using seismic records of KiK-net stations in the Kanto Basin. In this study, we used earthquake accelerograms observed in boreholes whose depths are deeper than the top face of Pre-Neogene basement and those on the surface at 12 seismic stations of KiK-net. We selected 243 local earthquakes whose epicenters are located around the Kanto Region. Those JMA magnitudes are in the range from 4.5 to 7.0. We picked the on-set of P-waves and S-waves using a vertical component and two horizontal components, respectively. Peak amplitudes of P-waves and S-waves were obtained using vertical components and vector sums of two horizontal components, respectively. We estimated parameters which represent site amplification factors beneath seismic stations, using peak amplitudes of S-waves observed in the deep borehole and those on the surface, to minimize the residuals between calculations by the theoretical equation and observations. Correlation coefficients between calculations and observations are high values in the range

Results of single borehole hydraulic tests in the Mizunami Underground Research Laboratory project. FY 2012 - FY 2015

International Nuclear Information System (INIS)

Onoe, Hironori; Takeuchi, Ryuji

2016-11-01

This report summarize the results of the single borehole hydraulic tests of 151 sections carried out at the -300 m Stage and the -500 m Stage of the Mizunami Underground Research Laboratory from FY 2012 to FY 2015. The details of each test (test interval depth, geology, etc.) as well as the interpreted hydraulic parameters and analytical methods used are presented in this report. Furthermore, the previous results of the single borehole hydraulic tests carried out in the Regional Hydrogeological Study Project and the Mizunami Underground Research Laboratory Project before FY 2012 are also summarized in this report. (author)

Identification of MHF (massive hydraulic fracturing) fracture planes and flow paths: A correlation of well log data with patterns in locations of induced seismicity

Energy Technology Data Exchange (ETDEWEB)

Dreesen, D.; Malzahn, M.; Fehler, M.; Dash, Z.

1987-01-01

One of the critical steps in developing a hot dry rock geothermal system is the creation of flow paths through the rock between two wellbores. To date, circulation systems have only been created by drilling one wellbore, hydraulically fracturing the well (which induces microearthquakes), locating the microearthquakes and then drilling a second wellbore through the zone of seismicity. A technique for analyzing the pattern of seismicity to determine where fracture planes are located in the seismically active region has recently been developed. This allows us to distinguish portions of the seismically active volume which are most likely to contain significant flow paths. We applied this technique to seismic data collected during a massive hydraulic fracturing (MHF) treatment and found that the fracture planes determined by the seismic method are confirmed by borehole temperature and caliper logs which indicate where permeable fractures and/or zones of weakness intersect the wellbores. A geometric model based on these planes and well log data has enhanced our understanding of the reservoir flow paths created by fracturing and is consistent with results obtained during production testing of the reservoir.

Aim and points of this workshop: The 2. Workshop on Seismic Observation in Deep Borehole (SODB) and its Applications

International Nuclear Information System (INIS)

Sugiyama, Yuichi

2014-01-01

The achievements of the first WS and the aim of the Second WS were explained. The purposes of this Second WS were: to re-recognize the significance of seismic ground motion evaluation based on newly added deep borehole seismic observation in addition to existing borehole investigation, geological surveys, and geophysical exploration; to acknowledge deep borehole seismic observation and geophysical exploration (hardware) as well as the site characteristic evaluation method (software) required for seismic ground motion evaluation; and to consolidate opinions on multi-purpose application of observation technology and data as well as acknowledge issues to be addressed and technological problems. The final goals of this WS were to clarify items and issues that present challenges for the future based on the discussions in this WS. (author)

Results of hydraulic tests at Gibson Dome No. 1, Elk Ridge No. 1, and E. J. Kubat boreholes, Paradox Basin, Utah

International Nuclear Information System (INIS)

Thackston, J.W.; Preslo, L.M.; Hoexter, D.E.; Donnelly, N.

1984-03-01

Hydraulic testing was conducted in three boreholes in southeastern Utah to provide a portion of the data needed to characterize the hydrogeology of the Elk Ridge and Gibson Dome areas of the western Paradox Basin, Utah. The tests at the E. J. Kubat borehole yielded representative values of transmissivity, hydraulic conductivity, storativity, and potentiometric levels of the Leadville Limestone. Testing at Elk Ridge No. 1 provided values of similar parameters for the combined thickness of the upper Honaker Trail, Elephant Canyon, and Cedar Mesa formations. Composite transmissivities of similar zones from these borehole tests compared closely with the results of testing at borehole GD-1. A comparison of results from lab tests on core with results of extensive borehole testing at GD-1 indicates that short-term drill stem tests in a single well can provide representative estimates of bulk transmissivities and hydraulic conductivities in this field area for test zones that have a hydraulic conductivity of greater than about 1 x 10 -7 cm/sec. However, lab tests produce more representative values of effective porosity and matrix permeability of individual strata. Results of lab tests and long-term borehole tests confirm that the lower Honaker Trail and upper Paradox formations have extremely low conductivities in the vicinity of the GD-1 borehole. The results of these tests were complete as of January 1981. 22 references, 29 figures, 5 tables

Ambient Seismic Imaging of Hydraulically Active Fractures at km Depths

Science.gov (United States)

Malin, P. E.; Sicking, C.

2017-12-01

Streaming Depth Images of ambient seismic signals using numerous, densely-distributed, receivers have revealed their connection to hydraulically active fractures at 0.5 to 5 km depths. Key for this type of imaging is very high-fold stacking over both multiple receives and periods of a few hours. Also important is suppression of waveforms from fixed, repeating sources such as pumps, generators, and traffic. A typical surface-based ambient SDI survey would use a 3D seismic receiver grid. It would have 1,000 to 4,000 uniformly distributed receivers at a density of 50/km2over the target. If acquired by borehole receivers buried 100 m deep, the density can be dropped by an order of magnitude. We show examples of the acquisition and signal processing scenarios used to produce the ambient images. (Sicking et al., SEG Interpretation, Nov 2017.) While the fracture-fluid source connection of SDI has been verified by drilling and various types of hydraulic tests, the precise nature of the signal's origin is not clear. At the current level of observation, the signals do not have identifiable phases, but can be focused using P wave velocities. Suggested sources are resonances of pressures fluctuations in the fractures, or small, continuous, slips on fractures surfaces. In either case, it appears that the driving mechanism is tectonic strain in an inherently unstable crust. Solid earth tides may enhance these strains. We illustrate the value of the ambient SDI method in its industrial application by showing case histories from energy industry and carbon-capture-sequestration projects. These include ambient images taken before, during, and after hydraulic treatments in un-conventional reservoirs. The results show not only locations of active fractures, but also their time responses to stimulation and production. Time-lapse ambient imaging can forecast and track events such as well interferences and production changes that can result from nearby treatments.

Seismic Readings from the Deepest Borehole in the New Madrid Seismic Zone

Energy Technology Data Exchange (ETDEWEB)

Woolery, Edward W [KY Geological Survey, Univ of KY; Wang, Zhenming [KY Geological Survey, Univ of KY; Sturchio, Neil C [Dept of earth and Env. Sciences, Univ of Ill at Chicago

2006-03-01

Since the 1980s, the research associated with the UK network has been primarily strong-motion seismology of engineering interest. Currently the University of Kentucky operates a strong-motion network of nine stations in the New Madrid Seismic Zone. A unique feature of the network is the inclusions of vertical strong-motion arrays, each with one or two downhole accelerometers. The deepest borehole array is 260 m below the surfaces at station VASA in Fulton County, Kentucky. A preliminary surface seismic refraction survey was conducted at the site before drilling the hole at VSAS (Woolery and Wang, 2002). The depth to the Paleozoic bedrock at the site was estimated to be approximately 595 m, and the depth to the first very stiff layer (i.e. Porters Creek Clay) was found to be about 260 m. These depths and stratigraphic interpretation correlated well with a proprietary seismic reflection line and the Ken-Ten Oil Exploration No. 1 Sanger hole (Schwalb, 1969), as well as our experience in the area (Street et al., 1995; Woolery et al., 1999).

Results of single borehole hydraulic testing in the Mizunami Underground Research Laboratory project. Phase 2

International Nuclear Information System (INIS)

Daimaru, Shuji; Takeuchi, Ryuji; Onoe, Hironori; Saegusa, Hiromitsu

2012-09-01

This report summarize the results of the single borehole hydraulic tests of 79 sections conducted as part of the Construction phase (Phase 2) in the Mizunami Underground Research Laboratory (MIU) Project. The details of each test (test interval depth, geology, etc.) as well as the interpreted hydraulic parameters and analytical method used are presented in this report. (author)

Porosity, Fracturing and Alteration of Young Oceanic Crust: New Seismic Analyses at Borehole 504B

Science.gov (United States)

Gregory, E. P. M.; Hobbs, R. W.; Peirce, C.; Wilson, D. J.

2017-12-01

DSDP/ODP borehole 504B, drilled 2111 m into 6.9 Ma oceanic crust, provides in-situ core and logging measurements of the lithology, fracturing and porosity of crust originally formed at the Costa Rica Rift and its subsequent alteration by hydrothermal fluids. A recent active seismic survey over the borehole and surrounding area reveals wider spatial variations in velocity that can be related to this porosity and fracturing. Over 10,000 airgun shots were fired in a 30 x 30 km grid over the borehole region, using both high-frequency and low-frequency airgun arrays. The shots were recorded on a 4.5 km-long streamer and 24 ocean-bottom seismographs, each equipped with a three-component geophone and an hydrophone. A vertical hydrophone array recorded the downgoing source wavelet, and underway gravity, magnetic field and multibeam bathymetry data were also recorded. This combined dataset enables the most comprehensive geophysical analysis of this area of crust to date, while the ground-truthing provided by 504B enables us to address the questions of what do the seismic oceanic crustal layers represent and what controls their characteristics as the crust ages? Wide-angle seismic modelling with a Monte Carlo based uncertainty analysis reveals new 2D and 3D Vp and Vs models of the area, which show relatively homogeneous crust around borehole 504B, and place the seismic layer 2B/2C, and seismic layer 2/3 boundaries coincident with fracturing and alteration fronts rather than the lithological boundaries between lavas and dykes, and dykes and gabbros, respectively. Analysis of Poisson's ratio, seismic anisotropy and particle motions reveal patterns in fracturing and porosity across the survey area, and locate possible fossilised hydrothermal circulation cells. These cells appear to have influenced the porosity of the crust through alteration and mineralisation processes, with faults inherited from initial crustal accretion influencing basement topographic highs and providing

Derivation of site-specific relationships between hydraulic parameters and p-wave velocities based on hydraulic and seismic tomography

Energy Technology Data Exchange (ETDEWEB)

Brauchler, R.; Doetsch, J.; Dietrich, P.; Sauter, M.

2012-01-10

In this study, hydraulic and seismic tomographic measurements were used to derive a site-specific relationship between the geophysical parameter p-wave velocity and the hydraulic parameters, diffusivity and specific storage. Our field study includes diffusivity tomograms derived from hydraulic travel time tomography, specific storage tomograms, derived from hydraulic attenuation tomography, and p-wave velocity tomograms, derived from seismic tomography. The tomographic inversion was performed in all three cases with the SIRT (Simultaneous Iterative Reconstruction Technique) algorithm, using a ray tracing technique with curved trajectories. The experimental set-up was designed such that the p-wave velocity tomogram overlaps the hydraulic tomograms by half. The experiments were performed at a wellcharacterized sand and gravel aquifer, located in the Leine River valley near Göttingen, Germany. Access to the shallow subsurface was provided by direct-push technology. The high spatial resolution of hydraulic and seismic tomography was exploited to derive representative site-specific relationships between the hydraulic and geophysical parameters, based on the area where geophysical and hydraulic tests were performed. The transformation of the p-wave velocities into hydraulic properties was undertaken using a k-means cluster analysis. Results demonstrate that the combination of hydraulic and geophysical tomographic data is a promising approach to improve hydrogeophysical site characterization.

Assessing the induced seismicity by hydraulic fracturing at the Wysin site (Poland)

Science.gov (United States)

Ángel López Comino, José; Cesca, Simone; Kriegerowski, Marius; Heimann, Sebastian; Dahm, Torsten; Mirek, Janusz; Lasocky, Stanislaw

2017-04-01

Induced seismicity related to industrial processes including shale gas and oil exploitation is a current issues that implies enough reasons to be concerned. Hydraulic fracturing usually induces weak events. However, scenarios with larger earthquakes are possible, e.g. if the injected fluids alter friction conditions and trigger the failure of neighbouring faults. This work is focused on a hydrofracking experiment monitored in the framework of the SHEER (SHale gas Exploration and Exploitation induced Risks) EU project at the Wysin site, located in the central-western part of the Peribaltic synclise of Pomerania, Poland. A specific network setup has been installed combining surface installation with three small-scale arrays and a shallow borehole installation. The fracking operations were carried out in June and July 2016 at a depth 4000 m. The monitoring has been operational before, during and after the termination of hydraulic fracturing operations. We apply a recently developed automated full waveform detection algorithm based on the stacking of smooth characteristic function and the identification of high coherence in the signals recorded at different stations. The method was tested with synthetic data and different detector levels yielding values of magnitude of completeness around 0.1. An unsupervised detection catalogue is generated with real data for a time period May-September 2016. We identify strong temporal changes (day/night) of the detection performance. A manual revision of the detected signals reveals that most detections are associated to local and regional seismic signals. Only two events could be assigned to the volume potentially affected by the fracking operations.

Cross-hole fracture connectivity assessed using hydraulic responses during liner installations in crystalline bedrock boreholes

Science.gov (United States)

Persaud, Elisha; Levison, Jana; Pehme, Peeter; Novakowski, Kentner; Parker, Beth

2018-01-01

In order to continually improve the current understanding of flow and transport in crystalline bedrock environments, developing and improving fracture system characterization techniques is an important area of study. The presented research examines the installation of flexible, impermeable FLUTe™ liners as a means for assessing cross-hole fracture connectivity. FLUTe™ liners are used to generate a new style of hydraulic pulse, with pressure response monitored in a nearby network of open boreholes drilled in gneissic rock of the Canadian Shield in eastern Ontario, Canada. Borehole liners were installed in six existing 10-15 cm diameter boreholes located 10-35 m apart and drilled to depths ranging between 25-45 m. Liner installation tests were completed consecutively with the number of observation wells available for each test ranging between one and six. The collected pressure response data have been analyzed to identify significant groundwater flow paths between source and observation boreholes as well as to estimate inter-well transmissivity and storativity using a conventional type-curve analysis. While the applied solution relies on a number of general assumptions, it has been found that reasonable comparison can be made to previously completed pulse interference and pumping tests. Results of this research indicate areas where method refinement is necessary, but, nonetheless, highlight the potential for use in crystalline bedrock environments. This method may provide value to future site characterization efforts given that it is complementary to, and can be used in conjunction with, other currently employed borehole liner applications, such as the removal of cross-connection at contaminated sites and the assessment of discrete fracture distributions when boreholes are sealed, recreating natural hydraulic gradient conditions.

High Resolution Vertical Seismic Profile from the Chicxulub IODP/ICDP Expedition 364 Borehole: Wave Speeds and Seismic Reflectivity.

Science.gov (United States)

Nixon, C.; Kofman, R.; Schmitt, D. R.; Lofi, J.; Gulick, S. P. S.; Christeson, G. L.; Saustrup, S., Sr.; Morgan, J. V.

2017-12-01

We acquired a closely-spaced vertical seismic profile (VSP) in the Chicxulub K-Pg Impact Crater drilling program borehole to calibrate the existing surface seismic profiles and provide complementary measurements of in situ seismic wave speeds. Downhole seismic records were obtained at spacings ranging from 1.25 m to 5 m along the borehole from 47.5 m to 1325 mwsf (meters wireline below sea floor) (Fig 1a) using a Sercel SlimwaveTM geophone chain (University of Alberta). The seismic source was a 30/30ci Sercel Mini GI airgun (University of Texas), fired a minimum of 5 times per station. Seismic data processing used a combination of a commercial processing package (Schlumberger's VISTA) and MatlabTM codes. The VSP displays detailed reflectivity (Fig. 1a) with the strongest reflection seen at 600 mwsf (280 ms one-way time), geologically corresponding to the sharp contact between the post-impact sediments and the target peak ring rock, thus confirming the pre-drilling interpretations of the seismic profiles. A two-way time trace extracted from the separated up-going wavefield matches the major reflection both in travel time and character. In the granitic rocks that form the peak ring of the Chicxulub impact crater, we observe P-wave velocities of 4000-4500 m/s which are significantly less than the expected values of granitoids ( 6000 m/s) (Fig. 1b). The VSP measured wave speeds are confirmed against downhole sonic logging and in laboratory velocimetry measurements; these data provide additional evidence that the crustal material displaced by the impact experienced a significant amount of damage. Samples and data provided by IODP. Samples can be requested at http://web.iodp.tamu.edu/sdrm after 19 October 2017. Expedition 364 was jointly funded by ECORD, ICDP, and IODP with contributions and logistical support from the Yucatan State Government and UNAM. The downhole seismic chain and wireline system is funded by grants to DRS from the Canada Foundation for Innovation and

Improvement of high resolution borehole seismics. Part 1: Development of processing methods for VSP surveys. Part 2: Piezoelectric signal transmitter for seismic measurements

International Nuclear Information System (INIS)

Cosma, C.; Heikkinen, P.; Pekonen, S.

1991-05-01

The purpose of the high resolution borehole seismics project has been to improve the reliability and resolution of seismic methods in the particular environment of nuclear waste repository sites. The results obtained, especially the data processing and interpretation methods developed, are applicable also to other geophysical methods (e.g. Georadar). The goals of the seismic development project have been: the development of processing and interpretation techniques for mapping fractured zones, and the design and construction of a seismic source complying with the requirements of repository site characterization programs. Because these two aspects of the work are very different in nature, we have structured the report as two self contained parts. Part 1 describes the development of interpretive techniques. We have used for demonstrating the effect of different methods a VSP data set collected at the SCV site during Stage 1 of the project. Five techniques have been studied: FK-filtering, three versions of Tau-p filtering and a new technique that we have developed lately, Image Space filtering. Part 2 refers to the construction of the piezoelectric source. Earlier results obtained over short distances with low energy piezoelectric transmitters let us believe that the same principle could be applied for seismic signal transmitters, if solutions for higher energy and lower frequency output were found. The instrument which we have constructed is a cylindrical unit which can be placed in a borehole and is able to produce a radial strain when excited axially. The minimum borehole diameter is 56 mm. (au)

Seismic monitoring of hydraulic fracturing: techniques for determining fluid flow paths and state of stress away from a wellbore

Energy Technology Data Exchange (ETDEWEB)

Fehler, M.; House, L.; Kaieda, H.

1986-01-01

Hydraulic fracturing has gained in popularity in recent years as a way to determine the orientations and magnitudes of tectonic stresses. By augmenting conventional hydraulic fracturing measurements with detection and mapping of the microearthquakes induced by fracturing, we can supplement and idependently confirm information obtained from conventional analysis. Important information obtained from seismic monitoring includes: the state of stress of the rock, orientation and spacing of the major joint sets, and measurements of rock elastic parameters at locations distant from the wellbore. While conventional well logging operations can provide information about several of these parameters, the zone of interrogation is usually limited to the immediate proximity of the borehole. The seismic waveforms of the microearthquakes contain a wealth of information about the rock in regions that are otherwise inaccessible for study. By reliably locating the hypocenters of many microearthquakes, we have inferred the joint patterns in the rock. We observed that microearthquake locations do not define a simple, thin, planar distribution, that the fault plane solutions are consistent with shear slippage, and that spectral analysis indicates that the source dimensions and slip along the faults are small. Hence we believe that the microearthquakes result from slip along preexisting joints, and not from tensile extension at the tip of the fracture. Orientations of the principal stresses can be estimated by using fault plane solutions of the larger microearthquakes. By using a joint earthquake location scheme, and/or calibrations with downhole detonators, rock velocities and heterogeneities thereof can be investigated in rock volumes that are far enough from the borehole to be representative of intrincis rock properties.

Construction of System for Seismic Observation in Deep Borehole (SODB) - Overview and Achievement Status of the Project

International Nuclear Information System (INIS)

Kobayashi, Genyu

2014-01-01

The seismic responses of each unit at the Kashiwazaki-Kariwa NPP differed greatly during the 2007 Niigata-ken Chuetsu-oki Earthquake; the deep sedimentary structure around the site greatly affected these differences. To clarify underground structure and to evaluate ground motion amplification and attenuation effects more accurately in accordance with deep sedimentary structure, JNES initiated the SODB project. Deployment of a vertical seismometer array in a 3000-meter deep borehole was completed in June 2012 on the premises of NIIT. Horizontal arrays were also placed on the ground surface. Experiences and achievements in the JNES project were introduced, including development of seismic observation technology in deep boreholes, site amplification measurements from logging data, application of borehole observation data to maintenance of nuclear power plant safety, and so on. Afterwards, the relationships of other presentations in this WS, were explained. (authors)

Combination of surface and borehole seismic data for robust target-oriented imaging

Science.gov (United States)

Liu, Yi; van der Neut, Joost; Arntsen, Børge; Wapenaar, Kees

2016-05-01

A novel application of seismic interferometry (SI) and Marchenko imaging using both surface and borehole data is presented. A series of redatuming schemes is proposed to combine both data sets for robust deep local imaging in the presence of velocity uncertainties. The redatuming schemes create a virtual acquisition geometry where both sources and receivers lie at the horizontal borehole level, thus only a local velocity model near the borehole is needed for imaging, and erroneous velocities in the shallow area have no effect on imaging around the borehole level. By joining the advantages of SI and Marchenko imaging, a macrovelocity model is no longer required and the proposed schemes use only single-component data. Furthermore, the schemes result in a set of virtual data that have fewer spurious events and internal multiples than previous virtual source redatuming methods. Two numerical examples are shown to illustrate the workflow and to demonstrate the benefits of the method. One is a synthetic model and the other is a realistic model of a field in the North Sea. In both tests, improved local images near the boreholes are obtained using the redatumed data without accurate velocities, because the redatumed data are close to the target.

The measurement of the vertical component of hydraulic conductivity in single-cased and uncased boreholes

International Nuclear Information System (INIS)

Black, J.H.; Noy, D.J.; Brightman, M.A.

1987-01-01

The project aimed to assess the different existing methods of measuring vertical hydraulic conductivity in single boreholes by carrying out some actual field testing. A review of existing techniques for both field practice and analysis of the results is reported. After consideration of the various techniques a combination method of testing is proposed. A set of equipment to carry out this combination of tests was designed and built. The uncased testing revealed that it was possible to derive a value for vertical hydraulic conductivity. The doublet method, however, was not particularly successful and numerical simulation was cumbersome. The type-curve approach of appraising whether or not analysis concepts were appropriate proved the most robust method. It is clear that reconnaissance measurements of environmental pressure are very useful in defining where detailed testing should take place. The second phase of testing through perforations proved very difficult. There were many problems associated with location both of the wireline testing system within the borehole and especially of the previous measurements. However, analysis of the results in terms of skin indicated that the perforations produced a negative skin. The measurement of vertical hydraulic conductivity cannot at the moment be regarded as routine

Hydraulically Induced Seismicity in South-Eastern Brazil Linked to Water Wells

Science.gov (United States)

Convers, J.; Assumpcao, M.; Barbosa, J. R.

2017-12-01

While hydraulic stimulus on seismic activity is most commonly associated with hydraulic fracturing processes, we find in SE Brazil a rare case of seismicity influenced by hydraulic stimulation linked to seasonal rain and water wells in a farming area. These are thought to be the main factors influencing the seasonal seismicity activity in Jurupema, a farming town located in the interior of the state of Sao Paulo, southern Brazil. With temporary seismic station deployments during 2016 and 2017, we analyze the seismicity in this area, its temporal and spatial distribution, and its association with the drilling of ground water wells in this particular area. In a region where water wells are often drilled to provide irrigation for farming, these are often perforated down to about 100 m depth, penetrating below the uppermost sandstone rock layer ( 50 m) into a fractured basaltic rock layer, reaching the confined aquifer within it. While the wells are constantly pumped during the dry season, during the course of the rainy season (when these are not being used), a possible infiltration into the confined basaltic aquifer, from both the rainwater and the upper sandstone aquifer, adds changes to the pore pressure of the fractured rock, and modifies the tectonic pre-stress conditions, to facilitate stress release mechanisms in pre-existing faults and cracks. With our temporary seismic station deployments, we not only examine the seismicity in this region during both 2016 and 2017, but we additionally compare its characteristics to the nearby Bebedouro case in an apparent induced seismic case of analogous source, and seismic activity with magnitudes up to 2.9 occurring between 2005 and 2010.

Implications of the "observer effect" on modelling a long-term pumping test with hydraulically conductive boreholes in a discrete fracture network system.

Science.gov (United States)

Holton, D.; Frampton, A.; Cvetkovic, V.

2006-12-01

The Onkalo underground research facility for rock characterisation for nuclear waste disposal is located at Olkiluoto island, just off the Finnish coast in the Baltic Sea. Prior to the start of the excavation of the Onkalo facility, an extensive amount of hydraulic data has been collected during various pumping experiments from a large number of boreholes placed throughout an area of approximately 10 km2, reaching depths of 1000 meters below sea level. In particular, the hydraulic borehole data includes classical measurements of pressure, but also new measurements of flow rate and flow direction in boreholes (so called flow-logging). These measurements indicate large variations in heterogeneity and are a clear reflection of the discrete nature of the system. Here we present results from an ongoing project which aims to explore and asses the implications of these new flow-logging measurements to site descriptive modelling and modelling at performance assessment scales. The main challange of the first phase of this project is to obtain a greater understanding of a strongly heterogenious and anisotropic groundwater system in which open boreholes are located; that is, a system in which the observation boreholes themselves create new hydraulic conductive features of the groundwater system. The results presented are from recent hydraulic flow modelling simulations with a combined continuous porous media and discrete fracture network approach using a commercial finite-element software. An advantage of this approach is we may adapt a continuum mesh on the regional scale, were only a few conductive features are known, together with a local scale discrete fracture network approach, where detailed site-investigation has revealed a large amount of conductive features. Current findings indicate the system is sensitive to certain combinations of hydraulic features, and we quantify the significance of including these variations in terms of their implications for reduction of

Isotropic events observed with a borehole array in the Chelungpu fault zone, Taiwan.

Science.gov (United States)

Ma, Kuo-Fong; Lin, Yen-Yu; Lee, Shiann-Jong; Mori, Jim; Brodsky, Emily E

2012-07-27

Shear failure is the dominant mode of earthquake-causing rock failure along faults. High fluid pressure can also potentially induce rock failure by opening cavities and cracks, but an active example of this process has not been directly observed in a fault zone. Using borehole array data collected along the low-stress Chelungpu fault zone, Taiwan, we observed several small seismic events (I-type events) in a fluid-rich permeable zone directly below the impermeable slip zone of the 1999 moment magnitude 7.6 Chi-Chi earthquake. Modeling of the events suggests an isotropic, nonshear source mechanism likely associated with natural hydraulic fractures. These seismic events may be associated with the formation of veins and other fluid features often observed in rocks surrounding fault zones and may be similar to artificially induced hydraulic fracturing.

kISMET: Stress analysis and intermediate-scale hydraulic fracturing at the Sanford Underground Research Facility

Science.gov (United States)

Dobson, P. F.; Oldenburg, C. M.; Wu, Y.; Cook, P. J.; Kneafsey, T. J.; Nakagawa, S.; Ulrich, C.; Siler, D. L.; Guglielmi, Y.; Ajo Franklin, J. B.; Rutqvist, J.; Daley, T. M.; Birkholzer, J. T.; Wang, H. F.; Lord, N.; Haimson, B. C.; Sone, H.; Vigilante, P.; Roggenthen, W.; Doe, T.; Lee, M.; Ingraham, M. D.; Huang, H.; Mattson, E.; Johnson, T. C.; Zhou, J.; Zoback, M. D.; Morris, J.; White, J. A.; Johnson, P. A.; Coblentz, D. D.; Heise, J.

2017-12-01

In 2015, we established a field test facility at the Sanford Underground Research Facility (SURF), and in 2016 we carried out in situ hydraulic fracturing experiments to characterize the stress field, understand the effects of crystalline rock fabric on fracturing, and gain experience in monitoring using geophysical methods. The kISMET (permeability (k) and Induced Seismicity Management for Energy Technologies) project test site was established in the West Access Drift at the 4850 ft level, 1478 m below ground in phyllite of the Precambrian Poorman Formation. The kISMET team drilled and cored five near-vertical boreholes in a line on 3 m spacing, deviating the two outermost boreholes slightly to create a five-spot pattern around the test borehole centered in the test volume 40 m below the drift invert (floor) at a total depth of 1518 m. Laboratory measurements of core from the center test borehole showed P-wave velocity heterogeneity along each core indicating strong, fine-scale ( 1 cm or smaller) changes in the mechanical properties of the rock. Tensile strength ranges between 3‒7.5 MPa and 5‒12 MPa. Pre-fracturing numerical simulations with a discrete element code were carried out to predict fracture size and magnitude of microseismicity. Field measurements of the stress field were made using hydraulic fracturing, which produced remarkably uniformly oriented fractures suggesting rock fabric did not play a significant role in controlling fracture orientation. Electrical resistivity tomography (ERT) and continuous active seismic source monitoring (CASSM) were deployed in the four monitoring boreholes, and passive seismic accelerometer-based measurements in the West Access Drift were carried out during the generation of a larger fracture (so-called stimulation test). ERT was not able to detect the fracture created, nor did the accelerometers in the drift, but microseismicity was detected for the first (deepest) hydraulic-fracturing stress measurement. Analytical

Local fluid flow and borehole strain in the South Iceland Seismic Zone

Science.gov (United States)

Jónsson, S.; Segall, P.; Ágústsson, K.; Agnew, D.

2003-12-01

Installation of 175 borehole strainmeters is planned for PBO. It is therefore vital to understand the behavior of existing strainmeter installations. We investigate signals recorded by three borehole dilatometers in the south Iceland seismic zone following two Mw6.5 earthquakes in June 2000. Poroelastic relaxation has been documented following these events based on InSAR and water level data [Jónsson et al., 2003, Nature]. According to poroelastic theory for a homogeneous isotropic (unfractured) medium, the anticipated post-seismic volumetric strain has the same sign as the coseismic strain step. For example, coseismic compression results in pore-pressure increases; post-earthquake fluid drainage causes additional compression. However, we find that observed strain changes vary considerably between different instruments after the earthquakes. One instrument (HEL) behaves as expected with transient strain increasing with the same sign as the coseismic strain step. Another instrument (SAU) shows partial strain relaxation, opposite in sign to the coseismic signal. The third (BUR) exhibits complete strain relaxation by 3-4 days after the earthquakes (i.e., BUR does not record any permanent strain). BUR has responded in the same fashion to three different earthquakes and two volcanic eruptions, demonstrating conclusively that the transient response is due to processes local to the borehole. Fluid drainage from cracks can explain these observations. Rapid straining results in compression (extension) of the rock and strainmeter. Fluid filled fractures near the borehole transmit normal stress, due to the relative incompressibility of water. Thus, at short time scales the instrument records a coseismic strain step. With time, however, fluid flows out of (in to) the fractures, and the normal stress transmitted across the fractures decreases (increases). As the stress relaxes the strainmeter expands (contracts), reversing the coseismic strain. Barometric responses are

Seismic Observation in Deep Boreholes and Its Applications - Workshop Proceedings, Niigata Institute of Technology, Kashiwazaki, Japan

International Nuclear Information System (INIS)

2014-01-01

4 was only 70% that of Unit 2 at the same site. Given these circumstances, JNES initiated the 'Observation and Evaluation Study of Ground Motion Amplification' project by drilling a three-kilometer deep borehole on the premises of the Niigata Institute of Technology, which is located near the Kashiwazaki site, and proposed a series of workshops related to deep underground seismic observation and ground motion evaluation to the Seismic Subgroup of the OECD/NEA/IAGE Group at the April 2010 meeting. The first was held from 24-26 November 2010 as part of the first Kashiwazaki International Symposium on seismic safety, and the second was held on 7 to 9 November 2012. In the second WS, 36 papers were presented by the participants from eight countries including two international organizations, and discussed in three sessions (i.e. observation technology, evaluation of the observed seismic motion and the multipurpose use). Regarding the observation technology session, useful lessons-learned in probe development, setup and maintenance under the challenging conditions posed by great depth were described. This information from SAFORD and Kashiwazaki was thought to be particularly valuable for the planning and operation of similar facilities. As for the seismic observations from a deep borehole, it was identified that such observations are very effective for investigation of the earthquake generating process and are important for detailed understanding of the three-dimensional underground structure. There is not yet much experience with observation and application of a deep borehole, and therefore future developments and achievements are expected. The importance of simple ground motion evaluation technology combined with geophysical exploration was also acknowledged. Examples of multipurpose utilization and the advantage of seismic observations in deep boreholes were discussed. Multipurpose use was discussed not only for seismic design and evaluation of nuclear installations

Observations from borehole dilution logging experiments in fractured crystalline rock under variable hydraulic conditions

Science.gov (United States)

Harte, Philip T.; Anderson, Alton; Williams, John H.

2014-01-01

Identifying hydraulically active fractures in low permeability, crystalline-bedrock aquifers requires a variety of geophysical and hydrogeophysical borehole tools and approaches. One such approach is Single Borehole Dilution Tests (SBDT), which in some low flow cases have been shown to provide greater resolution of borehole flow than other logging procedures, such as vertical differential Heat Pulse Flowmeter (HPFM) logging. Because the tools used in SBDT collect continuous profiles of water quality or dye changes, they can identify horizontal flow zones and vertical flow. We used SBDT with a food grade blue dye as a tracer and dual photometer-nephelometer measurements to identify low flow zones.SBDT were conducted at seven wells with open boreholes (exceeding 300 ft). At most of the wells HPFM logs were also collected. The seven wells are set in low-permeability, fractured granite and gneiss rocks underlying a former tetrachloroeythylene (PCE) source area at the Savage Municipal Well Superfund site in Milford, NH. Time series SBDT logs were collected at each of the seven wells under three distinct hydraulic conditions: (1) ambient conditions prior to a pump test at an adjacent well, (2) mid test, after 2-3 days of the start of the pump test, and (3) at the end of the test, after 8-9 days of the pump test. None of the SBDT were conducted under pumping conditions in the logged well. For each condition, wells were initially passively spiked with blue dye once and subsequent time series measurements were made.Measurement accuracy and precision of the photometer tool is important in SBDT when attempting to detect low rates of borehole flow. Tests indicate that under ambient conditions, none of the wells had detectable flow as measured with HPFM logging. With SBDT, 4 of the 7 showed the presence of some very low flow. None of 5 (2 of the 7 wells initially logged with HPFM under ambient conditions were not re-logged) wells logged with the HPFM during the pump test had

Exploratory borehole Leuggern. Working program

International Nuclear Information System (INIS)

1984-07-01

An extensive geophysical borehole logging programme will serve to verify the results of the core analysis and complement the core data. Numerous borehole logs are to be registered with different types of tools. These allow one to determine various parameters essential for the full description of the rock sequences penetrated. A first category of logs enables the petrographical identification of the different rock types and indicates porous zones that are either water- or hydrocarbon-bearing. A second category provides data e.g. on the degree of pore and fracture fill, rock density and rock temperature, natural gamma radiation and rock-mechanical properties. Other logs measure strike and dip of the sedimentary layers and the position of rock fractures. A fourth category provides information on the diameter and the deviation of the borehole, the quality of casing cementations and the position of casing joints. In addition, well shooting surveys will supply exact values of seismic velocities for the various rock units; data that are needed for the depth correction of the reflection profiles from Nagra's regional seismic network. With numerous hydrological tests ranging from a production tests of the Muschelkalk and Buntsandstein aquifers to labelled slug-tests in low-permeability crystalline sections, the hydraulic conditions of deep groundwater flow will be investigated. The recovered water samples will undergo full physical and geochemical analysis. Furthermore, their isotope content is to be measured in order to estimate the age of the various formation waters and their time of residence in the subsurface. To round off the scientific investigations, a series of rock-mechanical and geotechnical laboratory tests will provide characteristic values to be applied eventually in the design and construction of shafts and caverns for an underground repository

Seismic characteristics of tensile fracture growth induced by hydraulic fracturing

Science.gov (United States)

Eaton, D. W. S.; Van der Baan, M.; Boroumand, N.

2014-12-01

Hydraulic fracturing is a process of injecting high-pressure slurry into a rockmass to enhance its permeability. Variants of this process are used for unconventional oil and gas development, engineered geothermal systems and block-cave mining; similar processes occur within volcanic systems. Opening of hydraulic fractures is well documented by mineback trials and tiltmeter monitoring and is a physical requirement to accommodate the volume of injected fluid. Numerous microseismic monitoring investigations acquired in the audio-frequency band are interpreted to show a prevalence of shear-dominated failure mechanisms surrounding the tensile fracture. Moreover, the radiated seismic energy in the audio-frequency band appears to be a miniscule fraction (<< 1%) of the net injected energy, i.e., the integral of the product of fluid pressure and injection rate. We use a simple penny-shaped crack model as a predictive framework to describe seismic characteristics of tensile opening during hydraulic fracturing. This model provides a useful scaling relation that links seismic moment to effective fluid pressure within the crack. Based on downhole recordings corrected for attenuation, a significant fraction of observed microseismic events are characterized by S/P amplitude ratio < 5. Despite the relatively small aperture of the monitoring arrays, which precludes both full moment-tensor analysis and definitive identification of nodal planes or axes, this ratio provides a strong indication that observed microseismic source mechanisms have a component of tensile failure. In addition, we find some instances of periodic spectral notches that can be explained by an opening/closing failure mechanism, in which fracture propagation outpaces fluid velocity within the crack. Finally, aseismic growth of tensile fractures may be indicative of a scenario in which injected energy is consumed to create new fracture surfaces. Taken together, our observations and modeling provide evidence that

The multi-parameter borehole system and high resolution seismic studies in the western part of the main Marmara Fault in the frame of MARSITE Project.

Science.gov (United States)

Ozel, Oguz; Guralp, Cansun; Tunc, Suleyman; Yalcinkaya, Esref

2016-04-01

The main objective of this study is to install a multi-parameter borehole system and surface array as close to the main Marmara Fault (MMF) in the western Marmara Sea as possible, and measure continuously the evolution of the state of the fault zone surrounding the MMF and to detect any anomaly or change, which may occur before earthquakes by making use of the data from the arrays already running in the eastern part of the Marmara Sea. The multi-parameter borehole system is composed of very wide dynamic range and stable borehole (VBB) broad band seismic sensor, and incorporate strain meter, tilt meter, and temperature and local hydrostatic pressure measuring devices. The borehole seismic station uses the latest update technologies and design ideas to record "Earth tides" signals to the smallest magnitude -3 events. Additionally, a surface microearthquake observation array, consisting of 8-10 seismometers around the borehole is established to obtain continuous high resolution locations of micro-seismicity and to better understand the existing seismically active structures and their roles in local tectonic settings.Bringing face to face the seismograms of microearthquakes recorded by borehole and surface instruments portrays quite different contents. The shorter recording duration and nearly flat frequency spectrum up to the Nyquist frequencies of borehole records are faced with longer recording duration and rapid decay of spectral amplitudes at higher frequencies of a surface seismogram. The main causative of the observed differences are near surface geology effects that mask most of the source related information the seismograms include, and that give rise to scattering, generating longer duration seismograms. In view of these circumstances, studies on microearthquakes employing surface seismograms may bring on misleading results. Particularly, the works on earthquake physics and nucleation process of earthquakes requires elaborate analysis of tiny events. It is

Maturity of nearby faults influences seismic hazard from hydraulic fracturing

Science.gov (United States)

Kozłowska, Maria; Brudzinski, Michael R.; Friberg, Paul; Skoumal, Robert J.; Baxter, Nicholas D.; Currie, Brian S.

2018-02-01

Understanding the causes of human-induced earthquakes is paramount to reducing societal risk. We investigated five cases of seismicity associated with hydraulic fracturing (HF) in Ohio since 2013 that, because of their isolation from other injection activities, provide an ideal setting for studying the relations between high-pressure injection and earthquakes. Our analysis revealed two distinct groups: (i) deeper earthquakes in the Precambrian basement, with larger magnitudes (M > 2), b-values 1.5, and few post–shut-in earthquakes. Based on geologic history, laboratory experiments, and fault modeling, we interpret the deep seismicity as slip on more mature faults in older crystalline rocks and the shallow seismicity as slip on immature faults in younger sedimentary rocks. This suggests that HF inducing deeper seismicity may pose higher seismic hazards. Wells inducing deeper seismicity produced more water than wells with shallow seismicity, indicating more extensive hydrologic connections outside the target formation, consistent with pore pressure diffusion influencing seismicity. However, for both groups, the 2 to 3 h between onset of HF and seismicity is too short for typical fluid pressure diffusion rates across distances of ˜1 km and argues for poroelastic stress transfer also having a primary influence on seismicity.

Maturity of nearby faults influences seismic hazard from hydraulic fracturing.

Science.gov (United States)

Kozłowska, Maria; Brudzinski, Michael R; Friberg, Paul; Skoumal, Robert J; Baxter, Nicholas D; Currie, Brian S

2018-02-20

Understanding the causes of human-induced earthquakes is paramount to reducing societal risk. We investigated five cases of seismicity associated with hydraulic fracturing (HF) in Ohio since 2013 that, because of their isolation from other injection activities, provide an ideal setting for studying the relations between high-pressure injection and earthquakes. Our analysis revealed two distinct groups: ( i ) deeper earthquakes in the Precambrian basement, with larger magnitudes (M > 2), b-values 1.5, and few post-shut-in earthquakes. Based on geologic history, laboratory experiments, and fault modeling, we interpret the deep seismicity as slip on more mature faults in older crystalline rocks and the shallow seismicity as slip on immature faults in younger sedimentary rocks. This suggests that HF inducing deeper seismicity may pose higher seismic hazards. Wells inducing deeper seismicity produced more water than wells with shallow seismicity, indicating more extensive hydrologic connections outside the target formation, consistent with pore pressure diffusion influencing seismicity. However, for both groups, the 2 to 3 h between onset of HF and seismicity is too short for typical fluid pressure diffusion rates across distances of ∼1 km and argues for poroelastic stress transfer also having a primary influence on seismicity.

Installation of borehole seismometer for earthquake characteristics in deep geological environment

Energy Technology Data Exchange (ETDEWEB)

Park, Dong Hee; Choi, Weon Hack; Cho, Sung Il; Chang, Chun Joong [KHNP CRI, Seoul (Korea, Republic of)

2014-10-15

Deep geological disposal is currently accepted as the most appropriate method for permanently removing spent nuclear fuel from the living sphere of humans. For implementation of deep geological disposal, we need to understand the geological changes that have taken place over the past 100,000 years, encompassing active faults, volcanic activity, elevation, ubsidence, which as yet have not been considered in assessing the site characteristics for general facilities, as well as to investigate and analyze the geological structures, fracture systems and seismic responses regarding deep geological environment about 500 meters or more underground. In regions with high seismic activity, such as Japan, the Western United States and Taiwan, borehole seismometers installed deep underground are used to monitor seismic activity during the course of seismic wave propagation at various depths and to study the stress changes due to earthquakes and analyze the connection to fault movements. Korea Hydro and Nuclear Power Co., Ltd. (KHNP) have installed the deep borehole earthquake observatory at depths of about 300 to 600 meters in order to study the seismic response characteristics in deep geological environment on June, 2014 in Andong area. This paper will show the status of deep borehole earthquake observatory and the results of background noise response characteristics of these deep borehole seismic data as a basic data analysis. We present here the status of deep borehole seismometer installation by KHNP. In order to basic data analysis for the borehole seismic observation data, this study shows the results of the orientation of seismometer and background noise characteristics by using a probability density function. Together with the ground motion data recorded by the borehole seismometers can be utilized as basic data for seismic response characteristics studies with regard to spent nuclear fuel disposal depth and as the input data for seismic hazard assessment that

Construction of System for Seismic Observation in Deep Borehole (SODB) - Development of Multi-depth, High-temperature/pressure resistance seismometer

International Nuclear Information System (INIS)

Mamada, Yutaka

2014-01-01

The development of a high quality system for seismic observation in deep boreholes, the installation process at the NIIT site, and the data sharing plan for this observation were explained. The key points of the development were high temperature resistance (150 degrees Celsius), high pressure resistance (30 MPa), and a high dynamic/wide frequency range seismometer which allows for observation of micro-tremor to strong motions as well as a cascade-connection-type borehole seismometer, which allows multiple probes to be set at several depths in a single borehole. The developed system consists of broadband (0.1-50 Hz) and high dynamic range (up to 1000 gal) seismometer with electronic parts on the ground and only the pendulum part in the borehole (it became a servo-type seismometer). Durability and maintenance may be issues in the future. (author)

Hydraulic Conductivity Measurements with HTU at Eurajoki, Olkiluoto, Borehole OL-KR15 and OL-KR15B, Year 2004

Energy Technology Data Exchange (ETDEWEB)

Haemaelaeinen, H.

2005-07-01

As a part of the site investigations for the disposal of spent nuclear fuel, hydraulic conductivity measurements were carried out in borehole OL-KR15 at Eurajoki, Olkiluoto. The objective was to investigate the distribution of the hydraulic conductivity in the surrounding bedrock volume. Measurements were carried out during 2003-2004 in two phases. The total length of the borehole OL-KR15 is 518,85 m and 158 45,14 m. Of the 471 ,5 m + 44,5 m total measurable length 414 m was covered with 237 standard tests with 2 m packer separation as specified in the research plan, partly with 1 m overlaps. 259 tests were initiated, but some of them ended to hardware or software errors or unsuitable parameter values. Double-packer constant-head method was used throughout with nominal 200 kPa overpressure. Injection stage lasted normally 20 minutes and fall-off stage 10 minutes. The tests were often shortened if there were clear indications that the hydraulic conductivity is below the measuring range of the system. The pressure in the test section was let to stabilise at least 5 min before injection. In some test sections the stabilisation or injection stage lasted several hours. Two transient (Horner and 1/Q) interpretations and one stationary-state (Moye) interpretation were made in-situ immediately after the test. The Hydraulic Testing Unit (HTU-system) is owned by Posiva Oy and it was operated by Geopros Oy. (orig.)

Hydraulic Conductivity Measurements with HTU at Eurajoki, Olkiluoto, Borehole OL-KR15 and OL-KR15B, Year 2004

International Nuclear Information System (INIS)

Haemaelaeinen, H.

2005-01-01

As a part of the site investigations for the disposal of spent nuclear fuel, hydraulic conductivity measurements were carried out in borehole OL-KR15 at Eurajoki, Olkiluoto. The objective was to investigate the distribution of the hydraulic conductivity in the surrounding bedrock volume. Measurements were carried out during 2003-2004 in two phases. The total length of the borehole OL-KR15 is 518,85 m and 158 45,14 m. Of the 471 ,5 m + 44,5 m total measurable length 414 m was covered with 237 standard tests with 2 m packer separation as specified in the research plan, partly with 1 m overlaps. 259 tests were initiated, but some of them ended to hardware or software errors or unsuitable parameter values. Double-packer constant-head method was used throughout with nominal 200 kPa overpressure. Injection stage lasted normally 20 minutes and fall-off stage 10 minutes. The tests were often shortened if there were clear indications that the hydraulic conductivity is below the measuring range of the system. The pressure in the test section was let to stabilise at least 5 min before injection. In some test sections the stabilisation or injection stage lasted several hours. Two transient (Horner and 1/Q) interpretations and one stationary-state (Moye) interpretation were made in-situ immediately after the test. The Hydraulic Testing Unit (HTU-system) is owned by Posiva Oy and it was operated by Geopros Oy. (orig.)

Borehole Volumetric Strainmeter Calibration From a Nearby Seismic Broadband Array at Etna Volcano

Science.gov (United States)

Currenti, G.; Zuccarello, L.; Bonaccorso, A.; Sicali, A.

2017-10-01

Strainmeter and broadband seismic signals have been analyzed jointly with the aim of calibrating a borehole strainmeter at Etna volcano by using a seismo-geodetic technique. Our results reveal a good coherence between the dynamic strains estimated from seismometer data and strains recorded by a dilatometer in a low-frequency range [0.03-0.06 Hz] at the arrival of teleseismic waves. This significant coherence enabled estimating the calibration coefficient and making a comparison with calibration results derived from other methods. In particular, we verified that the proposed approach provides a calibration coefficient that matches the results obtained from the comparison of the recorded strain both with theoretical strain tides and with normal-mode synthetic straingrams. The approach presented here has the advantage of exploiting recorded seismic data, avoiding the use of computed strain from theoretical models.

High-Resolution Wellbore Temperature Logging Combined with a Borehole-Scale Heat Budget: Conceptual and Analytical Approaches to Characterize Hydraulically Active Fractures and Groundwater Origin

Directory of Open Access Journals (Sweden)

Guillaume Meyzonnat

2018-01-01

Full Text Available This work aims to provide an overview of the thermal processes that shape wellbore temperature profiles under static and dynamic conditions. Understanding of the respective influences of advection and conduction heat fluxes is improved through the use of a new heat budget at the borehole scale. Keeping in mind the thermal processes involved, a qualitative interpretation of the temperature profiles allows the occurrence, the position, and the origin of groundwater flowing into wellbores from hydraulically active fractures to be constrained. With the use of a heat budget developed at the borehole scale, temperature logging efficiency has been quantitatively enhanced and allows inflow temperatures to be calculated through the simultaneous use of a flowmeter. Under certain hydraulic or pumping conditions, both inflow intensities and associated temperatures can also be directly modelled from temperature data and the use of the heat budget. Theoretical and applied examples of the heat budget application are provided. Applied examples are shown using high-resolution temperature logging, spinner flow metering, and televiewing for three wells installed in fractured bedrock aquifers in the St-Lawrence Lowlands, Quebec, Canada. Through relatively rapid manipulations, thermal measurements in such cases can be used to detect the intervals or discrete positions of hydraulically active fractures in wellbores, as well as the existence of ambient flows with a high degree of sensitivity, even at very low flows. Heat budget calculations at the borehole scale during pumping indicate that heat advection fluxes rapidly dominate over heat conduction fluxes with the borehole wall. The full characterization of inflow intensities provides information about the distribution of hydraulic properties with depth. The full knowledge of inflow temperatures indicates horizons that are drained from within the aquifer, providing advantageous information on the depth from which

Intermediate-Scale Hydraulic Fracturing in a Deep Mine - kISMET Project Summary 2016

Energy Technology Data Exchange (ETDEWEB)

Oldenburg, C. M. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Dobson, P. F. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Wu, Y. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Cook, P. J. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Kneafsey, T. J. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Nakagawa, S. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Ulrich, C. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Siler, D. L. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Guglielmi, Y. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Ajo-Franklin, J. B. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Rutqvist, J. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Daley, T. M. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Birkholzer, J. T. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Wang, H. F. [Univ. of Wisconsin, Madison, WI (United States); Lord, N. E. [Univ. of Wisconsin, Madison, WI (United States); Haimson, B. C. [Univ. of Wisconsin, Madison, WI (United States); Sone, H. [Univ. of Wisconsin, Madison, WI (United States); Vigilante, P. [Univ. of Wisconsin, Madison, WI (United States); Roggenthen, W. M. [South Dakota School of Mines and Technology, Rapid City, SD (United States); Doe, T. W. [Golder Associates Inc., Toronto, ON (Canada); Lee, M. Y. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Ingraham, M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Huang, H. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Mattson, E. D. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Zhou, J. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Johnson, T. J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Morris, J. P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); White, J. A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Johnson, P. A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Coblentz, D. D. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Heise, J. [Stanford Underground Research Facility, Lead, SD (United States); Zoback, M. D. [Stanford Univ., CA (United States)

2016-11-04

In support of the U.S. DOE SubTER Crosscut initiative, we established a field test facility in a deep mine and designed and carried out in situ hydraulic fracturing experiments in the crystalline rock at the site to characterize the stress field, understand the effects of rock fabric on fracturing, and gain experience in monitoring using geophysical methods. The project also included pre- and post-fracturing simulation and analysis, laboratory measurements and experiments, and we conducted an extended analysis of the local stress state using previously collected data. Some of these activities are still ongoing. The kISMET (permeability (k) and Induced Seismicity Management for Energy Technologies) experiments meet objectives in SubTER’s “stress” pillar and the “new subsurface signals” pillar. The kISMET site was established in the West Access Drift of SURF 4850 ft (1478 m) below ground (on the 4850L) in phyllite of the Precambrian Poorman Formation. We drilled and cored five near-vertical boreholes in a line on 3 m spacing, deviating the two outermost boreholes slightly to create a five-spot pattern around the test borehole centered in the test volume at ~1528 m (5013 ft). Laboratory measurements of core from the center test borehole showed P-wave velocity heterogeneity along each core indicating strong, fine-scale (~1 cm or smaller) changes in the mechanical properties of the rock. The load-displacement record on the core suggests that the elastic stiffness is anisotropic. Tensile strength ranges between 3-7.5 MPa and 5-12 MPa. Permeability measurements are planned, as are two types of laboratory miniature hydraulic fracturing experiments to investigate the importance of rock fabric (anisotropy and heterogeneity) on near-borehole hydraulic fracture generation. Pre-fracturing numerical simulations with INL’s FALCON discrete element code predicted a fracture radius of 1.2 m for a corresponding injection volume of 1.2 L for the planned fractures, and

Hydraulic fracturing and the Crooked Lake Sequences: Insights gleaned from regional seismic networks

Science.gov (United States)

Schultz, Ryan; Stern, Virginia; Novakovic, Mark; Atkinson, Gail; Gu, Yu Jeffrey

2015-04-01

Within central Alberta, Canada, a new sequence of earthquakes has been recognized as of 1 December 2013 in a region of previous seismic quiescence near Crooked Lake, ~30 km west of the town of Fox Creek. We utilize a cross-correlation detection algorithm to detect more than 160 events to the end of 2014, which is temporally distinguished into five subsequences. This observation is corroborated by the uniqueness of waveforms clustered by subsequence. The Crooked Lake Sequences have come under scrutiny due to its strong temporal correlation (>99.99%) to the timing of hydraulic fracturing operations in the Duvernay Formation. We assert that individual subsequences are related to fracturing stimulation and, despite adverse initial station geometry, double-difference techniques allow us to spatially relate each cluster back to a unique horizontal well. Overall, we find that seismicity in the Crooked Lake Sequences is consistent with first-order observations of hydraulic fracturing induced seismicity.

Development of a thermal hydraulic modelling of ground water of the Malm in the Munich metropolitan area; Entwicklung einer thermisch-hydraulischen Grundwassermodellierung des Malm im Grossraum Muenchen

Energy Technology Data Exchange (ETDEWEB)

Dussel, M.; Lueschen, E.; Thomas, R. [Leibniz-Institut fuer Angewandte Geophysik, Hannover (DE)] (and others)

2011-10-24

The mutual potential influence of geothermal duplicates and the scientific investigation of the relationship between seismic and hydraulic parameters are investigated in the joint research project 'Geothermal characterization of fractured karst limestone aquifers in the Munich metropolitan area'. Thirteen doublets and triplets being in production or sunk illustrate the great geothermal potential and provide important data on the development of a thermal-hydraulic modeling of the reservoir. 3D seismic Unterhaching, 3D structural model, hydrogeological model and a high-resolution 3D temperature model form the basis of the numerical modeling. Different seismic signatures, seismic attributes and variations in the interval velocities characterize the ground geophysically, and were interpreted under consideration of geological and hydrogeological background information as well as borehole measurements in terms of hydraulically conductive homogeneous areas. For the Munich metropolitan area, the numerical modeling is a decision aid for the future optimized and sustainable hydrothermal utilization of the Malm aquifer.

Observations of joint persistence and connectivity across boreholes

Energy Technology Data Exchange (ETDEWEB)

Thapa, B.B.; Karasaki, K.

1996-01-01

Observations of joint persistence and connectivity are made by comparison of digital borehole wall images of fractures, fluid conductivity logs and hydraulic injections test results. The fractures were found to be generally impersistent across vertical boreholes about 8 m apart. Many hydraulic connections were found in the same volume of rock. Direct connections through single fractures seem to be rare and connectivity appears to be controlled by fracture networks, even over small volumes.

A newly developed borehole flowmeter technology for heterogeneous aquifers

International Nuclear Information System (INIS)

Young, S.C.

1990-01-01

Extensive borehole flowmeter tests were performed at 37 fully-screened wells on a one-hectare test site to characterize the three-dimensional hydraulic conductivity field of an alluvial aquifer with a σ lnK of 4.7. During the site investigations, several major advancements with respect to borehole flowmeter technology were developed. The milestones included: (1) the development of a field-durable electromagnetic borehole flowmeter with a lower detection limit of 0.1 l/min; (2) the realization of the importance of the pumping rate with respect to the calculated value for the depth-averaged hydraulic conductivity; and (3) an evaluation of alternative methods for calculating the depth-averaged hydraulic conductivity. The predicted three-dimensional hydraulic conductivity field was compared to the results of 10 small-scale (3 to 7 m) tracer tests, information about the depositional history of the aquifer, and the results of three large-scale aquifer tests. The hydraulic conductivity data predict the major features of the tracer breakthrough curves, maps the outline of a former river meander in an aerial photograph, and leads to a geometric mean consistent with the average hydraulic conductivity of the aquifer. (Author) (14 refs., 15 figs., 2 tabs.)

Establishment of borehole observation system and high resolution seismic studies in the western part of the main Marmara Fault in the frame of MARSite Project

Science.gov (United States)

Ozel, A.; Yalcinkaya, E.; Guralp, C. M.; Tunc, S.; Meral Ozel, N.

2013-12-01

The main objective of this study is to install a multi-parameter borehole system and surface array as close to the main Marmara Fault (MMF) in the western Marmara Sea as possible, and measure continuously the evolution of the state of the fault zone surrounding the MMF and to detect any anomaly or change which may occur before earthquakes by making use of the data from the arrays already running in the eastern part of the Marmara Sea. The multi-parameter borehole system will be composed of very wide dynamic range and stable borehole (VBB) broad band seismic sensor, and incorporate 3-D strain meter, tilt meter, and temperature and local hydrostatic pressure measuring devices. The borehole seismic station will use the latest update technologies and design ideas to record 'Earth tides' signals to the smallest magnitude -3 events. Bringing face to face the seismograms of microearthquakes recorded by borehole and surface instruments portrays quite different contents. The shorter recording duration and nearly flat frequency spectrum up to the Nyquist frequencies of borehole records are faced with longer recording duration and rapid decay of spectral amplitudes at higher frequencies of a surface seismogram. The main causative of the observed differences are near surface geology effects that mask most of the source related information the seismograms include, and that give rise to scattering, generating longer duration seismograms. In view of these circumstances, studies on microearthquakes employing surface seismograms may bring on misleading results. Particularly, the works on earthquake physics and nucleation process of earthquakes requires elaborate analysis of tiny events. It is obvious from the studies on the nucleation process of the 1999 earthquake that tens of minutes before the major rupture initiate noteworthy microearthquake activity happened. The starting point of the 1999 rupture was a site of swarm activity noticed a few decades prior the main shock

Long-term pumping test in borehole KR24 flow measurements

Energy Technology Data Exchange (ETDEWEB)

Rouhiainen, P.; Poellaenen, J. [PRG-Tec Oy, Espoo (Finland)

2005-09-15

The Difference Flow method can be used for the relatively fast determination of transmissivity and hydraulic head in fractures or fractured zones in cored boreholes. In this study, the Difference Flow method was used for hydraulic crosshole interference tests. The tests were performed in boreholes KR24 (pumped borehole) KR4, KR7, KR8, KRlO, KR14, KR22, KR22B, KR26, KR27, KR27B, KR28 and KR28B at Olkiluoto during the first and second quarters of 2004. The distance between the boreholes varies from approximately tens of meters to hundreds of meters. All the measurements were carried out in open boreholes, i.e. no packers were used. For interpretation, a normal single hole test was first performed in each borehole. Flow rates and drawdown were first measured both without pumping and with pumping the borehole under test. For practical reasons, the data set is neither complete nor similar in all tested boreholes. Connected flow to borehole KR24 was detected in all these boreholes. These flow responses were concentrated on a few zones. (orig.)

Seismic Travel Time Tomography in Modeling Low Velocity Anomalies between the Boreholes

Science.gov (United States)

Octova, A.; Sule, R.

2018-04-01

Travel time cross-hole seismic tomography is applied to describing the structure of the subsurface. The sources are placed at one borehole and some receivers are placed in the others. First arrival travel time data that received by each receiver is used as the input data in seismic tomography method. This research is devided into three steps. The first step is reconstructing the synthetic model based on field parameters. Field parameters are divided into 24 receivers and 45 receivers. The second step is applying inversion process for the field data that consists of five pairs bore holes. The last step is testing quality of tomogram with resolution test. Data processing using FAST software produces an explicit shape and resemble the initial model reconstruction of synthetic model with 45 receivers. The tomography processing in field data indicates cavities in several place between the bore holes. Cavities are identified on BH2A-BH1, BH4A-BH2A and BH4A-BH5 with elongated and rounded structure. In resolution tests using a checker-board, anomalies still can be identified up to 2 meter x 2 meter size. Travel time cross-hole seismic tomography analysis proves this mothod is very good to describing subsurface structure and boundary layer. Size and anomalies position can be recognized and interpreted easily.

First field test of NAPL detection with high resolution borehole seismic imaging

International Nuclear Information System (INIS)

Geller, Jil T.; Peterson, John E.; Williams, Kenneth H.; Ajo-Franklin, Jonathan B.; Majer, Ernest L.

2002-01-01

The purpose of this field test is to evaluate the detectability of NAPLs by high resolution tomographic borehole seismic imaging. The site is a former Department of Energy (DOE) manufacturing facility in Pinellas County, Florida. Cross-hole seismic and radar measurements were made in a shallow aquifer contaminated with non-aqueous phase liquids (NAPLs). Cone penetration test (CPT) and induction logging were performed for lithology and conductivity, respectively. The main challenge is to distinguish fluid phase heterogeneities from anomalies arising from geologic structure. Our approach is to compare measurements between locations of known contamination with a nearby uncontaminated location of similar lithology where differences in signal transmission may be attributed to fluid phase changes. The CPT data show similar lithologic structure at the locations both within and outside the NAPL-contaminated area. Zones of low seismic amplitude at about 7 m depth appear more extensive in the NAPL-contaminated area. These zones may be the result of fluid phase heterogeneities (NAPL or gas), or they may be due to the lithology, i.e. attenuating nature of the layer itself, or the transition between two distinct layers. The presence of lithologic contrasts, specifically from higher permeability sands to lower permeability silts and clays, also indicate potential locations of NAPL, as they could be flow barriers to downward NAPL migration

New developments in high resolution borehole seismology and their applications to reservoir development and management

Energy Technology Data Exchange (ETDEWEB)

Paulsson, B.N.P. [Chevron Petroleum Technology Company, La Habra, CA (United States)

1997-08-01

Single-well seismology, Reverse Vertical Seismic Profiles (VSP`s) and Crosswell seismology are three new seismic techniques that we jointly refer to as borehole seismology. Borehole seismic techniques are of great interest because they can obtain much higher resolution images of oil and gas reservoirs than what is obtainable with currently used seismic techniques. The quality of oil and gas reservoir management decisions depend on the knowledge of both the large and the fine scale features in the reservoirs. Borehole seismology is capable of mapping reservoirs with an order of magnitude improvement in resolution compared with currently used technology. In borehole seismology we use a high frequency seismic source in an oil or gas well and record the signal in the same well, in other wells, or on the surface of the earth.

Summary of the Lavia borehole investications in 1984

International Nuclear Information System (INIS)

Aeikaes, T.; Oehberg, A.; Ryhaenen, V.

1985-02-01

Industrial Power Company Ltd (TVO) drilled in the spring 1984 a 1001 m deep borehole, diameter 56 mm, in Lavia. The borehole is used during the years 1984-85 for developing and testing research methods and equipment needed in site investigations of spent fuel final disposal in the future. In 1984 hydraulical and geophysical tests were made and groundwater samples were taken. The drilling site is a wide outcropped area in the northern part of the porphyritic granite formation of Lavia. Geological and fracture mapping as well as geophysical measurements on the surface were made in the area surrounding the drilling site. The bedrock consists of homonous porphyritic granite, in which quartzdiorite occurs in thin incalations. Magnetic or electric anomalies were not observed. Fracture frequency is low and the fractures appear mainly in two sets. The rock types vary in the borehole from porphyritic granite to diorite. Due to slight mineralogical variations, the diorite is either granodiorite, quartzdiorite or tonalite. Granite occurs as veins. Hydraulic conductivity was measured systematically with a packer separation of 30 m between the depths 73-973 m. Hydraulic conductivity is generally 10 -10 -10 -11 m/s. Electric, radiometric, magnetic and acoustic measurements were made in the borehole. In addition, the caliper and the temperature of the borehole were measured. The results of these geophysical measurements indicate the properties of rock types and fracturing in the borehole. On the basis of the results e.g. fracture porosity was interpreted. The results of acoustic tube wave measurement correlate well with hydraulic conductivity. Water samples were taken from four depths. The deepest level was 910 m. The samples were taken with a packer separation of 5 m. In the water analyses it was observed that at several depths remarkable amounts of flushing water from drilling were still remaining in the rock

Microseismic monitoring during Hydraulic stimulation in Pohang (Korea) for EGS pilot project

Science.gov (United States)

Kim, M.; Yoon, B.; Lee, C.; Park, K. G.; Yoon, W. S.; Song, Y.; Lee, T. J.

2017-12-01

Since the geothermal anomaly in the Pohang area has been reported in 1960s, various geological and geophysical surveys have been conducted by Korea Institute of Geoscience and Mineral Resources (KIGAM) including gravity, seismic, airborne magnetic and magneto-telluric surveys. Based on these explorations, the Enhanced Geothermal System (EGS) pilot project has been carried out in Pohang since the end of 2010. One vertical well (PX-2, MD 4,348 m) and one deviated well (PX-1, MD 4,362 m) have been drilled in granite rock for the EGS. Microseismic (MS) monitoring is the best way to understand how the fracture grows during the hydraulic stimulation. KIGAM has set up 9 shallow borehole stations (100-130 m), 4 surface stations and two borehole geophones (1,350 and 1,550 m deep) within 5 km radius from injection well for the MS monitoring during hydraulic stimulation. The first hydraulic stimulation started on January 29th to February 20th, 2016 at PX-2 and the second stimulation was conducted in PX-1 from December 15th, 2016 to January 11th, 2017. Several hundreds of MS events occurred during stimulation and the biggest event was ML 2.3 during the shut in period of the second stimulation. Based on the results of the MS monitoring, a soft stimulation is scheduled at PX-1 in cooperation with one of the European Horizon2020 project, DESTRESS (Demonstration of soft stimulation treatments of geothermal reservoirs). We will present the MS monitoring system in Pohang and the data of the stimulation with the MS monitoring results. We believe that the data from Pohang will improve the understanding of seismic behavior due to hydraulic stimulation in crystalline rocks and also will contribute to success of the Pohang EGS project.

Integration of borehole and seismic data to unravel complex stratigraphy: Case studies from the Mannville Group, Western Canada

Science.gov (United States)

Sarzalejo Silva, Sabrina Ester

Understanding the stratigraphic architecture of geologically complex reservoirs, such as the heavy oil deposits of Western Canada, is essential to achieve an efficient hydrocarbon recovery. Borehole and 3-D seismic data were integrated to define the stratigraphic architecture and generate 3-dimensional geological models of the Mannville Group in Saskatchewan. The Mannville is a stratigraphically complex unit formed of fluvial to marine deposits. Two areas in west-central and southern Saskatchewan were examined in this study. In west-central Saskatchewan, the area corresponds to a stratigraphically controlled heavy oil reservoir with production from the undifferentiated Dina-Cummings Members of the Lower Cretaceous Mannville Group. The southern area, although non-prospective for hydrocarbons, shares many similarities with time-equivalent strata in areas of heavy oil production. Seismic sequence stratigraphic principles together with log signatures permitted the subdivision of the Mannville into different packages. An initial geological model was generated integrating seismic and well-log data Multiattribute analysis and neural networks were used to generate a pseudo-lithology or gamma-ray volume. The incorporation of borehole core data to the model and the subsequent integration with the lithological prediction were crucial to capture the distribution of reservoir and non-reservoir deposits in the study area. The ability to visualize the 3-D seismic data in a variety of ways, including arbitrary lines and stratal or horizon slicing techniques helped the definition of stratigraphic features such as channels and scroll bars that affect fluid flow in hydrocarbon producing areas. Small-scale heterogeneities in the reservoir were not resolved due to the resolution of the seismic data. Although not undertaken in this study, the resulting stratigraphic framework could be used to help construct a static reservoir model. Because of the small size of the 3-D seismic surveys

Experimental research on sealing of boreholes, shafts and ramps in welded tuff

International Nuclear Information System (INIS)

Fuenkajorn, K.

1996-01-01

Laboratory and in-situ experiments have been conducted to determine the mechanical and hydraulic performance of cement borehole seals in densely welded Apache Leap tuff. Test results indicate that under saturated conditions, commercial expansive cement can provide good bond strength and adequate hydraulic performance for borehole seal under changing stress conditions. The cement seal should be installed at the intact portion of the opening, and should have a length-to-diameter ratio greater than four. Drying increases borehole plug permeability and decreases mechanical and hydraulic bonds at the plug-rock interface. In-situ testing indicates that installation procedure may significantly affect the cement plug performance

水力冲孔有效影响半径数值模拟%Numerical Simulation on Effective Influence Radius of Hydraulic Flushing Borehole

Institute of Scientific and Technical Information of China (English)

魏建平; 刘英振; 王登科; 温志辉; 李向楠

2012-01-01

根据力学平衡方程和质量守恒定律及煤层渗透率、孔隙率、煤岩体积应变等参数的关系,建立了煤层底板巷水力冲孔气固耦合方程。通过模拟不同出煤量的水力冲孔有效影响半径变化,得出水力冲孔有效影响半径随冲出煤量和抽放时间的增加而增加。当冲出煤量为1 t/m时,有效影响半径为5.8 m,卸压增透效果十分理想。%According to the relationships among mechanics balance equation,the law of conservation of mass,permeability of coal seam,porosity,volume strain of coal,the gas-solid coupled equation of hydraulic flushing borehole in the coal seam floor is established.By simulating the changes of effective influence radius of hydraulic flushing borehole at different coal output,it obtains that the effective influence radius of hydraulic flushing borehole is increasing as the amount increasing of overflow coal and prolonging of drainage time.When the amount of overflow coal is 1t/m,effective influence radius is 5.8 m,the effects of pressure relief and antireflection are very good.

Recordings from the deepest borehole in the New Madrid Seismic Zone

Science.gov (United States)

Wang, Z.; Woolery, E.W.

2006-01-01

The recordings at the deepest vertical strong-motion array (VSAS) from three small events, the 21 October 2004 Tiptonville, Tennessee, earthquake; the 10 February 2005 Arkansas earthquake; and the 2 June 2005 Ridgely, Tennessee, earthquake show some interesting wave-propagation phenomena through the soils: the S-wave is attenuated from 260 m to 30 m depth and amplified from 30 m to the surface. The S-wave arrival times from the three events yielded different shear-wave velocity estimates for the soils. These different estimates may be the result of different incident angles of the S-waves due to different epicentral distances. The epicentral distances are about 22 km, 110 km, and 47 km for the Tiptonville, Arkansas, and Ridgely earthquakes, respectively. These recordings show the usefulness of the borehole strong-motion array. The vertical strong-motion arrays operated by the University of Kentucky have started to accumulate recordings that will provide a database for scientists and engineers to study the effects of the near-surface soils on the strong ground motion in the New Madrid Seismic Zone. More information about the Kentucky Seismic and Strong-Motion Network can be found at www.uky.edu/KGS/geologichazards. The digital recordings are available at ftp://kgsweb.uky.edu.

Seismicity Induced by Hydraulic Fracturing in Shales: A Bedding Plane Slip Model

Czech Academy of Sciences Publication Activity Database

Staněk, František; Eisner, Leo

2017-01-01

Roč. 122, č. 10 (2017), s. 7912-7926 ISSN 2169-9313 Institutional support: RVO:67985891 Keywords : microseismic * seismicity * hydraulic fracturing * bedding plane slip Subject RIV: DC - Siesmology, Volcanology, Earth Structure OBOR OECD: 1.7 Other natural sciences Impact factor: 3.350, year: 2016

Site characterization and validation - equipment design and techniques used in single borehole hydraulic testing, simulated drift experiment and crosshole testing

International Nuclear Information System (INIS)

Holmes, D.C.; Sehlstedt, M.

1991-10-01

This report describes the equipment and techniques used to investigate the variation of hydrogeological parameters within a fractured crystalline rock mass. The testing program was performed during stage 3 of the site characterization and validation programme at the Stripa mine in Sweden. This programme used a multidisciplinary approach, combining geophysical, geological and hydrogeological methods, to determine how groundwater moved through the rock mass. The hydrogeological work package involved three components. Firstly, novel single borehole techniques (focused packer testing) were used to determine the distribution of hydraulic conductivity and head along individual boreholes. Secondly, water was abstracted from boreholes which were drilled to simulate a tunnel (simulated drift experiment). Locations and magnitudes of flows were measured together with pressure responses at various points in the SCV rock mass. Thirdly, small scale crosshole tests, involving detailed interference testing, were used to determine the variability of hydrogeological parameters within previously identified, significant flow zones. (au)

Borehole Seismology: Fundamentals and Applications

International Nuclear Information System (INIS)

Bohnhoff, Marco

2014-01-01

Because boring in itself is very expensive and instrumentation is required to endure high temperatures and pressures, deep borehole observation was accompanied by an economic risk. However, it has great advantages with respect to micro-earthquake observation, which is enriched with a short period vibration signal, because deep borehole observation greatly reduces short period noise. These kind advantages were explained by referring to the relationship between earthquake size and frequency range. Examples of seismic observation in a borehole in a geothermal field in El Salvador and a CO 2 confinement project in the western part of Canada were introduced. (authors)

Using the automized system ''section'' to forecast velocity sections using data on borehole velocity measurement and seismic field prospecting

Energy Technology Data Exchange (ETDEWEB)

Dorman, M.I.; Gein, F.F.; Zubairov, F.B.

1981-01-01

A system of automated processing of seismic data is examined which makes it possible to set up rate functions at arbitrary points of a seismic prospecting section or at points conciding with boreholes in which rate measurements have not been completed. The basis for the forecasting method is data on seismic well logging investigations, seismic prospecting and some indirect observations on sections. The bases of a procedure realizing a forecasting method are set forth, as are those requirements which satisfy the system as a whole. The results of using the ''section'' system in a terrestrial section of Western Siberia are set forth.

Design of a single-borehole hydraulic test programme allowing for interpretation-based errors

International Nuclear Information System (INIS)

Black, J.H.

1987-07-01

Hydraulic testing using packers in single boreholes is one of the most important sources of data to safety assessment modelling in connection with the disposal of radioactive waste. It is also one of the most time-consuming and expensive. It is important that the results are as reliable as possible and as accurate as necessary for the use that is made of them. There are many causes of possible error and inaccuracy ranging from poor field practice to inappropriate interpretation procedure. The report examines and attempts to quantify the size of error arising from the accidental use of an inappropriate or inadequate interpretation procedure. In doing so, it can be seen which interpretation procedure or combination of procedures results in least error. Lastly, the report attempts to use the previous conclusions from interpretation to propose forms of field test procedure where interpretation-based errors will be minimised. Hydraulic tests (sometimes known as packer tests) come in three basic forms: slug/pulse, constant flow and constant head. They have different characteristics, some measuring a variable volume of rock (dependent on hydraulic conductivity) and some having a variable duration (dependent on hydraulic conductivity). A combination of different tests in the same interval is seen as desirable. For the purposes of assessing interpretation-based errors, slug and pulse tests are considered together as are constant flow and constant head tests. The same method is used in each case to assess errors. The method assumes that the simplest analysis procedure (cylindrical flow in homogeneous isotropic porous rock) will be used on each set of field data. The error is assessed by calculating synthetic data for alternative configurations (e.g. fissured rock, anisotropic rock, inhomogeneous rock - i.e. skin - etc.) and then analyzing this data using the simplest analysis procedure. 28 refs., 26 figs

Seismic VSP and crosshole investigations in Olkiluoto, 2002

International Nuclear Information System (INIS)

Enescu, N.; Cosma, C.; Balu, L.

2003-04-01

Vertical Seismic Profiling (VSP) and crosshole seismic surveys were conducted during 2002 at Olkiluoto site in Eurajoki, Finland. The VSP investigations were carried out in three boreholes (KR13, KR14 and KR19) with ten or eleven shot points for each borehole. Additionally, the data from a VSP investigation carried out in 1990 in borehole KR5 had been reprocessed with state of the art tools. One crosshole section (KR14-KR15 at 20 - 240 m interval) was measured and processed. Different receiver types were used for the VSP and crosshole: a 3-component geophone chain for VSP and a hydrophone chain for crosshole. VSP surveys have been carried out with a VIBSIST-1000 source - a time-distributed swept-impact source - instead of explosives. With this source, the seismic signals are produced as rapid series of impacts, the impact intervals being monotonically increased to achieve a nonrepeatable sequence. The VIBSIST-1000 uses a tractor-mounted hydraulic rock-breaker, powered through a computer controlled servo-hydraulic flow regulator. Using standard construction equipment ensures that the VIBSIST sources are safe, non-destructive and environmentally friendly. This also makes the method reliable and cost effective. The new VIBSIST source produces signals with levels of energy comparable to explosives. The VIBSIST appears to be more stable, but its most significant advantages are the low cost of preparation of the shot points and the speed of the acquisition. Crosshole surveys were carried out with a piezoelectric borehole source, the VIBSISTSPH54, which operates on the same principle as the surface VIBSIST source. The wide diversity of reflection angles, the local variations of reflectivity and, generally, the relatively weak seismic response of faults and fractured zones in crystalline rock demand intensive processing. The first stage of the processing sequence focuses on eliminating such wave-fields as the direct P, direct S, tube-waves and ground-roll, so that the

Seismic VSP and crosshole investigations in Olkiluoto, 2002

Energy Technology Data Exchange (ETDEWEB)

Enescu, N.; Cosma, C.; Balu, L. [Vibrometric Oy (Finland)

2003-04-01

Vertical Seismic Profiling (VSP) and crosshole seismic surveys were conducted during 2002 at Olkiluoto site in Eurajoki, Finland. The VSP investigations were carried out in three boreholes (KR13, KR14 and KR19) with ten or eleven shot points for each borehole. Additionally, the data from a VSP investigation carried out in 1990 in borehole KR5 had been reprocessed with state of the art tools. One crosshole section (KR14-KR15 at 20 - 240 m interval) was measured and processed. Different receiver types were used for the VSP and crosshole: a 3-component geophone chain for VSP and a hydrophone chain for crosshole. VSP surveys have been carried out with a VIBSIST-1000 source - a time-distributed swept-impact source - instead of explosives. With this source, the seismic signals are produced as rapid series of impacts, the impact intervals being monotonically increased to achieve a nonrepeatable sequence. The VIBSIST-1000 uses a tractor-mounted hydraulic rock-breaker, powered through a computer controlled servo-hydraulic flow regulator. Using standard construction equipment ensures that the VIBSIST sources are safe, non-destructive and environmentally friendly. This also makes the method reliable and cost effective. The new VIBSIST source produces signals with levels of energy comparable to explosives. The VIBSIST appears to be more stable, but its most significant advantages are the low cost of preparation of the shot points and the speed of the acquisition. Crosshole surveys were carried out with a piezoelectric borehole source, the VIBSISTSPH54, which operates on the same principle as the surface VIBSIST source. The wide diversity of reflection angles, the local variations of reflectivity and, generally, the relatively weak seismic response of faults and fractured zones in crystalline rock demand intensive processing. The first stage of the processing sequence focuses on eliminating such wave-fields as the direct P, direct S, tube-waves and ground-roll, so that the

Phase I Project: Fiber Optic Distributed Acoustic Sensing for Periodic Hydraulic Tests

Energy Technology Data Exchange (ETDEWEB)

Becker, Matthew

2017-12-31

The extraction of heat from hot rock requires circulation of fluid through fracture networks. Because the geometry and connectivity of these fractures determines the efficiency of fluid circulation, many tools are used to characterize fractures before and after development of the reservoir. Under this project, a new tool was developed that allows hydraulic connectivity between geothermal boreholes to be identified. Nanostrain in rock fractures is measured using fiber optic distributed acoustic sensing (DAS). This strain is measured in one borehole in response to periodic pressure pulses induced in another borehole. The strain in the fractures represents hydraulic connectivity between wells. DAS is typically used at frequencies of Hz to kHz, but strain at mHz frequencies were measured for this project. The tool was demonstrated in the laboratory and in the field. In the laboratory, strain in fiber optic cables was measured in response to compression due to oscillating fluid pressure. DAS recorded strains as small as 10 picometer/m in response to 1 cm of water level change. At a fractured crystalline rock field site, strain was measured in boreholes. Fiber-optic cable was mechanically coupled borehole walls using pressured flexible liners. In one borehole 30 m from the oscillating pumping source, pressure and strain were measured simultaneously. The DAS system measured fracture displacement at frequencies of less than 1 mHz (18 min periods) and amplitudes of less than 1 nm, in response to fluid pressure changes of less 20 Pa (2 mm of water). The attenuation and phase shift of the monitored strain signal is indicative of the permeability and storage (compliance) of the fracture network that connects the two wells. The strain response as a function of oscillation frequency is characteristic of the hydraulic structure of the formation. This is the first application of DAS to the measurement of low frequency strain in boreholes. It has enormous potential for monitoring

Observation of ground deformation associated with hydraulic fracturing and seismicity in the Western Canadian Sedimentary Basin

Science.gov (United States)

Kubanek, J.; Liu, Y.; Harrington, R. M.; Samsonov, S.

2017-12-01

In North America, the number of induced earthquakes related to fluid injection due to the unconventional recovery of oil and gas resources has increased significantly within the last five years. Recent studies demonstrate that InSAR is an effective tool to study surface deformation due to large-scale wastewater injection, and highlight the value of surface deformation monitoring with respect to understanding evolution of pore pressure and stress at depth - vital parameters to forecast fault reactivation, and thus, induced earthquakes. In contrast to earthquakes related to the injection of large amounts of wastewater, seismic activity related to the hydraulic fracturing procedure itself was, until recently, considered to play a minor role without significant hazard. In the Western Canadian Sedimentary Basin (WCSB), however, Mw>4 earthquakes have recently led to temporary shutdown of industrial injection activity, causing multi-million dollar losses to operators and raising safety concerns with the local population. Recent studies successfully utilize seismic data and modeling to link seismic activity with hydraulic fracturing in the WCSB. Although the study of surface deformation is likely the most promising tool for monitoring integrity of a well and to derive potential signatures prior to moderate or large induced events, InSAR has, to date, not been utilized to detect surface deformation related to hydraulic fracturing and seismicity. We therefore plan to analyze time-series of SAR data acquired between 1991 to present over two target sites in the WCSB that will enable the study of long- and short-term deformation. Since the conditions for InSAR are expected to be challenging due to spatial and temporal decorrelation, we have designed corner reflectors that will be installed at one target site to improve interferometric performance. The corner reflectors will be collocated with broadband seismometers and Trimble SeismoGeodetic Systems that simultaneously measure

Transportable 56-kN, 200-mm displacement hydraulic shaker for seismic simulation

International Nuclear Information System (INIS)

Smallwood, D.O.; Hunter, N.F.

1972-01-01

A large hydraulic shaker for seismic simulation is described. The shaker is 6.1 x 2.2 x 0.8 m and weighs 8800 kg. The shaker has a 56-kN force output driving a 7000 kg reaction mass, with a maximum displacement capability of 200 mm (p-p) over a frequency range from 1 to 50 Hz. The entire system, including the hydraulic power supplies, is designed to be self-contained and transportable. External support required for the system includes 110-V power for instrumentation, 64-kV . A (220- or 440-V) power for the hydraulic power supplies, and water for oil cooling. The system was successfully used to excite a four-story test structure at the AEC's Nevada Test Site. A brief description of the test series is given. (U.S.)

Modeling of fault reactivation and induced seismicity during hydraulic fracturing of shale-gas reservoirs

Science.gov (United States)

We have conducted numerical simulation studies to assess the potential for injection-induced fault reactivation and notable seismic events associated with shale-gas hydraulic fracturing operations. The modeling is generally tuned toward conditions usually encountered in the Marce...

Geophysical borehole logging in Lavia borehole - results and interpretation of sonic and tube wave measurements

International Nuclear Information System (INIS)

Andersson, P.; Stenberg, L.

1985-02-01

Swedish Nuclear Fuel and Waste Management Co, SKB has been contracted by Industrial Power Company LTD, TVO to perform geophysical logging in a borehole at Lavia in Western Finland. The logging has been conducted by Swedish Geological Co, SGAB in accordance with an agreement for cooperation with SKB. The depth of the borehole is 1001 m, diameter 56 mm and inclination 10-20 degrees to the vertical. The aim of the logging was to determine the various geophysical parameters in the borehole in order to interpret and understand the rock mass properties in the vicinity of the borehole. According to the contract the report covers the following main objectives: a technical description of the field work and the equipment used; a review of the theoretical base for the sonic and tube wave methods; an interpretation and presentation of the results obtained by sonic and tube wave mesurements. The evaluation of the sonic and tube wave measurements shows good correlation. On a qualitative basis there seems to be a correlation between tube wave generating points, the relative tube wave amplitudes and the hydraulic conductivity measurements performed as hydraulical tests between packers in the borehole. The low velocity anamalies in the sonic log are mainly caused by tectonic features like fractures and fracture zones but to some extent also by contacts between granite and diorite. The estimation of elastic properties of the rock mass from observation of tube wave velocity are in accordance with laboratory determinations made on core samples. (author)

Borehole geophysical and flowmeter data for eight boreholes in the vicinity of Jim Woodruff Lock and Dam, Lake Seminole, Jackson County, Florida

Science.gov (United States)

Clarke, John S.; Hamrick, Michael D.; Holloway, O. Gary

2011-01-01

Borehole geophysical logs and flowmeter data were collected in April 2011 from eight boreholes to identify the depth and orientation of cavernous zones within the Miocene Tampa Limestone in the vicinity of Jim Woodruff Lock and Dam in Jackson County, Florida. These data are used to assess leakage near the dam. Each of the eight boreholes was terminated in limestone at depths ranging from 84 to 104 feet. Large cavernous zones were encountered in most of the borings, with several exceeding 20-inches in diameter. The cavernous zones generally were between 1 and 5 feet in height, but a cavern in one of the borings reached a height of about 6 feet. The resistivity of limestone layers penetrated by the boreholes generally was less than 1,000 ohm-meters. Formation resistivity near the cavernous zones did not show an appreciable contrast from surrounding bedrock, probably because the bedrock is saturated, owing to its primary permeability. Measured flow rates in the eight boreholes determined using an electromagnetic flowmeter were all less than ±0.1 liter per second. These low flow rates suggest that vertical hydraulic gradients in the boreholes are negligible and that hydraulic head in the various cavernous zones shows only minor, if any, variation.

Source Characterization and Seismic Hazard Considerations for Hydraulic Fracture Induced Seismicity

Science.gov (United States)

Bosman, K.; Viegas, G. F.; Baig, A. M.; Urbancic, T.

2015-12-01

Large microseismic events (M>0) have been shown to be generated during hydraulic fracture treatments relatively frequently. These events are a concern both from public safety and engineering viewpoints. Recent microseismic monitoring projects in the Horn River Basin have utilized both downhole and surface sensors to record events associated with hydraulic fracturing. The resulting hybrid monitoring system has produced a large dataset with two distinct groups of events: large events recorded by the surface network (0structures; small events are concentrated at reservoir depth. Differences in behavior have been observed between these two datasets, leading to conclusions of different underlying processes responsible for the recorded activity. Both datasets show very low seismic efficiency, implying slip weakening and possibly the presence of fluids in the source region. Reservoir events have shear-tensile source mechanisms ranging between tensile opening and tensile closing, and fracture orientations dominated by the rock fabric which are not always optimally oriented to the regional stress field. The observed source characteristics are expected for events driven by increased pore pressure and reduced friction due to lubrication. On average, deep events show higher stress drop, apparent stress, and rupture velocity than reservoir events. This reflects higher confining stresses with depth, and possibly the release of stored energy in the existing zone of weakness. Deep events are dominated by shear failures, but source characteristics are smaller than for naturally occurring tectonic earthquakes of similar magnitude. Most importantly from a seismic hazard perspective, large earthquakes associated with hydrofracing have lower stress drops than tectonic earthquakes, and thus produce smaller peak ground acceleration and less damage on surface. The largest event recorded in this dataset has a moment magnitude of +2.9 and was felt by field crews in the area. The response

Hydraulic Shearing and Hydraulic Jacking Observed during Hydraulic Stimulations in Fractured Geothermal Reservoir in Pohang, Korea

Science.gov (United States)

Min, K. B.; Park, S.; Xie, L.; Kim, K. I.; Yoo, H.; Kim, K. Y.; Choi, J.; Yoon, K. S.; Yoon, W. S.; Lee, T. J.; Song, Y.

2017-12-01

Enhanced Geothermal System (EGS) relies on sufficient and irreversible enhancement of reservoir permeability through hydraulic stimulation and possibility of such desirable change of permeability is an open question that can undermine the universality of EGS concept. We report results of first hydraulic stimulation campaign conducted in two deep boreholes in fractured granodiorite geothermal reservoir in Pohang, Korea. Borehole PX-1, located at 4.22 km, was subjected to the injection of 3,907 m3 with flow rate of up to 18 kg/s followed by bleeding off of 1,207 m3. The borehole PX-2, located at 4.35 km, was subjected to the injection of 1,970 m3 with flow rate of up to 46 kg/sIn PX-1, a sharp distinct decline of wellhead pressure was observed at around 16 MPa of wellhead pressure which was similar to the predicted injection pressure to induce hydraulic shearing. Injectivity interpretation before and after the hydraulic shearing indicates that permanent increase of permeability was achieved by a factor of a few. In PX-2, however, injectivity was very small and hydraulic shearing was not observed due possibly to the near wellbore damage made by the remedying process of lost circulation such as using lost circulation material during drilling. Flow rate of larger than 40 kg/s was achieved at very high well head pressure of nearly 90 MPa. Hydraulic jacking, that is reversible opening and closure of fracture with change of injection pressure, was clearly observed. Although sharp increase of permeability due to fracture opening was achieved with elevated injection pressure, the increased permeability was reversed with decreased injection pressure.Two contrasting response observed in the same reservoir at two different boreholes which is apart only 600 m apart provide important implication that can be used for the stimulation strategy for EGS.This work was supported by the New and Renewable Energy Technology Development Program of the Korea Institute of Energy Technology

Seismic analysis of hydraulic control rod driving system

International Nuclear Information System (INIS)

Zheng, Yanhua; Bo, Hanliang; Dong, Duo

2002-01-01

A simplified mathematical model was developed for the Hydraulic Control Rod Driving System (HCRDS) of a 200 MW nuclear heating reactor, which incorporated the design of its chamfer-hole step cylinder, to analyze its seismic response characteristics. The control rod motion was analyzed for different sine-wave vibration loadings on platform vibrator. The vibration frequency domain and the minimum acceleration amplitude of the control rod needed to cause the control rod to step to its next setting were compared with the design acceleration amplitude spectrum. The system design was found to be safety within the calculated limits. The safety margin increased with increasing frequency. (author)

Hydraulic testing in granite using the sinusoidal variation of pressure

International Nuclear Information System (INIS)

Black, J.H.; Holmes, D.C.; Noy, D.J.

1982-09-01

Access to two boreholes at the Carwynnen test site in Cornwall enabled the trial of a number of innovative approaches to the hydrogeology of fractured crystalline rock. These methods ranged from the use of seisviewer data to measure the orientation of fractures to the use of the sinusoidal pressure technique to measure directional hydraulic diffusivity. The testing began with a short programme of site investigation consisting of borehole caliper and seisviewer logging followed by some single borehole hydraulic tests. The single borehole hydraulic testing was designed to assess whether the available boreholes and adjacent rock were suitable for testing using the sinusoidal method. The main testing methods were slug and pulse tests and were analysed using the fissured porous medium analysis proposed in Barker and Black (1983). Derived hydraulic conductivity (K) ranged from 2 x 10 -12 m/sec to 5 x 10 -7 m/sec with one near-surface zone of high K being perceived in both boreholes. The results were of the form which is typical of fractured rock and indicated a combination of high fracture frequency and permeable granite matrix. The results are described and discussed. (author)

Difference flow measurements in borehole KOV01 at Oskarshamn

International Nuclear Information System (INIS)

Poellaenen, J.; Rouhiainen, P.

2001-09-01

Posiva Flow Log/Difference Flow method can be used for relatively fast determination of hydraulic conductivity and hydraulic head in fractures or fractured zones in cored boreholes. This report presents the principles of the method as well as the results of the measurements carried out in borehole KOV01 at Oskarshamn in February and March 2001. The aim of the measurements presented in this report was to determine the depth and flow rate of flowing fractures in borehole KOV01 prior to groundwater sampling. The measurements in borehole KOV01 were carried out between 100-1000 m depth using the so called detailed flow logging mode; the flow rate into a 5 m long test section was measured. Detailed flow logging was repeated at the location of the detected flow anomalies using 0.5 m section length and 0.1 m point intervals. The borehole was pumped during these measurements. The occurrence of saline water in the borehole was studied by electric conductivity measurements. The flow guide encloses also an electrode for measuring of single point resistance of the bedrock. It was measured with 0.01 m point intervals during the detailed flow logging. Depth calibration was made on the basis of the known depth marks in the borehole. The depth marks were detected by caliper measurements and by single point resistance measurements

Hydraulic Fracture Induced Seismicity During A Multi-Stage Pad Completion in Western Canada: Evidence of Activation of Multiple, Parallel Faults

Science.gov (United States)

Maxwell, S.; Garrett, D.; Huang, J.; Usher, P.; Mamer, P.

2017-12-01

Following reports of injection induced seismicity in the Western Canadian Sedimentary Basin, regulators have imposed seismic monitoring and traffic light protocols for fracturing operations in specific areas. Here we describe a case study in one of these reservoirs, the Montney Shale in NE British Columbia, where induced seismicity was monitored with a local array during multi-stage hydraulic fracture stimulations on several wells from a single drilling pad. Seismicity primarily occurred during the injection time periods, and correlated with periods of high injection rates and wellhead pressures above fracturing pressures. Sequential hydraulic fracture stages were found to progressively activate several parallel, critically-stressed faults, as illuminated by multiple linear hypocenter patterns in the range between Mw 1 and 3. Moment tensor inversion of larger events indicated a double-couple mechanism consistent with the regional strike-slip stress state and the hypocenter lineations. The critically-stressed faults obliquely cross the well paths which were purposely drilled parallel to the minimum principal stress direction. Seismicity on specific faults started and stopped when fracture initiation points of individual injection stages were proximal to the intersection of the fault and well. The distance ranges when the seismicity occurs is consistent with expected hydraulic fracture dimensions, suggesting that the induced fault slip only occurs when a hydraulic fracture grows directly into the fault and the faults are temporarily exposed to significantly elevated fracture pressures during the injection. Some faults crossed multiple wells and the seismicity was found to restart during injection of proximal stages on adjacent wells, progressively expanding the seismogenic zone of the fault. Progressive fault slip is therefore inferred from the seismicity migrating further along the faults during successive injection stages. An accelerometer was also deployed close

Scientific results from the deepened Lopra-1 borehole, Faroe Islands: Borehole seismic studies of a volcanic succession from the Lopra-1/1A borehole in the Faroe Islands, northern North Atlantic

Directory of Open Access Journals (Sweden)

Cowper, David

2006-07-01

Full Text Available Extruded basalt flows overlying sedimentary sequences present a challenge to hydrocarbon exploration using reflection seismic techniques. The Lopra-1/1A re-entry well on the Faroese island of Suðuroy allowed us to study the seismic characteristics of a thick sequence of basalt flows from well logs and borehole seismic recordings. Data acquired during the deepening operation in 1996 are presented here.The re-entry well found that the seismic event at 2340 m, prognosed from the pre-drill Vertical Seismic Profile (VSP as a decrease in impedance, was not base basalt and the deepened well remainedwithin the lower series basalts. Nonetheless, compressional and shear sonic logs and a density log were recorded over the full open hole interval. These allowed a firm tie to be made with the reflectedwavefield from a new VSP. The sonic logs show a compressional to shear wavespeed ratio of 1.84 which is almost constant with depth. Sonic compressional wavespeeds are 3% higher than seismicvelocities, suggesting dispersion in the basalt flows. Azimuthal anisotropy was weakly indicated by the shear sonic log but its orientation is consistent with the directions of mapped master joints in the vicinity of the well.The VSP downgoing compressional wavelet shows good persistence, retaining a dominant period of 28 ms at 3510 m depth. Average vertical velocity is 5248 m/s, higher than previously reported.Attenuation can largely be modelled by geometrical spreading and scattering loss, consistent with other studies. Within the piled flows, the effective Q from scattering is about 35. Elastic layeredmedium modelling shows some hope that a mode-converted shear wave may be observed at moderate offsets. Like its predecessor, the 1996 VSP indicates a decrease in impedance below the final depth ofthe well. However, it is unlikely to be basement or sediment and is probably an event within the volcanic sequence.

Ice drilling for blasting boreholes in deep seismic surveys (JARE-43 by steam type drilling system

Directory of Open Access Journals (Sweden)

Atsushi Watanabe

2003-03-01

Full Text Available A seismic exploration was accomplished in the austral summer of 2001-2002 by the 43rd Japanese Antarctic Research Expedition (JARE-43 along a profile oblique to that held by JARE-41 on the Mizuho Plateau, East Antarctica. We used a steam type drilling system to obtain seven blasting boreholes. We spent 7 to 8 hours to make an enough depth of the hole for one shot point. The holes were 35 to 40 cm in diameter and 23.5 to 28.7 m in depth. The average drilling speed was 3.25 m/hr.

An integrated geophysical and hydraulic investigation to characterize a fractured-rock aquifer, Norwalk, Connecticut

Science.gov (United States)

Lane, J.W.; Williams, J.H.; Johnson, C.D.; Savino, D.M.; Haeni, F.P.

2002-01-01

The U.S. Geological Survey conducted an integrated geophysical and hydraulic investigation at the Norden Systems, Inc. site in Norwalk, Connecticut, where chlorinated solvents have contaminated a fractured-rock aquifer. Borehole, borehole-to-borehole, surface-geophysical, and hydraulic methods were used to characterize the site bedrock lithology and structure, fractures, and transmissive zone hydraulic properties. The geophysical and hydraulic methods included conventional logs, borehole imagery, borehole radar, flowmeter under ambient and stressed hydraulic conditions, and azimuthal square-array direct-current resistivity soundings. Integrated interpretation of geophysical logs at borehole and borehole-to-borehole scales indicates that the bedrock foliation strikes northwest and dips northeast, and strikes north-northeast to northeast and dips both southeast and northwest. Although steeply dipping fractures that cross-cut foliation are observed, most fractures are parallel or sub-parallel to foliation. Steeply dipping reflectors observed in the radar reflection data from three boreholes near the main building delineate a north-northeast trending feature interpreted as a fracture zone. Results of radar tomography conducted close to a suspected contaminant source area indicate that a zone of low electromagnetic (EM) velocity and high EM attenuation is present above 50 ft in depth - the region containing the highest density of fractures. Flowmeter logging was used to estimate hydraulic properties in the boreholes. Thirty-three transmissive fracture zones were identified in 11 of the boreholes. The vertical separation between transmissive zones typically is 10 to 20 ft. Open-hole and discrete-zone transmissivity was estimated from heat-pulse flowmeter data acquired under ambient and stressed conditions. The open-hole transmissivity ranges from 2 to 86 ft2/d. The estimated transmissivity of individual transmissive zones ranges from 0.4 to 68 ft2/d. Drawdown monitoring

The ICDP Snake River Geothermal Drilling Project: preliminary overview of borehole geophysics

Science.gov (United States)

Schmitt, Douglas R.; Liberty, Lee M.; Kessler, James E.; Kuck, Jochem; Kofman, Randolph; Bishop, Ross; Shervais, John W.; Evans, James P.; Champion, Duane E.

2012-01-01

Hotspot: The Snake River Geothermal Drilling Project was undertaken to better understand the geothermal systems in three locations across the Snake River Plain with varying geological and hydrological structure. An extensive series of standard and specialized geophysical logs were obtained in each of the wells. Hydrogen-index neutron and γ-γ density logs employing active sources were deployed through the drill string, and although not fully calibrated for such a situation do provide semi-quantitative information related to the ‘stratigraphy’ of the basalt flows and on the existence of alteration minerals. Electrical resistivity logs highlight the existence of some fracture and mineralized zones. Magnetic susceptibility together with the vector magnetic field measurements display substantial variations that, in combination with laboratory measurements, may provide a tool for tracking magnetic field reversals along the borehole. Full waveform sonic logs highlight the variations in compressional and shear velocity along the borehole. These, together with the high resolution borehole seismic measurements display changes with depth that are not yet understood. The borehole seismic measurements indicate that seismic arrivals are obtained at depth in the formations and that strong seismic reflections are produced at lithological contacts seen in the corresponding core logging. Finally, oriented ultrasonic borehole televiewer images were obtained over most of the wells and these correlate well with the nearly 6 km of core obtained. This good image log to core correlations, particularly with regards to drilling induced breakouts and tensile borehole and core fractures will allow for confident estimates of stress directions and or placing constraints on stress magnitudes. Such correlations will be used to orient in core orientation giving information useful in hydrological assessments, paleomagnetic dating, and structural volcanology.

Permeability, storage and hydraulic diffusivity controlled by earthquakes

Science.gov (United States)

Brodsky, E. E.; Fulton, P. M.; Xue, L.

2016-12-01

Earthquakes can increase permeability in fractured rocks. In the farfield, such permeability increases are attributed to seismic waves and can last for months after the initial earthquake. Laboratory studies suggest that unclogging of fractures by the transient flow driven by seismic waves is a viable mechanism. These dynamic permeability increases may contribute to permeability enhancement in the seismic clouds accompanying hydraulic fracking. Permeability enhancement by seismic waves could potentially be engineered and the experiments suggest the process will be most effective at a preferred frequency. We have recently observed similar processes inside active fault zones after major earthquakes. A borehole observatory in the fault that generated the M9.0 2011 Tohoku earthquake reveals a sequence of temperature pulses during the secondary aftershock sequence of an M7.3 aftershock. The pulses are attributed to fluid advection by a flow through a zone of transiently increased permeability. Directly after the M7.3 earthquake, the newly damaged fault zone is highly susceptible to further permeability enhancement, but ultimately heals within a month and becomes no longer as sensitive. The observation suggests that the newly damaged fault zone is more prone to fluid pulsing than would be expected based on the long-term permeability structure. Even longer term healing is seen inside the fault zone of the 2008 M7.9 Wenchuan earthquake. The competition between damage and healing (or clogging and unclogging) results in dynamically controlled permeability, storage and hydraulic diffusivity. Recent measurements of in situ fault zone architecture at the 1-10 meter scale suggest that active fault zones often have hydraulic diffusivities near 10-2 m2/s. This uniformity is true even within the damage zone of the San Andreas fault where permeability and storage increases balance each other to achieve this value of diffusivity over a 400 m wide region. We speculate that fault zones

Comparative study of geological, hydrological, and geophysical borehole investigations

International Nuclear Information System (INIS)

Magnusson, K.A.; Duran, O.

1984-09-01

The understanding of the permeability of the bedrock can be improved by supplementing the results of the water injection tests with information from core mapping, TB-inspection and borehole geophysics. The comparison between different borehole investigations encompasses core mapping, TV-inspection and various geophysical bore hole measurements. The study includes data from two different study areas, namely Kraakemaala and Finnsjoen. In these two areas, extensive geological, hydrological and geophysical investigation have been carried out. The fractures and microfractures in crystalline rock constitute the main transport paths for both groundwater and electric currents. They will therefore govern both the permeability and the resistivity of the rock. In order to get a better understanding of the influence of fractures on permeability and resistivity, a detailed comparison has been made between the hydraulic conductivity, respectively, and the character of fractures in the core and the borehole wall. The fractures show very large variations in hydraulic conductivity. Microfractures and most of the thin fractures have no measurable hydraulic conductivity (in this case -9 m s -1 ), while test sections which contain a single isloated fracture can have no measurable, to rather high hydraulic conductivities (> 10 -7 m s -1 ). Wide fracture zones often have hydraulic conductivities which vary from very low (less than 2 x 10 -9 m s -1 ) to high values (10 -5 m s -1 ). This indicates that the hydraulic conductivity is governed by a few discrete fractures. The resistivity shows a continous variation in the range 1,000- 100,000 ohm-m and a relatively poor correlation with hydraulic conductivities. The observed difference is considered to the effect of restriction of water flow on a few channels, while electric surface condition, i.e. current transport through thin water films, makes current transport possible through fractures with very small aperatures. (Author)

Quantitative elastic migration. Applications to 3D borehole seismic surveys; Migration elastique quantitative. Applications a la sismique de puits 3D

Energy Technology Data Exchange (ETDEWEB)

Clochard, V.

1998-12-02

3D VSP imaging is nowadays a strategic requirement by petroleum companies. It is used to precise in details the geology close to the well. Because of the lack of redundancy and limited coverage in the data. this kind of technology is more restrictive than surface seismic which allows an investigation at a higher scale. Our contribution was to develop an elastic quantitative imagine (GRT migration) which can be applied to 3 components borehole dataset. The method is similar to the Kirchhoff migration using sophistical weighting of the seismic amplitudes. In reality. GRT migration uses pre-calculated Green functions (travel time. amplitude. polarization). The maps are obtained by 3D ray tracing (wavefront construction) in the velocity model. The migration algorithm works with elementary and independent tasks. which is useful to process different kind of dataset (fixed or moving geophone antenna). The study has been followed with validations using asymptotic analytical solution. The ability of reconstruction in 3D borehole survey has been tested in the Overthrust synthetic model. The application to a real circular 3D VSP shows various problems like velocity model building, anisotropy factor and the preprocessing (deconvolution. wave mode separation) which can destroy seismic amplitudes. An isotropic 3 components preprocessing of the whole dataset allows a better lateral reconstruction. The choice of a big migration aperture can help the reconstruction of strong geological dip in spite of migration smiles. Finally, the methodology can be applied to PS converted waves. (author)

The Application of Borehole Seismic Techniques in Mine Development at the Millennium Uranium Deposit, Northern Saskatchewan, Canada

Energy Technology Data Exchange (ETDEWEB)

Wood, G.; O’Dowd, C., E-mail: garnet_wood@cameco.com [Cameco Corporation, Saskatoon, Saskatchewan (Canada); Cosma, C.; Enescu, N. [Vibrometric Canada Ltd., Toronto, Ontario (Canada)

2014-05-15

The Millennium uranium deposit is located within the Athabasca Basin of northern Saskatchewan, Canada. The deposit is situated in metasedimentary rocks, is controlled by multiple sub-vertical faults, and crossfaults and is overlain by over 500 m of intensely altered, porous Manitou Falls group sandstones. The rock quality directly surrounding the deposit is greatly reduced because of alteration and post-Athabasca sandstone structures, which provide conduits for the migration of basinal and meteoric fluids. This leads to significant risk for mine development and shaft sinking, because of the increased potential for water inflow into mine workings. To mitigate the risk involved with mining in such complex geology several projects were proposed as part of a pre-feasibility study. Of these, seismic methods were identified as the best tool to potentially identify alteration and structurally compromised zones. Subsequently, a comprehensive surface and borehole seismic program was completed in an attempt to delineate these engineering hazards and to provide assurance of success of the shaft sinking and mine development. This was the first time a seismic program of this scale was undertaken for geotechnical studies during mine development in the Athabasca Basin. (author)

Insight into subdecimeter fracturing processes during hydraulic fracture experiment in Äspö hard rock laboratory, Sweden

Science.gov (United States)

Kwiatek, Grzegorz; Martínez-Garzón, Patricia; Plenkers, Katrin; Leonhardt, Maria; Zang, Arno; Dresen, Georg; Bohnhoff, Marco

2017-04-01

We analyze the nano- and picoseismicity recorded during a hydraulic fracturing in-situ experiment performed in Äspö Hard Rock Laboratory, Sweden. The fracturing experiment included six fracture stages driven by three different water injection schemes (continuous, progressive and pulse pressurization) and was performed inside a 28 m long, horizontal borehole located at 410 m depth. The fracturing process was monitored with two different seismic networks covering a wide frequency band between 0.01 Hz and 100000 Hz and included broadband seismometers, geophones, high-frequency accelerometers and acoustic emission sensors. The combined seismic network allowed for detection and detailed analysis of seismicity with moment magnitudes MW<-4 (source sizes approx. on cm scale) that occurred solely during the hydraulic fracturing and refracturing stages. We relocated the seismicity catalog using the double-difference technique and calculated the source parameters (seismic moment, source size, stress drop, focal mechanism and seismic moment tensors). The physical characteristics of induced seismicity are compared to the stimulation parameters and to the formation parameters of the site. The seismic activity varies significantly depending on stimulation strategy with conventional, continuous stimulation being the most seismogenic. We find a systematic spatio-temporal migration of microseismic events (propagation away and towards wellbore injection interval) and temporal transitions in source mechanisms (opening - shearing - collapse) both being controlled by changes in fluid injection pressure. The derived focal mechanism parameters are in accordance with the local stress field orientation, and signify the reactivation of pre-existing rock flaws. The seismicity follows statistical and source scaling relations observed at different scales elsewhere, however, at an extremely low level of seismic efficiency.

Development of a quality management system for borehole investigations. (1) Quality assurance and quality control methodology for hydraulic packer testing

International Nuclear Information System (INIS)

Takeuchi, Shinji; Kunimaru, Takanori; Ota, Kunio; Frieg, Bernd

2011-01-01

A quality assurance and quality control (QA/QC) system for the hydraulic packer tests has been established based on the surface-based investigations at JAEA's underground research laboratories in Mizunami and Horonobe. The established QA/QC system covers field investigations (data acquisition) and data analysis. For the field investigations, the adopted procedure is selection of a test section based on a detail fluid logging and checking with tally list, followed by inspection of test tools such as pressure transducers and shut-in valves, etc., test method selection using a 'sequential hydraulic test' for deciding appropriate method, and finally data quality confirmation by pressure changes and derivatives on a log-log plots during testing. Test event logs should also be described during testing for traceability. For the test data analysis, a quick analysis for rough estimation of hydraulic parameters, and a detailed analysis using type curve and/or numerical analyses are conducted stepwise. The established QA/QC system has been applied to the recent borehole investigations and its efficiency has been confirmed. (author)

Performance of MarSite Multi parameter Borehole Instrumentation

Science.gov (United States)

Guralp, Cansun; Tunc, Suleyman; Ozel, Oguz; Meral Ozel, Nurcan; Necmioglu, Ocal

2017-04-01

In this paper we present two year results obtained from the integrated multiparameter borehole system at Marsite. The very broad band (VBB) system have been operating since installation in November 2014; one year in a water filled borehole and one year in a dry Borehole. from January 2016. The real time data has been available to the community. The two Borehole environments are compared showing the superior performance of dry borehole environ- ment compared to water filled for a very broad band (VBB) seismometer. The practical considerations applied in both borehole installations are compared and the best borehole practical installation techniques are presented and discussed. The data is also compared with a surface 120 second broad band sensor and the seismic arrays with in MarSite region. The very long term performance, (one year data in a dry hole) of the VBB Borehole seismometer and the Dilatometer will be presented The high frequency performance of the VBB seismometer which extends to 150 Hz and the dilatometer are compared characterizing the results from the dilatometer.

Co-seismic strain changes of Wenchuan Mw7. 9 earthquake recorded by borehole strainmeters on Tibetan plateau

Directory of Open Access Journals (Sweden)

Fu Guangyu

2011-08-01

Full Text Available Co-seismic strain changes of the Wenchuan Mw7. 9 earthquake recorded with three four-component borehole strainmeters showed NW-SE and roughly EW extensions, respectively, at two locations in the interior and northern part of Tibetan plateau, and NS shortening at a location south of the epicenter, in agreement with the tectonic stress field of this region. The observed values of as much as 10−7 are, however, larger than theoretical values obtained with half-space and spherical-earth dislocation theories, implying the existence of other effects, such as local crustal structure and initial stress.

Can deep boreholes solve America's nuclear waste problem?

International Nuclear Information System (INIS)

Bates, E.A.; Driscoll, M.J.; Lester, R.K.; Arnold, B.W.

2014-01-01

The United States is in need of a new and more adaptive long-term strategy for spent nuclear fuel. In this communication, we outline the fundamental reasons why deep borehole disposal should receive more detailed investigation, alongside traditional shallow mined repositories. This potential solution is supported by advancing drilling technologies and an improving understanding of extremely long fluid residence times in deep bedrock. Radionuclide isolation is supported by verifiable and stable geologic barriers such as long transport distances to aquifers, low permeability, and reducing chemical conditions. The modular nature of implementing deep borehole disposal could offer unique programmatic and economic advantages. Experience with a pilot borehole program will be required to confirm the feasibility of drilling and emplacement operations, and key chemical and hydraulic conditions. - Highlights: • To meet obligations, the U.S. should diversify used nuclear fuel disposal options. • Hydraulic and chemical systems isolated for ≥10 My can be found in deep bedrock. • Robust concepts in nuclear fuel disposal are enabled by maturing drilling technology. • Disposal in deep boreholes could ease siting, provide modularity, and lower costs

Seismic Prediction While Drilling (SPWD): Seismic exploration ahead of the drill bit using phased array sources

Science.gov (United States)

Jaksch, Katrin; Giese, Rüdiger; Kopf, Matthias

2010-05-01

In the case of drilling for deep reservoirs previous exploration is indispensable. In recent years the focus shifted more on geological structures like small layers or hydrothermal fault systems. Beside 2D- or 3D-seismics from the surface and seismic measurements like Vertical Seismic Profile (VSP) or Seismic While Drilling (SWD) within a borehole these methods cannot always resolute this structures. The resolution is worsen the deeper and smaller the sought-after structures are. So, potential horizons like small layers in oil exploration or fault zones usable for geothermal energy production could be failed or not identified while drilling. The application of a device to explore the geology with a high resolution ahead of the drill bit in direction of drilling would be of high importance. Such a device would allow adjusting the drilling path according to the real geology and would minimize the risk of discovery and hence the costs for drilling. Within the project SPWD a device for seismic exploration ahead of the drill bit will be developed. This device should allow the seismic exploration to predict areas about 50 to 100 meters ahead of the drill bit with a resolution of one meter. At the GFZ a first prototype consisting of different units for seismic sources, receivers and data loggers has been designed and manufactured. As seismic sources four standard magnetostrictive actuators and as receivers four 3-component-geophones are used. Every unit, actuator or geophone, can be rotated in steps of 15° around the longitudinal axis of the prototype to test different measurement configurations. The SPWD prototype emits signal frequencies of about 500 up to 5000 Hz which are significant higher than in VSP and SWD. An increased radiation of seismic wave energy in the direction of the borehole axis allows the view in areas to be drilled. Therefore, every actuator must be controlled independently of each other regarding to amplitude and phase of the source signal to

Borehole project - Final report of phase 3

International Nuclear Information System (INIS)

Pusch, R.; Ramqvist, G.

2008-03-01

The report describes borehole plugging techniques for use in deep boreholes extending from the ground surface, and construction and placement of plugs in holes of different lengths and orientations bored from the repository rooms. The principle employed is the one proposed in earlier phases of the project, i.e. to tightly seal those parts of boreholes where the rock has few fractures and a low hydraulic conductivity, and filling of those parts that intersect water-bearing fracture zones with physically stable material that does not need to be low-permeable. Four methods for tight plugging have been identified and tested and a technique has been found for filling boreholes that are intersected by fracture zones. The upper end of boreholes extending from the ground surface needs a 'mechanical' seal for which copper metal and concrete work well. The experience from plugging of a 550 m deep borehole at Olkiluoto (OL-KR24) has been compiled and plans worked out for sampling and testing of contacting clay and concrete in this hole and in short holes in the Aespoe URL. (orig.)

Hydraulic Conductivity Measurements with HTU at Eurajoki, Olkiluoto, Boreholes OL-KR16, 16B, 17, 17B, 18 and 18B, Year 2004

Energy Technology Data Exchange (ETDEWEB)

Haemaelaeinen, H.

2005-07-01

As a part of the site investigations for the disposal of spent nuclear fuel, hydraulic con- ductivity measurements were carried out in boreholes OL-KR16, 16B, 17, 17 B, 18 and 18B at Eurajoki, Olkiluoto. The objective was to investigate the distribution of the hydraulic conductivity in the surrounding bedrock volume. Measurements were carried out during spring-summer 2004. The total lengths of the boreholes are: OL-KR16 170,20 m, OL-KR17 157,13 m and OL-KR18 125,49 m. Corresponding B-holes are around 45 m deep, parallel and adjacent to their 'parent' holes so representing the cased sections of them. The conbined measurable length of the holes is about 453,57 m, of which 429,15 m was covered with 217 standard tests at 2 m packer separation as specified in the research plan. 246 tests were initiated, but some had to be cancelled due to errors or unsuitable control parameters. Double-packer constant-head method was used throughout with nominal 200 kPa overpressure. Injection stage lasted normally 20 minutes and fall-off stage 10 minutes. The tests were often shortened if there were clear indications that the hydraulic conductivity is below the measuring range of the system. The pressure in the test section was let to stabilise at least 5 min before injection. In some test sections the stabilisation, injection or fall-off stage lasted several hours. Two transient (Horner and 1/Q) interpretations and one stationary-state (Moye) interpretation were made in-situ immediately after the test. The Hydraulic Testing Unit (HTU-system) is owned by Posiva Oy and it was operated by Geopros Oy. (orig.)

Drilling, logging, and testing information from borehole UE-25 UZ number-sign 16, Yucca Mountain, Nevada

International Nuclear Information System (INIS)

Thamir, F.; Thordarson, W.; Kume, J.; Rousseau, J.; Cunningham, D.M. Jr.

1998-01-01

Borehole UE-25 UZ number-sign 16 is the first of two boreholes that may be used to determine the subsurface structure at Yucca Mountain by using vertical seismic profiling. This report contains information collected while this borehole was being drilled, logged, and tested from May 27, 1992, to April 22, 1994. It does not contain the vertical seismic profiling data. This report is intended to be used as: (1) a reference for drilling similar boreholes in the same area, (2) a data source on this borehole, and (3) a reference for other information that is available from this borehole. The reference information includes drilling chronology, equipment, parameters, coring methods, penetration rates, completion information, drilling problems, and corrective actions. The data sources include lithology, fracture logs, a list of available borehole logs, and depths at which water was recorded. Other information is listed in an appendix that includes studies done after April 22, 1994

Geophysical data from boreholes DM1, DM2, DM3, and DM3a, New Hydraulic Fracturing Facility, Oak Ridge National Laboratory, Oak Ridge, Tennessee

International Nuclear Information System (INIS)

Haase, C.S.

1987-03-01

A comprehensive suite of geophysical logs was obtained from four deep monitoring boreholes at the New Hydrofracture Facility. The logging was an attempt to obtain stratigraphic, structural, and hydrologic information on the subsurface environment surrounding the hydrofracture facility. Logs obtained include caliper, gamma, neutron, density, single-point resistance, long- and short-normal resistivity, spontaneous potential, temperature, acoustic velocity, variable density, and borehole televiewer. Analysis and interpretation of the geophysical logs allowed the stratigraphic section at the facility to be determined and, by comparison with calibrated geophysical logs from borehole ORNL-Joy No. 2, allowed detailed inferences to be drawn about rock types and properties at the hydrofracture facility. Porosity values measured from the logs for Conasauga Group strata, as well as permeability values inferred from the logs, are low. Several intervals of apparently greater permeability, associated primarily with limestone-rich portions of the Maryville Limestone and sandstone-rich portions of the Rome Formation, were noted. Numerous fractures were identified by using several logs in combination. No one geophysical log was reliable for fracture identification although the acoustic-televiewer log appeared to have the greatest success. In addition to their characterization of subsurface conditions in the vicinity of the hydrofracture facility, the geophysical logs provided data on the extent of hydraulic fractures. Anomalies on single-point resistance logs that corresponded to prominent fractures identified on televiewer logs indicate intervals affected by hydraulic fractures associated with waste injection at the New Hydrofracture Facility. 14 refs

Reliability of Source Mechanisms for a Hydraulic Fracturing Dataset

Science.gov (United States)

Eyre, T.; Van der Baan, M.

2016-12-01

Non-double-couple components have been inferred for induced seismicity due to fluid injection, yet these components are often poorly constrained due to the acquisition geometry. Likewise non-double-couple components in microseismic recordings are not uncommon. Microseismic source mechanisms provide an insight into the fracturing behaviour of a hydraulically stimulated reservoir. However, source inversion in a hydraulic fracturing environment is complicated by the likelihood of volumetric contributions to the source due to the presence of high pressure fluids, which greatly increases the possible solution space and therefore the non-uniqueness of the solutions. Microseismic data is usually recorded on either 2D surface or borehole arrays of sensors. In many cases, surface arrays appear to constrain source mechanisms with high shear components, whereas borehole arrays tend to constrain more variable mechanisms including those with high tensile components. The abilities of each geometry to constrain the true source mechanisms are therefore called into question.The ability to distinguish between shear and tensile source mechanisms with different acquisition geometries is investigated using synthetic data. For both inversions, both P- and S- wave amplitudes recorded on three component sensors need to be included to obtain reliable solutions. Surface arrays appear to give more reliable solutions due to a greater sampling of the focal sphere, but in reality tend to record signals with a low signal to noise ratio. Borehole arrays can produce acceptable results, however the reliability is much more affected by relative source-receiver locations and source orientation, with biases produced in many of the solutions. Therefore more care must be taken when interpreting results.These findings are taken into account when interpreting a microseismic dataset of 470 events recorded by two vertical borehole arrays monitoring a horizontal treatment well. Source locations and

Outburst Prevention Technology with Borehole Hydraulic Jet Through Strata in Floor Gateway%底板巷穿层钻孔水力冲孔防突技术

Institute of Scientific and Technical Information of China (English)

刘明举; 郭献林; 李波; 王冕

2011-01-01

针对新安矿14211运输巷掘进过程中面临的煤与瓦斯突出问题,为了研究和确定适合新安煤田三软煤层赋存特点的水力冲孔工艺和消突评价体系,使其快速消除工作面突出危险性,提高煤巷掘进速度,采用底板巷穿层钻孔水力冲孔防突措施,按照考察出的冲孔影响半径均匀布置钻孔,排出部分煤体和瓦斯,使煤体卸压增透.试验结果表明,底板巷穿层水力冲孔技术较好地适应和利用了三软煤层的赋存特点,消除了工作面的突出危险性,掘进速度也由之前的40 m/月提高到75m/月,提高了87.5%.%According to coal and gas outburst problems occurred in the heading process of the No.14211 transportation gateway in Xin'an Mine, in order to study and set up the borehole hydraulic jet technique and the outburst evaluation system suitable for the three soft seam deposit features in Xin'an Coalfield, to rapidly eliminate the outburst danger of the heading face and to improve the seam gateway heading speed, the outburst prevention measures with borehole hydraulic jet through the strata in the floor gateway were applied.According the investigation of the borehole hydraulic jet influence radius, a layout of the berehole pattern was evenly set up and a partial coal and gas could be discharged.Thus the seam pressure could be released and the permeability of the seam could be improved.The experiment result showed that the borehole hydraulic jet technology passed through strata in the floor gateway would be well suitable for and utilization of the deposit features of the three soft seam and could eliminate the outburst danger of the heading face.Thus the heading speed could be improved from the previous 40 m/month to 75 m/month and the heading efficiency was improved by 87.5％.

Developments of borehole strain observation outside China

Institute of Scientific and Technical Information of China (English)

邱泽华; 石耀霖

2004-01-01

Borehole strain observation is playing an increasingly important role in the study on the crustal movements. It hasbeen used by many countries such as China, USA, Japan, Peru, Australia, South Africa, Iceland and Italy, in research fields of plate tectonics, earthquake, volcanic eruption, dam safety, oil field subsidence, mining collapse andso on. Borehole strainmeter has been improved rapidly and tends to get more and more components included inone probe. Based on observations by this kind of instruments, studies on seismic strain step, slow earthquake,earthquake precursor and volcanic eruption forecasting have made remarkable achievements. In the coming years,borehole strain observation is going to become one major geodetic means, together with GPS and InSAR.

Compressive and Shear Wave Velocity Profiles using Seismic Refraction Technique

International Nuclear Information System (INIS)

Aziman, M; Hazreek, Z A M; Azhar, A T S; Haimi, D S

2016-01-01

Seismic refraction measurement is one of the geophysics exploration techniques to determine soil profile. Meanwhile, the borehole technique is an established way to identify the changes of soil layer based on number of blows penetrating the soil. Both techniques are commonly adopted for subsurface investigation. The seismic refraction test is a non-destructive and relatively fast assessment compared to borehole technique. The soil velocities of compressive wave and shear wave derived from the seismic refraction measurements can be directly utilised to calculate soil parameters such as soil modulus and Poisson’s ratio. This study investigates the seismic refraction techniques to obtain compressive and shear wave velocity profile. Using the vertical and horizontal geophones as well as vertical and horizontal strike directions of the transient seismic source, the propagation of compressive wave and shear wave can be examined, respectively. The study was conducted at Sejagung Sri Medan. The seismic velocity profile was obtained at a depth of 20 m. The velocity of the shear wave is about half of the velocity of the compression wave. The soil profiles of compressive and shear wave velocities were verified using the borehole data and showed good agreement with the borehole data. (paper)

Characterization and interpretation of a fractured rocky massif from borehole data. Boreholes of geothermal project at Soultz-sous-Forets and other examples of unidirectional sampling; Caracterisation et interpretation d`un volume rocheux fracture a partir de donnees de forages. Les forages geothermiques de Soultz-sous-Forets et autres exemples d`echantillonnages unidirectionnels

Energy Technology Data Exchange (ETDEWEB)

Dezayes, CH

1995-12-18

In this thesis, we study fractures from borehole data on two sites: in one, located at Soultz-sous-Forets (Alsace) in the Rhine graben, boreholes reach a delta Jurassic series forming a petroleum reservoir. At Soultz, fractures have been studied on cores and borehole images. Striated faults present on cores permit to determine the tectonic history of the granite, completed by field study in Vosges Massif. This history corresponds to the Rhine graben history knowing by different authors. The analysis of vertical induced fractures observed on borehole images indicates a present-day NW-SE to NNW-SSE compression. These variations of stress direction are confirmed by others in situ measurements, as hydraulic injection, micro-seismicity, etc... On cores and borehole images, numerous fractures have been observed. Most of them are linked to the E-W distension, which permits the Rhine graben opening at Oligocene. At greatest scale, in quartz minerals, the micro-fractures are constitute by fluid inclusion trails. Several sets are related to the E-W distension, but others sets are linked to compressive stages. These sets are not observed on cores. This is a under-sampling of some fractures by the boreholes, but theses fractures exit into to rock massif. On borehole images, fracture density is weakest than the cores, however the set organisation is the same. At Ravenscar, the distribution of fracture spacing along different unidirectional sampling shows a exponential negative law. However, the fracture density varies with sampling. (author) 199 refs.

Site study plan for EDBH [Engineering Design Boreholes] seismic surveys, Deaf Smith County site, Texas: Revision 1

International Nuclear Information System (INIS)

Hume, H.

1987-12-01

This site study plan describes seismic reflection surveys to run north-south and east-west across the Deaf Smith County site, and intersecting near the Engineering Design Boreholes (EDBH). Both conventional and shallow high-resolution surveys will be run. The field program has been designed to acquire subsurface geologic and stratigraphic data to address information/data needs resulting from Federal and State regulations and Repository program requirements. The data acquired by the conventional surveys will be common-depth- point, seismic reflection data optimized for reflection events that indicate geologic structure near the repository horizon. The data will also resolve the basement structure and shallow reflection events up to about the top of the evaporite sequence. Field acquisition includes a testing phase to check/select parameters and a production phase. The field data will be subjected immediately to conventional data processing and interpretation to determine if there are any anamolous structural for stratigraphic conditions that could affect the choice of the EDBH sites. After the EDBH's have been drilled and logged, including vertical seismic profiling, the data will be reprocessed and reinterpreted for detailed structural and stratigraphic information to guide shaft development. The shallow high-resulition seismic reflection lines will be run along the same alignments, but the lines will be shorter and limited to immediate vicinity of the EDBH sites. These lines are planned to detect faults or thick channel sands that may be present at the EDBH sites. 23 refs. , 7 figs., 5 tabs

Comparative study of methods to estimate hydraulic parameters in the hydraulically undisturbed Opalinus Clay (Switzerland)

Energy Technology Data Exchange (ETDEWEB)

Yu, C.; Matray, J.-M. [Institut de Radioprotection et de Sûreté Nucléaire, Fontenay-aux-Roses, (France); Yu, C.; Gonçalvès, J. [Aix Marseille Université UMR 6635 CEREGE Technopôle Environnement Arbois-Méditerranée Aix-en-Provence, Cedex 4 (France); and others

2017-04-15

The deep borehole (DB) experiment gave the opportunity to acquire hydraulic parameters in a hydraulically undisturbed zone of the Opalinus Clay at the Mont Terri rock laboratory (Switzerland). Three methods were used to estimate hydraulic conductivity and specific storage values of the Opalinus Clay formation and its bounding formations through the 248 m deep borehole BDB-1: application of a Poiseuille-type law involving petrophysical measurements, spectral analysis of pressure time series and in situ hydraulic tests. The hydraulic conductivity range in the Opalinus Clay given by the first method is 2 × 10{sup -14}-6 × 10{sup -13} m s{sup -1} for a cementation factor ranging between 2 and 3. These results show low vertical variability whereas in situ hydraulic tests suggest higher values up to 7 × 10{sup -12} m s{sup -1}. Core analysis provides economical estimates of the homogeneous matrix hydraulic properties but do not account for heterogeneities at larger scale such as potential tectonic conductive features. Specific storage values obtained by spectral analysis are consistent and in the order of 10{sup -6} m{sup -1}, while formulations using phase shift and gain between pore pressure signals were found to be inappropriate to evaluate hydraulic conductivity in the Opalinus Clay. The values obtained are globally in good agreement with the ones obtained previously at the rock laboratory. (authors)

Direct Imaging of Natural Fractures and Stress Compartments Stimulated by Hydraulic Fracturing

Science.gov (United States)

Lacazette, A.; Vermilye, J. M.

2014-12-01

This contribution will present results from passive seismic studies of hydraulic fracture treatments in North American and Asian basins. One of the key data types is a comparatively new surface-based seismic imaging product - "Tomographic Fracture Images®" (TFI®). The procedure is an extension of Seismic Emission Tomography (SET), which is well-established and widely used. Conventional microseismic results - microearthquake hypocenter locations, magnitudes, and focal mechanism solutions - are also obtained from the data via a branch of the processing workflow. TFI is accomplished by summing the individual time steps in a multidimensional SET hypervolume over extended periods of time, such as an entire frac stage. The dimensions of a SET hypervolume are the X, Y, and Z coordinates of the voxels, the time step (typically on the order of 100 milliseconds), and the seismic activity value. The resulting summed volume is skeletonized to produce images of the main fracture surfaces, which are known to occupy the maximum activity surfaces of the high activity clouds from theory, field studies, and experiments. The orientation vs. area of the resulting TFIs can be analyzed in detail and compared with independent data sets such as volumetric structural attributes from reflection seismic data and borehole fracture data. We find that the primary effect of hydraulic fracturing is to stimulate preexisting natural fracture networks and faults. The combination of TFIs with hypocenter distributions and microearthquake focal mechanisms provides detailed information on subsurface stress compartmentalization. Faults are directly imaged which allows discrimination of fault planes from auxiliary planes of focal mechanism solutions. Examples that will be shown include simultaneous movement on a thrust fault and tear fault and examples of radically different stress compartments (e.g. extensional vs. wrench faulting) stimulated during a single hydraulic fracture treatment. The figure

Borehole Array Observations of Non-Volcanic Tremor at SAFOD

Science.gov (United States)

Ellsworth, W. L.; Luetgert, J. H.; Oppenheimer, D. H.

2005-12-01

We report on the observation of non-volcanic tremor made in the San Andreas Fault Observatory at Depth in May, 2005 during the deployment of a multi-level borehole seismic array in the SAFOD main hole. The seismic array consisted of 80 levels of hydraulically-clamped 3-component, 15 Hz omni-directional geophones spaced 15.24 m apart along a 1200 m section of the inclined borehole between 1538 and 2363 m below the ground surface. The array was provided by Paulsson Geophysical Services, Inc. (P/GSI), and recorded at a sample rate of 4000 sps on 24-bit Geode digital recorders provided by Geometrics, Inc. More than 2 TB of continuous data were recorded during the 2-week deployment. Selected local earthquakes and explosions recorded by the array are available at the Northern California Earthquake Data Center, and the entire unedited data set is available as assembled data at the IRIS Data Management Center. Both data sets are currently in the industry standard SEG2 format. Episodes of non-volcanic tremor are common along this reach of the San Andreas Fault according to Nadeau and Dolenc [2004, DOI: 10.1126/science.1107142], with many originating about 30 km southeast of SAFOD beneath the southern end of the Parkfield segment and northern end of the Simmler segment of the fault. We identified tremor episodes using spectrograms routinely produced by the Northern California Seismic Network (http://quake.usgs.gov/cgi-bin/sgrampark.pl) on which they appear as periods of elevated noise relative to the background. A particularly strong tremor episode occurred on May 10, 2005 between 19:39 and 20:00 UTC. In SAFOD, tremor spectral levels exceed the instrumental noise floor to at least 40 Hz. The spatially unaliased recording of the tremor wavefield on the P/GSI array reveal individual phases that can be tracked continuously across the array. The wavefield is composed of both up- and down-going shear waves that form quasi-stationary interference patterns in which areas of

Hydrogeological study of single water conducting fracture using a crosshole hydraulic test apparatus

International Nuclear Information System (INIS)

Yamamoto, Hajime; Shimo, Michito; Yamamoto, Takuya

1998-03-01

The Crosshole Injection Test Apparatus has been constructed to evaluate the hydraulic properties and conditions, such as hydraulic conductivity and its anisotropy, storage coefficient, pore pressure etc. within a rock near a drift. The construction started in FY93 and completed on August FY96 as a set of equipments for the use of crosshole hydraulic test, which is composed of one injection borehole instrument, one observation borehole instrument and a set of on-ground instrument. In FY96, in-situ feasibility test was conducted at a 550 m level drift in Kamaishi In Situ Test Site which has been operated by PNC, and the performance of the equipment and its applicability to various types of injection method were confirmed. In this year, a hydrogeological investigation on the single water conducting fracture was conducted at a 250 m level drift in Kamaishi In Situ Test Site, using two boreholes, KCH-3 and KCH-4, both of which are 30 m depth and inclined by 45 degrees from the surface. Pressure responses at the KCH-3 borehole during the drilling of KCH-4 borehole, the results of Borehole TV logging and core observation indicated that a major conductive single-fracture was successfully isolated by the packers. As a result of a series of the single-hole and the crosshole tests (sinusoidal and constant flowrate test), the hydraulic parameters of the single-fracture (such as hydraulic conductivity and storage coefficient) were determined. This report shows all the test result, analysed data, and also describes the hydro-geological structure near the drift. (author)

Wind seismic noise introduced by external infrastructure: field data and transfer mechanism

Science.gov (United States)

Martysevich, Pavel; Starovoyt, Yuri

2017-04-01

Background seismic noise generated by wind was analyzed at six co-located seismic and infrasound arrays with the use of the wind speed data. The main factors affecting the noise level were identified as (a) external structures as antenna towers for intrasite communication, vegetation and heavy solar panels fixtures, (b) borehole casing and (c) local lithology. The wind-induced seismic noise peaks in the spectra can be predicted by combination of inverted pendulum model for antenna towers and structures used to support solar panels, free- or clamped-tube resonance of the borehole casing and is dependent on the type of sedimentary upper layer. Observed resonance frequencies are in agreement with calculated clamped / free tube modes for towers and borehole casings. Improvement of the seismic data quality can be achieved by minimizing the impact of surrounding structures close to seismic boreholes. The need and the advantage of the borehole installation may vanish and appear to be even not necessary at locations with non-consolidated sediments because the impact of surrounding structures on seismic background may significantly deteriorate the installation quality and therefore the detection capability of the array. Several IMS arrays where the radio telemetry antennas are used for data delivery to the central site may benefit from the redesign of the intrasite communication system by its substitute with the fiber-optic net as less harmful engineering solution.

Deep Downhole Seismic Testing at the Waste Treatment Plant Site, Hanford, WA. Volume III P-Wave Measurements in Borehole C4997 Seismic Records, Wave-Arrival Identifications and Interpreted P-Wave Velocity Profile.

Energy Technology Data Exchange (ETDEWEB)

Stokoe, Kenneth H.; Li, Song Cheng; Cox, Brady R.; Menq, Farn-Yuh

2007-06-06

In this volume (III), all P-wave measurements are presented that were performed in Borehole C4997 at the Waste Treatment Plant (WTP) with T-Rex as the seismic source and the Lawrence Berkeley National Laboratory (LBNL) 3-D wireline geophone as the at-depth borehole receiver. P-wave measurements were performed over the depth range of 390 to 1220 ft, typically in 10-ft intervals. However, in some interbeds, 5-ft depth intervals were used. Compression (P) waves were generated by moving the base plate of T-Rex for a given number of cycles at a fixed frequency as discussed in Section 2. This process was repeated so that signal averaging in the time domain was performed using 3 to about 15 averages, with 5 averages typically used. In addition to the LBNL 3-D geophone, called the lower receiver herein, a 3-D geophone from Redpath Geophysics was fixed at a depth of 40 ft (later relocated to 27.5 ft due to visibility in borehole after rain) in Borehole C4997, and a 3-D geophone from the University of Texas was embedded near the borehole at about 1.5 ft below the ground surface. This volume is organized into 12 sections as follows: Section 1: Introduction, Section 2: Explanation of Terminology, Section 3: Vp Profile at Borehole C4997, Sections 4 to 6: Unfiltered P-wave records of lower vertical receiver, reaction mass, and reference receiver, Sections 7 to 9: Filtered P-wave signals of lower vertical receiver, reaction mass and reference receiver, Section 10: Expanded and filtered P-wave signals of lower vertical receiver, and Sections 11 and 12: Waterfall plots of unfiltered and filtered lower vertical receiver signals.

Proposed Construction of Boulder Seismic Station Monitoring Sites, Boulder, Wyoming. Environmental Assessment

Science.gov (United States)

2009-02-01

boreholes at the Boulder Seismic Station for research, development, test, and evaluation (RDT&E) as part of the U.S. Nuclear Treaty monitoring...14 LIST OF FIGURES Figure 1. Location of the proposed Boulder Seismic Station, borehole locations and associated buffers...juncture of Spring Creek and Scab Creek Road (Figure 1). Currently, the Boulder Seismic Station has a 13-element array of seismometers on the property

Research borehole drilling activity for boreholes DH-18, DH-19, DC-12, DC-13, DC-14, DC-15, and deepening of existing borehole DC-7

International Nuclear Information System (INIS)

1979-09-01

This report is an environmental evaluation of the impacts of proposed borehole drilling activities at the Hanford Site, northwest of Richland, Washington. The proposed action is to drill six research boreholes ranging in depth from 137 to 1372 meters (m) [250 to 4500 +- feet (ft)]. In addition, an existing borehole (DC-7) will be extended from 1249 to 1524 m (4099 to 5000 +- ft). The purpose of the US Department of Energy's (DOE) borehole drilling activities is to collect data on in situ rock formations that are considered potentialy suitable for nuclear waste repositories. The technical program efforts necessary to identify and qualify specific underground waste facility sites in candidate rock formations include geologic and hydrologic studies (seismicity and tectonics, rock structure and stratigraphy, lithology, etc.). Borehole drilling is an integral part of the geological studies and is essential to a thorough understanding of potentially suitable geologic formations. The purpose of the proposed drilling activities is to obtain data for evaluating Columbia River basalts that are being evaluated by the National Waste Terminal Storage (NWTS) Program to determine their suitability potential for nuclear waste repositories. Unavoidable impact to the environment is limited primarily to the clearing of land needed for access and drilling operations. Considerations exercised during site preparation, drilling, and subsequent site restoration will limit modification of the natural environment to the minimum required for accomplishment of test objectives

Interpretation of Flow Logs from Nevada Test Site Boreholes to Estimate Hydraulic Conductivity Using Numerical Simulations Constrained by Single-Well Aquifer Tests

Science.gov (United States)

Garcia, C. Amanda; Halford, Keith J.; Laczniak, Randell J.

2010-01-01

Hydraulic conductivities of volcanic and carbonate lithologic units at the Nevada Test Site were estimated from flow logs and aquifer-test data. Borehole flow and drawdown were integrated and interpreted using a radial, axisymmetric flow model, AnalyzeHOLE. This integrated approach is used because complex well completions and heterogeneous aquifers and confining units produce vertical flow in the annular space and aquifers adjacent to the wellbore. AnalyzeHOLE simulates vertical flow, in addition to horizontal flow, which accounts for converging flow toward screen ends and diverging flow toward transmissive intervals. Simulated aquifers and confining units uniformly are subdivided by depth into intervals in which the hydraulic conductivity is estimated with the Parameter ESTimation (PEST) software. Between 50 and 150 hydraulic-conductivity parameters were estimated by minimizing weighted differences between simulated and measured flow and drawdown. Transmissivity estimates from single-well or multiple-well aquifer tests were used to constrain estimates of hydraulic conductivity. The distribution of hydraulic conductivity within each lithology had a minimum variance because estimates were constrained with Tikhonov regularization. AnalyzeHOLE simulated hydraulic-conductivity estimates for lithologic units across screened and cased intervals are as much as 100 times less than those estimated using proportional flow-log analyses applied across screened intervals only. Smaller estimates of hydraulic conductivity for individual lithologic units are simulated because sections of the unit behind cased intervals of the wellbore are not assumed to be impermeable, and therefore, can contribute flow to the wellbore. Simulated hydraulic-conductivity estimates vary by more than three orders of magnitude across a lithologic unit, indicating a high degree of heterogeneity in volcanic and carbonate-rock units. The higher water transmitting potential of carbonate-rock units relative

Interpretation of Flow Logs from Nevada Test Site Boreholes to Estimate Hydraulic conductivity Using Numerical Simulations Constrained by Single-Well Aquifer Tests

Energy Technology Data Exchange (ETDEWEB)

Garcia, C. Amanda; Halford, Keith J.; Laczniak, Randell J.

2010-02-12

Hydraulic conductivities of volcanic and carbonate lithologic units at the Nevada Test Site were estimated from flow logs and aquifer-test data. Borehole flow and drawdown were integrated and interpreted using a radial, axisymmetric flow model, AnalyzeHOLE. This integrated approach is used because complex well completions and heterogeneous aquifers and confining units produce vertical flow in the annular space and aquifers adjacent to the wellbore. AnalyzeHOLE simulates vertical flow, in addition to horizontal flow, which accounts for converging flow toward screen ends and diverging flow toward transmissive intervals. Simulated aquifers and confining units uniformly are subdivided by depth into intervals in which the hydraulic conductivity is estimated with the Parameter ESTimation (PEST) software. Between 50 and 150 hydraulic-conductivity parameters were estimated by minimizing weighted differences between simulated and measured flow and drawdown. Transmissivity estimates from single-well or multiple-well aquifer tests were used to constrain estimates of hydraulic conductivity. The distribution of hydraulic conductivity within each lithology had a minimum variance because estimates were constrained with Tikhonov regularization. AnalyzeHOLE simulated hydraulic-conductivity estimates for lithologic units across screened and cased intervals are as much as 100 times less than those estimated using proportional flow-log analyses applied across screened intervals only. Smaller estimates of hydraulic conductivity for individual lithologic units are simulated because sections of the unit behind cased intervals of the wellbore are not assumed to be impermeable, and therefore, can contribute flow to the wellbore. Simulated hydraulic-conductivity estimates vary by more than three orders of magnitude across a lithologic unit, indicating a high degree of heterogeneity in volcanic and carbonate-rock units. The higher water transmitting potential of carbonate-rock units relative

Modeling borehole microseismic and strain signals measured by a distributed fiber optic sensor

Science.gov (United States)

Mellors, R. J.; Sherman, C. S.; Ryerson, F. J.; Morris, J.; Allen, G. S.; Messerly, M. J.; Carr, T.; Kavousi, P.

2017-12-01

The advent of distributed fiber optic sensors installed in boreholes provides a new and data-rich perspective on the subsurface environment. This includes the long-term capability for vertical seismic profiles, monitoring of active borehole processes such as well stimulation, and measuring of microseismic signals. The distributed fiber sensor, which measures strain (or strain-rate), is an active sensor with highest sensitivity parallel to the fiber and subject to varying types of noise, both external and internal. We take a systems approach and include the response of the electronics, fiber/cable, and subsurface to improve interpretation of the signals. This aids in understanding noise sources, assessing error bounds on amplitudes, and developing appropriate algorithms for improving the image. Ultimately, a robust understanding will allow identification of areas for future improvement and possible optimization in fiber and cable design. The subsurface signals are simulated in two ways: 1) a massively parallel multi-physics code that is capable of modeling hydraulic stimulation of heterogeneous reservoir with a pre-existing discrete fracture network, and 2) a parallelized 3D finite difference code for high-frequency seismic signals. Geometry and parameters for the simulations are derived from fiber deployments, including the Marcellus Shale Energy and Environment Laboratory (MSEEL) project in West Virginia. The combination mimics both the low-frequency strain signals generated during the fracture process and high-frequency signals from microseismic and perforation shots. Results are compared with available fiber data and demonstrate that quantitative interpretation of the fiber data provides valuable constraints on the fracture geometry and microseismic activity. These constraints appear difficult, if not impossible, to obtain otherwise.

Field investigation of mining-induced seismicity on local geohydrology

International Nuclear Information System (INIS)

Hsiung, S.M.; Chowdhury, A.H.; Philip, J.; Blake, W.

1993-01-01

Hydraulic response of the rock mass due to earthquakes is one of the concerns in the assessment of the long-term performance of a repository. Studies performed by other researchers indicated no systematic difference between natural earthquakes and mining-induced seismic events. The purpose of this field study at the Lucky Friday Mine is intended to obtain a better understanding regarding the local geohydrologic changes due to mining-induced seismicity and to evaluate analytical methods for simulation of these changes. Three saturated zones with faults and vein features were packed-off along a borehole drilled at approximately 20 degrees downward in a southerly direction from a depth about 1,737 m (5,700 ft) below surface for water pressure monitoring. The response of water pressure change to mine seismicity is found to be more pronounced in Zone 3, which contains the Lucky Friday Main Vein, than Zone 2, with the South Control Fault, and Zone 1, with the associated fractures parallel to the South Control Fault. The maximum observed pressure increase in Zone 3 was about 1.53 x 10 -2 MPa (2.22 psi) due to a seismic event of Richter drops in Zone 1 resulting from a number of seismic events are suspected to be related to slips along the associated fractures of the South Control Fault, or the South Control Fault itself, which initiated the seismic events. Water pressure increase in Zone 3 was found to be a function of event magnitude and distance

New simulation tools for long-term hydraulic design for a geological repository

International Nuclear Information System (INIS)

Richard, S.; Chaudon, L.

1995-01-01

Hydraulic concepts for a geological repository were investigated. Numerical simulations were adapted for this purpose and an experimental rheoelectric method based on an analogy between hydraulic flows and electric currents was developed. The results are discussed in this paper. A simplified representation of the host rock was adopted to account for the geometric details of the concept; this rock was described by a homogeneous porous medium associated with two major discontinuities. Steady-state hydraulic conditions were considered, and heating by the waste packages was assumed to be negligible (these conditions correspond to the long-term repository setting). The hydraulic structures obtained by the two methods are comparable, but significant differences were observed in the drained water distribution in the excavations; these discrepancies highlight the importance of the calculation mesh dimensions. Drainage barriers (drainage drifts and boreholes) surrounding the disposal boreholes may reduce water circulation in the disposal areas to their initial levels by constituting a partial hydraulic Faraday cage. This could be achieved with a reasonable number of boreholes if necessary

Evaluation of the shear probability of gaps during the hydraulic stimulation; Abschaetzung der Scherwahrscheinlichkeit von Klueften waehrend der hydraulischen Stimulation

Energy Technology Data Exchange (ETDEWEB)

Meller, Carola; Kohl, Thomas; Gaucher, Emmanuel [Karlsruher Institut fuer Technologie (KIT), Karlsruhe (Germany). Abt. Geothermie; Genter, Albert [GEIE Exploitation Miniere de la Chaleur, Kutzenhauzen (France)

2011-10-24

Induced seismicity is a ubiquitous problem in the hydraulic stimulation of geothermal reservoirs and the production phase. The relationships and processes that determine the behaviour of individual fractures are still not entirely clear. Induced earthquakes are a hard estimable uncertainty leading to a negative attitude among the publicity to geothermal projects. Thus, one way to eliminate the induced seismicity has to be created. Under this aspect, a three-dimensional hydraulic model is sought, that describes the probability of a gap to shear during the phase of injection within a given field of tension. This is done taking into account the spatial distribution of the gap, its orientation in the field of tension and the gap structure. The model is based on data which were measured in individual wells at the site Soultz-sous-Forets in Alsace. The states of stress and fracture distribution are shown and evaluated in dependence on depth and scale-dependent. For analysis, 3-D Mohr circles, stereo systems with frequency distributions and structural distributions of fractures, along the borehole were used. The calculated probability distribution provides a quantitative assessment of the induced seismicity and their dependence on the pressure distribution and the temporal evolution of the pressure front within the injection process.

Vertical seismic profiling and integration with reflection seismic studies at Laxemar, 2000

International Nuclear Information System (INIS)

Juhlin, C.; Bergman, B.; Cosma, C.; Keskinen, J.; Enescu, N.

2002-02-01

Vertical seismic profile (VSP) data were acquired in October 2000 in the 1700 m deep KLX02 borehole, near Laxemar in southeastern Sweden. The objectives of the VSP were to image reflectors in the borehole for correlation with surface seismic and borehole data, study the signal penetration of explosive versus mechanical sources and determine the seismic velocity as a function of depth. Five principal source points were used, one located close to the KLX02 wellhead and 4 others that were offset by about 200 m to 400 m. An explosive source was only used at the wellhead and consisted of 15 grams of dynamite in 90 cm deep shot holes in bedrock. A swept impact seismic source (SIST) was also used at the wellhead, as well as at the other four offset source points. The primary SIST source consisted of a computer controlled mechanical hammer mounted on a tractor. By activating the hammer over a 15 second sweep length, the total energy transferred to the ground is on the same order as that produced by the dynamite. The recorded data are then processed to generate seismic records that are equivalent to a single impact source. A smaller hand held SIST source was also tested at the wellhead. Tests of both the tractor mounted source and dynamite were made at a location offset somewhat from the wellhead at a site containing loose sediments at the surface. Full waveform sonic, resistivity and gamma logs were also acquired in conjunction the VSP survey. A comparison between the explosive and large SIST source shows that comparable energy levels are produced by the two methods. The SIST source appears to be more stable in terms of the energy level, although the frequency content of data are somewhat lower. However, its most significant advantage is the low cost of preparation of the source points and the speed of the acquisition. Numerous reflections are observed on the VSP, as is the case on the surface seismic, implying a complex structure in the vicinity of the KLX02 borehole

Vertical seismic profiling and integration with reflection seismic studies at Laxemar, 2000

Energy Technology Data Exchange (ETDEWEB)

Juhlin, C.; Bergman, B. [Uppsala Univ. (Sweden); Cosma, C.; Keskinen, J.; Enescu, N. [Vibrometric Oy, Helsinki (Finland)

2002-02-01

Vertical seismic profile (VSP) data were acquired in October 2000 in the 1700 m deep KLX02 borehole, near Laxemar in southeastern Sweden. The objectives of the VSP were to image reflectors in the borehole for correlation with surface seismic and borehole data, study the signal penetration of explosive versus mechanical sources and determine the seismic velocity as a function of depth. Five principal source points were used, one located close to the KLX02 wellhead and 4 others that were offset by about 200 m to 400 m. An explosive source was only used at the wellhead and consisted of 15 grams of dynamite in 90 cm deep shot holes in bedrock. A swept impact seismic source (SIST) was also used at the wellhead, as well as at the other four offset source points. The primary SIST source consisted of a computer controlled mechanical hammer mounted on a tractor. By activating the hammer over a 15 second sweep length, the total energy transferred to the ground is on the same order as that produced by the dynamite. The recorded data are then processed to generate seismic records that are equivalent to a single impact source. A smaller hand held SIST source was also tested at the wellhead. Tests of both the tractor mounted source and dynamite were made at a location offset somewhat from the wellhead at a site containing loose sediments at the surface. Full waveform sonic, resistivity and gamma logs were also acquired in conjunction the VSP survey. A comparison between the explosive and large SIST source shows that comparable energy levels are produced by the two methods. The SIST source appears to be more stable in terms of the energy level, although the frequency content of data are somewhat lower. However, its most significant advantage is the low cost of preparation of the source points and the speed of the acquisition. Numerous reflections are observed on the VSP, as is the case on the surface seismic, implying a complex structure in the vicinity of the KLX02 borehole

Measurement of in-situ hydraulic conductivity in the Cretaceous Pierre Shale

International Nuclear Information System (INIS)

Neuzil, C.E.; Bredehoeft, J.D.

1981-01-01

A recent study of the hydrology of the Cretaceous Pierre Shale utilized three techniques for measuring the hydraulic conductivity of tight materials. Regional hydraulic conductivity was obtained from a hydrodynamic model analysis of the aquifer-aquitard system which includes the Pierre Shale. Laboratory values were obtained from consolidation tests on core samples. In-situ values of hydraulic conductivity were obtained by using a borehole slug test designed specifically for tight formations. The test is conducted by isolating a portion of the borehole with one or two packers, abruptly pressurizing the shut-in portion, and recording the pressure decay with time. The test utilizes the analytical solution for pressure decay as water flows into the surrounding formation. Consistent results were obtained using the test on three successively smaller portions of a borehole in the Pierre Shale. The in-situ tests and laboratory tests yielded comparable values; the regional hydraulic conductivity was two to three orders of magnitude larger. This suggests that the lower values represent intergranular hydraulic conductivity of the intact shale and the regional values represent secondary permeability due to fractures. Calculations based on fracture flow theory demonstrate that small fractures could account for the observed differences

A multi-packer completion to measure hydraulic heads in a lightly fractured area in the Oxfordian limestone

International Nuclear Information System (INIS)

Scholz, E.; Cruchaudet, M.; Delay, J.; Piedevache, M.

2010-01-01

Document available in extended abstract form only. Andra has designed a new type of borehole completion in order to monitor simultaneously hydraulic heads. This completion is installed in a 420 m deep borehole drilled in the Oxfordian limestone formation. The borehole is located in the South-West of Andra's Underground Research Laboratory (URL) in a lightly fractured area. The multi-packer completion is built and installed by Solexperts. This device is composed of five measurement intervals isolated with rubber expandable packers and supported by stainless steel tubing. The packers are inflated with water at a pressure of 10 bars above the water pressure at that depth. Each measurement interval comprises an interval module embedding a pressure / temperature gauge connected to the interval through a filter. The gauges are connected through one cable to a data acquisition system on surface. This completion is removable. The packers can be deflated and the completion can be installed in another borehole. The packers are positioned in the EST461 borehole according to the caliper logging and the results of permeability tests. The hydraulic head measurements are compared with the local rainfall. Interval 1 (the deepest) shows a stable hydraulic head whereas intervals 2 to 5 show hydraulic head variations. The amplitude of the hydraulic head variations are closely related to the interval depth: the deepest the interval, the lowest the hydraulic head variation. Hydraulic heads in intervals 4 and 5 are similar. These intervals are probably connected. (authors)

Onshore and offshore seismic and lithostratigraphic analysis of a deeply incised Quaternary buried valley system in the Northern Netherlands

NARCIS (Netherlands)

Kluiving, S.J.; Aleid Bosch, J.H.; Ebbing, J.H.J.; Mesdag, C.S.; Westerhoff, R.S.

2003-01-01

High-resolution seismic data (onshore and offshore), geophysical borehole data as well as detailed lithofacies from airlift boreholes were acquired in northern Netherlands on and around the island of Ameland. Marine and land seismic data combined with information from land boreholes have been

NCSRR digital seismic network in Romania

International Nuclear Information System (INIS)

Aldea, A.; Albota, E.; Demetriu, S.; Poiata, N.; Kashima, T.

2007-01-01

Digital seismic instrumentation donated by Japan International Cooperation Agency (JICA) to the National Center for Seismic Risk Reduction (NCSRR, Romania) allowed the installation in 2003 of a new Romanian seismic network. In 2005-2006 the network was developed by investments from NCSRR within the budget ensured by Ministry of Transports, Construction and Tourism (MTCT). The NCSRR seismic network contains three types of instrumentation: (i) free-field stations - outside the capital city Bucharest (8 accelerometers), (ii) instrumented buildings - in Bucharest (5 buildings), and (iii) stations with free-field and borehole sensors - in Bucharest (8 sites with ground surface sensor and sensors in 15 boreholes with depths up to 153 m). Since its installation, the NCSRR network recorded more than 170 seismic motions from 26 earthquakes with moment magnitudes ranging from 3.2 to 6.0. The seismic instrumentation was accompanied by investigations of ground conditions and site response: PS logging tests, single-station and array microtremor measurements. The development of seismic monitoring in Romania is a major contribution of JICA Project, creating the premises for a better understanding and modelling of earthquake ground motion, site effects and building response. (authors)

Improving our understanding of the evolution of mountain belts via the Collisional Orogeny in the Scandinavian Caledonides (COSC) project: Results from seismic investigations and plans for the 2.5 km deep COSC-2 borehole

Science.gov (United States)

Juhlin, C.; Almqvist, B. S. G.; Buske, S.; Giese, R.; Hedin, P.; Lorenz, H.

2017-12-01

Mountain belts (orogens) have influenced, and do influence, geological processes and climatic conditions considerably, perhaps more than any other natural phenomenon. The Alpine-Himalayan mountain belt is the prime example of a collisional orogen today. However, research in an active orogen is mostly constrained to observe and interpret the expression of processes at the surface, while the driving processes act at depth, often at mid-crustal levels (20 km) and deeper. About 440 million years ago, an orogen comparable in dimension and tectonic setting to today's Alpine-Himalayan orogen was developing in what is western Scandinavia today. Since then, erosion has removed much of the overburden and exposed the deep interior of the orogen, facilitating direct observation of rocks that are deep in the crust in modern orogens. In the COSC project we study how large rock volumes (allochthons) were transported during the collision of two continents and the associated deformation. The emplacement of high-grade metamorphic allochthons during orogeny has been the focus of COSC-1 research, centered on a 2.5 km deep fully cored borehole drilled in the summer of 2014 through the lower part of the high-grade Seve Nappe Complex near the town of Åre in western Sweden. The planned COSC-2 borehole (also fully cored to 2.5 km) will complement the COSC-1 borehole and allow a 5 km deep tectonostratigraphic column of the Caledonides to be constructed. The rock volume in the proximity of the COSC-2 borehole will be imaged with a combination of very-high and high-resolution geophysical experiments, such as a combination of high frequency seismics; zero offset and walk-away vertical seismic profiling (VSP); and a sparse 3D coverage around the drill site combined with 2D seismic profiles of several kilometers length in different directions. Downhole geophysical logging will provide additional information on the in-situ rock physical properties. Data from surface surveys will be calibrated

Deep Downhole Seismic Testing at the Waste Treatment Plant Site, Hanford, WA. Volume I P-Wave Measurements in Borehole C4993 Seismic Records, Wave-Arrival Identifications and Interpreted P-Wave Velocity Profile.

Energy Technology Data Exchange (ETDEWEB)

Stokoe, Kenneth H.; Li, Song Cheng; Cox, Brady R.; Menq, Farn-Yuh

2007-07-06

In this volume (I), all P-wave measurements are presented that were performed in Borehole C4993 at the Waste Treatment Plant (WTP) with T-Rex as the seismic source and the Lawrence Berkeley National Laboratory (LBNL) 3-D wireline geophone as the at-depth borehole receiver. P-wave measurements were performed over the depth range of 370 to 1400 ft, typically in 10-ft intervals. However, in some interbeds, 5-ft depth intervals were used, while below about 1200 ft, depth intervals of 20 ft were used. Compression (P) waves were generated by moving the base plate of T-Rex for a given number of cycles at a fixed frequency as discussed in Section 2. This process was repeated so that signal averaging in the time domain was performed using 3 to about 15 averages, with 5 averages typically used. In addition to the LBNL 3-D geophone, called the lower receiver herein, a 3-D geophone from Redpath Geophysics was fixed at a depth of 22 ft in Borehole C4993, and a 3-D geophone from the University of Texas was embedded near the borehole at about 1.5 ft below the ground surface. This volume is organized into 12 sections as follows: Section 1: Introduction, Section 2: Explanation of Terminology, Section 3: Vp Profile at Borehole C4993, Sections 4 to 6: Unfiltered P-wave records of lower vertical receiver, reaction mass, and reference receiver, Sections 7 to 9: Filtered P-wave signals of lower vertical receiver, reaction mass and reference receiver, Section 10: Expanded and filtered P-wave signals of lower vertical receiver, and Sections 11 and 12: Waterfall plots of unfiltered and filtered lower vertical receiver signals.

Deep Downhole Seismic Testing at the Waste Treatment Plant Site, Hanford, WA. Volume II P-Wave Measurements in Borehole C4996 Seismic Records, Wave-Arrival Identifications and Interpreted P-Wave Velocity Profile.

Energy Technology Data Exchange (ETDEWEB)

Stokoe, Kenneth H.; Li, Song Cheng; Cox, Brady R.; Menq, Farn-Yuh

2007-07-06

In this volume (II), all P-wave measurements are presented that were performed in Borehole C4996 at the Waste Treatment Plant (WTP) with T-Rex as the seismic source and the Lawrence Berkeley National Laboratory (LBNL) 3-D wireline geophone as the at-depth borehole receiver. P-wave measurements were performed over the depth range of 360 to 1400 ft, typically in 10-ft intervals. However, in some interbeds, 5-ft depth intervals were used, while below about 1180 ft, depth intervals of 20 ft were used. Compression (P) waves were generated by moving the base plate of T-Rex for a given number of cycles at a fixed frequency as discussed in Section 2. This process was repeated so that signal averaging in the time domain was performed using 3 to about 15 averages, with 5 averages typically used. In addition to the LBNL 3-D geophone, called the lower receiver herein, a 3-D geophone from Redpath Geophysics was fixed at a depth of 22 ft in Borehole C4996, and a 3-D geophone from the University of Texas was embedded near the borehole at about 1.5 ft below the ground surface. This volume is organized into 12 sections as follows: Section 1: Introduction, Section 2: Explanation of Terminology, Section 3: Vp Profile at Borehole C4996, Sections 4 to 6: Unfiltered P-wave records of lower vertical receiver, reaction mass, and reference receiver, Sections 7 to 9: Filtered P-wave signals of lower vertical receiver, reaction mass and reference receiver, Section 10: Expanded and filtered P-wave signals of lower vertical receiver, and Sections 11 and 12: Waterfall plots of unfiltered and filtered lower vertical receiver signals.

Numerical Borehole Breakdown Investigations using XFEM

Science.gov (United States)

Beckhuis, Sven; Leonhart, Dirk; Meschke, Günther

2016-04-01

During pressurization of a wellbore a typical downhole pressure record shows the following regimes: first the applied wellbore pressure balances the reservoir pressure, then after the compressive circumferential hole stresses are overcome, tensile stresses are induced on the inside surface of the hole. When the magnitude of these stresses reach the tensile failure stress of the surrounding rock medium, a fracture is initiated and propagates into the reservoir. [1] In standard theories this pressure, the so called breakdown pressure, is the peak pressure in the down-hole pressure record. However experimental investigations [2] show that the breakdown did not occur even if a fracture was initiated at the borehole wall. Drilling muds had the tendency to seal and stabilize fractures and prevent fracture propagation. Also fracture mechanics analysis of breakdown process in mini-frac or leak off tests [3] show that the breakdown pressure could be either equal or larger than the fracture initiation pressure. In order to gain a deeper understanding of the breakdown process in reservoir rock, numerical investigations using the extended finite element method (XFEM) for hydraulic fracturing of porous materials [4] are discussed. The reservoir rock is assumed to be pre-fractured. During pressurization of the borehole, the injection pressure, the pressure distribution and the position of the highest flux along the fracture for different fracturing fluid viscosities are recorded and the influence of the aforementioned values on the stability of fracture propagation is discussed. [1] YEW, C. H. (1997), "Mechanics of Hydraulic Fracturing", Gulf Publishing Company [2] MORITA, N.; BLACK, A. D.; FUH, G.-F. (1996), "Borehole Breakdown Pressure with Drilling Fluids". International Journal of Rock Mechanics and Mining Sciences 33, pp. 39-51 [3] DETOURNAY, E.; CARBONELL, R. (1996), "Fracture Mechanics Analysis of the Breakdown Process in Minifrac or Leakoff Test", Society of Petroleum

The hydraulic structure of the Gole Larghe Fault Zone (Italian Southern Alps) through the seismic cycle

Science.gov (United States)

Bistacchi, A.; Mittempergher, S.; Di Toro, G.; Smith, S. A. F.; Garofalo, P. S.

2017-12-01

The 600 m-thick, strike slip Gole Larghe Fault Zone (GLFZ) experienced several hundred seismic slip events at c. 8 km depth, well-documented by numerous pseudotachylytes, was then exhumed and is now exposed in beautiful and very continuous outcrops. The fault zone was also characterized by hydrous fluid flow during the seismic cycle, demonstrated by alteration halos and precipitation of hydrothermal minerals in veins and cataclasites. We have characterized the GLFZ with > 2 km of scanlines and semi-automatic mapping of faults and fractures on several photogrammetric 3D Digital Outcrop Models (3D DOMs). This allowed us obtaining 3D Discrete Fracture Network (DFN) models, based on robust probability density functions for parameters of fault and fracture sets, and simulating the fault zone hydraulic properties. In addition, the correlation between evidences of fluid flow and the fault/fracture network parameters have been studied with a geostatistical approach, allowing generating more realistic time-varying permeability models of the fault zone. Based on this dataset, we have developed a FEM hydraulic model of the GLFZ for a period of some tens of years, covering one seismic event and a postseismic period. The higher permeability is attained in the syn- to early post-seismic period, when fractures are (re)opened by off-fault deformation, then permeability decreases in the postseismic due to fracture sealing. The flow model yields a flow pattern consistent with the observed alteration/mineralization pattern and a marked channelling of fluid flow in the inner part of the fault zone, due to permeability anisotropy related to the spatial arrangement of different fracture sets. Amongst possible seismological applications of our study, we will discuss the possibility to evaluate the coseismic fracture intensity due to off-fault damage, and the heterogeneity and evolution of mechanical parameters due to fluid-rock interaction.

Location Capability and Site Characterization Installing a Borehole VBB Seismometer: the OGS Experience in Ferrara (Italy)

Science.gov (United States)

Pesaresi, D.; Barnaba, C.

2014-12-01

The Centro di Ricerche Sismologiche (CRS, Seismological Research Centre) of the Istituto Nazionale di Oceanografia e di Geofisica Sperimentale (OGS, Italian National Institute for Oceanography and Experimental Geophysics) in Udine (Italy) after the strong earthquake of magnitude M=6.4 occurred in 1976 in the Italian Friuli-Venezia Giulia region, started to operate the Northeastern Italy Seismic Network: it currently consists of 19 very sensitive broad band and 17 simpler short period seismic stations, all telemetered to and acquired in real time at the OGS CRS data centre in Udine. The southwestern edge of the OGS seismic network stands on the Po alluvial basin: earthquake localization and characterization in this area is affected by the presence of soft alluvial deposits. Following the ML=5.9 earthquake that struck the Emilia region around Ferrara in Northern Italy on May 20, 2012, a cooperation of Istituto Nazionale di Geofisica e Vulcanologia, OGS, the Comune di Ferrara and the University of Ferrara lead to the reinstallation of a previously existing very broad band (VBB) borehole seismic station in Ferrara and to the deployment of a temporary seismographic network consisting of eight portable seismological stations, to record the local earthquakes that occurred during the seismic sequence. The aim of the OGS intervention was on one hand to extend its real time seismic monitoring capabilities toward South-West, including Ferrara and its surroundings, and on the other hand to evaluate seismic site responses in the area. We will introduce details of the Ferrara VBB borehole station and the OGS temporary seismographic network configuration and installation. We will then illustrate the location capability performances, and finally we will shortly describe seismic site characterization with surface/borehole comparisons in terms of seismic noise, site amplification and resonance frequencies.

Geostatistical methods for rock mass quality prediction using borehole and geophysical survey data

Science.gov (United States)

Chen, J.; Rubin, Y.; Sege, J. E.; Li, X.; Hehua, Z.

2015-12-01

For long, deep tunnels, the number of geotechnical borehole investigations during the preconstruction stage is generally limited. Yet tunnels are often constructed in geological structures with complex geometries, and in which the rock mass is fragmented from past structural deformations. Tunnel Geology Prediction (TGP) is a geophysical technique widely used during tunnel construction in China to ensure safety during construction and to prevent geological disasters. In this paper, geostatistical techniques were applied in order to integrate seismic velocity from TGP and borehole information into spatial predictions of RMR (Rock Mass Rating) in unexcavated areas. This approach is intended to apply conditional probability methods to transform seismic velocities to directly observed RMR values. The initial spatial distribution of RMR, inferred from the boreholes, was updated by including geophysical survey data in a co-kriging approach. The method applied to a real tunnel project shows significant improvements in rock mass quality predictions after including geophysical survey data, leading to better decision-making for construction safety design.

Borehole Gravity Meter Surveys at the Waste Treatment Plant, Hanford, Washington.

Energy Technology Data Exchange (ETDEWEB)

MacQueen, Jeffrey D.; Mann, Ethan

2007-04-06

Microg-LaCoste (MGL) was contracted by Pacfic Northwest National Laboratories (PNNL) to record borehole gravity density data in 3 wells at the HanfordWaste Treatment Plant (WTP) site. The survey was designed to provide highly accurate density information for use in seismic modeling. The borehole gravity meter (BHGM) tool has a very large depth of investigation (hundreds of feet) compared to other density tools so it is not influenced by casing or near welbore effects, such as washouts.

Long term monitoring of water production flow rates in boreholes in the Callovo-Oxfordian argillaceous rock

International Nuclear Information System (INIS)

Vinsot, A.; Delay, J.; La Vaissiere, R. de; Cruchaudet, M.

2010-01-01

Document available in extended abstract form only. Water production was observed in several boreholes in the Callovo-Oxfordian argillaceous rock (COx). These boreholes were implemented in 2005 in the Andra's Underground Research Laboratory (URL) at more than 400 m in depth. Despite the low COx permeability: close to 10-13 m/s, two original experimental setups made it possible to monitor water production flow rates ranging from 0.5 to 50 mL/day during 3 to 4 years in 4 boreholes. This contribution describes the water flow rate evaluation methods and the results obtained from several experimental phases which may be considered as a series of constant pressure production tests. The first experimental concept was based on seepage water collection. It consisted in filling with gas the interval of an ascending borehole at a pressure close to 1 bar and closing it. The hydraulic pressure in the rock surrounding the sealed interval was higher than 30 bars. Due to the hydraulic pressure difference between the interval and the surrounding rock, the interstitial water of the formation flowed into the interval, accumulated at its base by gravity and was pumped out at a controlled flow rate. The pumping rate was adjusted so that the water level would not exceed 40 cm inside the 5-meter-long interval. The water level was deduced from the difference between two absolute pressure measurements: one above the water surface in the gas phase and the other at the bottom of the water column. The total volume of the daily produced formation water was obtained by adding the water volume pumped out during the day and the water volume difference inside the interval between the beginning and the end of the day. This kind of experiment was performed in two boreholes. The second experimental concept was based on water circulation. It consisted in filling with water the interval of a descending borehole. Two water circulation lines and one pressure control line linked the test interval to

Linearized inversion frameworks toward high-resolution seismic imaging

KAUST Repository

Aldawood, Ali

2016-01-01

installed along the earth surface or down boreholes. Seismic imaging is a powerful tool to map these reflected and scattered energy back to their subsurface scattering or reflection points. Seismic imaging is conventionally based on the single

Experimental investigations regarding the use of sand as an inhibitor of air convection in deep seismic boreholes

Science.gov (United States)

Holcomb, L. Gary; Sandoval, Leo; Hutt, Bob

1998-01-01

have been plagued by quite high levels of horizontal noise. Therefore, there has been a definite need for a new technique for controlling low level tilt noise in deep boreholes and the use of sand has been under consideration for several years.Figure 1 contains conceptual illustrations of both the conventional holelock installed KS sensor system and the same sensor installed in sand. This figure demonstrates the major differences between the two installation methods. The curved arrows in the borehole on the left in the figure denote possible air convection cells which are believed to be the source of tilt noise in some of the conventional installations. This air motion is eliminated in a sand installation by filling most of the free air volume surrounding the seismometer with sand as shown in the right hand portion of the figure. The sand actually performs two functions; it prevents air motion and provides a remarkably ridgid clamping of the seismometer in the borehole. This report presents the results of quantitative experimental investigations into the effectiveness of controlling low level air convection in seismic borehole installations with sand. The main body of the experimental effort consisted of installing two KS-540001 sensor systems in closely spaced shallow boreholes, allowing the sensors to reach equilibrium operation, and then pouring sand into both boreholes to observe any changes caused by pouring sand into the holes. The hypothesis of the experiment was that the sand would fill up the entire free air volume between the sensor package and the borehole walls thereby preventing movement of the air in the vicinity of the sensor package. The validity of this hypothesis had been qualitatively proven by earlier experiments at ASL and by the sand installations at the IRIS/ASL stations ANMO in 1995 and COLA in 1996. This experiment documents the degree of improved noise levels to be expected if KS instruments are installed in sand instead of in the conventional

An analytical study on excitation of nuclear-coupled thermal-hydraulic instability due to seismically induced resonance in BWR

Energy Technology Data Exchange (ETDEWEB)

Hirano, Masashi [Japan Atomic Energy Research Institute, Ibaraki-ken (Japan)

1997-07-01

This paper describes the results of a scoping study on seismically induced resonance of nuclear-coupled thermal-hydraulic instability in BWRs, which was conducted by using TRAC-BF1 within a framework of a point kinetics model. As a result of the analysis, it is shown that a reactivity insertion could occur accompanied by in-surge of coolant into the core resulted from the excitation of the nuclear-coupled instability by the external acceleration. In order to analyze this phenomenon more in detail, it is necessary to couple a thermal-hydraulic code with a three-dimensional nuclear kinetics code.

Sealing of investigation boreholes, Phase 4 - Final report

Energy Technology Data Exchange (ETDEWEB)

Pusch, Roland [Drawrite AB, Luleaa Technical University, Luleaa (Sweden); Ramqvist, Gunnar [El-Tekno AB, Figeholm (Sweden); Bockgaard, Niclas [Golder Associates, Goeteborg (Sweden); Ekman, Lennart [LE Geokonsult AB, Baelinge (Sweden)

2011-09-15

The report describes the outcome of Phase 4 of the project 'Sealing of investigation boreholes', which deals with 1) characterization and planning of borehole sealing, 2) performance and quality assessment, 3) sealing of large diameter holes, and 4) interaction of clay and concrete plugs. A specific goal was to find ways to characterize, plan and seal of boreholes so that their impact on the overall hydraulic performance of the repository rock can predicted and controlled. The work comprised selection of representative 'reference holes' at the Laxemar and Forsmark sites for development of a general programme for planning and simulating implementation of borehole plugging campaigns, considering also cost issues. A second aim was to define and quantify the role of seals in the reference holes for finding out how important sealing really is. A third was to test a practical way to seal large diameter boreholes and a fourth to find out how concrete matures and performs in contact with smectite clay. The study demonstrated, in conclusion, the need for developing techniques for preparing deep boreholes before lasting seals are installed in them, since poor sealing can short-circuit hydraulically important fracture zones intersected by the holes. The practically oriented sealing activities showed that the technique developed for tight sealing of large-diameter boreholes is practical and feasible. The issue of chemical stability was investigated by testing the performance and constitution of a plug consisting of CBI concrete in contact with smectite-rich seals for almost three years. This study showed that none of them underwent substantial degradation in this period of time, but chemical reactions and thereby generated changes in physical behaviour of the plug components had taken place, particularly in the clay. The rate of degradation is, however, not yet known. It was concluded from this study that it is suitable to carry out a corresponding

Sealing of investigation boreholes, Phase 4 - Final report

International Nuclear Information System (INIS)

Pusch, Roland; Ramqvist, Gunnar; Bockgaard, Niclas; Ekman, Lennart

2011-09-01

The report describes the outcome of Phase 4 of the project 'Sealing of investigation boreholes', which deals with 1) characterization and planning of borehole sealing, 2) performance and quality assessment, 3) sealing of large diameter holes, and 4) interaction of clay and concrete plugs. A specific goal was to find ways to characterize, plan and seal of boreholes so that their impact on the overall hydraulic performance of the repository rock can predicted and controlled. The work comprised selection of representative 'reference holes' at the Laxemar and Forsmark sites for development of a general programme for planning and simulating implementation of borehole plugging campaigns, considering also cost issues. A second aim was to define and quantify the role of seals in the reference holes for finding out how important sealing really is. A third was to test a practical way to seal large diameter boreholes and a fourth to find out how concrete matures and performs in contact with smectite clay. The study demonstrated, in conclusion, the need for developing techniques for preparing deep boreholes before lasting seals are installed in them, since poor sealing can short-circuit hydraulically important fracture zones intersected by the holes. The practically oriented sealing activities showed that the technique developed for tight sealing of large-diameter boreholes is practical and feasible. The issue of chemical stability was investigated by testing the performance and constitution of a plug consisting of CBI concrete in contact with smectite-rich seals for almost three years. This study showed that none of them underwent substantial degradation in this period of time, but chemical reactions and thereby generated changes in physical behaviour of the plug components had taken place, particularly in the clay. The rate of degradation is, however, not yet known. It was concluded from this study that it is suitable to carry out a corresponding investigation of the plugs

Seismic Structure of Perth Basin (Australia) and surroundings from Passive Seismic Deployments

Science.gov (United States)

Issa, N.; Saygin, E.; Lumley, D. E.; Hoskin, T. E.

2016-12-01

We image the subsurface structure of Perth Basin, Western Australia and surroundings by using ambient seismic noise data from 14 seismic stations recently deployed by University of Western Australia (UWA) and other available permanent stations from Geoscience Australia seismic network and the Australian Seismometers in Schools program. Each of these 14 UWA seismic stations comprises a broadband sensor and a high fidelity 3-component 10 Hz geophone, recording in tandem at 250 Hz and 1000 Hz. The other stations used in this study are equipped with short period and broadband sensors. In addition, one shallow borehole station is operated with eight 3 component geophones at depths of between 2 and 44 m. The network is deployed to characterize natural seismicity in the basin and to try and identify any microseismic activity across Darling Fault Zone (DFZ), bounding the basin to the east. The DFZ stretches to approximately 1000 km north-south in Western Australia, and is one of the longest fault zones on the earth with a limited number of detected earthquakes. We use seismic noise cross- and auto-correlation methods to map seismic velocity perturbations across the basin and the transition from DFZ to the basin. Retrieved Green's functions are stable and show clear dispersed waveforms. Travel times of the surface wave Green's functions from noise cross-correlations are inverted with a two-step probabilistic framework to map the absolute shear wave velocities as a function of depth. The single station auto-correlations from the seismic noise yields P wave reflectivity under each station, marking the major discontinuities. Resulting images show the shear velocity perturbations across the region. We also quantify the variation of ambient seismic noise at different depths in the near surface using the geophones in the shallow borehole array.

Seismic VSP Investigations at Olkiluoto, 2005

Energy Technology Data Exchange (ETDEWEB)

Enescu, N.; Cosma, C.; Balu, L. (Vibrometric, Vantaa (Finland))

2007-08-15

Posiva Oy carries out R and D related tasks for spent nuclear fuel disposal in Finland. The site characterization has been conducted since 1987 in Olkiluoto in western Finland. The ONKALO underground characterization facility has been under construction since 2004. Vibrometric Oy has been contracted to carry out seismic VSP survey in four drillholes in the immediate vicinity of ONKALO, for the characterization of the seismically responsive structures. Four drillholes, KR8, KR27, KR29 and KR38 were included to the project. Seven seismic source locations on ground surface were used for each drillhole. The source locations were optimized with respect to the drillhole and ONKALO and were configured as linear arrays to produce optimum imaging focused on the ONKALO volume. A mechanical Vibsist source, using a hydraulic rock breaker mounted on a 22 t excavator, was used as source of seismic signal. The signal was recorded with downhole 3-component geophones. The recording array was 8-level long, with 5 m spacing between levels. Acquisition was run throughout the drillholes. Processing of the VSP profiles consisted of time decoding of the impact sequences, filtering and image point (IP) transform. The interpretation was carried out interactively, seeking for best match of orientation of each reflection according to different borehole profiles where the features were seen. The interpretations were built as an add-on to a previous seismic model of the site. The most distinct reflectors were interpreted, compiled to as a part of a terrain model composed of 3D surfaces, and transferred digitally together with other results (3D elements of reflector locations) into Posiva's 3D modeling system. Some of the reflectors have already received direct confirmation from ONKALO observations. (orig.)

Seismic VSP Investigations at Olkiluoto, 2005

International Nuclear Information System (INIS)

Enescu, N.; Cosma, C.; Balu, L.

2007-08-01

Posiva Oy carries out R and D related tasks for spent nuclear fuel disposal in Finland. The site characterization has been conducted since 1987 in Olkiluoto in western Finland. The ONKALO underground characterization facility has been under construction since 2004. Vibrometric Oy has been contracted to carry out seismic VSP survey in four drillholes in the immediate vicinity of ONKALO, for the characterization of the seismically responsive structures. Four drillholes, KR8, KR27, KR29 and KR38 were included to the project. Seven seismic source locations on ground surface were used for each drillhole. The source locations were optimized with respect to the drillhole and ONKALO and were configured as linear arrays to produce optimum imaging focused on the ONKALO volume. A mechanical Vibsist source, using a hydraulic rock breaker mounted on a 22 t excavator, was used as source of seismic signal. The signal was recorded with downhole 3-component geophones. The recording array was 8-level long, with 5 m spacing between levels. Acquisition was run throughout the drillholes. Processing of the VSP profiles consisted of time decoding of the impact sequences, filtering and image point (IP) transform. The interpretation was carried out interactively, seeking for best match of orientation of each reflection according to different borehole profiles where the features were seen. The interpretations were built as an add-on to a previous seismic model of the site. The most distinct reflectors were interpreted, compiled to as a part of a terrain model composed of 3D surfaces, and transferred digitally together with other results (3D elements of reflector locations) into Posiva's 3D modeling system. Some of the reflectors have already received direct confirmation from ONKALO observations. (orig.)

Flow measurements in boreholes PHO1 and PHO2 in ONKALO

International Nuclear Information System (INIS)

Rouhiainen, P.; Pollanen, J.

2005-10-01

Posiva Flow Log/Difference Flow method can be used for relatively fast determination of hydraulic properties of fractures or fractured zones in boreholes. The flow sensor for flow along a borehole and a special flow guide are used for this measurement. This report presents the principles of the method as well as the results of the measurements carried out in the underground facilities of the ONKALO. Pilot boreholes PH01 and PH02 were measured. Borehole PH01 was measured on February 2004 and borehole PH02 on December 2004. Borehole PH01 was measured using 2 m section when it was in natural sate (without pumping it) and when water was pumped out from it. The upper part of the borehole was also measured when water was injected into the borehole. In addition to this, a detailed flow log was performed with 0.1 m point intervals using 0.5 m section length when water was pumped out from the borehole. Borehole PH02 was measured only with 0.5 m section length. The borehole was open during measurements and there was a natural outflow from the borehole during measurements. The flow guide encloses an electrode for single point resistance measurement, which was also carried out with 0.01 m point intervals during the flow measurements. Flow measurement and single point resistance measurement were used to locate flowing fractures and to evaluate their transmissivity. Electric conductivity (EC) and temperature of water was registered during flow logging. The conductivity values are temperature corrected to 25 deg C. (orig.)

Continuous monitoring of volcanoes with borehole strainmeters

Science.gov (United States)

Linde, Alan T.; Sacks, Selwyn

Monitoring of volcanoes using various physical techniques has the potential to provide important information about the shape, size and location of the underlying magma bodies. Volcanoes erupt when the pressure in a magma chamber some kilometers below the surface overcomes the strength of the intervening rock, resulting in detectable deformations of the surrounding crust. Seismic activity may accompany and precede eruptions and, from the patterns of earthquake locations, inferences may be made about the location of magma and its movement. Ground deformation near volcanoes provides more direct evidence on these, but continuous monitoring of such deformation is necessary for all the important aspects of an eruption to be recorded. Sacks-Evertson borehole strainmeters have recorded strain changes associated with eruptions of Hekla, Iceland and Izu-Oshima, Japan. Those data have made possible well-constrained models of the geometry of the magma reservoirs and of the changes in their geometry during the eruption. The Hekla eruption produced clear changes in strain at the nearest instrument (15 km from the volcano) starting about 30 minutes before the surface breakout. The borehole instrument on Oshima showed an unequivocal increase in the amplitude of the solid earth tides beginning some years before the eruption. Deformational changes, detected by a borehole strainmeter and a very long baseline tiltmeter, and corresponding to the remote triggered seismicity at Long Valley, California in the several days immediately following the Landers earthquake are indicative of pressure changes in the magma body under Long Valley, raising the question of whether such transients are of more general importance in the eruption process. We extrapolate the experience with borehole strainmeters to estimate what could be learned from an installation of a small network of such instruments on Mauna Loa. Since the process of conduit formation from the magma sources in Mauna Loa and other

Seismic velocities and geologic logs from boreholes at three downhole arrays in San Francisco, California

Science.gov (United States)

Gibbs, James F.; Fumal, Thomas E.; Borcherdt, Roger D.; Warrick, Richard E.; Liu, Hsi-Ping; Westerlund, Robert E.

1994-01-01

The Loma Prieta earthquake of October 17, 1989 (1704 PST), has reinforced observations made by Wood and others (1908) after the 1906 San Francisco earthquake, that poor ground conditions (soft soil) increase the likelihood of shaking damage to structures. Since 1908 many studies (for example Borcherdt, 1970, Borcherdt and Gibbs, 1976, Borcherdt and Glassmoyer, 1992) have shown that soft soils amplify seismic waves at frequencies that can be damaging to structures. Damage in the City of San Francisco from the Loma Prieta earthquake was concentrated in the Marina District, the Embarcadero, and the China Basin areas. Each of these areas, to some degree, is underlain by soft soil deposits. These concentrations of damage raise important questions regarding the amplification effects of such deposits at damaging levels of motion. Unfortunately, no strong-motion recordings were obtained in these areas during the Loma Prieta earthquake and only a limited number (< 10) have been obtained on other soft soil sites in the United States. Consequently, important questions exist regarding the response of such deposits during damaging earthquakes, especially questions regarding the nonlinear soil response. Towards developing a data set to address these important questions, borehole strong-motion arrays have been installed at three locations. These arrays consist of groups of wide-dynamic-range pore-pressure transducers and three-component accelerometers, the outputs of which are recorded digitally. The arrays are designed to provide an integrated set of data on ground shaking, liquifaction-induced ground failure, and structural response. This report describes the detailed geologic, seismic, and material-property determinations derived at each of these sites.

Lattice Boltzmann methods applied to large-scale three-dimensional virtual cores constructed from digital optical borehole images of the karst carbonate Biscayne aquifer in southeastern Florida

Science.gov (United States)

Sukop, Michael C.; Cunningham, Kevin J.

2014-11-01

Digital optical borehole images at approximately 2 mm vertical resolution and borehole caliper data were used to create three-dimensional renderings of the distribution of (1) matrix porosity and (2) vuggy megaporosity for the karst carbonate Biscayne aquifer in southeastern Florida. The renderings based on the borehole data were used as input into Lattice Boltzmann methods to obtain intrinsic permeability estimates for this extremely transmissive aquifer, where traditional aquifer test methods may fail due to very small drawdowns and non-Darcian flow that can reduce apparent hydraulic conductivity. Variogram analysis of the borehole data suggests a nearly isotropic rock structure at lag lengths up to the nominal borehole diameter. A strong correlation between the diameter of the borehole and the presence of vuggy megaporosity in the data set led to a bias in the variogram where the computed horizontal spatial autocorrelation is strong at lag distances greater than the nominal borehole size. Lattice Boltzmann simulation of flow across a 0.4 × 0.4 × 17 m (2.72 m3 volume) parallel-walled column of rendered matrix and vuggy megaporosity indicates a high hydraulic conductivity of 53 m s-1. This value is similar to previous Lattice Boltzmann calculations of hydraulic conductivity in smaller limestone samples of the Biscayne aquifer. The development of simulation methods that reproduce dual-porosity systems with higher resolution and fidelity and that consider flow through horizontally longer renderings could provide improved estimates of the hydraulic conductivity and help to address questions about the importance of scale.

Temperature profiles in the Harwell boreholes

International Nuclear Information System (INIS)

Robins, N.S.

1983-03-01

Heat flow at Harwell is estimated at 45 mWm -2 (milli Watt per metre squared is the unit of heat flow). Thermal conductivity values for the formations penetrated range from 1.0 to 4.6 Wm -1 K -1 . The temperature profiles recorded in the boreholes enable the vertical groundwater flow patterns within two poorly permeable mudrock units to be evaluated. The two mudrock units act as leaky barriers each separating a pair of aquifer units which induce a vertical hydraulic gradient across the mudrocks. The flow velocity results for the upper mudrock units derived from the temperature profile are compatible with values for groundwater potential derived from hydraulic data (10 -9 ms -1 from the temperature profile and 10 -12 ms -1 from the hydraulic observations). The results from the lower mudrock sequence are incompatible and this may be due to some other overiding influence upon the temperature profile. (author)

Seismic hydraulic fracture migration originated by successive deep magma pulses: The 2011-2013 seismic series associated to the volcanic activity of El Hierro Island

Science.gov (United States)

Díaz-Moreno, A.; Ibáñez, J. M.; De Angelis, S.; García-Yeguas, A.; Prudencio, J.; Morales, J.; Tuvè, T.; García, L.

2015-11-01

In this manuscript we present a new interpretation of the seismic series that accompanied eruptive activity off the coast of El Hierro, Canary Islands, during 2011-2013. We estimated temporal variations of the Gutenberg-Richter b value throughout the period of analysis, and performed high-precision relocations of the preeruptive and syneruptive seismicity using a realistic 3-D velocity model. Our results suggest that eruptive activity and the accompanying seismicity were caused by repeated injections of magma from the mantle into the lower crust. These magma pulses occurred within a small and well-defined volume resulting in the emplacement of fresh magma along the crust-mantle boundary underneath El Hierro. We analyzed the distribution of earthquake hypocenters in time and space in order to assess seismic diffusivity in the lower crust. Our results suggest that very high earthquake rates underneath El Hierro represent the response of a stable lower crust to stress perturbations with pulsatory character, linked to the injection of magma from the mantle. Magma input from depth caused large stress perturbations to propagate into the lower crust generating energetic seismic swarms. The absence of any preferential alignment in the spatial pattern of seismicity reinforces our hypothesis that stress perturbation and related seismicity, had diffusive character. We conclude that the temporal and spatial evolution of seismicity was neither tracking the path of magma migration nor it defines the boundaries of magma storage volumes such as a midcrustal sill. Our conceptual model considers pulsatory magma injection from the upper mantle and its propagation along the Moho. We suggest, within this framework, that the spatial and temporal distributions of earthquake hypocenters reflect hydraulic fracturing processes associated with stress propagation due to magma movement.

kISMET: Stress and fracture characterization in a deep mine

Science.gov (United States)

Oldenburg, C. M.; Dobson, P. F.; Daley, T. M.; Birkholzer, J. T.; Cook, P. J.; Ajo Franklin, J. B.; Rutqvist, J.; Siler, D.; Kneafsey, T. J.; Nakagawa, S.; Wu, Y.; Guglielmi, Y.; Ulrich, C.; Marchesini, P.; Wang, H. F.; Haimson, B. C.; Sone, H.; Vigilante, P.; Roggenthen, W.; Doe, T.; Lee, M.; Mattson, E.; Huang, H.; Johnson, T. C.; Morris, J.; White, J. A.; Johnson, P. A.; Coblentz, D. D.; Heise, J.

2016-12-01

We are developing a community facility called kISMET (permeability (k) and Induced Seismicity Management for Energy Technologies) at the Sanford Underground Research Facility (SURF) in Lead, SD. The purpose of kISMET is to investigate stress and the effects of rock fabric on hydraulic fracturing. Although findings from kISMET may have broad applications that inform stress and fracturing in anisotropic rock, results will be most applicable to improving control of hydraulic fracturing for enhanced geothermal systems (EGS) in crystalline rock. At the kISMET site on the 4850 ft (1480 m depth) level of SURF, we have drilled and cored an array of nearly vertical boreholes in Precambrian phyllite. The array consists of four 50-m deep monitoring boreholes surrounding one 100-m deep borehole forming a 6 m-wide five-spot pattern at a depth of 1530 m. Previous investigations of the stress field at SURF suggest that the principal stress s1 is nearly vertical. By aligning the kISMET boreholes approximately with σ1, fractures created in the center borehole should in theory be perpendicular to σ3, the least principal horizontal stress. But the phyllite at kISMET has a strong fabric (foliation) that could influence fracturing. Stress measurements and stimulation using hydraulic fracturing will be carried out in the center borehole using a straddle packer and high-pressure pump. We will use an impression packer and image logs after stress testing and stimulation to determine fracture orientation and extent at the center borehole. In order to study the control of stress, rock fabric, and stimulation approach on size, aperture, and orientation of hydraulic fractures, we will carefully monitor the stress measurements and stimulation. For example, we will use continuous active source seismic (CASSM) in two of the monitoring boreholes to measure changes in seismic-wave velocity as water fills the fracture. Second, near real-time electrical resistance tomography (ERT) will be used in

Techniques for Field Operation of Straddle-packer System in Deep Borehole

International Nuclear Information System (INIS)

Kim, Kyung Su; Park, Kyung Woo; Kim, Geon Young; Ji, Sung Hoon; Koh, Yong Kwon; Choi, Jong Won

2010-05-01

It is necessary to establish an appropriate hydro-testing tool for the qualified characterization of deep geological environments, especially for the hydraulic properties of rock formation. This research project had been initiated for the purpose of establishment of advanced infra-structures in KURT. The straddle packer system was developed for hydraulic characterization of geological formation using deep borehole. This technical report consists of design concept, basic requirements, function of each part, field operation procedures and techniques, detail design drawings, and specifications. The qualified hydro-testing tool, which is suitable for medium to low permeable formation, using large and deep borehole, has been developed. This tool will be applied for the research project on development of HLW disposal technologies and the site characterization activities of LILW disposal project. Prior to field operation using this hydro-testing equipment, every researchers should be well acquainted with this technical report

HYDRAULIC ELEVATOR INSTALLATION ESTIMATION FOR THE WATER SOURCE WELL SAND-PACK CLEANING UP

Directory of Open Access Journals (Sweden)

V. V. Ivashechkin

2016-01-01

Full Text Available The article offers design of a hydraulic elevator installation for cleaning up water-source wells of sand packs. It considerers the installation hydraulic circuit according to which the normal pump feeds the high-level tank water into the borehole through two parallel water lines. The water-jet line with washing nozzle for destroying the sand-pack and the supply pipe-line coupled with the operational nozzle of the hydraulic elevator containing the inlet and the supply pipelines for respectively intaking the hydromixture and removing it from the well. The paper adduces equations for fluid motion in the supply and the water-jet pipelines and offers expressions for evaluating the required heads in them. For determining water flow in the supply and the water-jet pipe lines the author proposes to employ graphical approach allowing finding the regime point in Q–H chart by means of building characteristics of the pump and the pipe-lines. For calculating the useful vertical head, supply and dimensions of the hydraulic elevator the article employs the equation of motion quantity with consistency admission of the motion quantity before and after mixing the flows in the hydraulic elevator. The suggested correlations for evaluating the hydraulic elevator efficiency determine the sand pack removal duration as function of its sizes and the ejected fluid flow rate. A hydraulic-elevator installation parameters estimation example illustrates removing a sand pack from a water-source borehole of 41 m deep and 150 mm diameter bored in the village of Uzla of Myadelsk region, of Minsk oblast. The working efficiency of a manufactured and laboratory tested engineering prototype of the hydraulic elevator installation was acknowledged in actual tests at the indicated borehole site. With application of graphical approach, the suggested for the hydraulic elevator installation parameters calculation procedure allows selecting, with given depth and the borehole diameter

Optimal experimental design for placement of boreholes

Science.gov (United States)

Padalkina, Kateryna; Bücker, H. Martin; Seidler, Ralf; Rath, Volker; Marquart, Gabriele; Niederau, Jan; Herty, Michael

2014-05-01

Drilling for deep resources is an expensive endeavor. Among the many problems finding the optimal drilling location for boreholes is one of the challenging questions. We contribute to this discussion by using a simulation based assessment of possible future borehole locations. We study the problem of finding a new borehole location in a given geothermal reservoir in terms of a numerical optimization problem. In a geothermal reservoir the temporal and spatial distribution of temperature and hydraulic pressure may be simulated using the coupled differential equations for heat transport and mass and momentum conservation for Darcy flow. Within this model the permeability and thermal conductivity are dependent on the geological layers present in the subsurface model of the reservoir. In general, those values involve some uncertainty making it difficult to predict actual heat source in the ground. Within optimal experimental the question is which location and to which depth to drill the borehole in order to estimate conductivity and permeability with minimal uncertainty. We introduce a measure for computing the uncertainty based on simulations of the coupled differential equations. The measure is based on the Fisher information matrix of temperature data obtained through the simulations. We assume that the temperature data is available within the full borehole. A minimization of the measure representing the uncertainty in the unknown permeability and conductivity parameters is performed to determine the optimal borehole location. We present the theoretical framework as well as numerical results for several 2d subsurface models including up to six geological layers. Also, the effect of unknown layers on the introduced measure is studied. Finally, to obtain a more realistic estimate of optimal borehole locations, we couple the optimization to a cost model for deep drilling problems.

Preparatory hydrogeologic investigations for in situ migration experiments in Studsvik

International Nuclear Information System (INIS)

Klockars, C.-E.; Persson, O.; Carlsson, L.; Duran, O.; Lindstroem, D.; Magnusson, K.-Aa.; Scherman, S.

1980-11-01

The test area is located at Studsvik and covers an area of 8000 m 2 . Within the area, the Geological Survey of Sweden has carried out studies including:Geological and tectonic mapping of the bedrock. Geophysical studies from the ground surface, including refraction seismic measurements, resistivity measurements and electromagnetic measurements. Core drilling. Hammer drilling. Geophysical and geochemical borehole measurements. Hydraulic tests in and between different boreholes. The geological mapping shows that the test area is located within a bedrock consisting of metamorphic sedimentary gneisses, known as migmatite within which decimeter-to-meter-thick layers of amphibolite are present. Mapped fractures from the drill core have chiefly chlorite and calcite as fracture-filling materials. The fracture frequency is relatively high with a maximum in the strike direction of the fractures in a northwesterly direction. The resistivity loggings that have been carried out show that the bedrock has a low average resistivity of 24 000 ohm m. The seismic measurements also show a low-velocity zone within the central portion of the area, which indicates that the portion of the bedrock close to the ground surface has a relatively high fracture content. In the measurements of spontaneous potential (SP), pyrite-filled fractures in the core borehole gave electronegative deviations. The borehole liquid has low salinity (high resistivity), a low pH and a positive redox potential. The hydraulic measurements that have been carried out show that the bedrock possesses low conductivity, in the order of 10 -6 m/s. Hydraulic double packer measurements indicate a number of major transmissive sections along the length of the boreholes. Inter-hole measurements show that only a few of these transmissive sections have hydraulic connection with nearby boreholes. Measurements of radon content and the resistivity of the borehole liquid provide information on a borehole's dominant zones with

Reflection seismic methods applied to locating fracture zones in crystalline rock

International Nuclear Information System (INIS)

Juhlin, C.

1998-01-01

The reflection seismic method is a potentially powerful tool for identifying and localising fracture zones in crystalline rock if used properly. Borehole sonic logs across fracture zones show that they have reduced P-wave velocities compared to the surrounding intact rock. Diagnostically important S-wave velocity log information across the fracture zones is generally lacking. Generation of synthetic reflection seismic data and subsequent processing of these data show that structures dipping up towards 70 degrees from horizontal can be reliably imaged using surface seismic methods. Two real case studies where seismic reflection methods have been used to image fracture zones in crystalline rock are presented. Two examples using reflection seismic are presented. The first is from the 5354 m deep SG-4 borehole in the Middle Urals, Russia where strong seismic reflectors dipping from 25 to 50 degrees are observed on surface seismic reflection data crossing over the borehole. On vertical seismic profile data acquired in the borehole, the observed P-wave reflectivity is weak from these zones, however, strong converted P to S waves are observed. This can be explained by the source of the reflectors being fracture zones with a high P wave to S wave velocity ratio compared to the surrounding rock resulting in a high dependence on the angle of incidence for the reflection coefficient. A high P wave to S wave velocity ratio (high Poisson's ratio) is to be expected in fluid filled fractured rock. The second case is from Aevroe, SE Sweden, where two 1 km long crossing high resolution seismic reflection lines were acquired in October 1996. An E-W line was shot with 5 m geophone and shotpoint spacing and a N-S one with 10 m geophone and shotpoint spacing. An explosive source with a charge size of 100 grams was used along both lines. The data clearly image three major dipping reflectors in the upper 200 ms (600 m). The dipping ones intersect or project to the surface at/or close to

Numerical simulation of flow in deep open boreholes in a coastal freshwater lens, Pearl Harbor Aquifer, O‘ahu, Hawai‘i

Science.gov (United States)

Rotzoll, Kolja

2012-01-01

The Pearl Harbor aquifer in southern O‘ahu is one of the most important sources of freshwater in Hawai‘i. A thick freshwater lens overlays brackish and saltwater in this coastal aquifer. Salinity profiles collected from uncased deep monitor wells (DMWs) commonly are used to monitor freshwater-lens thickness. However, vertical flow in DMWs can cause the measured salinity to differ from salinity in the adjacent aquifer or in an aquifer without a DWM. Substantial borehole flow and displacement of salinity in DMWs over several hundred feet have been observed in the Pearl Harbor aquifer. The objective of this study was to evaluate the effects of borehole flow on measured salinity profiles from DMWs. A numerical modeling approach incorporated aquifer hydraulic characteristics and recharge and withdrawal rates representative of the Pearl Harbor aquifer. Borehole flow caused by vertical hydraulic gradients associated with both the natural regional flow system and groundwater withdrawals was simulated. Model results indicate that, with all other factors being equal, greater withdrawal rates, closer withdrawal locations, or higher hydraulic conductivities of the well cause greater borehole flow and displacement of salinity in the well. Borehole flow caused by the natural groundwater-flow system is five orders of magnitude greater than vertical flow in a homogeneous aquifer, and borehole-flow directions are consistent with the regional flow system: downward flow in inland recharge areas and upward flow in coastal discharge areas. Displacement of salinity inside the DMWs associated with the regional groundwater-flow system ranges from less than 1 to 220 ft, depending on the location and assumed hydraulic conductivity of the well. For example, upward displacements of the 2 percent and 50 percent salinity depths in a well in the coastal discharge part of the flow system are 17 and 4.4 ft, respectively, and the average salinity difference between aquifer and borehole is 0

IODP Expedition 340T: Borehole Logging at Atlantis Massif Oceanic Core Complex

Directory of Open Access Journals (Sweden)

Donna Blackman

2013-03-01

Full Text Available Integrated Ocean Drilling Program (IODP Expedition 340T returned to the 1.4-km-deep Hole U1309D at Atlantis Massif to carry out borehole logging including vertical seismic profiling (VSP. Seismic, resistivity, and temperature logs were obtained throughout the geologic section in the footwall of this oceanic core complex. Reliable downhole temperature measurements throughout and the first seismic coverage of the 800–1400 meters below seafloor (mbsf portionof the section were obtained. Distinct changes in velocity, resistivity, and magnetic susceptibility characterize the boundaries of altered, olivine-rich troctolite intervals within the otherwise dominantly gabbroic se-quence. Some narrow fault zones also are associated with downhole resistivity or velocity excursions. Small deviations in temperature were measured in borehole fluid adjacent to known faults at 750 mbsf and 1100 mbsf. This suggests that flow of seawater remains active along these zones of faulting and rock alteration. Vertical seismic profile station coverage at zero offsetnow extends the full length of the hole, including the uppermost 150 mbsf, where detachment processes are expected to have left their strongest imprint. Analysis of wallrock properties, together with alteration and structural characteristics of the cores from Site U1309, highlights the likely interplay between lithology, structure, lithospheric hydration, and core complex evolution.

A new seismic station in Romania the Bucovina seismic array

International Nuclear Information System (INIS)

Grigore, Adrian; Grecu, Bogdan; Ionescu, Constantin; Ghica, Daniela; Popa, Mihaela; Rizescu, Mihaela

2002-01-01

Recently, a new seismic monitoring station, the Bucovina Seismic Array, has been established in the northern part of Romania, in a joint effort of the Air Force Technical Applications Center, USA, and the National Institute for Earth Physics, Romania. The array consists of 10 seismic sensors (9 short-period and one broad band) located in boreholes and distributed in a 5 x 5 km area. On July 24, 2002 the official Opening Ceremony of Bucovina Seismic Array took place in the area near the city of Campulung Moldovenesc in the presence of Romanian Prime Minister, Adrian Nastase. Starting with this date, the new seismic monitoring system became fully operational by continuous recording and transmitting data in real-time to the National Data Center of Romania, in Bucharest and to the National Data Center of USA, in Florida. Bucovina Seismic Array, added to the present Seismic Network, will provide much better seismic monitoring coverage of Romania's territory, on-scale recording for weak-to-strong events, and will contribute to advanced seismological studies on seismic hazard and risk, local effects and microzonation, seismic source physics, Earth structure. (authors)

Fully Coupled Geomechanics and Discrete Flow Network Modeling of Hydraulic Fracturing for Geothermal Applications

Energy Technology Data Exchange (ETDEWEB)

Fu, P; Johnson, S M; Hao, Y; Carrigan, C R

2011-01-18

The primary objective of our current research is to develop a computational test bed for evaluating borehole techniques to enhance fluid flow and heat transfer in enhanced geothermal systems (EGS). Simulating processes resulting in hydraulic fracturing and/or the remobilization of existing fractures, especially the interaction between propagating fractures and existing fractures, represents a critical goal of our project. To this end, we are continuing to develop a hydraulic fracturing simulation capability within the Livermore Distinct Element Code (LDEC), a combined FEM/DEM analysis code with explicit solid-fluid mechanics coupling. LDEC simulations start from an initial fracture distribution which can be stochastically generated or upscaled from the statistics of an actual fracture distribution. During the hydraulic stimulation process, LDEC tracks the propagation of fractures and other modifications to the fracture system. The output is transferred to the Non-isothermal Unsaturated Flow and Transport (NUFT) code to capture heat transfer and flow at the reservoir scale. This approach is intended to offer flexibility in the types of analyses we can perform, including evaluating the effects of different system heterogeneities on the heat extraction rate as well as seismicity associated with geothermal operations. This paper details the basic methodology of our approach. Two numerical examples showing the capability and effectiveness of our simulator are also presented.

Induced Seismicity at the UK "Hot Dry Rock" Test Site for Geothermal Energy Production

Science.gov (United States)

Li, Xun; Main, Ian; Jupe, Andrew

2018-03-01

In enhanced geothermal systems (EGS), fluid is injected at high pressure in order to stimulate fracturing and/or fluid flow through otherwise relatively impermeable underlying hot rocks to generate power and/or heat. The stimulation induces micro-earthquakes whose precise triggering mechanism and relationship to new and pre-existing fracture networks are still the subject of some debate. Here we analyse the dataset for induced micro-earthquakes at the UK "hot dry rock" experimental geothermal site (Rosemanowes, Cornwall). We quantify the evolution of several metrics used to characterise induced seismicity, including the seismic strain partition factor and the "seismogenic index". The results show a low strain partition factor of 0.01% and a low seismogenenic index indicating that aseismic processes dominate. We also analyse the spatio-temporal distribution of hypocentres, using simple models for the evolution of hydraulic diffusivity by (a) isotropic and (b) anisotropic pore-pressure relaxation. The principal axes of the diffusivity or permeability tensor inferred from the spatial distribution of earthquake foci are aligned parallel to the present-day stress field, although the maximum permeability is vertical, whereas the maximum principal stress is horizontal. Our results are consistent with a triggering mechanism that involves (a) seismic shear slip along optimally-oriented pre-existing fractures, (b) a large component of aseismic slip with creep (c) activation of tensile fractures as hydraulic conduits created by both the present-day stress field and by the induced shear slip, both exploiting pre-existing joint sets exposed in borehole data.

The Investigation of a Sinkhole Area in Germany by Near-Surface Active Seismic Tomography

Science.gov (United States)

Tschache, S.; Becker, D.; Wadas, S. H.; Polom, U.; Krawczyk, C. M.

2017-12-01

In November 2010, a 30 m wide and 17 m deep sinkhole occurred in a residential area of Schmalkalden, Germany, which fortunately did not harm humans, but led to damage of buildings and property. Subsequent geoscientific investigations showed that the collapse was naturally caused by the subrosion of sulfates in a depth of about 80 m. In 2012, an early warning system was established including 3C borehole geophones deployed in 50 m depth around the backfilled sinkhole. During the acquisition of two shallow 2D shear wave seismic profiles, the signals generated by a micro-vibrator at the surface were additionally recorded by the four borehole geophones of the early warning system and a VSP probe in a fifth borehole. The travel time analysis of the direct arrivals enhanced the understanding of wave propagation in the area. Seismic velocity anomalies were detected and related to structural seismic images of the 2D profiles. Due to the promising first results, the experiment was further extended by distributing vibration points throughout the whole area around the sinkhole. This time, micro-vibrators for P- and S-wave generation were used. The signals were recorded by the borehole geophones and temporary installed seismometers at surface positions close to the boreholes. The travel times and signal attenuations are evaluated to detect potential instable zones. Furthermore, array analyses are performed. The first results reveal features in the active tomography datasets consistent with structures observed in the 2D seismic images. The advantages of the presented method are the low effort and good repeatability due to the permanently installed borehole geophones. It has the potential to determine P-wave and S-wave velocities in 3D. It supports the interpretation of established investigation methods as 2D surface seismics and VSP. In our further research we propose to evaluate the suitability of the method for the time lapse monitoring of changes in the seismic wave

Seismic Barrier Protection of Critical Infrastructure from Earthquakes

Science.gov (United States)

2017-05-01

We observe that such barrier structures reduce seismic wave powers by 10 – 40 dB that would otherwise reach the foundation location. Moreover, the... structure composed of opposing boreholes or trenches to mitigate seismic waves from diffracting and traveling in the vertical plane. Computational...seismic wave propagation models suggest that air or fluid filled subsurface V- shaped muffler structures are critical to the redirection and self

Borehole temperature variability at Hoher Sonnblick, Austria

Science.gov (United States)

Heinrich, Georg; Schöner, Wolfgang; Prinz, Rainer; Pfeiler, Stefan; Reisenhofer, Stefan; Riedl, Claudia

2016-04-01

The overarching aim of the project 'Atmosphere - permafrost relationship in the Austrian Alps - atmospheric extreme events and their relevance for the mean state of the active layer (ATMOperm)' is to improve the understanding of the impacts of atmospheric extreme events on the thermal state of the active layer using a combined measurement and modeling approach as the basis for a long-term monitoring strategy. For this purpose, the Sonnblick Observatory at the summit of Hoher Sonnblick (3106 m.a.s.l) is particularly well-suited due to its comprehensive long-term atmospheric and permafrost monitoring network (i.a. three 20 m deep boreholes since 2007). In ATMOperm, a robust and accurate permanent monitoring of active layer thickness at Hoher Sonnblick will be set up using innovative monitoring approaches by automated electrical resistivity tomography (ERT). The ERT monitoring is further supplemented by additional geophysical measurements such as ground penetrating radar, refraction seismic, electromagnetic induction and transient electromagnetics in order to optimally complement the gained ERT information. On the other hand, atmospheric energy fluxes over permafrost ground and their impact on the thermal state of permafrost and active layer thickness with a particular focus on atmospheric extreme events will be investigated based on physically-based permafrost modeling. For model evaluation, the borehole temperature records will play a key role and, therefore, an in-depth quality control of the borehole temperatures is an important prerequisite. In this study we will show preliminary results regarding the borehole temperature variability at Hoher Sonnblick with focus on the active layer. The borehole temperatures will be related to specific atmospheric conditions using the rich data set of atmospheric measurements of the site in order to detect potential errors in the borehole temperature measurements. Furthermore, we will evaluate the potential of filling gaps in

Study of observed microearthquakes at Masada Deep Borehole

Science.gov (United States)

Hofstetter, A.; Malin, P. E.

2017-12-01

Seismological measurements, conducted at great depths of several hundred of meters or even a few km, can provide useful information that one cannot get while conducting the measurements on the surface. We take advantage of Masada Deep borehole (MDBI), an abandoned oil well, for the installation of a seismometer at a large depth of 1,256 m (1,516 bsl). The station is located in the near vicinity of the East Masada fault, part of the Western Boundary Fault of the Dead Sea basin. We present seismic observations of microearthquakes which occurred along the Dead Sea fault (DSF). Many of them were not recorded by the Israel Seismic Network (ISN). The quiet site of the station has an obvious advantage in detection and identification of earthquakes and explosions. For example, the station detects about 30% more quarry explosions as compared to observations of the ISN. We demonstrate that borehole seismograms are clearer than the on-surface observations of nearby seismometer. We lowered the magnitude scale of observed events down to about M≈-3. Many of the earthquakes, sometimes clusters, occurred underneath the MDBI at depths of 10-25 km, having special signature. Using the cross-correlation technique we present several series of seismic activity either underneath the station or along the DSF. Frequency-magnitude relationship, known also as Gutenberg-Richter relationship, is somewhat higher than the determined value for the whole Dead Sea Fault.

Shallow velocity model in the area of Pozzo Pitarrone, Mt. Etna, from single station, array methods and borehole data

Directory of Open Access Journals (Sweden)

Luciano Zuccarello

2016-09-01

Full Text Available Seismic noise recorded by a temporary array installed around Pozzo Pitarrone, NE flank of Mt. Etna, have been analysed with several techniques. Single station HVSR method and SPAC array method have been applied to stationary seismic noise to investigate the local shallow structure. The inversion of dispersion curves produced a shear wave velocity model of the area reliable down to depth of about 130 m. A comparison of such model with the stratigraphic information available for the investigated area shows a good qualitative agreement. Taking advantage of a borehole station installed at 130 m depth, we could estimate also the P-wave velocity by comparing the borehole recordings of local earthquakes with the same event recorded at surface. Further insight on the P-wave velocity in the upper 130 m layer comes from the surface reflected wave observable in some cases at the borehole station. From this analysis we obtained an average P-wave velocity of about 1.2 km/s, compatible with the shear wave velocity found from the analysis of seismic noise.

Hydraulic fracture monitoring in hard rock at 410 m depth with an advanced fluid-injection protocol and extensive sensor array

Science.gov (United States)

Zang, Arno; Stephansson, Ove; Stenberg, Leif; Plenkers, Katrin; Specht, Sebastian; Milkereit, Claus; Schill, Eva; Kwiatek, Grzegorz; Dresen, Georg; Zimmermann, Günter; Dahm, Torsten; Weber, Michael

2017-02-01

In this paper, an underground experiment at the Äspö Hard Rock Laboratory (HRL) is described. Main goal is optimizing geothermal heat exchange in crystalline rock mass at depth by multistage hydraulic fracturing with minimal impact on the environment, that is, seismic events. For this, three arrays with acoustic emission, microseismicity and electromagnetic sensors are installed mapping hydraulic fracture initiation and growth. Fractures are driven by three different water injection schemes (continuous, progressive and pulse pressurization). After a brief review of hydraulic fracture operations in crystalline rock mass at mine scale, the site geology and the stress conditions at Äspö HRL are described. Then, the continuous, single-flow rate and alternative, multiple-flow rate fracture breakdown tests in a horizontal borehole at depth level 410 m are described together with the monitoring networks and sensitivity. Monitoring results include the primary catalogue of acoustic emission hypocentres obtained from four hydraulic fractures with the in situ trigger and localizing network. The continuous versus alternative water injection schemes are discussed in terms of the fracture breakdown pressure, the fracture pattern from impression packer result and the monitoring at the arrays. An example of multistage hydraulic fracturing with several phases of opening and closing of fracture walls is evaluated using data from acoustic emissions, seismic broad-band recordings and electromagnetic signal response. Based on our limited amount of in situ tests (six) and evaluation of three tests in Ävrö granodiorite, in the multiple-flow rate test with progressively increasing target pressure, the acoustic emission activity starts at a later stage in the fracturing process compared to the conventional fracturing case with continuous water injection. In tendency, also the total number and magnitude of acoustic events are found to be smaller in the progressive treatment with

Seismic Energy Generation and Partitioning into Various Regional Phases from Different Seismic Sources in the Middle East Region

Science.gov (United States)

2007-09-20

a), a 3C SP seismic station (b) and a sensor BlastMateIII, Oron quarry (c)............................... 9 Figure 7. Seismic Array MMAI (AS49) of... seismic stations of Jordan network at distance range 22-285 km (a), and at IMS array MMAI (AS49) at 350 km, BP filtered 2-8 Hz (b...sites and portable stations, inserts show detailed location of the tripartite array elements (st.6) and configuration of the explosion boreholes and

Preliminary stratigraphic and hydrogeologic cross sections and seismic profile of the Floridan aquifer system of Broward County, Florida

Science.gov (United States)

Reese, Ronald S.; Cunningham, Kevin J.

2013-01-01

To help water-resource managers evaluate the Floridan aquifer system (FAS) as an alternative water supply, the U.S. Geological Survey initiated a study, in cooperation with the Broward County Environmental Protection and Growth Management Department, to refine the hydrogeologic framework of the FAS in the eastern part of Broward County. This report presents three preliminary cross sections illustrating stratigraphy and hydrogeology in eastern Broward County as well as an interpreted seismic profile along one of the cross sections. Marker horizons were identified using borehole geophysical data and were initially used to perform well-to-well correlation. Core sample data were integrated with the borehole geophysical data to support stratigraphic and hydrogeologic interpretations of marker horizons. Stratigraphic and hydrogeologic units were correlated across the county using borehole geophysical data from multiple wells. Seismic-reflection data were collected along the Hillsboro Canal. Borehole geophysical data were used to identify and correlate hydrogeologic units in the seismic-reflection profile. Faults and collapse structures that intersect hydrogeologic units were also identified in the seismic profile. The information provided in the cross sections and the seismic profile is preliminary and subject to revision.

A Site Characterization Protocol for Evaluating the Potential for Triggered or Induced Seismicity Resulting from Wastewater Injection and Hydraulic Fracturing

Science.gov (United States)

Walters, R. J.; Zoback, M. D.; Gupta, A.; Baker, J.; Beroza, G. C.

2014-12-01

Regulatory and governmental agencies, individual companies and industry groups and others have recently proposed, or are developing, guidelines aimed at reducing the risk associated with earthquakes triggered by waste water injection or hydraulic fracturing. While there are a number of elements common to the guidelines proposed, not surprisingly, there are also some significant differences among them and, in a number of cases, important considerations that are not addressed. The goal of this work is to develop a comprehensive protocol for site characterization based on a rigorous scientific understanding of the responsible processes. Topics addressed will include the geologic setting (emphasizing faults that might be affected), historical seismicity, hydraulic characterization of injection and adjacent intervals, geomechanical characterization to identify potentially active faults, plans for seismic monitoring and reporting, plans for monitoring and reporting injection (pressure, volumes, and rates), other factors contributing to risk (potentially affected population centers, structures, and facilities), and implementing a modified Probabilistic Seismic Hazard Analysis (PSHA). The guidelines will be risk based and adaptable, rather than prescriptive, for a proposed activity and region of interest. They will be goal oriented and will rely, to the degree possible, on established best practice procedures, referring to existing procedures and recommendations. By developing a risk-based site characterization protocol, we hope to contribute to the development of rational and effective measures for reducing the risk posed by activities that potentially trigger earthquakes.

Anomalous fluid emission of a deep borehole in a seismically active area of Northern Apennines (Italy)

International Nuclear Information System (INIS)

Heinicke, J.; Italiano, F.; Koch, U.; Martinelli, G.; Telesca, L.

2010-01-01

The Miano borehole, 1047 m deep, is located close to the river Parma in the Northern Apennines, Italy. A measuring station has been installed to observe the discharge of fluids continuously since November 2004. The upwelling fluid of this artesian well is a mixture of thermal water and CH 4 as main components. In non-seismogenic areas, a relatively constant fluid emission would be expected, perhaps overlaid with long term variations from that kind of deep reservoir over time. However, the continuous record of the fluid emission, in particular the water discharge, the gas flow rate and the water temperature, show periods of stable values interrupted by anomalous periods of fluctuations in the recorded parameters. The anomalous variations of these parameters are of low amplitude in comparison to the total values but significant in their long-term trend. Meteorological effects due to rain and barometric pressure were not detected in recorded data probably due to reservoir depth and relatively high reservoir overpressure. Influences due to the ambient temperature after the discharge were evaluated by statistical analysis. Our results suggest that recorded changes in fluid emission parameters can be interpreted as a mixing process of different fluid components at depth by variations in pore pressure as a result of seismogenic stress variation. Local seismicity was analyzed in comparison to the fluid physico-chemical data. The analysis supports the idea that an influence on fluid transport conditions due to geodynamic processes exists. Water temperature data show frequent anomalies probably connected with possible precursory phenomena of local seismic events.

A hydraulic test device for free-flowing artesian boreholes with a ...

African Journals Online (AJOL)

Accurate parameter estimation for aquifers is very challenging, particularly for artesian aquifers in which the potentiometric surface is above ground level. A common approach to parameter estimation for artesian aquifers is to make use of free-flowing and recovery tests. However, such aquifer tests on artesian boreholes are ...

Seismic Barrier Protection of Critical Infrastructure

Science.gov (United States)

2017-05-14

structures , earthquake mitigation I. Introduction Damage caused by earthquakes to critical structures such as nuclear power plants, regional hospitals...the seismic power drop in dB to magnitude drop using the seismic moment magnitude scale, Mw. In figures 5 and 6, the V-trench structure as modeled...representing geological media and V-shaped muffler borehole / trench component structures . Bottom: In this simple analysis, the power drop observed

Artificial Water Reservoir Triggered Earthquakes at Koyna, India: Completion of the 3 km deep Pilot Borehole

Science.gov (United States)

Gupta, H. K.; Tiwari, V. M.; Satyanarayana, H.; Roy, S.; Arora, K.; Patro, P. K.; Shashidhar, D.; Mallika, K.; Akkiraju, V.; Misra, S.; Goswami, D.; Podugu, N.; Mishra, S.

2017-12-01

Koyna, near the west coast of India is the most prominent site of artificial water reservoir triggered seismicity (RTS). Soon after the impoundment of the Koyna Dam in 1962, RTS was observed. It has continued till now. It includes the largest RTS earthquake M 6.3 on December 10, 1967; 22 M≥5.0, and thousands of smaller earthquakes. The entire earthquake activity is limited to an area of about 30 km x 20 km, with most focal depths being within 6 km. There is no other earthquake source within 50 km of the Koyna Dam. An ICDP Workshop held in March 2011 found Koyna to be the most suitable site to investigate reservoir- triggered seismicity (RTS) through deep drilling. Studies carried out in the preparatory phase since 2011 include airborne magnetic and gravity-gradient surveys, MT surveys, drilling of 9 boreholes going to depths of 1500 m and logging, heat flow measurements, seismological investigations including the deployment of six borehole seismometers, and LiDAR. The Second ICDP Workshop held during 16- 18 May 2014, reviewed the progress made and detailed planning of putting the borehole observatory was discussed. The site of a 3 km deep pilot borehole was debated and among the 5 possible location. Based on the seismic activity and logistics the location of the first Pilot Borehole has been finalized and the drilling started on the 21st December 2016. The 3000 m deep borehole was completed on 11th June 2017. The basement was touched at 1247 m depth and there were no sediments below basalt. Several zones with immense fluid losses were encountered. Geophysical Logging has been completed. Cores were recovered from 1269, 1892 and 2091 depths. The cores are 9 m long and with 4 inches diameter. The core recovery is almost 100%. In-situ stress measurements have been conducted at depths of 1600 m onwards.

Gas injection test in a borehole of the Meuse/Haute Marne underground research laboratory: experimental overview and basic data analysis

International Nuclear Information System (INIS)

La Vaissiere, Remi de; Talandier, Jean; Piedevache, Mederic; Helmlinger, Benjamin; Lavanchy, Jean-Marc; Croise, Jean; Senger, Rainer

2012-01-01

Document available in extended abstract form only. Understanding of the fate and of the impact of gas produced by corrosion of metals, microbial degradation and the radiolysis of water within a deep geological disposal repository for radioactive waste, is of major relevance in the performance assessment including the long-term evolution of the repository. To address these issues, the French national Agency for the management of radioactive waste (Andra) has directed a field scale experiment examining the mechanisms controlling gas entry and gas migration in the Callovo-Oxfordian (COX) clay, the proposed host rock of the French deep geological repository project. This experiment, called PGZ1, studies the migration of nitrogen in the COX based on gas injection tests performed in a borehole of the Meuse/Haute Marne URL. This experiment is currently being performed under the auspices of the Euratom 7. Framework FORGE project. In this poster, we provide an overview on the field data and a basic analysis of the data. The advanced interpretation of the data was based on numerical modeling of the two-phase flow with 3 different approaches and numerical codes. The experimental layout consists of three boreholes. Two parallel boreholes (PGZ1201 and PGZ1202) were drilled from the GED drift and are equipped with a triple interval system to monitor the pressure evolutions in 3 intervals, associated with the hydraulic and gas injection tests in the selected test interval (PGZ1201, middle interval). The third borehole (PGZ1031) was drilled from the GEX drift and is equipped with an extensometer probe, to monitor potential deformation associated with the resulting stress changes. An initial hydraulic test (HYDRO1) was performed in the test interval to estimate the hydraulic conductivity of the COX prior to gas testing. The hydraulic test consisted in a sequence of injections of synthetic formation water (pressure pulse followed by a constant pressure and a final shut-in phase

Borehole geophysical investigations of Lavia deep testhole, Finland

International Nuclear Information System (INIS)

Saksa, Pauli

1985-02-01

According to the Goverment's decision in principle in 1983 Industrial Power Company Ltd (TVO) is making preparations for all the steps of final disposal of the spent fuel produced by its power plants. Before the actual site investigation phase, TVO drilled a deep borehole in Lavia, Western Finland. The borehole is used during 1984-85 for testing investigation techniques and methods used for bedrock characterization. Borehole geophysical loggings performed in Lavia consisted of galvanic electrical, transient electromagnetic, radiometric, temperature, seismic and magnetic msurements. This composite survey provided both lithological and structural information of rock mass. The neutron-neutron, density, natural gamma radiation and susceptibility methods characterized rock type. Fracturing and its type could be interpreted most effectively with resistivity, acoustic P-wave velocity and density logs. Temperature and tube-wave measurements revealed several fractured zones related to possible water flow in rock. Lavia investigations indicated that a high quality of instrumentation and careful calibration are necessary for site investigations. The large amount of log data also requires efficient data collection and processing systems both in the field and laboratory. (author)

Applicability estimation of flowmeter logging for detecting hydraulic pass

International Nuclear Information System (INIS)

Miyakawa, Kimio; Tanaka, Yasuji; Tanaka, Kazuhiro

1997-01-01

Estimation of the hydraulic pass governing hydrogeological structure contributes significantly to the siting HLW repository. Flowmeter logging can detect hydraulic passes by measuring vertical flow velocity of groundwater in the borehole. We reviewed application of this logging in situ. The hydraulic pass was detected with combination of ambient flow logging, with pumping and/or injecting induced flow logging. This application showed that the flowmeter logging detected hydraulic passes conveniently and accurately compared with other hydraulic tests. Hydraulic conductivity by using flowmeter logging was assessed above 10 -6 m/sec and within one order from comparison with injection packer tests. We suggest that appropriate application of the flowmeter logging for the siting is conducted before hydraulic tests because test sections and monitoring sections are decided rationally for procurement of quantitative hydraulic data. (author)

NNWSI [Nevada Nuclear Waste Storage Investigations] 51 seismic hole histories

International Nuclear Information System (INIS)

1987-09-01

This report is a compilation of data from fifty-one shallow boreholes drilled within the Nevada Test Site (NTS) and the adjacent Bureau of Land Management (BLM) lands. The boreholes were drilled to determine the alluvial thickness and subsurface structure. Once drilled the boreholes were used to emplace explosive charges of three seismic refraction surveys conducted in 1981, 1983 and 1984. The information presented in this report includes location maps, daily activities and reviews of hole condition

Observations of mechanical-hydraulic-geochemical interactions due to drainage of a surface water reservoir in Switzerland

Science.gov (United States)

Lunn, R. J.; Kinali, M.; Pytharouli, S.; Shipton, Z.; Stillings, M.; Lord, R.

2016-12-01

The drainage and refilling of a surface water reservoir beside the Grimsel Test Site (GTS) underground rock laboratory in Switzerland, has provided a unique opportunity to study in-situ rock mechanical, hydraulic and chemical interactions under large-scale stress changes. The reservoir was drained in October/November 2014 to enable dam maintenance and extension of the regional hydropower tunnel system. Reservoir drainage will have caused rapid unloading of the surrounding rock mass. The GTS sits 37m below the top of the reservoir and 200-600m away laterally within the mountainside on the eastern bank of the reservoir. Gradual refilling of the reservoir, via natural snowmelt and runoff, commenced in February 2015. As part of the European LASMO Project, researchers at Strathclyde, funded by Radioactive Waste Management Ltd., have been investigating mechanical-chemical-hydraulic coupling within the rock mass as an analogue for glacial unloading and loading of a future Geological Disposal Facility. We have deployed three 3-component and 6 single-component micro-seismometers within the GTS and surrounding hydropower tunnel network. In parallel, we have implemented a groundwater sampling programme, using boreholes within the GTS, for temporal determination of geochemistry and flow rate. Preliminary data analyses show geochemical anomalies during unloading, as well as detection of microseismic events. The signal-to-noise ratio of the micro-seismic data is extremely poor. Noise amplitude, and frequency content, variy throughout each day, between days, and from month-to-month on a highly unpredictable basis. This is probably due to the multitude of hydropower turbines and pump-storage systems within the surrounding mountains. To discriminate micro-seismic events, we have developed a new methodology for characterizing background noise within the seismic signal and combined this with cross-correlations techniques generally applied in microseismic analysis of hydraulic

Working program for deep borehole investigations. HDB-6,7,8, borehole

International Nuclear Information System (INIS)

Hama, Katsuhiro; Takahashi, Kazuharu; Ishii, Eiichi; Takeuchi, Ryuji; Sasaki, Manabu; Kunimaru, Takanori; Eki, Nobuhiro; Matsui, Hiroya

2003-08-01

optimized program for deep borehole (HDB-6, 7, 8) investigations has been drawn-up. This program addresses the general issues and provides input to the subsequent investigation programs and design for the shaft and experimental drifts. This document mainly describes the planned working program for the HDB-6, 7, 8 borehole investigations including associated laboratory programs during and after drilling. The working program is divided into the following investigation fields: borehole drilling geology, geophysics, hydrogeology, hydrochemistry, rock mechanics and long-term monitoring. Post-HDB borehole investigations; a VSP (Vertical Seismic Profiling) survey are planned in the surface-based investigations phase. (author)

Deep Downhole Seismic Testing at the Waste Treatment Plant Site, Hanford, WA. Volume IV S-Wave Measurements in Borehole C4993 Seismic Records, Wave-Arrival Identifications and Interpreted S-Wave Velocity Profile.

Energy Technology Data Exchange (ETDEWEB)

Stokoe, Kenneth H.; Li, Song Cheng; Cox, Brady R.; Menq, Farn-Yuh

2007-06-06

In this volume (IV), all S-wave measurements are presented that were performed in Borehole C4993 at the Waste Treatment Plant (WTP) with T-Rex as the seismic source and the Lawrence Berkeley National Laboratory (LBNL) 3-D wireline geophone as the at-depth borehole receiver. S-wave measurements were performed over the depth range of 370 to 1300 ft, typically in 10-ft intervals. However, in some interbeds, 5-ft depth intervals were used, while below about 1200 ft, depth intervals of 20 ft were used. Shear (S) waves were generated by moving the base plate of T-Rex for a given number of cycles at a fixed frequency as discussed in Section 2. This process was repeated so that signal averaging in the time domain was performed using 3 to about 15 averages, with 5 averages typically used. In addition, a second average shear wave record was recorded by reversing the polarity of the motion of the T-Rex base plate. In this sense, all the signals recorded in the field were averaged signals. In all cases, the base plate was moving perpendicular to a radial line between the base plate and the borehole which is in and out of the plane of the figure shown in Figure 1.1. The definition of “in-line”, “cross-line”, “forward”, and “reversed” directions in items 2 and 3 of Section 2 was based on the moving direction of the base plate. In addition to the LBNL 3-D geophone, called the lower receiver herein, a 3-D geophone from Redpath Geophysics was fixed at a depth of 22 ft in Borehole C4993, and a 3-D geophone from the University of Texas (UT) was embedded near the borehole at about 1.5 ft below the ground surface. The Redpath geophone and the UT geophone were properly aligned so that one of the horizontal components in each geophone was aligned with the direction of horizontal shaking of the T-Rex base plate. This volume is organized into 12 sections as follows. Section 1: Introduction, Section 2: Explanation of Terminology, Section 3: Vs Profile at Borehole C4993

Development of a Lunar Borehole Seismometer

Science.gov (United States)

Passmore, P. R.; Siegler, M.; Malin, P. E.; Passmore, K.; Zacny, K.; Avenson, B.; Weber, R. C.; Schmerr, N. C.; Nagihara, S.

2017-12-01

Nearly all seismic stations on Earth are buried below the ground. Burial provides controlled temperatures and greater seismic coupling at little cost. This is also true on the Moon and other planetary bodies. Burial of a seismometer under just 1 meter of lunar regolith would provide an isothermal environment and potentially reduce signal scattering noise by an order of magnitude. Here we explain how we will use an existing NASA SBIR and PIDDP funded subsurface heat flow probe deployment system to bury a miniaturized, broadband, optical seismometer 1 meter below the lunar surface. The system is sensitive, low mass and low power. We believe this system offers a compelling architecture for NASA's future seismic exploration of the solar system. We will report on a prototype 3-axis, broadband seismometer package that has been tested under low pressure conditions in lunar-regolith simulant. The deployment mechanism reaches 1m depth in less than 25 seconds. Our designed and tested system: 1) Would be deployed at least 1m below the lunar surface to achieve isothermal conditions without thermal shielding or heaters, increase seismic coupling, and decrease noise. 2) Is small (our prototype probe is a cylinder 50mm in diameter, 36cm long including electronics, potentially as small as 10 cm with sensors only). 3) Is low-mass (each sensor is 0.1 kg, so an extra redundancy 4-component seismograph plus 1.5 kg borehole sonde and recorder weighs less than 2 kg and is feasibly smaller with miniaturized electronics). 4) Is low-power (our complete 3-sensor borehole seismographic system's power consumption is about half a Watt, or 7% of Apollo's 7.1 W average and 30% of the InSight SEIS's 1.5W winter-time heating system). 5) Is broadband and highly sensitive (the "off the shelf" sensors have a wide passband: 0.005-1000 Hz - and high dynamic range of 183 dB (or about 10-9g Hz-1/2, with hopes for simple modifications to be at least an order of magnitude better). Burial also aids the

Automatic inverse methods for the analysis of pulse tests: application to four pulse tests at the Leuggern borehole

International Nuclear Information System (INIS)

Carrera, J.; Samper, J.; Vives, L.; Kuhlmann, U.

1989-07-01

Four pulse tests performed for NAGRA at the Leuggern borehole were analyzed using automatic test sequence matching techniques. Severe identifiability problems were unveiled during the process. Because of these problems, the identifiability of aquifer parameters (hydraulic conductivity, storativity and skin conductivity) from pulse tests similar to those performed in the Leuggern borehole was studied in two synthetic examples. The first of these had a positive skin effect and the second had a negative skin effect. These synthetic examples showed that, for the test conditions at the Leuggern borehole, estimating formation hydraulic conductivity may be nearly impossible for the cases of positive and negative skin factors. In addition, identifiability appears to be quite sensitive to the values of the parameters and to other factors such as skin thickness. Nevertheless, largely because of the manner in which the tests were conducted (i.e. relatively long injection time and performance of both injection and withdrawal), identifiability of the actual tests was much better than suggested by the synthetic examples. Only one of the four tests was nearly nonidentifiable. In all, the match between measured and computed aquifer responses was excellent for all the tests, and formation hydraulic conductivities were estimated within a relatively narrow uncertainty interval. (author) 19 refs., 59 figs., 28 tabs

Hydraulic Properties of Closely Spaced Dipping Open Fractures Intersecting a Fluid-Filled Borehole Derived From Tube Wave Generation and Scattering

Science.gov (United States)

Minato, Shohei; Ghose, Ranajit; Tsuji, Takeshi; Ikeda, Michiharu; Onishi, Kozo

2017-10-01

Fluid-filled fractures and fissures often determine the pathways and volume of fluid movement. They are critically important in crustal seismology and in the exploration of geothermal and hydrocarbon reservoirs. We introduce a model for tube wave scattering and generation at dipping, parallel-wall fractures intersecting a fluid-filled borehole. A new equation reveals the interaction of tube wavefield with multiple, closely spaced fractures, showing that the fracture dip significantly affects the tube waves. Numerical modeling demonstrates the possibility of imaging these fractures using a focusing analysis. The focused traces correspond well with the known fracture density, aperture, and dip angles. Testing the method on a VSP data set obtained at a fault-damaged zone in the Median Tectonic Line, Japan, presents evidences of tube waves being generated and scattered at open fractures and thin cataclasite layers. This finding leads to a new possibility for imaging, characterizing, and monitoring in situ hydraulic properties of dipping fractures using the tube wavefield.

Surface and Subsurface Geodesy Combined with Active Borehole Experimentation for the Advanced Characterization of EGS Reservoirs

Energy Technology Data Exchange (ETDEWEB)

Elsworth, Derek [Pennsylvania State Univ., University Park, PA (United States); Im, Kyungjae [Pennsylvania State Univ., University Park, PA (United States); Guglielmi, Yves [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Mattioli, Glen [Univ. of Texas, Arlington, TX (United States). UNAVCO

2016-11-14

We explore the utility of combining active downhole experimentation with borehole and surface geodesy to determine both the characteristics and evolving state of EGS reservoirs during stimulation through production. The study is divided into two parts. We demonstrate the feasibility of determining in situ reservoir characteristics of reservoir size, strain and fracture permeability and their dependence on feedbacks of stress and temperature using surface and borehole geodetic measurements (Part I). We then define the opportunity to apply the unique hydraulic pulse protocol (HPP) borehole tool to evaluate reservoir state. This can be accomplished by monitoring and co-inverting measured reservoir characteristics (from the HPP tool) with surface geodetic measurements of deformation, tilt and strain with continuous measurements of borehole-wall strain (via optical fiber and fiber Bragg gratings) and measured flow rates (Part II).

Equipment for hydraulic testing

International Nuclear Information System (INIS)

Jacobsson, L.; Norlander, H.

1981-07-01

Hydraulic testing in boreholes is one major task of the hydrogeological program in the Stripa Project. A new testing equipment for this purpose was constructed. It consists of a downhole part and a surface part. The downhole part consists of two packers enclosing two test-sections when inflated; one between the packers and one between the bottom packer and the bottom of the borehole. A probe for downhole electronics is also included in the downhole equipment together with electrical cable and nylon tubing. In order to perform shut-in and pulse tests with high accuracy a surface controlled downhole valve was constructed. The surface equipment consists of the data acquisition system, transducer amplifier and surface gauges. In the report detailed descriptions of each component in the whole testing equipment are given. (Auth.)

Seismic protection

International Nuclear Information System (INIS)

Herbert, R.

1988-01-01

To ensure that a nuclear reactor or other damage-susceptible installation is, so far as possible, tripped and already shut down before the arrival of an earthquake shock at its location, a ring of monitoring seismic sensors is provided around it, each sensor being spaced from it by a distance (possibly several kilometres) such that (taking into account the seismic-shock propagation velocity through the intervening ground) a shock monitored by the sensor and then advancing to the installation site will arrive there later than a warning signal emitted by the sensor and received at the installation, by an interval sufficient to allow the installation to trip and shut down, or otherwise assume an optimum anti-seismic mode, in response to the warning signal. Extra sensors located in boreholes may define effectively a three-dimensional (hemispherical) sensing boundary rather than a mere two-dimensional ring. (author)

Numerical Simulation of Borehole Flow in Deep Monitor Wells, Pearl Harbor Aquifer, Oahu, Hawaii

Science.gov (United States)

Rotzoll, K.; Oki, D. S.; El-Kadi, A. I.

2010-12-01

Salinity profiles collected from uncased deep monitor wells are commonly used to monitor freshwater-lens thickness in coastal aquifers. However, vertical flow in these wells can cause the measured salinity to differ from salinity in the adjacent aquifer. Substantial borehole flow has been observed in uncased wells in the Pearl Harbor aquifer, Oahu, Hawaii. A numerical modeling approach, incorporating aquifer hydraulic characteristics and recharge rates representative of the Pearl Harbor aquifer, was used to evaluate the effects of borehole flow on measured salinity profiles from deep monitor wells. Borehole flow caused by vertical hydraulic gradients associated with the natural regional groundwater-flow system and local groundwater withdrawals was simulated. Model results were used to estimate differences between vertical salinity profiles in deep monitor wells and the adjacent aquifer in areas of downward, horizontal, and upward flow within the regional flow system—for cases with and without nearby pumped wells. Aquifer heterogeneity, represented in the model as layers of contrasting permeability, was incorporated in model scenarios. Results from this study provide insight into the magnitude of the differences between vertical salinity profiles from deep monitor wells and the salinity distributions in the aquifers. These insights are relevant and are critically needed for management and predictive modeling purposes.

Seismic Observations in the Taipei Metropolitan Area Using the Downhole Network

Directory of Open Access Journals (Sweden)

Win-Gee Huang

2010-01-01

Full Text Available Underlain by soft soils, the Taipei Metropolitan Area (TMA experienced major damage due to ground-motion amplification during the Hualien earthquake of 1986, the Chi-Chi earthquake of 1999, the Hualien earthquake of 2002 and the Taitung earthquake of 2003. To study how a local site can substantially change the characteristics of seismic waves as they pass through soft deposits below the free surface, two complementary downhole seismic arrays have been operated in the TMA, since 1991 and 2008. The accelerometer downhole array is composed of eight boreholes at depths in excess of 300 meters. The downhole array velocity sensor collocated with accelerometer composed of four boreholes at depths up to 90 meters. The integrated seismic network monitors potential earthquakes originating from faults in and around the TMA and provides wide-dynamic range measurement of data ranging in amplitude from seismic background noise levels to damage levels as a result of shaking. The data sets can be used to address on the response of soft-soil deposits to ground motions. One of the major considerations is the nonlinear response of soft soil deposits at different levels of excitation. The collocated acceloerometer and velocity sensors at boreholes give the necessary data for studies of non-linearity to be acquired. Such measurements in anticipation of future large, damaging earthquakes will be of special importance for the mitigation of earthquake losses.

Cavola experiment site: geophysical investigations and deployment of a dense seismic array on a landslide

Directory of Open Access Journals (Sweden)

L. Martelli

2007-06-01

Full Text Available Geophysical site investigations have been performed in association with deployment of a dense array of 95 3-component seismometers on the Cavola landslide in the Northern Apennines. The aim of the array is to study propagation of seismic waves in the heterogeneous medium through comparison of observation and modelling. The small-aperture array (130 m×56 m operated continuously for three months in 2004. Cavola landslide consists of a clay body sliding over mudstone-shale basement, and has a record of historical activity, including destruction of a small village in 1960. The site investigations include down-hole logging of P- and S-wave travel times at a new borehole drilled within the array, two seismic refraction lines with both P-wave profiling and surface-wave analyses, geo-electrical profiles and seismic noise measurements. From the different approaches a consistent picture of the depths and seismic velocities for the landslide has emerged. Their estimates agree with resonance frequencies of seismic noise, and also with the logged depths to basement of 25 m at a new borehole and of 44 m at a pre-existing borehole. Velocities for S waves increase with depth, from 230 m/s at the surface to 625 m/s in basement immediately below the landslide.

Evidence for non-self-similarity of microearthquakes recorded at a Taiwan borehole seismometer array

OpenAIRE

Lin, Yen-Yu; Ma, Kuo-Fong; Kanamori, Hiroo; Song, Teh-Ru Alex; Lapusta, Nadia; Tsai, Victor C.

2016-01-01

We investigate the relationship between seismic moment M_0 and source duration t_w of microearthquakes by using high-quality seismic data recorded with a vertical borehole array installed in central Taiwan. We apply a waveform cross-correlation method to the three-component records and identify several event clusters with high waveform similarity, with event magnitudes ranging from 0.3 to 2.0. Three clusters—Clusters A, B and C—contain 11, 8 and 6 events with similar waveforms, respectively. ...

Seismic characterization of fracture properties

International Nuclear Information System (INIS)

Myer, L.R.; Hopkins, D.; Cook, N.G.W.; Pyrak-Nolte, L.J.

1990-01-01

The purpose of this paper is to show that there is a relationship, both empirical and theoretical, between the measured seismic response, the mechanical stiffness (also referred to as specific stiffness) of fractures and their hydraulic conductivity. Laboratory measurements of the mechanical stiffness, hydraulic conductivity and seismic properties of natural fractures are summarized. A theoretical model for the amplitude and group time delay for compressional and shear waves transmitted across a single fracture is presented. Predictions based on this model are compared with laboratory measurements. Finally, the results for a single fracture are extended to multiple parallel fractures. 13 refs., 6 figs

A Novel Method for Borehole Blockage Removal and Experimental Study on a Hydraulic Self-Propelled Nozzle in Underground Coal Mines

Directory of Open Access Journals (Sweden)

Zhaolong Ge

2016-08-01

Full Text Available When coal bed methane (CBM drainage boreholes cross fractured, soft, or water-swelling strata, they collapse and block frequently. Borehole blockages result in a rapid decrease in CBM extraction ability, which leads to a reduction in CBM output and threatens coal mine safety production. To solve these problems, a novel method that uses a self-propelled water-jet nozzle to dredge blocked boreholes in coal seams has been proposed on the basis of the existing technology. Based on a theoretical analysis of the reason for borehole caving and the theory of blockage removal, we optimized the nozzle inlet pressure and selected an appropriate high-pressure resin pipe. A field experiment on the blockage removal of blocked CBM drainage boreholes using the proposed method was run in the Fengchun coal mine, Qijiang, Chongqing, southwest China. In this field trial, the time spent to unblock a borehole varied between 18.52 and 34.98 min, which is much shorter than using a drilling rig. After blockage removal, the average pure volume of the methane drainage of a single borehole was increased from 0.03 L/min to ~1.91–7.30 L/min, and the methane drainage concentration of a single borehole increased from 5% to ~44%–85%. The extraction effect increased significantly.

Recent Earthquakes Mark the Onset of Induced Seismicity in Northeastern Pennsylvania

Science.gov (United States)

Martone, P.; Nikulin, A.; Pietras, J.

2017-12-01

The link between induced seismicity and injection of hydraulic fracturing wastewater has largely been accepted and corroborated through case studies in Colorado, Arkansas, Texas, and Oklahoma. To date, induced seismicity has largely impacted hydrocarbon-producing regions in the Central United States, while the seismic response in Eastern states, like Pennsylvania, has been relatively muted. In recent years, Pennsylvania exponentially increased hydrocarbon production from the Marcellus and Utica Shales and our results indicate that this activity has triggered an onset of induced seismicity in areas of the state where no previous seismic activity was reported. Three recent earthquakes in Northeastern Pennsylvania directly correlate to hydraulic fracturing activity, though USGS NEIC earthquake catalog locations have vertical errors up to 31km. We present signal analysis results of recorded waveforms of the three identified events and results of a high-precision relocation effort and improvements to the regional velocity model aimed at constraining the horizontal and vertical error in hypocenter position. We show that at least one event is positioned directly along the wellbore track of an active well and correlate its timing to the hydraulic fracturing schedule. Results show that in the absence of wastewater disposal in this area, it is possible to confidently make the connection between the hydraulic fracturing process and induced seismicity.

Vertical and horizontal seismic profiling investigations at Olkiluoto, 2001

Energy Technology Data Exchange (ETDEWEB)

Cosma, C.; Enescu, N.; Adam, E.; Balu, L. [Vibrometric Oy (Finland)

2003-03-01

Vertical Seismic Profiling (VSP) and Horizontal Seismic Profiling (HSP) surveys were conducted during 2001 at Olkiluoto site in Eurajoki, Finland. The VSP investigations were carried out in four boreholes with ten shot points for each borehole. Two HSP lines were measured with receivers laid on the bottom of an artificial pond and ten source points located around the pond. Different receiver types were used for the VSP and (HSP) a 3-component geophone chain for VSP and a hydrophone chain for HSP. All surveys have been carried out with a VIBSIST-1000 source - a time- distributed swept-impact source - instead of explosives. With this source, the seismic signals are produced as rapid series of impacts, the impact intervals being monotonically increased to achieve a non- repeatable sequence. The VIBSIST-1000 uses a tractor-mounted hydraulic rock-breaker, powered through a computer controlled servo- hydraulic flow regulator. Using standard construction equipment ensures that the VIBSIST sources are safe, nondestructive and environmentally friendly. This also makes the method reliable and cost effective. The new VIBSIST source produces signals with levels of energy comparable to explosives. The VIBSIST appears to be more stable, but its most significant advantages are the low cost of preparation of the shot points and the speed of the acquisition. The wide diversity of reflection angles, the local variations of reflectivity and, generally, the relatively weak seismic response of faults and fractured zones in crystalline rock demand intensive processing. The first stage of the processing sequence focuses on eliminating such wave-fields as the direct P, direct S, tube-waves and ground-roll, so that the weaker later events, e.g. reflections, become visible. The second stage of processing consists mainly of Image Point (IP) filtering techniques, aimed at enhancing the reflected wave fields and at separating events generated by reflectors with different orientations. Imaging

Drilling and the associated borehole measurements of the pilot hole ONK-PH2

International Nuclear Information System (INIS)

Oehberg, A.; Aaltonen, I.; Kemppainen, K.; Mattila, J.; Heikkinen, E.; Lahti, M.; Pussinen, V.; Niemonen, J.; Paaso, N.; Rouhiainen, P.

2005-11-01

The construction of the ONKALO access tunnel started in September 2004 at Olkiluoto. Most of the investigations related to the construction of the access tunnel aim to ensure successful excavations, reinforcement and sealing. Pilot holes are boreholes, which are core drilled along the tunnel profile. The length of the pilot holes typically varies from several tens of metres to a couple of hundred metres. The pilot holes will mostly aim to confirm the quality of the rock mass for tunnel construction, and in particular at identifying water conductive fractured zones and at providing information that could result in modifications of the existing construction plans. The pilot hole ONK-PH2 was drilled in December 2004. The length of the borehole is about 122 metres. The aim during the drilling work was to orientate core samples as much as possible. The deviation of the borehole was measured during and after the drilling phase. Electric conductivity was measured from the collected returning water samples. Logging of the core samples included the following parameters: lithology, foliation, fracturing, fracture frequency, RQD, fractured zones, core loss and weathering. The rock mechanical logging was based on Q-classification. The tests to determine rock strength and deformation properties were made with a Rock Tester-equipment. Difference Flow method was used for the determination of hydraulic conductivity and hydraulic head in fractures and fractured zones in the borehole. The overlapping i.e. the detailed flow logging mode was used. The flow logging was performed with 0.5 m section length and with 0.1 m depth increments. Geophysical borehole logging and optical imaging surveys of the pilot hole PH2 included the field work of all the surveys, the integration of the data as well as interpretation of the acoustic and borehole radar data. One of the objectives of the geochemical study was to get information of composition of ONKALO's groundwater before the construction will

a Borehole Seismic System for Active and Passive Seimsic Studies to 3 KM at Ptrc's Aquistore Project

Science.gov (United States)

Schmitt, D. R.; Nixon, C.; Kofman, R.; White, D. J.; Worth, K.

2015-12-01

We have constructed a downhole seismic recording system for application to depths of nearly 3 km and temperatures up to 135 °C at Aquistore, an independent research and monitoring project in which liquid CO2 is being stored in a brine and sandstone water formation. The key component to this system is a set of commercially available slim-hole 3-C sondes carrying 15 Hz geophones deployable in open and cased boreholes with diameters as small as 57 mm. The system is currently hosted on a 4-conductor wireline with digital information streamed to the surface recording unit. We have further incorporated these sondes into a mobile passive monitoring unit that includes a number of redundancies such as a multiple Tbyte network accessible RAID hard-drive system (NAS) and a self-designed uninterruptible power supply. The system can be remotely controlled via the internet. The system is currently deployed covering a range of depths from 2850 m to 2910 m. Ambient temperatures at this depth are approximately 110 °C with onboard tool temperatures running at 115 °C. Data is continuously streamed to the NAS for archiving, approximately 11 GBytes of data is recorded per day at the sampling period of 0.5 ms. The lack of noise at this depth allows short data snippets to be flagged with a simple amplitude threshold criteria. The greatly reduced data volume of the snippets allows for ready access via the internet to the system for ongoing quality control. Spurious events, mostly small amplitude tube waves originating at or near the surface, are readily discounted. Active seismic measurements are carried out simultaneously but these require that an appropriately accurate independent GPS based time synchronization be used. Various experiences with event detection, orientation of sondes using both explosives and seismic vibrator, potential overheating of the surface electronics, and issues related to loss of shore power provide for a detailed case study. Aquistore, managed by the

The induced earthquake sequence related to the St. Gallen deep geothermal project (Switzerland): Fault reactivation and fluid interactions imaged by microseismicity

Science.gov (United States)

Diehl, T.; Kraft, T.; Kissling, E.; Wiemer, S.

2017-09-01

In July 2013, a sequence of more than 340 earthquakes was induced by reservoir stimulations and well-control procedures following a gas kick at a deep geothermal drilling project close to the city of St. Gallen, Switzerland. The sequence culminated in an ML 3.5 earthquake, which was felt within 10-15 km from the epicenter. High-quality earthquake locations and 3-D reflection seismic data acquired in the St. Gallen project provide a unique data set, which allows high-resolution studies of earthquake triggering related to the injection of fluids into macroscopic fault zones. In this study, we present a high-precision earthquake catalog of the induced sequence. Absolute locations are constrained by a coupled hypocenter-velocity inversion, and subsequent double-difference relocations image the geometry of the ML 3.5 rupture and resolve the spatiotemporal evolution of seismicity. A joint interpretation of earthquake and seismic data shows that the majority of the seismicity occurred in the pre-Mesozoic basement, hundreds of meters below the borehole and the targeted Mesozoic sequence. We propose a hydraulic connectivity between the reactivated fault and the borehole, likely through faults mapped by seismic data. Despite the excellent quality of the seismic data, the association of seismicity with mapped faults remains ambiguous. In summary, our results document that the actual hydraulic properties of a fault system and hydraulic connections between its fault segments are complex and may not be predictable upfront. Incomplete knowledge of fault structures and stress heterogeneities within highly complex fault systems additionally challenge the degree of predictability of induced seismicity related to underground fluid injections.

PBO Borehole Strainmeters and Pore Pressure Sensors: Recording Hydrological Strain Signals

Science.gov (United States)

Gottlieb, M. H.; Hodgkinson, K. M.; Mencin, D.; Henderson, D. B.; Johnson, W.; Van Boskirk, E.; Pyatt, C.; Mattioli, G. S.

2017-12-01

UNAVCO operates a network of 75 borehole strainmeters along the west coast of the United States and Vancouver Island, Canada as part of the Plate Boundary Observatory (PBO), the geodetic component of the NSF-funded Earthscope program. Borehole strainmeters are designed to detect variations in the strain field at the nanostrain level and can easily detect transient strains caused by aseismic creep events, Episodic Tremor and Slip (ETS) events and seismically induced co- and post-seimic signals. In 2016, one strainmeter was installed in an Oklahoma oil field to characterize in-situ deformation during CO2 injection. Twenty-three strainmeter sites also have pore pressure sensors to measure fluctuations in groundwater pressure. Both the strainmeter network and the pore pressure sensors provide unique data against which those using water-level measurements, GPS time-series or InSAR data can compare possible subsidence signals caused by groundwater withdrawal or fluid re-injection. Operating for 12 years, the PBO strainmeter and pore pressure network provides a long-term, continuous, 1-sps record of deformation. PBO deploys GTSM21 tensor strainmeters from GTSM Technologies, which consist of four horizontal strain gauges stacked vertically, at different orientations, within a single 2 m-long instrument. The strainmeters are typically installed at depths of 200 to 250 m and grouted into the bottom of 15 cm diameter boreholes. The pore pressure sensors are Digiquartz Depth Sensors from Paros Scientific. These sensors are installed in 2" PVC, sampling groundwater through a screened section 15 m above the co-located strainmeter. These sensors are also recording at 1-sps with a resolution in the hundredths of hPa. High-rate local barometric pressure data and low-rate rainfall data also available at all locations. PBO Strainmeter and pore pressure data are available in SEED, SAC-ASCII and time-stamped ASCII format from the IRIS Data Managements Center. Strainmeter data are

Traveltime and waveform tomography analysis of synthetic borehole seismic data based on the CO2SINK project site, Germany

Science.gov (United States)

Yang, Can; Fan, Wenfang; Juhlin, Christopher

2010-05-01

Time lapse analysis of seismic data is very important for CO2 storage projects. Therefore, we have tested traveltime and waveform tomography methods to detect velocity changes in a CO2 injection reservoir using synthetic time lapse data. The structural model tested is based on the CO2SINK injection site at Ketzin, Germany where CO2 is being injected at about 630-650 m into a saline aquifer. First, we created synthetic time lapse moving source profiling (MSP) data, also known as walkaway profiling. The velocity model used for modeling was based on well logging and lithological information in the injection borehole. Gassmann fluid substitution was used to calculate the reservoir velocity after injection. In this substitution, we assumed a saturation of CO2 of 30%. The model velocity of the reservoir changed from 2750 m/s (before injection) to 2150 m/s (after injection). A 2D finite difference code available in Seismic Unix (www.cwp.mines.edu) was used. 60 source points were distributed along a surface line. The distance from the injection well was between 150m and 858m, with an interval of 12m. We recorded 21 channels at receiver depths from 470m to 670m, with an interval of 10m. The injection layer was assumed to be between 629m and 650m depth. The wavelet used for the synthetic data was a Gaussian derivative with an average frequency of 60Hz. Then first arrivals were picked on both data sets and used as input data for traveltime tomography. For traveltime tomography, the PS_tomo program was used. Since no data were recorded above 470m, the initial velocity model used above this depth was the true velocity model. Below 470m, the initial velocity model increases linearly from 3000m/s to 3250m/s. After inversion, the reservoir velocity and an anhydrite layer (high velocity layer) can be seen clearly in the final inverted velocity models. Using these velocity models as starting models, we performed waveform tomography in the frequency domain using a program supplied by

Instrument Correction and Dynamic Site Profile Validation at the Central United States Seismic Observatory, New Madrid Seismic Zone

Science.gov (United States)

Brengman, C.; Woolery, E. W.; Wang, Z.; Carpenter, S.

2016-12-01

The Central United States Seismic Observatory (CUSSO) is a vertical seismic array located in southwestern Kentucky within the New Madrid seismic zone. It is intended to describe the effects of local geology, including thick sediment overburden, on seismic-wave propagation, particularly strong-motion. The three-borehole array at CUSSO is composed of seismic sensors placed on the surface, and in the bedrock at various depths within the 585 m thick sediment overburden. The array's deep borehole provided a unique opportunity in the northern Mississippi embayment for the direct geological description and geophysical measurement of the complete late Cretaceous-Quaternary sediment column. A seven layer, intra-sediment velocity model is interpreted from the complex, inhomogeneous stratigraphy. The S- and P-wave sediment velocities range between 160 and 875 m/s and between 1000 and 2300 m/s, respectively, with bedrock velocities of 1452 and 3775 m/s, respectively. Cross-correlation and direct comparisons were used to filter out the instrument response and determine the instrument orientation, making CUSSO data ready for analysis, and making CUSSO a viable calibration site for other free-field sensors in the area. The corrected bedrock motions were numerically propagated through the CUSSO soil profile (transfer function) and compared, in terms of both peak acceleration and amplitude spectra, to the recorded surface observations. Initial observations reveal a complex spectral mix of amplification and de-amplification across the array, indicating the site effect in this deep sediment setting is not simply generated by the shallowest layers.

The 1996-2009 borehole dilatometer installations, operation, and maintenance at sites in Long Valley Caldera, CA

Science.gov (United States)

Myren, Glenn; Johnston, Malcolm; Mueller, Robert

2011-01-01

High seismicity levels with accelerating uplift (under the resurgent dome) in Long Valley caldera in the eastern Sierra Nevada from 1989 to 1997, triggered upgrades to dilational strainmeters and other instrumentation installed in the early 1980's following a series of magnitude 6 earthquakes. This included two additional high-resolution borehole strainmeters and replacement of the failed strainmeter at Devil's Postpile. The purpose of the borehole-monitoring network is to monitor crustal deformation and other geophysical parameters associated with volcanic intrusions and earthquakes in the Long Valley Caldera. Additional instrumentation was added at these sites to improve the capability of providing continuous monitoring of the magma source under the resurgent dome. Sites were selected in regions of hard crystalline rock, where the expected signals from magmatic activity were calculated to be a maximum and the probability of an earthquake of magnitude 4 or greater is large. For the most part, the dilatometers were installed near existing arrays of surface tiltmeters, seismometers, level line, and GPS arrays. At each site, attempts are made to separate tectonic and volcanic signals from known noise sources in each instrument type. Each of these sites was planned to be a multi-parameter monitoring site, which included measurements of 3-component seismic velocity and acceleration, borehole strain, tilt, pore pressure and magnetic field. Using seismicity, geophysical knowledge, geologic and topographic maps, and geologists recommendations, lists of preliminary sites were chosen. Additional requirements were access, and telemetry constraints. When the final site choice was made, a permit was obtained from the U.S. Forest Service. Following this selection process, two new borehole sites were installed on the north and south side of the Long Valley Caldera in June of 1999. One site was located near Big Spring Campground to the east of Crestview. The second site was

The hydraulic properties of fracture zones and tracer tests with non-reactive elements in Studsvik

International Nuclear Information System (INIS)

Klockars, C.-E.; Persson, O.; Landstroem, O.

1982-04-01

Tracer technique was applied in a rock formation within the Studsvik Energiteknik area in order to study hydrodynamic properties of discrete fracture zones between boreholes. The two hole method was applied in these studies; a nonreactive tracer is injected in one hole into a fracture zone which is in hydraulic contact with a central pump hole (observation hole). Hydraulic tests and TV inspection were carried out in the fracture zones. Chemical composition of the groundwater was determined. In summary, the following hydraulic properties were found for the fracture zones between the boreholes B1N-B6N and B5N-B6N respectively, under the prevailing conditions: 1) The fracture zones studied consists of a number of transport pathways with different mean transit times, varying from 100 to 1200 hours. 2) The fracture zone between boreholes B1N and B6N has a mean hydraulic conductivity of 6-7 x 10 -5 m/s and the fracture zone between boreholes B5N and B6N, 2 x 10 -4 m/s. 3) The kinematic porosity of the fracture zones studied, calculated as the ratio between the hydraulic conductivity of the rock mass and that of the fracture zone, is 2 x 10 -3 and 5 x 10 -3 , respectively. 4) The roughness factor β, which expresses the ratio between measured and theoretically calculated (plane-parallel) fracture conductivity for the fracture zones studied, is approximately 0.04 and 0.06, respectively. 5) Dispersivity for the flow channels within the fracture zones is of the order of 0.3-0.8 m. 6) The groundwater encountered is a nearly neutral, probably reducing, Na-Ca-HCO 3 water. The results of the tracer tests reveal the following: I-131 is a suitable nonreactive tracer for the test area. A test with simultaneous injection of I-131 and T (tritium) gave comparable breakthrough curves. (Author)

Fracture distribution determined by borehole TV in the vicinity of the Koongarra uranium ore field and predictable groundwater flow

International Nuclear Information System (INIS)

Miyakawa, Kimio; Tanaka, Yasuharu

1996-01-01

To contribute good understanding of geo-hydrogeological structure in and around the Koongarra uranium deposit, the borehole TV logging and the three dimensional groundwater flow analysis were conducted. The results of the borehole TV measurement showed directional trends in the schistosity represented folds which were the most characteristic structure in the site scale. This fold structure was in accord with the directional trends in fracture and fracture frequency, and the axes of the interference test drawdown. The three dimensional groundwater flow analysis was taken into account the hydraulic anisotropy which derived from the assumption that the direction normal to schistosity agree with minimum hydraulic conductivity. The result of analysis showed that directions of ground water flow agreed with drawdown axes, and the conceptual model of hydrogeological structure governed the site scale fold was verified. (author)

Optical seismic sensor systems and methods

Science.gov (United States)

Beal, A. Craig; Cummings, Malcolm E.; Zavriyev, Anton; Christensen, Caleb A.; Lee, Keun

2015-12-08

Disclosed is an optical seismic sensor system for measuring seismic events in a geological formation, including a surface unit for generating and processing an optical signal, and a sensor device optically connected to the surface unit for receiving the optical signal over an optical conduit. The sensor device includes at least one sensor head for sensing a seismic disturbance from at least one direction during a deployment of the sensor device within a borehole of the geological formation. The sensor head includes a frame and a reference mass attached to the frame via at least one flexure, such that movement of the reference mass relative to the frame is constrained to a single predetermined path.

Magnitude and Peak Amplitude Relationship for Microseismicity Induced by a Hydraulic Fracture Experiment

Science.gov (United States)

Smith, T.; Arce, A. C.; Ji, C.

2016-12-01

Waveform cross-correlation technique is widely used to improve the detection of small magnitude events induced by hydraulic fracturing. However, when events are detected, assigning a reliable magnitude is a challenging task, especially considering their small signal amplitude and high background noise during injections. In this study, we adopt the Match & Locate algorithm (M&L, Zhang and Wen, 2015) to analyze seven hours of continuous seismic observations from a hydraulic fracturing experiment in Central California. The site of the stimulated region is only 300-400m away from a 16-receiver vertical-borehole array which spans 230 m. The sampling rate is 4000 Hz. Both the injection sites and borehole array are more than 1.7 km below the surface. This dataset has previously been studied by an industry group, producing a catalog of 1134 events with moment magnitudes (Mw) ranging from -3.1 to -0.9. In this study, we select 202 events from this catalog with high signal to noise ratios to use as templates. Our M&L analysis produces a new catalog that contains 2119 events, which is 10 times more detections than the number of templates and about two times the original catalog. Using these two catalogs, we investigate the relationship of moment magnitude difference (ΔMW) and local magnitude difference (ΔML) between the detected event and corresponding template event. ΔML is computed using the peak amplitude ratio between the detected and template event for each channel. Our analysis yields an empirical relationship of ΔMW=0.64-0.65ΔML with an R2 of 0.99. The coefficient of 2/3 suggests that the information of the event's corner frequency is entirely lost (Hanks and Boore, 1984). The cause might not be unique, which implies that Earth's attenuation at this depth range (>1.7 km) is significant; or the 4000 Hz sampling rate is not sufficient. This relationship is crucial to estimate the b-value of the microseismicity induced by hydraulic fracture experiments. The analysis

Determination of Groundwater Velocity and Dispersion Parameters by Borehole Wall Multielectrode Geoelectrics

Science.gov (United States)

Kessels, W.; Wuttke, M. W.

2007-05-01

A single well technique to determine groundwater flow values and transport parameters is presented. Multielectrode arrays are placed at the filtered casing depth by an inflatable packer or are installed on the borehole wall behind the casing.Tracer water with a higher or lower specific electrical conductivity (salinity) which is injected between the electrodes. This tracer plume then moves into the natural groundwater flow field. The observation of this movement by geoelectric logging enables the determination of the groundwater velocity and salinity. The transport parameters "effective porosity" and "dispersion length" can also be derived. The geoelectric logging uses n borehole electrodes and two grounding electrodes. Thus, either n independent two point measurements or n*(n-1)/2 pole-to-pole measurements can be conducted to obtain a full set of geoelectric measurements. This set is used to derive all electrode combinations by applying the law of superposition and reciprocity. The tracer distribution around the borehole during and after injection depends on the hydraulic and transport parameters of the aquifer and the filter sand. The transport parameter "porosity" plus the total injected tracer volume determines the tracer distribution around the borehole. The transport parameter "dispersivity" determines the abruptness of the tracer front. The method was tested by undertaking measurements in a lab aquifer filled with sand. The results are discussed and the limitations of the method are shown. Multielectrode installations behind casing were tested in situ in the two scientific boreholes CAT-LUD-1 and CAT- LUD-1A drilled in the northern part of Germany. A multielectrode packer system was designed, built and tested in these boreholes. The results are compared with colloid observations in the borehole and hydraulic triangulation in surrounded observation wells. Here, the interpretation of these in situ measurements is mainly restricted to two point geoelectric

Uemachi flexure zone investigated by borehole database and numeical simulation

Science.gov (United States)

Inoue, N.; Kitada, N.; Takemura, K.

2014-12-01

The Uemachi fault zone extending north and south, locates in the center of the Osaka City, in Japan. The Uemachi fault is a blind reverse fault and forms the flexure zone. The effects of the Uemachi flexure zone are considered in constructing of lifelines and buildings. In this region, the geomorphological survey is difficult because of the regression of transgression. Many organizations have carried out investigations of fault structures. Various surveys have been conducted, such as seismic reflection survey in and around Osaka. Many borehole data for construction conformations have been collected and the geotechnical borehole database has been constructed. The investigation with several geological borehole data provides the subsurface geological information to the geotechnical borehole database. Various numerical simulations have been carried out to investigate the growth of a blind reverse fault in unconsolidated sediments. The displacement of the basement was given in two ways. One is based on the fault movement, such as dislocation model, the other is a movement of basement block of hanging wall. The Drucker-Prager and elastic model were used for the sediment and basement, respectively. The simulation with low and high angle fault movements, show the good agree with the actual distribution of the marine clay inferred from borehole data in the northern and southern Uemachi fault flexure zone, respectively. This research is partly funded by the Comprehensive Research on the Uemachi Fault Zone (from FY2010 to FY2012) by The Ministry of Education, Culture, Sports, Science and Technology (MEXT).

Installation of a very broad band borehole seismic station in Ferrara (Emilia)

OpenAIRE

Pesaresi, Damiano; Dall'Olio, Lorella; Rovelli, Antonio; Romanelli, Marco; Barnaba, Carla; Abu Zeid, Nasser

2012-01-01

The Istituto Nazionale di Geofisica e Vulcanologia (INGV) is the Italian agency devoted to monitor in real time the seismicity on the Italian territory. The seismicity in Italy is of course variable in time and space, being also very much dependant on local noise conditions. Specifically, monitoring seismicity in an alluvial basin like the Po one is a challenge, due to consistent site effects induced by soft alluvial deposits and bad coupling with the deep bedrock (Steidl et al., 1996). This...

Measuring the initial earth pressure of granite using hydraulic fracturing test; Goseong and Yuseong areas

Energy Technology Data Exchange (ETDEWEB)

Park, Byoung Yoon; Bae, Dae Seok; Kim, Chun Soo; Kim, Kyung Su; Koh, Young Kwon; Won, Kyung Sik [Korea Atomic Energy Research Institute, Taejeon (Korea)

2002-02-01

This report provides the initial earth pressure of granitic rocks obtained from Deep Core Drilling Program which is carried out as part of the assessment of deep geological environmental condition. These data are obtained by hydraulic fracturing test in three boreholes drilled up to 350{approx}500 m depth at the Yuseong and Goseong sites. These sites were selected based on the result of preliminary site evaluation study. The boreholes are NX-size (76 mm) and vertical. The procedure of hydraulic fracturing test is as follows: - Selecting the testing positions by preliminary investigation using BHTV logging. - Performing the hydraulic fracturing test at each selected position with depth.- Estimating the shut-in pressure by the bilinear pressure-decay-rate method. - Estimating the fracture reopening pressure from the pressure-time curves.- Estimating the horizontal principal stresses and the direction of principal stresses. 65 refs., 39 figs., 12 tabs. (Author)

Deep Borehole Field Test Laboratory and Borehole Testing Strategy

Energy Technology Data Exchange (ETDEWEB)

Kuhlman, Kristopher L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Brady, Patrick V. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); MacKinnon, Robert J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Heath, Jason E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Herrick, Courtney G. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Jensen, Richard P. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Gardner, W. Payton [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Sevougian, S. David [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bryan, Charles R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Jang, Je-Hun [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Stein, Emily R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bauer, Stephen J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Daley, Tom [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Freifeld, Barry M. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Birkholzer, Jens [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Spane, Frank A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2016-09-19

Deep Borehole Disposal (DBD) of high-level radioactive wastes has been considered an option for geological isolation for many years (Hess et al. 1957). Recent advances in drilling technology have decreased costs and increased reliability for large-diameter (i.e., ≥50 cm [19.7”]) boreholes to depths of several kilometers (Beswick 2008; Beswick et al. 2014). These advances have therefore also increased the feasibility of the DBD concept (Brady et al. 2009; Cornwall 2015), and the current field test design will demonstrate the DBD concept and these advances. The US Department of Energy (DOE) Strategy for the Management and Disposal of Used Nuclear Fuel and High-Level Radioactive Waste (DOE 2013) specifically recommended developing a research and development plan for DBD. DOE sought input or expression of interest from States, local communities, individuals, private groups, academia, or any other stakeholders willing to host a Deep Borehole Field Test (DBFT). The DBFT includes drilling two boreholes nominally 200m [656’] apart to approximately 5 km [16,400’] total depth, in a region where crystalline basement is expected to begin at less than 2 km depth [6,560’]. The characterization borehole (CB) is the smaller-diameter borehole (i.e., 21.6 cm [8.5”] diameter at total depth), and will be drilled first. The geologic, hydrogeologic, geochemical, geomechanical and thermal testing will take place in the CB. The field test borehole (FTB) is the larger-diameter borehole (i.e., 43.2 cm [17”] diameter at total depth). Surface handling and borehole emplacement of test package will be demonstrated using the FTB to evaluate engineering feasibility and safety of disposal operations (SNL 2016).

Passive seismic monitoring of natural and induced earthquakes: case studies, future directions and socio-economic relevance

Science.gov (United States)

Bohnhoff, Marco; Dresen, Georg; Ellsworth, William L.; Ito, Hisao; Cloetingh, Sierd; Negendank, Jörg

2010-01-01

An important discovery in crustal mechanics has been that the Earth’s crust is commonly stressed close to failure, even in tectonically quiet areas. As a result, small natural or man-made perturbations to the local stress field may trigger earthquakes. To understand these processes, Passive Seismic Monitoring (PSM) with seismometer arrays is a widely used technique that has been successfully applied to study seismicity at different magnitude levels ranging from acoustic emissions generated in the laboratory under controlled conditions, to seismicity induced by hydraulic stimulations in geological reservoirs, and up to great earthquakes occurring along plate boundaries. In all these environments the appropriate deployment of seismic sensors, i.e., directly on the rock sample, at the earth’s surface or in boreholes close to the seismic sources allows for the detection and location of brittle failure processes at sufficiently low magnitude-detection threshold and with adequate spatial resolution for further analysis. One principal aim is to develop an improved understanding of the physical processes occurring at the seismic source and their relationship to the host geologic environment. In this paper we review selected case studies and future directions of PSM efforts across a wide range of scales and environments. These include induced failure within small rock samples, hydrocarbon reservoirs, and natural seismicity at convergent and transform plate boundaries. Each example represents a milestone with regard to bridging the gap between laboratory-scale experiments under controlled boundary conditions and large-scale field studies. The common motivation for all studies is to refine the understanding of how earthquakes nucleate, how they proceed and how they interact in space and time. This is of special relevance at the larger end of the magnitude scale, i.e., for large devastating earthquakes due to their severe socio-economic impact.

Rock stress measurements in the deep boreholes at Kuhmo, Hyrynsalmi, Sievi, Eurajoki and Konginkangas

International Nuclear Information System (INIS)

Klasson, H.; Leijon, B.

1990-11-01

Hydraulic fracturing rock stress measurements, conducted in five boreholes are presented. The boreholes are located in different site investigation areas in Finland: Kuhmo-Romuvaara, Hyrynsalmi-Veitsivaara, Sievi-Syyry, Eurajoki-Olkiluoto and Konginkangas-Kivetty. The aim of the measurements was to provide rock stress data, forming input to the site selection process for an underground facility for disposal of high level radioactive waste from the Olkiluoto Nuclear Power Plant. A summary is given of the theoretical background to the hydrofracturing method, whilst the equipment and experimental procedures used in the present case are described in more detail. All results obtained are presented and subjected to critical discussion. The final stress parameters evaluated are magnitudes and directions of the maximum and minimum horizontal stresses. Testing was successfully completed according to the clan at Syyry, Olkiluoto and Kivetty. Testing was partly successful at Romuvaara but unsuccessful in the borehole at Veitsivaara

Horonobe Underground Research Laboratory project overview of the pilot borehole investigation of the ventilation shaft (PB-V01). Hydrogeological investigation

International Nuclear Information System (INIS)

Yabuuchi, Satoshi; Kunimaru, Takanori; Ishii, Eiichi; Hatsuyama, Yoshihiro; Ijiri, Yuji; Matsuoka, Kiyoyuki; Ibara, Tetsuo; Matsunami, Shinjiro; Makino, Akiya

2009-02-01

The Pilot Borehole Investigation of the Ventilation Shaft was conducted in Horonobe, Hokkaido, Japan from October 2007 to March 2008. Main purpose of the investigation is to understand geological, hydrogeological and hydrochemical properties of the formation where the Ventilation Shaft has been excavated. Hydraulic packer tests show that hydraulic conductivity lies in the range from 1.1E-11 to 1.4E-7 m/sec down to 500m in depth. This heterogeneity mainly depends on the distribution and permeability of groundwater inflow points, which were detected by Fluid Electric Conductivity logging. High conductive zones were found between 263m and 290m, 355m and 370m of the depth in the pilot borehole. An effective method for reducing groundwater inflow should be considered for the deeper Ventilation Shaft excavation. (author)

Continuous recording of seismic signals in Alpine permafrost

Science.gov (United States)

Hausmann, H.; Krainer, K.; Staudinger, M.; Brückl, E.

2009-04-01

three different types of applications. It enabled fast and efficient field work and provided excellent seismic data at two permafrost sites. At Krummgampen Valley (Ötztal Alps, Tyrol) 13 seismic profiles were measured at altitudes ranging from 2400 to 2900 m to assess information on the permafrost occurrences. At the crest of Hoher Sonnblick (3106 m, Hohe Tauern, Salzburg) seismic signals were recorded on 15 borehole geophones deployed in three 20 m deep boreholes for the application of seismic tomography and passive monitoring of rock falls.

穿层孔吞吐压裂水力强化抽采技术研究及应用%Research and application of gas drainage with hydraulic reinforcement of water stimulation fracture in borehole through strata

Institute of Scientific and Technical Information of China (English)

辛新平; 高建良; 马耕

2014-01-01

为了解决低透气性煤层高效抽采的难题，采用穿层孔吞吐压裂水力强化改善煤层透气性。分析了水力强化工艺穿层孔瓦斯运移产出过程，研究了水力强化对硬煤储层和软煤层中瓦斯渗透率的影响，分析了水力强化对煤体渗透率的作用及增透机理，并进行了现场效果应用。结果表明：穿层孔吞吐压裂技术提高了煤层透气性，形成瓦斯产出通道，在硬煤中水力强化可在顶底板形成“虚拟储层”，瓦斯以渗流为主，软煤中以扩散运移为主；吞吐压裂水力强化通过形成洞穴和裂隙，增加煤层渗透性，减少瓦斯抽采流量衰减系数，提高瓦斯抽采效率。现场实施吞吐压裂水力措施后抽采纯量由14.8 m³增加至31.9~42.8 m³；抽采体积分数由14.1%增加至73.9%~77.5%，该技术具有较高的实际推广应用价值。%In order to solve the problem of how to efficiently extract the coal seam with low permeabil-ity, the hydraulic measures of stimulation fracturing through strata borehole has been adopted to im-prove the permeability of coal seam. The gas migration process through borehole in the hydraulic en-hanced technology has been analyzed. The effect of hydraulic reinforcement measures on hard and soft coal seam permeability has been studied, and the effect and mechanism of hydraulic reinforcement on the permeability of coal mass has been analyzed, and finally, the field experiment of hydraulic fracturing has been carried out. Research results show that the hydraulic measures of stimulation fracturing through strata borehole technology can improve the permeability of coal seam and contribute to form gas flow channel. There is“virtual reservoir”in roof and floor in hard coal seam and the gas shows see-page mainly, while, in soft coal seam gas shows diffusion migration mainly. The hydraulic measures of stimulation fracturing can increase the permeability of coal seam through

An overview of the MIZ-1 borehole investigations during phase I/II. MIZ-1 progress report 03-01

International Nuclear Information System (INIS)

Ota, Kunio; Takeuchi, Shinji; Ikeda, Koki

2004-05-01

Surface-based investigations have now been carried out, in a step-by-step fashion, with the main aims of the development of conceptual models of the geological environment and the enhancement of the understanding of the undisturbed deep geological environment before excavation of the shafts and experimental drifts. The MIZ-1 borehole investigation programme was launched in December 2002, as a step of the field investigations at the MIU Construction Site. The overall goals of the MIZ-1 borehole investigations are to characterise the geological environment from the surface to over 1,000 m depth in the crystalline basement, to establish baseline conditions before excavation of the shafts and experimental drifts, and to provide a deep borehole for observing hydraulic responses during the shaft and drift excavation and experiments in the drifts during the Construction and the Operation Phases. The borehole is planned to be drilled in an overall south-westerly direction from the north-eastern area of the MIU Site. The planned inclination varies from vertical at shallower depths to 12deg from vertical at greater depths down to 1,350 m along the borehole length, which will be achieved by controlled directional drilling. In MIZ-1 Phase I/II (from March to May 2003), the borehole was drilled vertically, through the entire sedimentary formations, down to 123.00 m in the uppermost part of the Toki granite at the MIU Construction Site. The new method of wireline core drilling with a downhole motor was introduced for the drilling. Planned geological, geophysical and hydrochemical investigations and complementary hydraulic and hydrochemical monitoring were performed. In addition, as a complete loss of drilling fluid was encountered at 115.85 m along the borehole length, modified work procedures resulted in the execution of hydraulic tests with groundwater sampling, from necessity, in that section and of further drilling work. The local QC system was applied to all the

Determination of hydraulic characteristics of an aquifer capacity from ...

African Journals Online (AJOL)

Constant rate, single well pumping tests were conducted using boreholes located in four communities in the study area with the aim of determining the aquifer hydraulic properties using the Cooper Jacob method. Fractured shales yielded groundwater into the wells whose depths ranged from 26 to 35m while the static water ...

Characterisation of the hydraulic properties within the EDZ around drifts at level -490 m of the Meuse/Haute-Marne URL: A methodology for consistent interpretation of hydraulic tests

Science.gov (United States)

Baechler, S.; Lavanchy, J. M.; Armand, G.; Cruchaudet, M.

In order to investigate potential changes of the hydraulic properties of the EDZ over time in the Meuse/Haute-Marne underground research laboratory (URL), several hydraulic tests campaigns have been carried out between 2005 and 2008 in dedicated boreholes. After several test series, inconsistencies were noticed in the results, indicating, in particular cases, erratic, inexplicable property changes over time and spatial contrasts. It was therefore difficult to determine reliably potential trends of the EDZ hydraulic properties. It appeared necessary to re-evaluate both the interpretation concepts and assumptions applied to the numerical analyses of test data on the EDZ, trying to better constrain the flow model and the parameter variables. In order to improve the understanding of the geometrical, geomechanical and hydraulic properties of the EDZ, independent information from other investigation methods has been used to critically revise the conceptual model and formation parameters. In particular, results from a diffusion experiment and ultrasonic measurements allowed constraining the extent of the mechanical damaged zone around the borehole (BDZ). Storativity parameters were fitted due to their expected variability. Indeed, high storativity values can be presumed under the unsaturated conditions of the EDZ. The results of the reanalyses, performed with the numerical borehole simulator MULTISIM, demonstrated the good quality and consistency of the revised conceptual model with constrained BDZ and variable storativity. Overall the new simulation results obtained from selected test series are now very consistent. The revised conceptual model demonstrated its capacity to better represent the evolution and extension of the EDZ around a drift in Meuse/Haute-Marne URL. Further consistency checks are proposed to confirm the new model assumptions and the estimates of the single phase flow model in the EDZ.

Characterisation of the hydraulic properties within the EDZ around drifts at level -490 m of the Meuse/Haute-Marne URL: A methodology for consistent interpretation of hydraulic tests

International Nuclear Information System (INIS)

Baechler, S.; Lavanchy, J. M.; Armand, G.; Cruchaudet, M.

2011-01-01

In order to investigate potential changes of the hydraulic properties of the EDZ over time in the Meuse/Haute-Marne underground research laboratory (URL), several hydraulic tests campaigns have been carried out between 2005 and 2008 in dedicated boreholes. After several test series, inconsistencies were noticed in the results, indicating, in particular cases, erratic, inexplicable property changes over time and spatial contrasts. It was therefore difficult to determine reliably potential trends of the EDZ hydraulic properties. It appeared necessary to re-evaluate both the interpretation concepts and assumptions applied to the numerical analyses of test data on the EDZ, trying to better constrain the flow model and the parameter variables. In order to improve the understanding of the geometrical, geomechanical and hydraulic properties of the EDZ, independent information from other investigation methods has been used to critically revise the conceptual model and formation parameters. In particular, results from a diffusion experiment and ultrasonic measurements allowed constraining the extent of the mechanical damaged zone around the borehole (BDZ). Storativity parameters were fitted due to their expected variability. Indeed, high storativity values can be presumed under the unsaturated conditions of the EDZ. The results of the reanalyses, performed with the numerical borehole simulator MULTISIM, demonstrated the good quality and consistency of the revised conceptual model with constrained BDZ and variable storativity. Overall the new simulation results obtained from selected test series are now very consistent. The revised conceptual model demonstrated its capacity to better represent the evolution and extension of the EDZ around a drift in Meuse/Haute-Marne URL. Further consistency checks are proposed to confirm the new model assumptions and the estimates of the single phase flow model in the EDZ. (authors)

Seismic anisotropy in the vicinity of the Alpine fault, New Zealand, estimated by seismic interferometry

Science.gov (United States)

Takagi, R.; Okada, T.; Yoshida, K.; Townend, J.; Boese, C. M.; Baratin, L. M.; Chamberlain, C. J.; Savage, M. K.

2016-12-01

We estimate shear wave velocity anisotropy in shallow crust near the Alpine fault using seismic interferometry of borehole vertical arrays. We utilized four borehole observations: two sensors are deployed in two boreholes of the Deep Fault Drilling Project in the hanging wall side, and the other two sites are located in the footwall side. Surface sensors deployed just above each borehole are used to make vertical arrays. Crosscorrelating rotated horizontal seismograms observed by the borehole and surface sensors, we extracted polarized shear waves propagating from the bottom to the surface of each borehole. The extracted shear waves show polarization angle dependence of travel time, indicating shear wave anisotropy between the two sensors. In the hanging wall side, the estimated fast shear wave directions are parallel to the Alpine fault. Strong anisotropy of 20% is observed at the site within 100 m from the Alpine fault. The hanging wall consists of mylonite and schist characterized by fault parallel foliation. In addition, an acoustic borehole imaging reveals fractures parallel to the Alpine fault. The fault parallel anisotropy suggest structural anisotropy is predominant in the hanging wall, demonstrating consistency of geological and seismological observations. In the footwall side, on the other hand, the angle between the fast direction and the strike of the Alpine fault is 33-40 degrees. Since the footwall is composed of granitoid that may not have planar structure, stress induced anisotropy is possibly predominant. The direction of maximum horizontal stress (SHmax) estimated by focal mechanisms of regional earthquakes is 55 degrees of the Alpine fault. Possible interpretation of the difference between the fast direction and SHmax direction is depth rotation of stress field near the Alpine fault. Similar depth rotation of stress field is also observed in the SAFOD borehole at the San Andreas fault.

Borehole radar applied to the characterization of hydraulically conductive fracture zones in crystalline rock

International Nuclear Information System (INIS)

Olsson, O.; Falk, L.; Forslund, O.; Lundmark, L.; Sandberg, E.

1992-01-01

This paper discusses the borehole radar system, RAMAC, developed within the framework of the International Stripa Project, which can be used in three different measuring modes; single-hole reflection, cross-hole reflection and cross-hole tomography. The reflection modes basically provide geometrical data on features located at some distance from the borehole. In addition the strength of the reflections indicate the contrast in electrical properties. Single-hole reflection data are cylindrically symmetrical with respect to the borehole, which means that a unique fracture orientation cannot be obtained. A method has been devised where absolute orientation of fracture zones is obtained by combining single-hole reflection data from adjacent holes. Similar methods for the analysis of cross-hole reflection data have also been developed and found to be efficient. The radar operates in the frequency range 20-60 MHz which gives a resolution of 1-3 m in crystalline rock. The investigation range obtained in the Stripa granite is approximately 100 m in the single-hole mode and 200-300 m in the cross-hole model. Variations in the arrival time and amplitude of the direct wave between transmitter and receiver have been used for cross-hole tomographic imaging to yield maps of radar velocity and attenuation. The cross-hole measurement configuration coupled with tomographic inversion has less resolution than the reflection methods but provides better quantitative estimates of the values of measured properties. The analysis of the radar data has provided a consistent description of the fracture zones at the Stripa Cross-hole site in agreement with both geological and geophysical observations

Hydrogeological Characteristics of Fractured Rocks around the In-DEBS Test Borehole at the Underground Research Facility (KURT)

Science.gov (United States)

Ko, Nak-Youl; Kim, Geon Young; Kim, Kyung-Su

2016-04-01

In the concept of the deep geological disposal of radioactive wastes, canisters including high-level wastes are surrounded by engineered barrier, mainly composed of bentonite, and emplaced in disposal holes drilled in deep intact rocks. The heat from the high-level radioactive wastes and groundwater inflow can influence on the robustness of the canister and engineered barrier, and will be possible to fail the canister. Therefore, thermal-hydrological-mechanical (T-H-M) modeling for the condition of the disposal holes is necessary to secure the safety of the deep geological disposal. In order to understand the T-H-M coupling phenomena at the subsurface field condition, "In-DEBS (In-Situ Demonstration of Engineered Barrier System)" has been designed and implemented in the underground research facility, KURT (KAERI Underground Research Tunnel) in Korea. For selecting a suitable position of In-DEBS test and obtaining hydrological data to be used in T-H-M modeling as well as groundwater flow simulation around the test site, the fractured rock aquifer including the research modules of KURT was investigated through the in-situ tests at six boreholes. From the measured data and results of hydraulic tests, the range of hydraulic conductivity of each interval in the boreholes is about 10-7-10-8 m/s and that of influx is about 10-4-10-1 L/min for NX boreholes, which is expected to be equal to about 0.1-40 L/min for the In-DEBS test borehole (diameter of 860 mm). The test position was determined by the data and availability of some equipment for installing In-DEBS in the test borehole. The mapping for the wall of test borehole and the measurements of groundwater influx at the leaking locations was carried out. These hydrological data in the test site will be used as input of the T-H-M modeling for simulating In-DEBS test.

Seismic Prediction While Drilling (SPWD: Looking Ahead of the Drill Bit by Application of Phased Array Technology

Directory of Open Access Journals (Sweden)

Marco Groh

2010-04-01

Full Text Available Geophysical exploration is indispensable for planning deep drilling. Usually 2D- or 3D-seismics investigations are applied and, depending on the resulting geologic model for the underground, the drill site and drilling path are determined. In recent years the focus of exploration has shifted towards small-scale geological structures such as local layers and faults. Depending on the source frequencies and the target depth, 2D- or 3D-seismics from surface cannot always resolve such structures in particular at larger depths. In general, signal frequencies of about 30–70 Hz are typical for surface seismic methods. The deeper and smaller the sought-after structures are, the worse will be the resolution. Therefore, borehole seismic measurements like Vertical Seismic Profile (VSP or Seismic While Drilling (SWD have been developed (Fig. 1. For the VSP method geophones are normally integrated in the borehole, while the seismicsource generates seismic waves at the surface. The SWD method uses the drill bit as the seismic source. Hence, the quality of the seismic signals is highly dependent on the drilled rock and the type of drill bit, but even well-suited rock conditions and adequate drilling may not provide sufficient data quality.

Hydraulic fracturing rock stress measurement at Haestholmen, Finland

International Nuclear Information System (INIS)

Ljunggren, C.; Klasson, H.

1992-12-01

This report presents hydraulic fracturing measurements in two boreholes located on the Haestholmen island near Loviisa, Finland. The aim of the measurements was to provide stress data, forming input for the design of an underground facility for disposal of low- and medium-level waste as well as future plant decommissioning radioactive waste from the IVO reactor units situated on Haestholmen. The theoretical background to the hydrofracturing method is summarized, as is the equipment and experimental procedures used in the present case. All results obtained are presented and critically discussed. The final stress parameters presented are magnitudes and directions of the maximum and minimum horizontal stresses. Testing was successfully completed according to schedule in both boreholes.(orig.)

Characterization of deep-seated rock masses by means of borehole investigation

International Nuclear Information System (INIS)

1982-04-01

Swedish State Power Board. The main objective of the programme was to test a method of measuring in-situ rock stresses in the deep, water-filled boreholes and to correlate measured rock stresses with the hydraulic and geological properties of the rock mass. The investigations consist of the following activities: - Coredrillin of two main boreholes with a depth of 500 m and 250 m respectively. - Rock stress measurements at 11 and 9 main levels in the boreholes respectively. At each level at least 3 complete measurements were made. - Logging of the cores with respect to rock type, fractures and fracture characteristics. - Water injection tests in the boreholes. The rock mass investigated is composed of a gneiss granite of Svecocarelian age (1500 Ma), with inclusions of younger pegmatites and greenstones of variable ages. The fracture density is as a mean 2 fractures per meter with a marked decrease in frequency with increased depth. The fractures are generally coated with calcite and chlorite as the dominating coating minerals. For the rock stress measurements, the method of Leeman and Hayes was chosen. The result show that there is a very high stress level in the rock mass, recordings of about 70 MPa were taken below a horizontal fracture zone at 320 m depth. In this lower rock masses the high stresses were also illustrated by intense disking of the hollow core which made measurements impossible in large sections of the boreholes. Water injection tests were performed, mainly as double-packer tests alon the entire boreholes. For the evaluation, both stationary and transient calculation theories were used and the results show a good agreement. The hyddraulic conductivities of the rock mass vary from below 10 -10 m/s up to 10 -7 m/s. The conductivity decreases with depth, though there are zones even at great depth with high conductivity. (Author)

Analysis of aquifer tests conducted in borehole USW G-2, 1996, Yucca Mountain, Nevada

International Nuclear Information System (INIS)

O'Brien, G.M.

1998-01-01

Borehole USW G-2 is located north of Yucca Mountain in a large-hydraulic-gradient area. Two single-borehole aquifer tests were conducted in the borehole during 1996. A 54.9-hour pumping period was conducted February 6--8, 1996, and a 408-hour pumping period was conducted April 8--25, 1996. The purpose of testing was to obtain estimates of the aquifer-system transmissivity and to determine if perched water was affecting the observed water level in borehole USW G-2. This report presents and analyzes data collected between February 6 and December 17, 1996. Analysis of the aquifer-test data indicated that fracture flow, dual-porosity flow, and boundary-affected flow conditions were observed in the drawdown and recovery data. Transmissivity estimates ranged from 2.3 to 12 meters squared per day. The most representative transmissivity estimate for the interval tested is the early-time mean transmissivity of 9.4 meters squared per day. The Calico Hills Formation was the primary formation tested, but the top 3 meters of the nonpumping water column was within the overlying Topopah Spring Tuff. Persistent residual drawdown following pumping more than 6 million liters of water during aquifer testing may indicate that the bore-hole intersected a perched water body. After 236 days of recovery, residual drawdown was 0.5 meter. The quantitative effect of the perched water on the observed water level in borehole USW G-2, however, cannot be determined with the available data

High resolution reflection seismic mapping of shallow coal seams

CSIR Research Space (South Africa)

Mngadi, SB

2013-10-01

Full Text Available the extent of the mine workings. Two 94 m profiles (tied to boreholes) were surveyed using a sledgehammer source. Processing was optimized to image the shallow reflections. The refraction seismic models and stacked time sections were compared and integrated...

EGS hydraulic stimulation monitoring by surface arrays - location accuracy and completeness magnitude: the Basel Deep Heat Mining Project case study

Science.gov (United States)

Häge, Martin; Blascheck, Patrick; Joswig, Manfred

2013-01-01

The potential and limits of monitoring induced seismicity by surface-based mini arrays was evaluated for the hydraulic stimulation of the Basel Deep Heat Mining Project. This project aimed at the exploitation of geothermal heat from a depth of about 4,630 m. As reference for our results, a network of borehole stations by Geothermal Explorers Ltd. provided ground truth information. We utilized array processing, sonogram event detection and outlier-resistant, graphical jackknife location procedures to compensate for the decrease in signal-to-noise ratio at the surface. We could correctly resolve the NNW-SSE striking fault plane by relative master event locations. Statistical analysis of our catalog data resulted in M L 0.36 as completeness magnitude, but with significant day-to-night dependency. To compare to the performance of borehole data with M W 0.9 as completeness magnitude, we applied two methods for converting M L to M W which raised our M C to M W in the range of 0.99-1.13. Further, the b value for the duration of our measurement was calculated to 1.14 (related to M L), respectively 1.66 (related to M W), but changes over time could not be resolved from the error bars.

Imaging CO2 reservoirs using muons borehole detectors

Science.gov (United States)

Bonneville, A.; Bonal, N.; Lintereur, A.; Mellors, R. J.; Paulsson, B. N. P.; Rowe, C. A.; Varner, G. S.; Kouzes, R.; Flygare, J.; Mostafanezhad, I.; Yamaoka, J. A. K.; Guardincerri, E.; Chapline, G.

2016-12-01

Monitoring of the post-injection fate of CO2 in subsurface reservoirs is of utmost importance. Generally, monitoring options are active methods, such as 4D seismic reflection or pressure measurements in monitoring wells. We present a method of 4D density tomography of subsurface CO2 reservoirs using cosmic-ray muon detectors deployed in a borehole. Although muon flux rapidly decreases with depth, preliminary analyses indicate that the muon technique is sufficiently sensitive to effectively map density variations caused by fluid displacement at depths consistent with proposed CO2reservoirs. The intensity of the muon flux is, to first order, inversely proportional to the density times the path length, with resolution increasing with measurement time. The primary technical challenge preventing deployment of this technology in subsurface locations is the lack of miniaturized muon-tracking detectors both capable of fitting in standard boreholes and that will be able to resist the harsh underground conditions (temperature, pressure, corrosion) for long periods of time. Such a detector with these capabilities has been developed through a collaboration supported by the U.S. Department of Energy. A prototype has been tested in underground laboratories during 2016. In particular, we will present results from a series of tests performed in a tunnel comparing efficiencies, and angular and position resolution to measurements collected at the same locations by large instruments developed by Los Alamos and Sandia National Laboratories. We will also present the results of simulations of muon detection for various CO2 reservoir situations and muon detector configurations. Finally, to improve imaging of 3D subsurface structures, a combination of seismic data, gravity data, and muons can be used. Because seismic waves, gravity anomalies, and muons are all sensitive to density, the combination of two or three of these measurements promises to be a powerful way to improve spatial

Optimization of Deep Borehole Systems for HLW Disposal

International Nuclear Information System (INIS)

Driscoll, Michael; Baglietto, Emilio; Buongiorno, Jacopo; Lester, Richard; Brady, Patrick; Arnold, B. W.

2015-01-01

This is the final report on a project to update and improve the conceptual design of deep boreholes for high level nuclear waste disposal. The effort was concentrated on application to intact US legacy LWR fuel assemblies, but conducted in a way in which straightforward extension to other waste forms, host rock types and countries was preserved. The reference fuel design version consists of a vertical borehole drilled into granitic bedrock, with the uppermost kilometer serving as a caprock zone containing a diverse and redundant series of plugs. There follows a one to two kilometer waste canister emplacement zone having a hole diameter of approximately 40-50 cm. Individual holes are spaced 200-300 m apart to form a repository field. The choice of verticality and the use of a graphite based mud as filler between the waste canisters and the borehole wall liner was strongly influenced by the expectation that retrievability would continue to be emphasized in US and worldwide repository regulatory criteria. An advanced version was scoped out using zinc alloy cast in place to fill void space inside a disposal canister and its encapsulated fuel assembly. This excludes water and greatly improves both crush resistance and thermal conductivity. However the simpler option of using a sand fill was found adequate and is recommended for near-term use. Thermal-hydraulic modeling of the low permeability and porosity host rock and its small (@@@ 1%) saline water content showed that vertical convection induced by the waste's decay heat should not transport nuclides from the emplacement zone up to the biosphere atop the caprock. First order economic analysis indicated that borehole repositories should be cost-competitive with shallower mined repositories. It is concluded that proceeding with plans to drill a demonstration borehole to confirm expectations, and to carry out priority experiments, such as retention and replenishment of in-hole water is in order.

Optimization of Deep Borehole Systems for HLW Disposal

Energy Technology Data Exchange (ETDEWEB)

Driscoll, Michael [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Baglietto, Emilio [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Buongiorno, Jacopo [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Lester, Richard [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Brady, Patrick [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Arnold, B. W. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2015-09-09

This is the final report on a project to update and improve the conceptual design of deep boreholes for high level nuclear waste disposal. The effort was concentrated on application to intact US legacy LWR fuel assemblies, but conducted in a way in which straightforward extension to other waste forms, host rock types and countries was preserved. The reference fuel design version consists of a vertical borehole drilled into granitic bedrock, with the uppermost kilometer serving as a caprock zone containing a diverse and redundant series of plugs. There follows a one to two kilometer waste canister emplacement zone having a hole diameter of approximately 40-50 cm. Individual holes are spaced 200-300 m apart to form a repository field. The choice of verticality and the use of a graphite based mud as filler between the waste canisters and the borehole wall liner was strongly influenced by the expectation that retrievability would continue to be emphasized in US and worldwide repository regulatory criteria. An advanced version was scoped out using zinc alloy cast in place to fill void space inside a disposal canister and its encapsulated fuel assembly. This excludes water and greatly improves both crush resistance and thermal conductivity. However the simpler option of using a sand fill was found adequate and is recommended for near-term use. Thermal-hydraulic modeling of the low permeability and porosity host rock and its small (≤ 1%) saline water content showed that vertical convection induced by the waste’s decay heat should not transport nuclides from the emplacement zone up to the biosphere atop the caprock. First order economic analysis indicated that borehole repositories should be cost-competitive with shallower mined repositories. It is concluded that proceeding with plans to drill a demonstration borehole to confirm expectations, and to carry out priority experiments, such as retention and replenishment of in-hole water is in order.

Drilling, construction, geophysical log data, and lithologic log for boreholes USGS 142 and USGS 142A, Idaho National Laboratory, Idaho

Science.gov (United States)

Twining, Brian V.; Hodges, Mary K.V.; Schusler, Kyle; Mudge, Christopher

2017-07-27

Starting in 2014, the U.S. Geological Survey in cooperation with the U.S. Department of Energy, drilled and constructed boreholes USGS 142 and USGS 142A for stratigraphic framework analyses and long-term groundwater monitoring of the eastern Snake River Plain aquifer at the Idaho National Laboratory in southeast Idaho. Borehole USGS 142 initially was cored to collect rock and sediment core, then re-drilled to complete construction as a screened water-level monitoring well. Borehole USGS 142A was drilled and constructed as a monitoring well after construction problems with borehole USGS 142 prevented access to upper 100 feet (ft) of the aquifer. Boreholes USGS 142 and USGS 142A are separated by about 30 ft and have similar geology and hydrologic characteristics. Groundwater was first measured near 530 feet below land surface (ft BLS) at both borehole locations. Water levels measured through piezometers, separated by almost 1,200 ft, in borehole USGS 142 indicate upward hydraulic gradients at this location. Following construction and data collection, screened water-level access lines were placed in boreholes USGS 142 and USGS 142A to allow for recurring water level measurements.Borehole USGS 142 was cored continuously, starting at the first basalt contact (about 4.9 ft BLS) to a depth of 1,880 ft BLS. Excluding surface sediment, recovery of basalt, rhyolite, and sediment core at borehole USGS 142 was approximately 89 percent or 1,666 ft of total core recovered. Based on visual inspection of core and geophysical data, material examined from 4.9 to 1,880 ft BLS in borehole USGS 142 consists of approximately 45 basalt flows, 16 significant sediment and (or) sedimentary rock layers, and rhyolite welded tuff. Rhyolite was encountered at approximately 1,396 ft BLS. Sediment layers comprise a large percentage of the borehole between 739 and 1,396 ft BLS with grain sizes ranging from clay and silt to cobble size. Sedimentary rock layers had calcite cement. Basalt flows

Hydraulic properties from pumping tests data of aquifers in Azare ...

African Journals Online (AJOL)

Pumping test data from twelve boreholes in Azare area were analysed to determine the hydraulic properties of the aquifers, and the availability of water to meet the conjugate demands of the increasing population. The values of the aquifer constants obtained from the Cooper-Jacob's non-equilibrium graphical method were ...

Subsea ice-bearing permafrost on the U.S. Beaufort Margin: 2. Borehole constraints

Science.gov (United States)

Ruppel, Carolyn D.; Herman, Bruce M.; Brothers, Laura L.; Hart, Patrick E.

2016-01-01

Borehole logging data from legacy wells directly constrain the contemporary distribution of subsea permafrost in the sedimentary section at discrete locations on the U.S. Beaufort Margin and complement recent regional analyses of exploration seismic data to delineate the permafrost's offshore extent. Most usable borehole data were acquired on a ∼500 km stretch of the margin and within 30 km of the contemporary coastline from north of Lake Teshekpuk to nearly the U.S.-Canada border. Relying primarily on deep resistivity logs that should be largely unaffected by drilling fluids and hole conditions, the analysis reveals the persistence of several hundred vertical meters of ice-bonded permafrost in nearshore wells near Prudhoe Bay and Foggy Island Bay, with less permafrost detected to the east and west. Permafrost is inferred beneath many barrier islands and in some nearshore and lagoonal (back-barrier) wells. The analysis of borehole logs confirms the offshore pattern of ice-bearing subsea permafrost distribution determined based on regional seismic analyses and reveals that ice content generally diminishes with distance from the coastline. Lacking better well distribution, it is not possible to determine the absolute seaward extent of ice-bearing permafrost, nor the distribution of permafrost beneath the present-day continental shelf at the end of the Pleistocene. However, the recovery of gas hydrate from an outer shelf well (Belcher) and previous delineation of a log signature possibly indicating gas hydrate in an inner shelf well (Hammerhead 2) imply that permafrost may once have extended across much of the shelf offshore Camden Bay.

A novel muon detector for borehole density tomography

Science.gov (United States)

Bonneville, Alain; Kouzes, Richard T.; Yamaoka, Jared; Rowe, Charlotte; Guardincerri, Elena; Durham, J. Matthew; Morris, Christopher L.; Poulson, Daniel C.; Plaud-Ramos, Kenie; Morley, Deborah J.; Bacon, Jeffrey D.; Bynes, James; Cercillieux, Julien; Ketter, Chris; Le, Khanh; Mostafanezhad, Isar; Varner, Gary; Flygare, Joshua; Lintereur, Azaree T.

2017-04-01

Muons can be used to image the density of materials through which they pass, including geological structures. Subsurface applications of the technology include tracking fluid migration during injection or production, with increasing concern regarding such timely issues as induced seismicity or chemical leakage into aquifers. Current density monitoring options include gravimetric data collection and active or passive seismic surveys. One alternative, or complement, to these methods is the development of a muon detector that is sufficiently compact and robust for deployment in a borehole. Such a muon detector can enable imaging of density structure to monitor small changes in density - a proxy for fluid migration - at depths up to 1500 m. Such a detector has been developed, and Monte Carlo modeling methods applied to simulate the anticipated detector response. Testing and measurements using a prototype detector in the laboratory and shallow underground laboratory demonstrated robust response. A satisfactory comparison with a large drift tube-based muon detector is also presented.

Proceedings of the 89th (Fall, fiscal 1993) SEGJ (the Society of Exploration Geophysicists of Japan) Conference. Butsuri tansa gakkai dai 89 kai (1993 nendo shuki) gakujutsu koenkai ronbunshu

Energy Technology Data Exchange (ETDEWEB)

1993-10-01

The 89th SEGJ Conference was held during October 12-14, 1993. With relation to the exploration of elastic wave, reported are comparison study on an S/N ratio improvement method for noise in VIBROSEIS exploration, discrimination of the pseudo bright spot by AVO (amplitude versus offset) method in petroleum exploration, cross-adit and cross-well velocity tomography, AE doublet analysis in the hydraulic fracturing experiment on hot dry rock, estimation of crack extension surface, exploration of Aso caldera, seismic exploration ahead of the tunnel face, etc. Borehole televiewer by ultrasonic wave image is also reported. Relating to electrical prospecting, reports are made on simultaneous analysis of resistivity and charging rate, grasp of fluid transfer by SP change in the hydraulic fracturing experiment, synthetic focused resistivity logging using array normal logging equipment, borehole resistivity profiling, etc. Lectures totals 64 including reports further made on migration, refraction method analysis, VSP (vertical seismic profile), ground vibration, gravity/magnetic force/thermal structure, simulation, etc.

Seismic signatures of the Lodgepole fractured reservoir in Utah-Wyoming overthrust belt

Energy Technology Data Exchange (ETDEWEB)

Parra, J.; Collier, H.; Angstman, B.

1997-08-01

In low porosity, low permeability zones, natural fractures are the primary source of permeability which affect both production and injection of fluids. The open fractures do not contribute much to porosity, but they provide an increased drainage network to any porosity. An important approach to characterizing the fracture orientation and fracture permeability of reservoir formations is one based upon the effects of such conditions on the propagation of acoustic and seismic waves in the rock. We present the feasibility of using seismic measurement techniques to map the fracture zones between wells spaced 2400 ft at depths of about 1000 ft. For this purpose we constructed computer models (which include azimuthal anisotropy) using Lodgepole reservoir parameters to predict seismic signatures recorded at the borehole scale, crosswell scale, and 3 D seismic scale. We have integrated well logs with existing 2D surfaces seismic to produce petrophysical and geological cross sections to determine the reservoir parameters and geometry for the computer models. In particular, the model responses are used to evaluate if surface seismic and crosswell seismic measurements can capture the anisotropy due to vertical fractures. Preliminary results suggested that seismic waves transmitted between two wells will propagate in carbonate fracture reservoirs, and the signal can be received above the noise level at the distance of 2400 ft. In addition, the large velocities contrast between the main fracture zone and the underlying unfractured Boundary Ridge Member, suggested that borehole reflection imaging may be appropriate to map and fracture zone thickness variation and fracture distributions in the reservoir.

A multi-scale case study of natural fracture systems in outcrops and boreholes with applications to reservoir modelling

NARCIS (Netherlands)

Taal-van Koppen, J.K.J.

2008-01-01

Fractured reservoirs are notoriously difficult to characterize because the resolution of seismic data is too low to detect fractures whereas borehole data is detailed but sparse. Therefore, outcrops can be of great support in gaining knowledge of the three-dimensional geometry of fracture networks,

Spectral characteristics of seismic noise using data of Kazakhstan monitoring stations

International Nuclear Information System (INIS)

Mikhajlova, N.N.; Komarov, I.I.

2006-01-01

Spectral specifications of seismic noise research for PS23-Makanchi, Karatau, Akbulak, AS057-Borovoye and new three-component station AS059-Aktyubinsk was done. Spectral noise density models were obtained for day and night time and spectral density values variation. Noise close to low-level universal noise model is peculiar for all stations, which provides their high efficiency while seismic monitoring. Noise parameters dependence on seismic receivers installation conditions was investigated separately. Based on three stations (Makanchi, Borovoye, and Aktyubinsk), spectral density change features are shown after borehole equipment installation. (author)

Statistical Analysis and Modelling of Olkiluoto Structures

International Nuclear Information System (INIS)

Hellae, P.; Vaittinen, T.; Saksa, P.; Nummela, J.

2004-11-01

Posiva Oy is carrying out investigations for the disposal of the spent nuclear fuel at the Olkiluoto site in SW Finland. The investigations have focused on the central part of the island. The layout design of the entire repository requires characterization of notably larger areas and must rely at least at the current stage on borehole information from a rather sparse network and on the geophysical soundings providing information outside and between the holes. In this work, the structural data according to the current version of the Olkiluoto bedrock model is analyzed. The bedrock model relies much on the borehole data although results of the seismic surveys and, for example, pumping tests are used in determining the orientation and continuation of the structures. Especially in the analysis, questions related to the frequency of structures and size of the structures are discussed. The structures observed in the boreholes are mainly dipping gently to the southeast. About 9 % of the sample length belongs to structures. The proportion is higher in the upper parts of the rock. The number of fracture and crushed zones seems not to depend greatly on the depth, whereas the hydraulic features concentrate on the depth range above -100 m. Below level -300 m, the hydraulic conductivity occurs in connection of fractured zones. Especially the hydraulic features, but also fracture and crushed zones often occur in groups. The frequency of the structure (area of structures per total volume) is estimated to be of the order of 1/100m. The size of the local structures was estimated by calculating the intersection of the zone to the nearest borehole where the zone has not been detected. Stochastic models using the Fracman software by Golder Associates were generated based on the bedrock model data complemented with the magnetic ground survey data. The seismic surveys (from boreholes KR5, KR13, KR14, and KR19) were used as alternative input data. The generated models were tested by

Hydraulic testing in crystalline rock

International Nuclear Information System (INIS)

Almen, K.E.; Andersson, J.E.; Carlsson, L.; Hansson, K.; Larsson, N.A.

1986-12-01

Swedish Geolocical Company (SGAB) conducted and carried out single-hole hydraulic testing in borehole Fi 6 in the Finnsjoen area of central Sweden. The purpose was to make a comprehensive evaluation of different methods applicable in crystalline rocks and to recommend methods for use in current and scheduled investigations in a range of low hydraulic conductivity rocks. A total of eight different methods of testing were compared using the same equipment. This equipment was thoroughly tested as regards the elasticity of the packers and change in volume of the test section. The use of a hydraulically operated down-hole valve enabled all the tests to be conducted. Twelve different 3-m long sections were tested. The hydraulic conductivity calculated ranged from about 5x10 -14 m/s to 1x10 -6 m/s. The methods used were water injection under constant head and then at a constant rate-of-flow, each of which was followed by a pressure fall-off period. Water loss, pressure pulse, slug and drill stem tests were also performed. Interpretation was carried out using standard transient evaluation methods for flow in porous media. The methods used showed themselves to be best suited to specific conductivity ranges. Among the less time-consuming methods, water loss, slug and drill stem tests usually gave somewhat higher hydraulic conductivity values but still comparable to those obtained using the more time-consuming tests. These latter tests, however, provided supplementary information on hydraulic and physical properties and flow conditions, together with hydraulic conductivity values representing a larger volume of rock. (orig./HP)

Hydraulic fracturing tests in anhydrite interbeds in the WIPP, Marker Beds 139 and 140

Energy Technology Data Exchange (ETDEWEB)

Howard, C L [RE/SPEC Inc., Albuquerque, NM (United States); Wawersik, W. R.; Carlson, L. V.; Henfling, J. A.; Borns, D. J.; Beauheim, R. L.; Roberts, R. M.

1997-05-01

Hydraulic fracturing tests were integrated with hydrologic tests to estimate the conditions under which gas pressure in the disposal rooms in the Waste Isolation Pilot Plant, Carlsbad, NM (WIPP) will initiate and advance fracturing in nearby anhydrite interbeds. The measurements were made in two marker beds in the Salado formation, MB139 and MB140, to explore the consequences of existing excavations for the extrapolation of results to undisturbed ground. The interpretation of these measurements is based on the pressure-time records in two injection boreholes and several nearby hydrologic observation holes. Data interpretations were aided by post-test borehole video surveys of fracture traces that were made visible by ultraviolet illumination of fluorescent dye in the hydraulic fracturing fluid. The conclusions of this report relate to the upper- and lower-bound gas pressures in the WIPP, the paths of hydraulically and gas-driven fractures in MB139 and MB140, the stress states in MB139 and MB140, and the probable in situ stress states in these interbeds in undisturbed ground far away from the WIPP.

Hydraulic shock damper for fuel assemblies of nuclear reactors

International Nuclear Information System (INIS)

Jabson, F.S.

1978-01-01

A typical embodiment of this invention provides a hydraulic mechanism for alleviating the effect of seismic forces and other stresses that are applied to a fuel assembly in a nuclear reactor. Illustratively, hollow guide posts potrude into a fuel assembly end fitting grid from biased spring pads. Plungers that move with the spring pads plug one end of each of the respective guide posts. Plates on the end fitting grid that have individual holes for fluid discharge partially plug the other ends of the respective guide posts, thereby providing a hydraulic means for absorbing the longitudinal component of seismic shocks and other anticipated forces. (Auth.)

Characterizing Hydraulic Properties and Ground-Water Chemistry in Fractured-Rock Aquifers: A User's Manual for the Multifunction Bedrock-Aquifer Transportable Testing Tool (BAT3)

Science.gov (United States)

Shapiro, Allen M.

2007-01-01

A borehole testing apparatus has been designed to isolate discrete intervals of a bedrock borehole and conduct hydraulic tests or collect water samples for geochemical analyses. This borehole testing apparatus, referred to as the Multifunction Bedrock-Aquifer Transportable Testing Tool (BAT3), includes two borehole packers, which when inflated can form a pressure-tight seal against smooth borehole walls; a pump apparatus to withdraw water from between the two packers; a fluid-injection apparatus to inject water between the two packers; pressure transducers to monitor fluid pressure between the two packers, as well as above and below the packers; flowmeters to monitor rates of fluid withdrawal or fluid injection; and data-acquisition equipment to record and store digital records from the pressure transducers and flowmeters. The generic design of this apparatus was originally discussed in United States Patent Number 6,761,062 (Shapiro, 2004). The prototype of the apparatus discussed in this report is designed for boreholes that are approximately 6 inches in diameter and can be used to depths of approximately 300 feet below land surface. The apparatus is designed to fit in five hard plastic boxes that can be shipped by overnight freight car-riers. The equipment can be assembled rapidly once it is removed from the shipping boxes, and the length of the test interval (the distance between the two packers) can be adjusted to account for different borehole conditions without reconfiguring the downhole components. The downhole components of the Multifunction BAT3 can be lowered in a borehole using steel pipe or a cable; a truck mounted winch or a winch and tripod can be used for this purpose. The equipment used to raise and lower the downhole components of the Multifunction BAT3 must be supplied on site, along with electrical power, a compressor or cylinders of compressed gas to inflate the packers and operate downhole valves, and the proper length of tubing to connect the

Effects of the deviation characteristics of nuclear waste emplacement boreholes on borehole liner stresses

International Nuclear Information System (INIS)

Glowka, D.A.

1990-09-01

This report investigates the effects of borehole deviation on the useability of lined boreholes for the disposal of high-level nuclear waste at the proposed Yucca Mountain Repository in Nevada. Items that lead to constraints on borehole deviation include excessive stresses that could cause liner failure and possible binding of a waste container inside the liner during waste emplacement and retrieval operations. Liner stress models are developed for two general borehole configurations, one for boreholes drilled with a steerable bit and one for boreholes drilled with a non-steerable bit. Procedures are developed for calculating liner stresses that arise both during insertion of the liner into a borehole and during the thermal expansion process that follows waste emplacement. The effects of borehole curvature on the ability of the waste container to pass freely inside the liner without binding are also examined. Based on the results, specifications on borehole deviation allowances are developed for specific vertical and horizontal borehole configurations of current interest. 11 refs., 22 figs., 4 tabs

CONSIDERATIONS ON FLUID DYNAMICS INSIDE A HYDRAULIC SEISMIC ENERGY ABSORBER

Directory of Open Access Journals (Sweden)

ȘCHEAUA Fănel

2013-06-01

Full Text Available This study presents a method for obtaining a simplified model of a seismic energy dissipation device whose operating principle is based on viscous fluid as a solution for structural isolation against seismic actions. The device operation is based on the resistance force developed by the working fluid when the piston tends to move due to occurrence of a seismic motion. A 3D model achieved is introduced in CFD analysis for emphasize dynamic fluid flow inside the device dissipation cylinder.

Increasing the effectiveness of the hydraulic fracturing of seams with the use of the pattern recognition method

Energy Technology Data Exchange (ETDEWEB)

Rasizade, Ya M; Nagiev, T M; Kuznetsov, V I; Mikerin, B P

1977-08-01

An examination is made of using a sequential diagnostic procedure for increasing the effectiveness of the hydraulic fracturing of seams in boreholes of the gas and oil drilling administration of the Khadyzhenneft' association. The use of the pattern recognition method was shown to make it possible to increase the effectiveness of hydraulic fracturing by up to 80%. 4 references, 1 figure, 3 tables.

Borehole logging

International Nuclear Information System (INIS)

Olsen, H.

1995-01-01

Numerous ground water investigations have been accomplished by means of borehole logging. Borehole logging can be applied to establish new water recovery wells, to control the existing water producing wells and source areas and to estimate ground water quality. (EG)

Burar seismic station: evaluation of seismic performance

International Nuclear Information System (INIS)

Ghica, Daniela; Popa, Mihaela

2005-01-01

A new seismic monitoring system, the Bucovina Seismic Array (BURAR), has been established since July 2002, in the Northern part of Romania, in a joint effort of the Air Force Technical Applications Center, USA, and the National Institute for Earth Physics (NIEP), Romania. The small-aperture array consists of 10 seismic sensors (9 vertical short-period and one three-component broad band) located in boreholes and distributed in a 5 x 5 km 2 area. At present, the seismic data are continuously recorded by the BURAR and transmitted in real-time to the Romanian National Data Center in Bucharest and National Data Center of the USA, in Florida. Based on the BURAR seismic information gathered at the National Data Center, NIEP (ROM N DC), in the August 2002 - December 2004 time interval, analysis and statistical assessments were performed. Following the preliminary processing of the data, several observations on the global performance of the BURAR system were emphasized. Data investigation showed an excellent efficiency of the BURAR system particularly in detecting teleseismic and regional events. Also, a statistical analysis for the BURAR detection capability of the local Vrancea events was performed in terms of depth and magnitude for the year 2004. The high signal detection capability of the BURAR resulted, generally, in improving the location solutions for the Vrancea seismic events. The location solution accuracy is enhanced when adding BURAR recordings, especially in the case of low magnitude events (recorded by few stations). The location accuracy is increased, both in terms of constraining hypocenter depth and epicentral coordinates. Our analysis certifies the importance of the BURAR system in NIEP efforts to elaborate seismic bulletins. Furthermore, the specific procedures for array data processing (beam forming, f-k analysis) increase significantly the signal-to-noise ratio by summing up the coherent signals from the array components, and ensure a better accuracy

An analysis of seismic background noise variation and evaluation of detection capability of Keskin Array (BRTR PS-43) in Turkey

Science.gov (United States)

Bakir, M. E.; Ozel, N. M.; Semin, K. U.

2011-12-01

Bogazici University, Kandilli Observatory and Earthquake Research Institute (KOERI) is currently operating the Keskin seismic array (BRTR-PS 43) located in town Keskin, providing real-time data to IDC. The instrumentaion of seismic array includes six short period borehole seismometers and one broadband borehole seismometer. The seismic background noise variation of Keskin array are studied in order to estimate the local and regional event detection capability in the frequency range from 1 Hz to 10 Hz. The Power density spectrum and also probability density function of Keskin array data were computed for seasonal and diurnal noise variations between 2008 and 2010. The computation will be extended to cover the period between 2005 and 2008. We attempt to determine the precise frequency characteristics of the background noise, which will help us to assess the station sensitivity. Minimum detectable magnitude versus distance for Keskin seismic array will be analyzed based on the seismic noise analysis. Detailed analysis results of seismic background noise and detection capability will be presented by this research.

Completion summary for boreholes USGS 140 and USGS 141 near the Advanced Test Reactor Complex, Idaho National Laboratory, Idaho

Science.gov (United States)

Twining, Brian V.; Bartholomay, Roy C.; Hodges, Mary K.V.

2014-01-01

with gravel was described. Basalt flows generally ranged in thickness from 3 to 76 ft (average of 14 ft) and varied from highly fractured to dense with high to low vesiculation. Geophysical and borehole video logs were collected during certain stages of the drilling and construction process at boreholes USGS 140 and USGS 141. Geophysical logs were examined synergistically with the core material for borehole USGS 140; additionally, geophysical data were examined to confirm geologic and hydrologic similarities between boreholes USGS 140 and USGS 141 because core was not collected for borehole USGS 141. Geophysical data suggest the occurrence of fractured and (or) vesiculated basalt, dense basalt, and sediment layering in both the saturated and unsaturated zones in borehole USGS 141. Omni-directional density measurements were used to assess the completeness of the grout annular seal behind 6-in. diameter well casing. Furthermore, gyroscopic deviation measurements were used to measure horizontal and vertical displacement at all depths in boreholes USGS 140 and USGS 141. Single-well aquifer tests were done following construction at wells USGS 140 and USGS 141 and data examined after the tests were used to provide estimates of specific-capacity, transmissivity, and hydraulic conductivity. The specific capacity, transmissivity, and hydraulic conductivity for well USGS 140 were estimated at 2,370 gallons per minute per foot [(gal/min)/ft)], 4.06 × 105 feet squared per day (ft2/d), and 740 feet per day (ft/d), respectively. The specific capacity, transmissivity, and hydraulic conductivity for well USGS 141 were estimated at 470 (gal/min)/ft, 5.95 × 104 ft2/d, and 110 ft/d, respectively. Measured flow rates remained relatively constant in well USGS 140 with averages of 23.9 and 23.7 gal/min during the first and second aquifer tests, respectively, and in well USGS 141 with an average of 23.4 gal/min. Water samples were analyzed for cations, anions, metals, nutrients, volatile

Modeling of Hydraulic Fracture Propagation at the kISMET Site Using a Fully Coupled 3D Network-Flow and Quasi- Static Discrete Element Model

Energy Technology Data Exchange (ETDEWEB)

Zhou, Jing [Idaho National Lab. (INL), Idaho Falls, ID (United States); Huang, Hai [Idaho National Lab. (INL), Idaho Falls, ID (United States); Mattson, Earl [Idaho National Lab. (INL), Idaho Falls, ID (United States); Wang, Herb F. [Univ. of Wisconsin, Madison, WI (United States); Haimson, Bezalel C. [Univ. of Wisconsin, Madison, WI (United States); Doe, Thomas W. [Golder Associates Inc., Redmond, VA (United States); Oldenburg, Curtis M. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Dobson, Patrick F. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2017-02-01

Aimed at supporting the design of hydraulic fracturing experiments at the kISMET site, ~1500 m below ground in a deep mine, we performed pre-experimental hydraulic fracturing simulations in order to estimate the breakdown pressure, propagation pressure, fracture geometry, and the magnitude of induced seismicity using a newly developed fully coupled three-dimensional (3D) network flow and quasi-static discrete element model (DEM). The quasi-static DEM model, which is constructed by Delaunay tessellation of the rock volume, considers rock fabric heterogeneities by using the “disordered” DEM mesh and adding random perturbations to the stiffness and tensile/shear strengths of individual DEM elements and the elastic beams between them. A conjugate 3D flow network based on the DEM lattice is constructed to calculate the fluid flow in both the fracture and porous matrix. One distinctive advantage of the model is that fracturing is naturally described by the breakage of elastic beams between DEM elements. It is also extremely convenient to introduce mechanical anisotropy into the model by simply assigning orientation-dependent tensile/shear strengths to the elastic beams. In this paper, the 3D hydraulic fracturing model was verified against the analytic solution for a penny-shaped crack model. We applied the model to simulate fracture propagation from a vertical open borehole based on initial estimates of rock mechanical properties and in-situ stress conditions. The breakdown pressure and propagation pressure are directly obtained from the simulation. In addition, the released elastic strain energies of individual fracturing events were calculated and used as a conservative estimate for the magnitudes of the potential induced seismic activities associated with fracturing. The comparisons between model predictions and experimental results are still ongoing.

Seismic modeling of multidimensional heterogeneity scales of Mallik gas hydrate reservoirs, Northwest Territories of Canada

Science.gov (United States)

Huang, Jun-Wei; Bellefleur, Gilles; Milkereit, Bernd

2009-07-01

In hydrate-bearing sediments, the velocity and attenuation of compressional and shear waves depend primarily on the spatial distribution of hydrates in the pore space of the subsurface lithologies. Recent characterizations of gas hydrate accumulations based on seismic velocity and attenuation generally assume homogeneous sedimentary layers and neglect effects from large- and small-scale heterogeneities of hydrate-bearing sediments. We present an algorithm, based on stochastic medium theory, to construct heterogeneous multivariable models that mimic heterogeneities of hydrate-bearing sediments at the level of detail provided by borehole logging data. Using this algorithm, we model some key petrophysical properties of gas hydrates within heterogeneous sediments near the Mallik well site, Northwest Territories, Canada. The modeled density, and P and S wave velocities used in combination with a modified Biot-Gassmann theory provide a first-order estimate of the in situ volume of gas hydrate near the Mallik 5L-38 borehole. Our results suggest a range of 528 to 768 × 106 m3/km2 of natural gas trapped within hydrates, nearly an order of magnitude lower than earlier estimates which did not include effects of small-scale heterogeneities. Further, the petrophysical models are combined with a 3-D finite difference modeling algorithm to study seismic attenuation due to scattering and leaky mode propagation. Simulations of a near-offset vertical seismic profile and cross-borehole numerical surveys demonstrate that attenuation of seismic energy may not be directly related to the intrinsic attenuation of hydrate-bearing sediments but, instead, may be largely attributed to scattering from small-scale heterogeneities and highly attenuate leaky mode propagation of seismic waves through larger-scale heterogeneities in sediments.

Calculation of NPP pipeline seismic stability

International Nuclear Information System (INIS)

Kirillov, A.P.; Ambriashvili, Yu.K.; Kaliberda, I.V.

1982-01-01

A simplified design procedure of seismic pipeline stability of NPP at WWER reactor is described. The simplified design procedure envisages during the selection and arrangement of pipeline saddle and hydraulic shock absorbers use of method of introduction of resilient mountings of very high rigidity into the calculated scheme of the pipeline and performance of calculations with step-by-step method. It is concluded that the application of the design procedure considered permits to determine strains due to seismic loads, to analyze stressed state in pipeline elements and supporting power of pipe-line saddle with provision for seismic loads to plan measures on seismic protection

Aseismic and seismic slip induced by fluid injection from poroelastic and rate-state friction modeling

Science.gov (United States)

Liu, Y.; Deng, K.; Harrington, R. M.; Clerc, F.

2016-12-01

Solid matrix stress change and pore pressure diffusion caused by fluid injection has been postulated as key factors for inducing earthquakes and aseismic slip on pre-existing faults. In this study, we have developed a numerical model that simulates aseismic and seismic slip in a rate-and-state friction framework with poroelastic stress perturbations from multi-stage hydraulic fracturing scenarios. We apply the physics-based model to the 2013-2015 earthquake sequences near Fox Creek, Alberta, Canada, where three magnitude 4.5 earthquakes were potentially induced by nearby hydraulic fracturing activity. In particular, we use the relocated December 2013 seismicity sequence to approximate the fault orientation, and find the seismicity migration spatiotemporally correlate with the positive Coulomb stress changes calculated from the poroelastic model. When the poroelastic stress changes are introduced to the rate-state friction model, we find that slip on the fault evolves from aseismic to seismic in a manner similar to the onset of seismicity. For a 15-stage hydraulic fracturing that lasted for 10 days, modeled fault slip rate starts to accelerate after 3 days of fracking, and rapidly develops into a seismic event, which also temporally coincides with the onset of induced seismicity. The poroelastic stress perturbation and consequently fault slip rate continue to evolve and remain high for several weeks after hydraulic fracturing has stopped, which may explain the continued seismicity after shut-in. In a comparison numerical experiment, fault slip rate quickly decreases to the interseismic level when stress perturbations are instantaneously returned to zero at shut-in. Furthermore, when stress perturbations are removed just a few hours after the fault slip rate starts to accelerate (that is, hydraulic fracturing is shut down prematurely), only aseismic slip is observed in the model. Our preliminary results thus suggest the design of fracturing duration and flow

Assessing the monitoring performance using a synthetic microseismic catalogue for hydraulic fracturing

Science.gov (United States)

Ángel López Comino, José; Kriegerowski, Marius; Cesca, Simone; Dahm, Torsten; Mirek, Janusz; Lasocki, Stanislaw

2016-04-01

Hydraulic fracturing is considered among the human operations which could induce or trigger seismicity or microseismic activity. The influence of hydraulic fracturing operations is typically expected in terms of weak magnitude events. However, the sensitivity of the rock mass to trigger seismicity varies significantly for different sites and cannot be easily predicted prior to operations. In order to assess the sensitivity of microseismity to hydraulic fracturing operations, we perform a seismic monitoring at a shale gas exploration/exploitation site in the central-western part of the Peribaltic synclise at Pomerania (Poland). The monitoring will be continued before, during and after the termination of hydraulic fracturing operations. The fracking operations are planned in April 2016 at a depth 4000 m. A specific network setup has been installed since summer 2015, including a distributed network of broadband stations and three small-scale arrays. The network covers a region of 60 km2. The aperture of small scale arrays is between 450 and 950 m. So far no fracturing operations have been performed, but seismic data can already be used to assess the seismic noise and background microseismicity, and to investigate and assess the detection performance of our monitoring setup. Here we adopt a recently developed tool to generate a synthetic catalogue and waveform dataset, which realistically account for the expected microseismicity. Synthetic waveforms are generated for a local crustal model, considering a realistic distribution of hypocenters, magnitudes, moment tensors, and source durations. Noise free synthetic seismograms are superposed to real noise traces, to reproduce true monitoring conditions at the different station locations. We estimate the detection probability for different magnitudes, source-receiver distances, and noise conditions. This information is used to estimate the magnitude of completeness at the depth of the hydraulic fracturing horizontal wells

Crosshole investigations - results from seismic borehole tomography

International Nuclear Information System (INIS)

Pihl, J.; Hammarstroem, M.; Ivansson, S.; Moren, P.

1986-12-01

The specially developed system for seismic tomography measurements has proved reliable and versatile in field work. The same equipment can be used for measurements from tens of metres up to a distance of 1000 m. The explosive source has proven reliable, in use although time-consuming. It can be used over the full range of distances. The quality of the tomographic analysis is strongly dependent on the areas under study. In homogeneous rock, and at moderate (i.e. up to 200 m) distances, high-precision tomograms can be obtained. On the other hand, if the rock is heterogeneous, and/or the measuring distance large, the many possible solutions make the interpretation difficult. Information from other types of investigations are then usually needed in order to obtain a satisfactory result. Three-dimensional measurements are possible, although time-consuming. (orig./DG)

Crosshole investigations: Hydrogeological results and interpretations

International Nuclear Information System (INIS)

Black, J.H.; Holmes, D.C.; Brightman, M.A.

1987-12-01

The Crosshole Programme was an integrated geophysical and hydrogeological study of a limited volume of rock (known as the Crosshole Site) within the Stripa mine. Borehole radar, borehole seismic and hydraulic methods were developed for specific application to fractured crystalline rock. The hydrogeological investigations contained both single borehole and crosshole test techniques. A novel technique, using a sinusoidal variation of pressure, formed the main method of crosshole testing and was assessed during the programme. The strategy of crosshole testing was strongly influenced by the results from the geophysical measurements. The longer term, larger scale hydrogeological response of the region was asessed by examining the variation of heads over the region. These were responding to the presence of an old drift. A method of overall assessment involving minimising the divergence from a homogeneous response yielded credible values of hydraulic conductivity for the rock as a whole. (orig./DG)

Seismic and Geodetic Monitoring of the Nicoya, Costa Rica, Seismic Gap

Science.gov (United States)

Protti, M.; Gonzalez, V.; Schwartz, S.; Dixon, T.; Kato, T.; Kaneda, Y.; Simila, G.; Sampson, D.

2007-05-01

The Nicoya segment of the Middle America Trench has been recognized as a mature seismic gap with potential to generate a large earthquake in the near future (it ruptured with large earthquakes in 1853, 1900 and 1950). Low level of background seismicity and fast crustal deformation of the forearc are indicatives of strong coupling along the plate interface. Given its high seismic potential, the available data and especially the fact that the Nicoya peninsula extends over large part of the rupture area, this gap was selected as one of the two sites for a MARGINS-SEIZE experiment. With the goal of documenting the evolution of loading and stress release along this seismic gap, an international effort involving several institutions from Costa Rica, the United States and Japan is being carried out for over a decade in the region. This effort involves the installation of temporary and permanent seismic and geodetic networks. The seismic network includes short period, broad band and strong motion instruments. The seismic monitoring has provided valuable information on the geometry and characteristics of the plate interface. The geodetic network includes temporary and permanent GPS stations as well as surface and borehole tiltmeters. The geodetic networks have helped quantify the extend and degree of coupling. A continuously recording, three- station GPS network on the Nicoya Peninsula, Costa Rica, recorded what we believe is the first slow slip event observed along the plate interface of the Costa Rica subduction zone. We will present results from these monitoring networks. Collaborative international efforts are focused on expanding these seismic and geodetic networks to provide improved resolution of future creep events, to enhanced understanding of the mechanical behavior of the Nicoya subduction segment of the Middle American Trench and possibly capture the next large earthquake and its potential precursor deformation.

Completion summary for boreholes TAN-2271 and TAN‑2272 at Test Area North, Idaho National Laboratory, Idaho

Science.gov (United States)

Twining, Brian V.; Bartholomay, Roy C.; Hodges, Mary K.V.

2016-06-30

255 ft BLS and the second between 272 and 282 ft BLS. Basalt texture for borehole TAN-2271 generally was described as aphanitic, phaneritic, and porphyritic. Sediment layers, starting near 122 ft BLS, generally were composed of fine-grained sand and silt with a lesser amount of clay. Basalt flows generally ranged in thickness from 2 to 78 ft and varied from highly fractured to dense with high to low vesiculation. Geophysical data and limited core material collected from TAN-2272 show similar lithologic sequences to those reported for TAN-2271.Geophysical and borehole video logs were collected during certain stages of the drilling and construction process at boreholes TAN-2271 and TAN-2272. Geophysical logs were examined synergistically with available core material to confirm geologic and hydrologic similarities and suggest possible fractured network interconnection between boreholes TAN-2271 and TAN-2272. Natural gamma log measurements were used to assess the completeness of the vapor port lines behind 10-in. diameter well casing. Electromagnetic flow meter results were used to identify downward flow conditions that exist for boreholes TAN-2271 and TAN-2272. Furthermore, gyroscopic deviation measurements were used to measure horizontal and vertical displacement at all depths in boreholes TAN-2271 and TAN-2272.After borehole construction was completed, single‑well aquifer tests were done within wells TAN-2271 and TAN‑2272 to provide estimates of transmissivity and hydraulic conductivity. The transmissivity and hydraulic conductivity were estimated for the pumping well and observation well during the aquifer tests conducted on August 25 and August 27, 2015. Estimates for transmissivity range from 4.1 . 103 feet squared per day (ft2/d) to 8.1 . 103 ft2/d; estimates for hydraulic conductivity range from 5.8 to 11.5 feet per day (ft/d). Both TAN-2271 and TAN‑2272 show sustained pumping rates of about 30 gallons per minute (gal/min) with measured drawdown in the

Seismic velocity uncertainties and their effect on geothermal predictions: A case study

Science.gov (United States)

Rabbel, Wolfgang; Köhn, Daniel; Bahadur Motra, Hem; Niederau, Jan; Thorwart, Martin; Wuttke, Frank; Descramble Working Group

2017-04-01

Geothermal exploration relies in large parts on geophysical subsurface models derived from seismic reflection profiling. These models are the framework of hydro-geothermal modeling, which further requires estimating thermal and hydraulic parameters to be attributed to the seismic strata. All petrophysical and structural properties involved in this process can be determined only with limited accuracy and thus impose uncertainties onto the resulting model predictions of temperature-depth profiles and hydraulic flow, too. In the present study we analyze sources and effects of uncertainties of the seismic velocity field, which translate directly into depth uncertainties of the hydraulically and thermally relevant horizons. Geological sources of these uncertainties are subsurface heterogeneity and seismic anisotropy, methodical sources are limitations in spread length and physical resolution. We demonstrate these effects using data of the EU-Horizon 2020 project DESCRAMBLE investigating a shallow super-critical geothermal reservoir in the Larderello area. The study is based on 2D- and 3D seismic reflection data and laboratory measurements on representative rock samples under simulated in-situ conditions. The rock samples consistently show P-wave anisotropy values of 10-20% order of magnitude. However, the uncertainty of layer depths induced by anisotropy is likely to be lower depending on the accuracy, with which the spatial orientation of bedding planes can be determined from the seismic reflection images.

Vibrational modes of hydraulic fractures: Inference of fracture geometry from resonant frequencies and attenuation

Science.gov (United States)

Lipovsky, Bradley P.; Dunham, Eric M.

2015-02-01

Oscillatory seismic signals arising from resonant vibrations of hydraulic fractures are observed in many geologic systems, including volcanoes, glaciers and ice sheets, and hydrocarbon and geothermal reservoirs. To better quantify the physical dimensions of fluid-filled cracks and properties of the fluids within them, we study wave motion along a thin hydraulic fracture waveguide. We present a linearized analysis, valid at wavelengths greater than the fracture aperture, that accounts for quasi-static elastic deformation of the fracture walls, as well as fluid viscosity, inertia, and compressibility. In the long-wavelength limit, anomalously dispersed guided waves known as crack or Krauklis waves propagate with restoring force from fracture wall elasticity. At shorter wavelengths, the waves become sound waves within the fluid channel. Wave attenuation in our model is due to fluid viscosity, rather than seismic radiation from crack tips or fracture wall roughness. We characterize viscous damping at both low frequencies, where the flow is always fully developed, and at high frequencies, where the flow has a nearly constant velocity profile away from viscous boundary layers near the fracture walls. Most observable seismic signals from resonating fractures likely arise in the boundary layer crack wave limit, where fluid-solid coupling is pronounced and attenuation is minimal. We present a method to estimate the aperture and length of a resonating hydraulic fracture using both the seismically observed quality factor and characteristic frequency. Finally, we develop scaling relations between seismic moment and characteristic frequency that might be useful when interpreting the statistics of hydraulic fracture events.

Borehole radar and BIPS investigations in boreholes at the Boda area

Energy Technology Data Exchange (ETDEWEB)

Carlsten, S.; Straahle, A. [GEOSIGMA AB, Uppsala (Sweden)

2000-12-01

As part of the studies conducted in the Boda area, measurements with borehole radar, borehole TV (BIPS) and deviation measurements were performed during May 2000. The investigations were carried out in four percussion-drilled boreholes with a total length of 514 m. Two boreholes are vertical and two are directed into and below the cave area. The BIPS measurement showed the presence of 14 open fractures. Largest apparent aperture width of open fractures was 133 mm. In the lowest part in boreholes 2, 3, and 4, particles in suspension deteriorated the visibility. BIPS has revealed a dominating subhorizontal fracture set and another striking NW to N-S with a dip close to vertical. Possible but very uncertain is a third fracture set striking NE and dipping steeply towards S. The open and partly open fractures forms an average block size 11 m wide and 6 m high, while the length of the block is uncertain. Of 98 borehole radar reflectors interpreted to intersect within BIPS-mapped sections, 90 were possible to combine with BIPS-mapped structures, i.e. 92% of the radar reflectors. The fractured rock around Boda is a shallow feature, since borehole radar and BIPS measurements shows no evidence of increased fracturing or the presence of caves at larger depth in the Boda area. The result indicates that the formation of the superficial fracture system (with caves included) at Boda in all probability is connected to glacial action, such as banking.

Borehole radar and BIPS investigations in boreholes at the Boda area

International Nuclear Information System (INIS)

Carlsten, S.; Straahle, A.

2000-12-01

As part of the studies conducted in the Boda area, measurements with borehole radar, borehole TV (BIPS) and deviation measurements were performed during May 2000. The investigations were carried out in four percussion-drilled boreholes with a total length of 514 m. Two boreholes are vertical and two are directed into and below the cave area. The BIPS measurement showed the presence of 14 open fractures. Largest apparent aperture width of open fractures was 133 mm. In the lowest part in boreholes 2, 3, and 4, particles in suspension deteriorated the visibility. BIPS has revealed a dominating subhorizontal fracture set and another striking NW to N-S with a dip close to vertical. Possible but very uncertain is a third fracture set striking NE and dipping steeply towards S. The open and partly open fractures forms an average block size 11 m wide and 6 m high, while the length of the block is uncertain. Of 98 borehole radar reflectors interpreted to intersect within BIPS-mapped sections, 90 were possible to combine with BIPS-mapped structures, i.e. 92% of the radar reflectors. The fractured rock around Boda is a shallow feature, since borehole radar and BIPS measurements shows no evidence of increased fracturing or the presence of caves at larger depth in the Boda area. The result indicates that the formation of the superficial fracture system (with caves included) at Boda in all probability is connected to glacial action, such as banking

ANZA Seismic Network- From Monitoring to Science

Science.gov (United States)

Vernon, F.; Eakin, J.; Martynov, V.; Newman, R.; Offield, G.; Hindley, A.; Astiz, L.

2007-05-01

The ANZA Seismic Network (http:eqinfo.ucsd.edu) utilizes broadband and strong motion sensors with 24-bit dataloggers combined with real-time telemetry to monitor local and regional seismicity in southernmost California. The ANZA network provides real-time data to the IRIS DMC, California Integrated Seismic Network (CISN), other regional networks, and the Advanced National Seismic System (ANSS), in addition to providing near real-time information and monitoring to the greater San Diego community. Twelve high dynamic range broadband and strong motion sensors adjacent to the San Jacinto Fault zone contribute data for earthquake source studies and continue the monitoring of the seismic activity of the San Jacinto fault initiated 24 years ago. Five additional stations are located in the San Diego region with one more station on San Clemente Island. The ANZA network uses the advance wireless networking capabilities of the NSF High Performance Wireless Research and Education Network (http:hpwren.ucsd.edu) to provide the communication infrastructure for the real-time telemetry of Anza seismic stations. The ANZA network uses the Antelope data acquisition software. The combination of high quality hardware, communications, and software allow for an annual network uptime in excess of 99.5% with a median annual station real-time data return rate of 99.3%. Approximately 90,000 events, dominantly local sources but including regional and teleseismic events, comprise the ANZA network waveform database. All waveform data and event data are managed using the Datascope relational database. The ANZA network data has been used in a variety of scientific research including detailed structure of the San Jacinto Fault Zone, earthquake source physics, spatial and temporal studies of aftershocks, array studies of teleseismic body waves, and array studies on the source of microseisms. To augment the location, detection, and high frequency observations of the seismic source spectrum from local

Borehole sealing method and apparatus

International Nuclear Information System (INIS)

Hartley, J.N.; Jansen, G. Jr.

1977-01-01

A method and apparatus is described for sealing boreholes in the earth. The borehole is blocked at the sealing level, and a sealing apparatus capable of melting rock and earth is positioned in the borehole just above seal level. The apparatus is heated to rock-melting temperature and powdered rock or other sealing material is transported down the borehole to the apparatus where it is melted, pooling on the mechanical block and allowed to cool and solidify, sealing the hole. Any length of the borehole can be sealed by slowly raising the apparatus in the borehole while continuously supplying powdered rock to the apparatus to be melted and added to the top of the column of molten and cooling rock, forming a continuous borehole seal. The sealing apparatus consists of a heater capable of melting rock, including means for supplying power to the heater, means for transporting powdered rock down the borehole to the heater, means for cooling the apparatus and means for positioning the apparatus in the borehole. 5 claims, 1 figure

Combined Borehole Seismic and Electromagnetic Inversion For High-Resolution Petrophysical Assessment Of Hydocarbon Reservoirs

Energy Technology Data Exchange (ETDEWEB)

Carlos Torres-Verdin; G. Michael Hoversten; Ki Ha Lee; Gregory Newman; Kurt Nihei

2008-12-31

This report summarizes the work performed between January 2005 and December 2007, under DOE research contract DE-FC26-04NT15507. The project is was performed by the Center for Petroleum and Geosystems Engineering of The University of Texas at Austin and Lawrence Berkeley National Laboratory under the auspices of the National Energy Technology Office (NETL) and the Strategic Center for Natural Gas and Oil (SCNGO). During the three-year project, we developed new methods to combine borehole sonic and electromagnetic (EM) measurements for the improved assessment of elastic and petrophysical properties of rock formations penetrated by a well. Sonic measurements consisted of full waveform acoustic amplitudes acquired with monopole and dipole sources, whereas EM measurements consisted of frequency-domain voltages acquired with multi-coil induction systems. The combination of sonic and EM measurements permitted the joint estimation of elastic and petrophysical properties in the presence of mud-filtrate invasion. It was conclusively shown that the combined interpretation of sonic and EM measurements reduced non-uniqueness in the estimation of elastic and petrophysical properties and improved the spatial resolution of the estimations compared to estimations yielded separately from the two types of measurements. Moreover, this approach enabled the assessment of dynamic petrophysical properties such as permeability, as it incorporated the physics of mud-filtrate invasion in the interpretation of the measurements. The first part of the project considered the development of fast and reliable numerical algorithms to simulate borehole sonic waveforms in 2D, 3D, and radial 1D media. Such algorithms were subsequently used in the quantitative estimation of elastic properties jointly from borehole sonic and EM measurements. In the second part of the project we developed a new algorithm to estimate water saturation, porosity, and dry-rock elastic moduli jointly from borehole sonic and

Deep hydraulic tests in a large earth-slide rich in clay

Science.gov (United States)

Ronchetti, Francesco; Piccinini, Leonardo; Deiana, Manuela; Corsini, Alessandro

2017-04-01

Different hydraulic tests have been conducted and replicated in a large earth slide characterized by a landslide body that is rich in clay, has a mean thickness of 30 meters, and is located in the Northern Apennines, Italy. All the tests were performed to estimate the hydrogeological properties of the landslide and to design future mitigation measures. To define the geometry of the sliding mass, the stratigraphy in more than 15 boreholes was analyzed. The boreholes were subsequently equipped with inclinometers and open standpipe piezometers. According to the stratigraphy, the landslide body is characterized by the presence of gravel layers in a clay-rich matrix. This study compares the results from the different techniques applied to 2 boreholes, 5 open standpipe piezometers and 1 well. The number of tests performed for each test type were 31 slug tests (ST), 4 falling head tests (FT), 5 low-flow pumping tests (PT), 1 point dilution (PD) test, and 2 aquifer tests (AT). Moreover, the test data was evaluated with different solutions. The ST data was evaluated with the Hvorslev and KGS solutions; the FT data was evaluated with the AGI and Hvorslev solutions; the PT data was evaluated with the Muskat solutions; the AT data was evaluated with the Theis, Cooper-Jacob, Neuman, Moench and Tartakosky-Neuman solutions; and the PD test data was evaluated with the classical solution where Darcy velocity is calculated as a function of the rate of dilution. The results show that hydraulic conductivity (K), storage (S) and specific storage (Ss) vary in the horizontal plane and with the depth (K ranges between 1.0E-5 and 1.0E-8 m/s; S ranges between 4.0E-3 and 5E-5; and Ss ranges between 1.0E-3 and 3.0E-3 1/m). The horizontal and vertical variability is correlated with the lithologic heterogeneity highlighted by the borehole stratigraphy. Moreover, all the hydraulic tests conducted on the landslide body give highly consistent results. Comparison of results derived from different

Co-seismic response of water level in the Jingle well (China) associated with the Gorkha Nepal (Mw 7.8) earthquake

Science.gov (United States)

He, Anhua; Fan, Xuefang; Zhao, Gang; Liu, Yang; Singh, Ramesh P.; Hu, Yuliang

2017-09-01

Changes in co-seismic water levels associated with the Gorkha Nepal earthquake (25 April 2015, Mw 7.8) were recorded in the Jingle well in Shanxi Province China (longitude E112.03°, latitude N38.35°, about 2769 km from epicenter). Based on the observed water levels, we clearly identified signals relating to P, S and surface waves. However, the water temperature recorded at a depth of 350 m shows no co-seismic changes. A spectrum analysis of co-seismic variations of water level shows that the oscillation frequency and amplitude of water level in the borehole are determined by the natural frequency of the borehole, which is not associated with the propagation of seismic waves. The borehole-aquifer system shows a large amplification associated with ground vibrations generated by earthquakes. Considering the local hydro-geological map and the temperature gradient of the Jingle well, a large volume ;groundwater reservoir; model can be used to explain these processes. Due to seismic wave propagation, the volume of a well-confined aquifer expands and contracts forming fractures that change the water flow. In the well-confined aquifer, water levels oscillate simultaneously with high amplitude ground shaking during earthquakes. However, the water in the center of the ;underground reservoir; remains relatively stationary, without any changes in the water temperature. In addition, a possible precursor wave is recorded in the water level at the Jingle well prior to the Gorkha earthquake.

Borehole Muon Detector Development

Science.gov (United States)

Bonneville, A.; Flygare, J.; Kouzes, R.; Lintereur, A.; Yamaoka, J. A. K.; Varner, G. S.

2015-12-01

Increasing atmospheric CO2 concentrations have spurred investigation into carbon sequestration methods. One of the possibilities being considered, storing super-critical CO2 in underground reservoirs, has drawn more attention and pilot projects are being supported worldwide. Monitoring of the post-injection fate of CO2 is of utmost importance. Generally, monitoring options are active methods, such as 4D seismic reflection or pressure measurements in monitoring wells. We propose here to develop a 4-D density tomography of subsurface CO2 reservoirs using cosmic-ray muon detectors deployed in a borehole. Muon detection is a relatively mature field of particle physics and there are many muon detector designs, though most are quite large and not designed for subsurface measurements. The primary technical challenge preventing deployment of this technology in the subsurface is the lack of miniaturized muon-tracking detectors capable of fitting in standard boreholes and that will resist the harsh underground conditions. A detector with these capabilities is being developed by a collaboration supported by the U.S. Department of Energy. Current simulations based on a Monte Carlo modeling code predict that the incoming muon angle can be resolved with an error of approximately two degrees, using either underground or sea level spectra. The robustness of the design comes primarily from the use of scintillating rods as opposed to drift tubes. The rods are arrayed in alternating layers to provide a coordinate scheme. Preliminary testing and measurements are currently being performed to test and enhance the performance of the scintillating rods, in both a laboratory and a shallow underground facility. The simulation predictions and data from the experiments will be presented.

24-CHANNEL GEOPHONE ARRAY FOR HORIZONTAL OR VERTICAL BOREHOLES

Energy Technology Data Exchange (ETDEWEB)

Erik C. Westman

2003-10-24

Improved ground-imaging capabilities have enormous potential to increase energy, environmental, and economic benefits by improving exploration accuracy and reducing energy consumption during the mining cycle. Seismic tomography has been used successfully to monitor and evaluate geologic conditions ahead of a mining face. A primary limitation to existing seismic tomography, however, is the placement of sensors. The goal of this project is to develop an array of 24 seismic sensors capable of being mounted in either a vertical or horizontal borehole. Development of this technology reduces energy usage in excavation, transportation, ventilation, and processing phases of the mining operation because less waste is mined and the mining cycle suffers fewer interruptions. This new technology benefits all types of mines, including metal/nonmetal, coal, and quarrying. The primary research tasks focused on sensor placement method, sensor housing and clamping design, and cabling and connector selection. An initial design is described in the report. Following assembly, a prototype was tested in the laboratory as well as at a surface stone quarry. Data analysis and tool performance were used for subsequent design modifications. A final design is described, of which several components are available for patent application. Industry partners have shown clear support for this research and demonstrated an interest in commercialization following project completion.

Tanjung Enim IV coal exploration project. Volume I. Exploration work of South Arahan area in 2000/2001

Energy Technology Data Exchange (ETDEWEB)

NONE

2001-03-01

In the 1996-2001 period, the project has been carried out in Banjarsari/Tanjung Enim areas and South Arahan area of South Sumatra. This report described the results of the project conducted in South Arahan area in 2000/2001. The area for survey is 40km{sup 2} in north block and 10km{sup 2} in south block, and the following were carried out: surface reconnaissance, geological mapping, drilling, geophysical logging, seismic survey (seismic reflection survey and VSP survey), and sampling for coal quality analysis. The number of boreholes drilled was 11 including 8 in north area and 3 in south area, and the total length was 1,847m. Physical logging was executed in all 11 boreholes, and VSP survey was done in one borehole per each block. As to the hydraulic test, water poring test was conducted at 3 boreholes in north block. In the report, the results of the survey were classified into the following 4 items: 1) outline of the survey; 2) field activities; 3) analysis of the results; 4) summarization. (NEDO)

Geo-Proxy-Based Site Classification for Regional Zonation of Seismic Site Effects in South Korea

Directory of Open Access Journals (Sweden)

Chang-Guk Sun

2018-02-01

Full Text Available Seismic site effects and topographic effects related to ground motion occur during an earthquake due to site-specific geotechnical or geological characteristics, including the geological or geographical structure and the characteristics of near-surface sub-soil layers. Site-specific site effects due to geological conditions have been confirmed in recent earthquake events. Earthquake-induced damage has mainly occurred at accumulated soft soil layers under basins or along coasts and rivers. An alternative method has recently been proposed for evaluating regional seismic site effects and amplification factors using digital elevation models (DEM. High-quality DEMs at high resolutions may be employed to resolve finer-scale variations in topographic gradients and consequently, correlated site response parameters. Because there are many regions in South Korea lacking borehole datasets, which are insufficient for site classification only using borehole datasets, a DEM-based proxy for seismic zonation can be effective. Thus, in this study, geo-proxy-based site classification was proposed based on empirical correlations with site response parameters and conducted for regional zonation of seismic site effects to identify the amplification of characteristics in the western metropolitan areas of South Korea, depending on the site-specific geo-spatial conditions.

Integrated seismic analysis of the Chalk Group in eastern Denmark—Implications for estimates of maximum palaeo-burial in southwest Scandinavia

DEFF Research Database (Denmark)

Nielsen, Lars; Boldreel, Lars Ole; Hansen, Thomas Mejer

2011-01-01

Group. The sonic velocities are consistent with the overall seismic layering, although they show additional fine-scale layering. Integration of gamma and sonic log with porosity data shows that seismic velocity is sensitive to clay content. In intervals near boundaries of the refraction model, moderate......The origin of the topography of southwest Scandinavia is subject to discussion. Analysis of borehole seismic velocity has formed the basis for interpretation of several hundred metres of Neogene uplift in parts of Denmark.Here, refraction seismic data constrain a 7.5km long P-wave velocity model...... of the Chalk Group below the Stevns peninsula, eastern part of the Danish Basin. The model contains four layers in the ~860m thick Chalk Group with mean velocities of 2.2km/s, 2.4km/s, 3.1km/s, and 3.9–4.3km/s. Sonic and gamma wireline log data from two cored boreholes represent the upper ~450m of the Chalk...

Non-linear degradation model of cement barriers in a borehole repository for disused radioactive sources

International Nuclear Information System (INIS)

Gharbieh, Heidar K.; Cota, Stela

2015-01-01

Narrow diameter borehole facilities (a few tens of centimeters), like the BOSS concept developed by the IAEA, provide a safe and cost effective disposal option for radioactive waste and particularly disused sources. The BOSS concept (borehole disposal of sealed radioactive sources) comprises a multi-barrier system of cement grout and stainless steel components. In order to predict the long-time performance of the cement barriers as an input of a future safety assessment under the specific hydrochemical and hydrological conditions, a non-linear degradation model was developed in this work. With the assistance of the program 'PHREEQC' it describes the change of the porosity and the hydraulic conductivity with time, which also let to conclusions concerning the change of the sorption capacity of the cement grout. This work includes the theoretical approach and illustrates the non-liner degradation by means of an exemplary water composition found in the saturated zone and the dimensions of the backfill made of cement grout representing a barrier of the BOSS borehole facility. (author)

Integrating surface and borehole geophysics in ground water studies - an example using electromagnetic soundings in south Florida

Science.gov (United States)

Paillet, Frederick; Hite, Laura; Carlson, Matthew

1999-01-01

Time domain surface electromagnetic soundings, borehole induction logs, and other borehole logging techniques are used to construct a realistic model for the shallow subsurface hydraulic properties of unconsolidated sediments in south Florida. Induction logs are used to calibrate surface induction soundings in units of pore water salinity by correlating water sample specific electrical conductivity with the electrical conductivity of the formation over the sampled interval for a two‐layered aquifer model. Geophysical logs are also used to show that a constant conductivity layer model is appropriate for the south Florida study. Several physically independent log measurements are used to quantify the dependence of formation electrical conductivity on such parameters as salinity, permeability, and clay mineral fraction. The combined interpretation of electromagnetic soundings and induction logs was verified by logging three validation boreholes, confirming quantitative estimates of formation conductivity and thickness in the upper model layer, and qualitative estimates of conductivity in the lower model layer.

Geophysical and geological borehole investigations for the characterization of a site for radioactive waste disposal

International Nuclear Information System (INIS)

Olsson, O.; Ahlbom, K.

1984-02-01

In the Swedish program for site investigations detailed geological and geophysical investigations are performed at areas of 4-6 km 2 at the surface. Normally around 10 deep core bore holes are drilled. The length of the holes is normally from 600 to 1000 m. The holes are drilled to verify the location of fracture zones and to investigate the physical and hydraulic properties of the fracture zones at large depths. Investigations have been performed in a number of sites with mainly granitic and gneissic rocks. The core from these boreholes is logged with the aid of a microcomputer system. The cores are mapped with respect to rock type, structure, fractures and fracture minerals. Indications of water flow, shearing and core-discing are also studied. The boreholes are logged with a suite of geophysical logs. Several different electrical logs are used and have been found to be good indicators of fracture zones. Normally the electrical logs in combination with the fracture frequency are used to define the limits of fracture zones crossing the borehole. The temperature log and the salinity log have proved to be good indicators of permeable zones. The data from each hole is correlated with data obtained from the other holes and the surface investigations to build a fracture zone model which is used for the hydraulic modelling of the site. In order to verify the extension of the fracture zones at a distance from the borehole cross-hole techniques have been applied. At the Swedish test site Finnsjoe and in the Stripa mine the suitability of the mise a la masse technique for mapping of fracture zones was tested. At the Finnsjoe site it was possible to map a fairly complex fracture system over distances up to 150 m. In the Stripa mine the object was to follow the extent of a major fracture zone for distances up to 600 m. It was possible to obtain an indication of the orientation of the fracture zone

Optimizing the design of vertical seismic profiling (VSP) for imaging fracture zones over hardrock basement geothermal environments

Science.gov (United States)

Reiser, Fabienne; Schmelzbach, Cedric; Maurer, Hansruedi; Greenhalgh, Stewart; Hellwig, Olaf

2017-04-01

A primary focus of geothermal seismic imaging is to map dipping faults and fracture zones that control rock permeability and fluid flow. Vertical seismic profiling (VSP) is therefore a most valuable means to image the immediate surroundings of an existing borehole to guide, for example, the placing of new boreholes to optimize production from known faults and fractures. We simulated 2D and 3D acoustic synthetic seismic data and processed it through to pre-stack depth migration to optimize VSP survey layouts for mapping moderately to steeply dipping fracture zones within possible basement geothermal reservoirs. Our VSP survey optimization procedure for sequentially selecting source locations to define the area where source points are best located for optimal imaging makes use of a cross-correlation statistic, by which a subset of migrated shot gathers is compared with a target or reference image from a comprehensive set of source gathers. In geothermal exploration at established sites, it is reasonable to assume that sufficient à priori information is available to construct such a target image. We generally obtained good results with a relatively small number of optimally chosen source positions distributed over an ideal source location area for different fracture zone scenarios (different dips, azimuths, and distances from the surveying borehole). Adding further sources outside the optimal source area did not necessarily improve the results, but rather resulted in image distortions. It was found that fracture zones located at borehole-receiver depths and laterally offset from the borehole by 300 m can be imaged reliably for a range of the different dips, but more source positions and large offsets between sources and the borehole are required for imaging steeply dipping interfaces. When such features cross-cut the borehole, they are particularly difficult to image. For fracture zones with different azimuths, 3D effects are observed. Far offset source positions

Performance evaluation of groundwater model hydrostratigraphy from airborne electromagnetic data and lithological borehole logs

DEFF Research Database (Denmark)

Marker, Pernille Aabye; Foged, N.; He, X.

2015-01-01

resistivity and clay fraction are classified into hydrostratigraphic zones using k-means clustering. Hydraulic conductivity values of the zones are estimated by hydrological calibration using hydraulic head and stream discharge observations. The method is applied to a Danish case study. Benchmarking......Large-scale hydrological models are important decision support tools in water resources management. The largest source of uncertainty in such models is the hydrostratigraphic model. Geometry and configuration of hydrogeological units are often poorly determined from hydrogeological data alone. Due...... present a novel method to automatically integrate large AEM data sets and lithological information into large-scale hydrological models. Clay-fraction maps are produced by translating geophysical resistivity into clay-fraction values using lithological borehole information. Voxel models of electrical...

Site Characterization Data from the U3ax/bl Exploratory Boreholes at the Nevada Test Site

International Nuclear Information System (INIS)

2005-01-01

This report provides qualitative analyses and preliminary interpretations of hydrogeologic data obtained from two 45-degree, slanted exploratory boreholes drilled within the Area 3 Radioactive Waste Management Site (RWMS) at the Nevada Test Site. Borehole UE-3bl-D1 was drilled beneath the U3ax/bl mixed waste disposal unit, and Borehole UE-3bl-U1 was drilled in undisturbed alluvium adjacent to the disposal unit. The U3ax/bl disposal unit is located within two conjoined subsidence craters, U3ax and U3bl, which were created by underground nuclear testing. Data from these boreholes were collected to support site characterization activities for the U3ax/bl disposal unit and the entire Area 3 RWMS. Site characterization at disposal units within the Area 3 RWMS must address the possibility that subsidence craters and associated disturbed alluvium of the chimneys beneath the craters might serve as pathways for contaminant migration. The two boreholes were drilled and sampled to compare hydrogeologic properties of alluvium below the waste disposal unit with those of adjacent undisturbed alluvium. Whether Borehole UE-3bl-D1 actually penetrated the chimney of the U3bl crater is uncertain. Analyses of core samples showed little difference in hydrogeologic properties between the two boreholes. Important findings of this study include the following: No hazardous or radioactive constituents of waste disposal concern were found in the samples obtained from either borehole. No significant differences in physical and hydrogeologic properties between boreholes is evident, and no evidence of significant trends with depth for any of these properties was observed. The values observed are typical of sandy materials. The alluvium is dry, with volumetric water content ranging from 5.6 to 16.2 percent. Both boreholes exhibit a slight increase in water content with depth, the only such trend observed. Water potential measurements on core samples from both boreholes show a large positive

Site Characterization Data from the U3ax/bl Exploratory Boreholes at the Nevada Test Site

Energy Technology Data Exchange (ETDEWEB)

Bechtel Nevada; U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office

2005-08-01

This report provides qualitative analyses and preliminary interpretations of hydrogeologic data obtained from two 45-degree, slanted exploratory boreholes drilled within the Area 3 Radioactive Waste Management Site (RWMS) at the Nevada Test Site. Borehole UE-3bl-D1 was drilled beneath the U3ax/bl mixed waste disposal unit, and Borehole UE-3bl-U1 was drilled in undisturbed alluvium adjacent to the disposal unit. The U3ax/bl disposal unit is located within two conjoined subsidence craters, U3ax and U3bl, which were created by underground nuclear testing. Data from these boreholes were collected to support site characterization activities for the U3ax/bl disposal unit and the entire Area 3 RWMS. Site characterization at disposal units within the Area 3 RWMS must address the possibility that subsidence craters and associated disturbed alluvium of the chimneys beneath the craters might serve as pathways for contaminant migration. The two boreholes were drilled and sampled to compare hydrogeologic properties of alluvium below the waste disposal unit with those of adjacent undisturbed alluvium. Whether Borehole UE-3bl-D1 actually penetrated the chimney of the U3bl crater is uncertain. Analyses of core samples showed little difference in hydrogeologic properties between the two boreholes. Important findings of this study include the following: No hazardous or radioactive constituents of waste disposal concern were found in the samples obtained from either borehole. No significant differences in physical and hydrogeologic properties between boreholes is evident, and no evidence of significant trends with depth for any of these properties was observed. The values observed are typical of sandy materials. The alluvium is dry, with volumetric water content ranging from 5.6 to 16.2 percent. Both boreholes exhibit a slight increase in water content with depth, the only such trend observed. Water potential measurements on core samples from both boreholes show a large positive

Evaluation of induced seismicity forecast models in the Induced Seismicity Test Bench

Science.gov (United States)

Király, Eszter; Gischig, Valentin; Zechar, Jeremy; Doetsch, Joseph; Karvounis, Dimitrios; Wiemer, Stefan

2016-04-01

Induced earthquakes often accompany fluid injection, and the seismic hazard they pose threatens various underground engineering projects. Models to monitor and control induced seismic hazard with traffic light systems should be probabilistic, forward-looking, and updated as new data arrive. Here, we propose an Induced Seismicity Test Bench to test and rank such models. We apply the test bench to data from the Basel 2006 and Soultz-sous-Forêts 2004 geothermal stimulation projects, and we assess forecasts from two models that incorporate a different mix of physical understanding and stochastic representation of the induced sequences: Shapiro in Space (SiS) and Hydraulics and Seismics (HySei). SiS is based on three pillars: the seismicity rate is computed with help of the seismogenic index and a simple exponential decay of the seismicity; the magnitude distribution follows the Gutenberg-Richter relation; and seismicity is distributed in space based on smoothing seismicity during the learning period with 3D Gaussian kernels. The HySei model describes seismicity triggered by pressure diffusion with irreversible permeability enhancement. Our results show that neither model is fully superior to the other. HySei forecasts the seismicity rate well, but is only mediocre at forecasting the spatial distribution. On the other hand, SiS forecasts the spatial distribution well but not the seismicity rate. The shut-in phase is a difficult moment for both models in both reservoirs: the models tend to underpredict the seismicity rate around, and shortly after, shut-in. Ensemble models that combine HySei's rate forecast with SiS's spatial forecast outperform each individual model.

Hydrologic testing methodology and results from deep basalt boreholes

International Nuclear Information System (INIS)

Strait, S.R.; Spane, F.A.; Jackson, R.L.; Pidcoe, W.W.

1982-05-01

The objective of the hydrologic field-testing program is to provide data for characterization of the groundwater systems wihin the Pasco Basin that are significant to understanding waste isolation. The effort is directed toward characterizing the areal and vertical distributions of hydraulic head, hydraulic properties, and hydrochemistry. Data obtained from these studies provide input for numerical modeling of groundwater flow and solute transport. These models are then used for evaluating potential waste migration as a function of space and time. The groundwater system beneath the Hanford Site and surrounding area consists of a thick, accordantly layered sequence of basalt flows and associated sedimentary interbed that primarily occur in the upper part of the Columbia River basalt. Permeable horizons of the sequence are associated with the interbeds and the interflow zones within the basalt. The columnar interiors of a flow act as low-permeability aquitards, separating the more-permeable interflows or interbeds. This paper discusses the hydrologic field-gathering activities, specifically, field-testing methodology and test results from deep basalt boreholes

Application of conditional simulation of heterogeneous rock properties to seismic scattering and attenuation analysis in gas hydrate reservoirs

Science.gov (United States)

Huang, Jun-Wei; Bellefleur, Gilles; Milkereit, Bernd

2012-02-01

We present a conditional simulation algorithm to parameterize three-dimensional heterogeneities and construct heterogeneous petrophysical reservoir models. The models match the data at borehole locations, simulate heterogeneities at the same resolution as borehole logging data elsewhere in the model space, and simultaneously honor the correlations among multiple rock properties. The model provides a heterogeneous environment in which a variety of geophysical experiments can be simulated. This includes the estimation of petrophysical properties and the study of geophysical response to the heterogeneities. As an example, we model the elastic properties of a gas hydrate accumulation located at Mallik, Northwest Territories, Canada. The modeled properties include compressional and shear-wave velocities that primarily depend on the saturation of hydrate in the pore space of the subsurface lithologies. We introduce the conditional heterogeneous petrophysical models into a finite difference modeling program to study seismic scattering and attenuation due to multi-scale heterogeneity. Similarities between resonance scattering analysis of synthetic and field Vertical Seismic Profile data reveal heterogeneity with a horizontal-scale of approximately 50 m in the shallow part of the gas hydrate interval. A cross-borehole numerical experiment demonstrates that apparent seismic energy loss can occur in a pure elastic medium without any intrinsic attenuation of hydrate-bearing sediments. This apparent attenuation is largely attributed to attenuative leaky mode propagation of seismic waves through large-scale gas hydrate occurrence as well as scattering from patchy distribution of gas hydrate.

Local seismic network at the Olkiluoto site. Annual Report for 2007

International Nuclear Information System (INIS)

Saari, J.; Lakio, A.

2008-05-01

In February 2002, Posiva Oy established a local seismic network of six stations on the island of Olkiluoto. Later, in June 2004, the seismic network was expanded with two new seismic stations. At that time started the excavation of the underground characterisation facility (the ONKALO) and the basic operation procedure was changed more suitable for the demands of the new situation. In the beginning of 2006, the target area of the seismic monitoring expanded to semiregional scale. Four new seismic stations started in the beginning of February 2006 and the focus of interpretation was expanded to an area, called the seismic semi-regional area. At the end of 2006, two new borehole geophones were installed in order to improve the sensitivity and the depth resolution of the measurements inside the ONKALO block. The purpose of the microearthquake measurements at Olkiluoto is to improve understanding of the structure, behaviour and long term stability of the bedrock. The studies include both tectonic and excavation-induced microearthquakes. An additional task of monitoring is related to safeguarding of the ONKALO. This report gives the results of microseismic monitoring during the year 2007. Also the changes in the structure and the operation procedure of the network are described. The true orientation of the borehole sensor OL-OS13 was calculated. The correct orientation of triaxial seismometer is essential when the fault plane solution of an earthquake is calculated. The other borehole sensor OL-OS14 was permanently disconnected in October 2007. The network has operated continuously in 2007. Altogether 2207 events have been located in the Olkiluoto area, in reported time period. Altogether 2207 events have been located in 2007. Most of them (1912) are explosions occurred inside the seismic semiregional area and especially inside the ONKALO block (1891 events). The magnitudes of the observed events inside the semi-regional area range from ML = -2.1 to ML = 1.5 (ML

Reassessment of seismic reflection data from the Finnsjoen study site and prospectives for future surveys

International Nuclear Information System (INIS)

Cosma, C.; Juhlin, C.

1994-02-01

Reprocessing of data from the seismic reflection survey performed at Finnsjoen in 1987 show that reflection seismics is a viable technique for mapping fracture zones in crystalline rock. Application of state of the art processing algorithms clearly image a gently dipping fracture zone located in the depth interval 200-400 m. In addition, several other reflectors were imaged in the reprocessed section, both gently and steeply dipping ones. Correlations with borehole data indicate that the origin of these reflections are also fractures zones. The data acquisition procedures used at the Finnsjoen survey were basically sound and could, with minor modifications, be applied at other sites. The results indicate that both sources and receivers in future surveys should be placed in boreholes a few meter below the ground surface. 30 refs

Hydrologic test results for the Rattlesnake Ridge interbed and Pomona basalt flow top at Borehole DB-15

International Nuclear Information System (INIS)

Strait, S.R.; Brown, W.R.

1983-07-01

This report presents results and description of hydrologic test activities for the Rattlesnake Ridge interbed and Pomona basalt flow top at Borehole DB-15. Hydrologic tests conducted include constant discharge air-lift and constant discharge submersible pumping tests. An observed hydraulic head for the test interval was 409 ± 1 feet above mean sea level. Transmissivity values determined from hydrologic tests performed, ranged between 493 and 469 ft 2 /day. The best estimate of transmissivity is 480 ft 2 /day. The best estimate of equivalent hydraulic conductivity, based on an effective test thickness of 56 feet is 8.6 ft/day. 4 refs., 7 figs., 2 tabs

Interpretation of reflection seismics in the area North of Laegeren - Zurich Weinland

International Nuclear Information System (INIS)

Naef, H.; Birkhaeuser, P.; Roth, P.

1995-05-01

The investigations of potential siting areas for a repository for high-level radioactive waste which are concentrated in the crystalline basement of Northern Switzerland have been expanded since the late 1980s to include suitable sedimentary units. After extensive desk study evaluation, the approximately 100 m thick Opalinus Clay of the Tabular Jura east of the Aare river was chosen as the most promising sedimentary option. In this area not only the Opalinus Clay but also the over- and underlying units are clay-rich, in contrast to the tabular Jura west of the Aare river. In the area North of Laegeren - Zurich Weinland, where the Opalinus Clay is situated in the optimum depth range of 400 to 1000 m below surface, approximately 220 km of new high-resolution seismic profiles were recorded and interpreted together with existing seismic lines. Due to thorough field work and data processing, a very good quality of seismic lines was obtained. This allowed precise mapping of the marker horizons in general and the Opalinus Clay in detail. The goal of this study was to determine and delineate the most important tectonic units as well as to describe the potential host rocks in these units. By way of interactive interpretation of all available seismic lines, borehole data and surface data from the investigation area, depth maps of the most prominent marker horizons have been calculated and geological cross-sections constructed along the new seismic lines. The regional seismic character of the Middle Mesozoic units was modelled using borehole data from Weiach and Herdern. From this model the thickness of the Opalinus Clay along the new seismic lines was determined. The results indicate a relatively constant thickness of 95 to 120 m in the investigation area. (author) figs., tabs., refs

Waste Isolation Pilot Plant borehole data

International Nuclear Information System (INIS)

1995-04-01

Data pertaining to all the surface boreholes used at the WIPP site for site characterization hydrological testing and resource evaluation exist in numerous source documents. This project was initiated to develop a comprehensive data base that would include the data on all WIPP related surface boreholes from the Atomic Energy Commission, Waste Isolation Pilot Plant Energy Research and Development Administration, Department of Energy, and Hydrologic Test Borehole Programs. The data compiled from each borehole includes: operator, permit number, location, total depth, type of well, driller, drilling record, casing record, plugging schedule, and stratigraphic summary. There are six groups of boreholes contained in this data base, they are as follows: Commercially Drilled Potash Boreholes, Energy Department Wells, Geologic Exploration Boreholes, Hydrologic Test Boreholes, Potash Boreholes, and Subsurface Exploration Boreholes. There were numerous references which contained borehole data. In some cases the data found in one document was inconsistent with data in another document. In order to ensure consistency and accuracy in the data base, the same references were used for as many of the boreholes as possible. For example, all elevations and locations were taken from Compilation and Comparison of Test-Hole Location Surveys in the Vicinity of the WIPP Site. SAND 88-1065, Table 3-5. There are some sections where a data field is left blank. In this case, the information was either not applicable or was unavailable

Waste Isolation Pilot Plant borehole data

Energy Technology Data Exchange (ETDEWEB)

NONE

1995-04-01

Data pertaining to all the surface boreholes used at the WIPP site for site characterization hydrological testing and resource evaluation exist in numerous source documents. This project was initiated to develop a comprehensive data base that would include the data on all WIPP related surface boreholes from the Atomic Energy Commission, Waste Isolation Pilot Plant Energy Research and Development Administration, Department of Energy, and Hydrologic Test Borehole Programs. The data compiled from each borehole includes: operator, permit number, location, total depth, type of well, driller, drilling record, casing record, plugging schedule, and stratigraphic summary. There are six groups of boreholes contained in this data base, they are as follows: Commercially Drilled Potash Boreholes, Energy Department Wells, Geologic Exploration Boreholes, Hydrologic Test Boreholes, Potash Boreholes, and Subsurface Exploration Boreholes. There were numerous references which contained borehole data. In some cases the data found in one document was inconsistent with data in another document. In order to ensure consistency and accuracy in the data base, the same references were used for as many of the boreholes as possible. For example, all elevations and locations were taken from Compilation and Comparison of Test-Hole Location Surveys in the Vicinity of the WIPP Site. SAND 88-1065, Table 3-5. There are some sections where a data field is left blank. In this case, the information was either not applicable or was unavailable.

Inter-source seismic interferometry by multidimensional deconvolution (MDD) for borehole sources

NARCIS (Netherlands)

Liu, Y.; Wapenaar, C.P.A.; Romdhane, A.

2014-01-01

Seismic interferometry (SI) is usually implemented by crosscorrelation (CC) to retrieve the impulse response between pairs of receiver positions. An alternative approach by multidimensional deconvolution (MDD) has been developed and shown in various studies the potential to suppress artifacts due to

Effects of the deviation characteristics of nuclear waste emplacement boreholes on borehole liner stresses; Yucca Mountain Project

Energy Technology Data Exchange (ETDEWEB)

Glowka, D.A.

1990-09-01

This report investigates the effects of borehole deviation on the useability of lined boreholes for the disposal of high-level nuclear waste at the proposed Yucca Mountain Repository in Nevada. Items that lead to constraints on borehole deviation include excessive stresses that could cause liner failure and possible binding of a waste container inside the liner during waste emplacement and retrieval operations. Liner stress models are developed for two general borehole configurations, one for boreholes drilled with a steerable bit and one for boreholes drilled with a non-steerable bit. Procedures are developed for calculating liner stresses that arise both during insertion of the liner into a borehole and during the thermal expansion process that follows waste emplacement. The effects of borehole curvature on the ability of the waste container to pass freely inside the liner without binding are also examined. Based on the results, specifications on borehole deviation allowances are developed for specific vertical and horizontal borehole configurations of current interest. 11 refs., 22 figs., 4 tabs.

PBO Borehole Strainmeters: 2017 Episodic Tremor and Slip Event for Southern Vancouver Island, BC, Canada through Olympia, WA, USA

Science.gov (United States)

Van Boskirk, E. J.; Hodgkinson, K. M.; Gottlieb, M. H.; Johnson, W.; Henderson, D. B.; Mencin, D.; Mattioli, G. S.

2017-12-01

The Plate Boundary Observatory's (PBO) borehole strainmeters along the Cascadia Subduction Zone (CSZ) record the development and migration of Episodic Tremor and Slip (ETS). Along the southern Vancouver Island to Olympia, WA portion of the CSZ ETS events seem to repeat every 14 months. ETS events are non-volcanic tremor swarms that occur over periods of weeks, often migrating along segments of the subduction zone and can release the energy equivalent to a M7 or greater earthquake. Each ETS event is different; initial propagation location, ETS movement, duration, and direction all vary. Constraints provided by strainmeter observations of ETS events illuminate strain release patterns along the subducting slab interface and may help resolve questions regarding the location of the locked zone of the slab and what role ETS events play in the CSZ earthquake cycle. The 2017 CSZ ETS began in early February continuing through early April. Beginning in the northern Olympic Peninsula, near Port Angeles, it migrated south towards Olympia over the course of a week. After a two week pause it resumed under the Straits of Juan de Fuca and propagated northwest under Vancouver Island. There are 15 PBO borehole strainmeters along this segment, and ETS strain observations correlate with seismic and GPS measurements. The PBO borehole strainmeters are sensitive even over great distances from the ETS epicenters, and observe compression or extension relative to the ETS migration. Openly available PBO borehole strainmeter data used by the community has made significant contributions to understanding the ETS process, including the determination that ETS slip is tidally modulated. Data are publically available through UNAVCO and IRIS, which provide links to online tutorials and scripts. There are 32 strainmeters covering the CSZ from southern Vancouver Island, Canada to northern California, USA, and data spans back to 2005. Each site has a Gladwin tensor borehole strainmeter, a Malin three

Addresing environmental challenges to shale gas and hydraulic fracturing

Energy Technology Data Exchange (ETDEWEB)

Vadillo Fernandez, L.; Rodriguez Gomez, V.; Fernadez Naranjo, F.J.

2016-07-01

This article reviews the main issues of unconventional gas extracted by hydraulic fracturing techniques. Topics such as technology, fracturing stages, flowback characterization and alternatives of disposal and reuse, water consumption, physicochemical features of the geological formations, development of the fractures performed by hydraulic fracturing, well flow decline, land use and occupation and induced seismicity are presented, as well as the scientific debate: the potential steps of methane gas and groundwater contamination. (Author)

Anatomy of the high-frequency ambient seismic wave field at the TCDP borehole.

OpenAIRE

Hillers , Gregor; Campillo , Michel; Lin , Y.-Y.; Ma , K.F.; Roux , Philippe

2012-01-01

International audience; The Taiwan Chelungpu-fault Drilling Project (TCDP) installed a vertical seismic array between 950 and 1270 m depth in an active thrust fault environment. In this paper we analyze continuous noise records of the TCDP array between 1 and 16 Hz. We apply multiple array processing and noise correlation techniques to study the noise source process, properties of the propagation medium, and the ambient seismic wave field. Diurnal amplitude and slowness patterns suggest that ...

Radiation borehole logging method

International Nuclear Information System (INIS)

Wylie, A.; Mathew, P.J.

1977-01-01

A method of obtaining an indication of the diameter of a borehole is described. The method comprises subjecting the walls of the borehole to monoenergetic gamma radiation and making measurements of the intensity of gamma radiation backscattered from the walls. The energy of the radiation is sufficiently high for the shape to be substantially independent of the density and composition of the borehole walls

Report on the Test and Evaluation of the Kinemetrics/Quanterra Q730B Borehole Digitizers; TOPICAL

International Nuclear Information System (INIS)

KROMER, RICHARD P.; MCDONALD, TIMOTHY S.

1999-01-01

Sandia National Laboratories has tested and evaluated the Kinemetrics/Quanterra Q730B-bb (broadband) and Q730B-sp (short period) borehole installation remote digitizers. The test results included in this report were for response to static and dynamic input signals, seismic application performance, data time-tag accuracy, and reference signal generator (calibrator) performance. Most test methodologies used were based on IEEE Standards 1057 for Digitizing Waveform Recorders and P1241 (Preliminary Draft) for Analog to Digital Converters; others were designed by Sandia specifically for seismic application evaluation and for supplementary criteria not addressed in the IEEE standards. When appropriate, test instrumentation calibration is traceable to the National Institute for Standards Technology (NIST)

Neutron borehole logging correction technique

International Nuclear Information System (INIS)

Goldman, L.H.

1978-01-01

In accordance with an illustrative embodiment of the present invention, a method and apparatus is disclosed for logging earth formations traversed by a borehole in which an earth formation is irradiated with neutrons and gamma radiation produced thereby in the formation and in the borehole is detected. A sleeve or shield for capturing neutrons from the borehole and producing gamma radiation characteristic of that capture is provided to give an indication of the contribution of borehole capture events to the total detected gamma radiation. It is then possible to correct from those borehole effects the total detected gamma radiation and any earth formation parameters determined therefrom

Linkages of fracture network geometry and hydro-mechanical properties to spatio-temporal variations of seismicity in Koyna-Warna Seismic Zone

Science.gov (United States)

Selles, A.; Mikhailov, V. O.; Arora, K.; Ponomarev, A.; Gopinadh, D.; Smirnov, V.; Srinu, Y.; Satyavani, N.; Chadha, R. K.; Davulluri, S.; Rao, N. P.

2017-12-01

Well logging data and core samples from the deep boreholes in the Koyna-Warna Seismic Zone (KWSZ) provided a glimpse of the 3-D fracture network responsible for triggered earthquakes in the region. The space-time pattern of earthquakes during the last five decades show strong linkage of favourably oriented fractures system deciphered from airborne LiDAR and borehole structural logging to the seismicity. We used SAR interferometry data on surface displacements to estimate activity of the inferred faults. The failure in rocks at depths is largely governed by overlying lithostatic and pore fluid pressure in the rock matrix which are subject to change in space and time. While lithostatic pressure tends to increase with depth pore pressure is prone to fluctuations due to any change in the hydrological regime. Based on the earthquake catalogue data, the seasonal variations in seismic activity associated with annual fluctuations in the reservoir water level were analyzed over the time span of the entire history of seismological observations in this region. The regularities in the time changes in the structure of seasonal variations are revealed. An increase in pore fluid pressure can result in rock fracture and oscillating pore fluid pressures due to a reservoir loading and unloading cycles can cause iterative and cumulative damage, ultimately resulting in brittle failure under relatively low effective mean stress conditions. These regularities were verified by laboratory physical modeling. Based on our observations of main trends of spatio-temporal variations in seismicity as well as the spatial distribution of fracture network a conceptual model is presented to explain the triggered earthquakes in the KWSZ. The work was supported under the joint Russian-Indian project of the Russian Science Foundation (RSF) and the Department of Science and Technology (DST) of India (RSF project no. 16-47-02003 and DST project INT/RUS/RSF/P-13).

Hydraulic testing around Room Q: Evaluation of the effects of mining on the hydraulic properties of Salado Evaporites

Energy Technology Data Exchange (ETDEWEB)

Domski, P.S.; Upton, D.T. [INTERA, Inc., Albuquerque, NM (United States); Beauheim, R.L. [Sandia National Laboratories, Albuquerque, NM (United States)

1996-03-01

Room Q is a 109-m-long cylindrical excavation in the Salado Formation at the Waste Isolation Pilot Plant (WIPP) site. Fifteen boreholes were drilled and instrumented around Room Q so that tests could be conducted to determine the effects of room excavation on the hydraulic properties of the surrounding evaporate rocks. Pressure-buildup and pressure-pulse tests were conducted in all of the boreholes before Room Q was mined. The data sets from only eight of the boreholes are adequate for parameter estimation, and five of those are of poor quality. Constant-pressure flow tests and pressure-buildup tests were conducted after Room Q was mined, producing eleven interpretable data sets, including two of poor quality. Pre-mining transmissivities interpreted from the three good-quality data sets ranged from 1 x 10{sup -15} to 5 x 10{sup -14} m{sup 2}/s (permeability-thickness products of 2 x 10{sup -22} to 9 x 10{sup -21} m{sup 3}) for test intervals ranging in length from 0.85 to 1.37 m. Pre-mining average permeabilities, which can be considered representative of undisturbed, far-field conditions, were 6 x 10{sup -20} and 8 x 10{sup -20} m{sup 2} for anhydrite, and 3 x 10{sup -22} m{sup 2} for halite. Post-mining transmissivities interpreted from the good-quality data sets ranged from 1 x 10{sup -16} to 3 x 10{sup -13} m{sup 2}/s (permeability-thickness products of 2 x 10{sup -23} to 5 x 10{sup -20} m{sup 3}). Post-mining average permeabilities for anhydrite ranged from 8 x 10{sup -20} to 1 x 10{sup -19} m{sup 2}. The changes in hydraulic properties and pore pressures that were observed can be attributed to one or a combination of three processes: stress reduction, changes in pore connectivity, and flow towards Room Q. The effects of the three processes cannot be individually quantified with the available data.

Hydraulic testing around Room Q: Evaluation of the effects of mining on the hydraulic properties of Salado Evaporites

International Nuclear Information System (INIS)

Domski, P.S.; Upton, D.T.; Beauheim, R.L.

1996-03-01

Room Q is a 109-m-long cylindrical excavation in the Salado Formation at the Waste Isolation Pilot Plant (WIPP) site. Fifteen boreholes were drilled and instrumented around Room Q so that tests could be conducted to determine the effects of room excavation on the hydraulic properties of the surrounding evaporate rocks. Pressure-buildup and pressure-pulse tests were conducted in all of the boreholes before Room Q was mined. The data sets from only eight of the boreholes are adequate for parameter estimation, and five of those are of poor quality. Constant-pressure flow tests and pressure-buildup tests were conducted after Room Q was mined, producing eleven interpretable data sets, including two of poor quality. Pre-mining transmissivities interpreted from the three good-quality data sets ranged from 1 x 10 -15 to 5 x 10 -14 m 2 /s (permeability-thickness products of 2 x 10 -22 to 9 x 10 -21 m 3 ) for test intervals ranging in length from 0.85 to 1.37 m. Pre-mining average permeabilities, which can be considered representative of undisturbed, far-field conditions, were 6 x 10 -20 and 8 x 10 -20 m 2 for anhydrite, and 3 x 10 -22 m 2 for halite. Post-mining transmissivities interpreted from the good-quality data sets ranged from 1 x 10 -16 to 3 x 10 -13 m 2 /s (permeability-thickness products of 2 x 10 -23 to 5 x 10 -20 m 3 ). Post-mining average permeabilities for anhydrite ranged from 8 x 10 -20 to 1 x 10 -19 m 2 . The changes in hydraulic properties and pore pressures that were observed can be attributed to one or a combination of three processes: stress reduction, changes in pore connectivity, and flow towards Room Q. The effects of the three processes cannot be individually quantified with the available data

Influence of various excavation techniques on the structure and physical properties of 'near-field' rock around large boreholes

International Nuclear Information System (INIS)

Pusch, R.

1989-12-01

The procedure employed in the excavation of canister deposition holes affects the structure and physical properties of the 'near-field' rock. Except for smooth blasting, the generated damage appears to be less important than the increase in 'axial' hydraulic conductivity that is caused by stress release effects, but both combine to yield significant local flow passages. This is particularly obvious where the rock structure yield steep wedges, which is frequently occurring in granite. Percussion drilling is concluded to cause rich fine-fissuring to a distance of up to one centimeter from the borehole wall, and 'discing'. Richer fissuring and some generation of new fractures and growth of preexisting ones are produced within several decimeters from the borehole wall by full-face drilling. Core drilling has the least effect on the rock structure. Smooth blasting produces a particular form of regular fractures which appear to be determinants of the hydraulic conductivity of the near-field rock. Theoretically, its conductivity in the axial direction of blasted big holes or tunnels should be in the range of 10 -8 - 10 -6 m/s, which is in agreement with measurements in the Stripa mine. (orig.)

Cleaning of boreholes

International Nuclear Information System (INIS)

Rautio, T.; Alaverronen, M.; Lohva, K.; Teivaala, V.

2004-09-01

In terms of long-term safety it is a risk that the boreholes can eventually function as short-circuits between the repository and ground surface. Therefore sealing of investigation boreholes is an important issue for the long- term safety of high-level nuclear waste repositories. In order to seal a borehole properly, the conditions of the borehole have to meet certain predetermined requirements. One of the requirements is that no instruments or materials endangering the plugging operation or the long-term function of the sealing materials, are allowed to be left in the borehole. Sometimes drilling equipment will be left in the hole or it cannot be recovered from the hole with the given constraints of time, cost and resources in spite of attempts. Additionally various measurements may be carried out in the holes after the drilling has been completed and measuring devices may get stuck in holes. Consequently cleaning of the borehole is carried out as an essential activity before sealing can be implemented. There are two common reasons identified for the drill strings to get stuck in holes. First the drill string may get stuck due to acute drilling problems. The second case is where rods are left as casing in a hole either based on the structure of the upper part of the hole or in order to support the hole. To remove the drilling or measuring equipment lost in a borehole, special techniques and professional skill must be applied. Removing measuring equipment from a hole is often demanding and time consuming work. A vital part of the cleaning operation is planning the work in advance. In order to make the plan and to select the suitable methods it is important to know the condition of the stuck material. It is also important to know the exact depth where the equipment are stuck and to have an estimate of the reasons why they have got stuck. It is also very important to know the correct dimensions of the equipment or drill string before commencing the cleaning work

Assimilation of ambient seismic noise in hydrological models allows estimation of hydraulic conductivity in unsaturated media

Science.gov (United States)

Fores, B.; Champollion, C.; Mainsant, G.; Fort, A.; Albaric, J.

2016-12-01

Karstic hydrosystems represent one of the main water resources in the Mediterranean area but are challenging for geophysical methods. The GEK (Geodesy in Karstic Environment) observatory has been setup in 2011 to study the unsaturated zone of a karstic system in the south of France. The unsaturated zone (the epikarst) is thick and up to 100m on the site. Since 2011, gravity, rainfall and evapotranspiration are monitored. Together, they allow precise estimation of the global water storage changes but lack depth resolution. Surface waves velocity variations, obtained from ambient seismic noise monitoring are used here to overcome this lack. Indeed, velocities depend on saturation and the depths where changes occur can be defined as surface waves are dispersive. From October 2014 to November 2015, two seismometers have been recording noise. Velocity changes at a narrow frequency band (6-8 Hz) have shown a clear annual cycle. Minimum velocity is several months late on precipitations, which is coherent with a slow infiltration and a maximum sensitivity at -40m for these frequencies and this site. Models have been made with the Hydrus-1D software which allows modeling 1D-flow in variably saturated media. With a stochastic sampling, we have researched the underground parameters that reproduce the most the different observations (gravity, evapotranspiration and rainfall, and velocity changes). We show that velocity changes clearly constrain the hydraulic conductivity of the medium. Ambient seismic noise is therefore a promising method to study unsaturated zone which are too deep or too heterogeneous for classic methods.

A compendium of P- and S-wave velocities from surface-to-borehole logging; summary and reanalysis of previously published data and analysis of unpublished data

Science.gov (United States)

Boore, David M.

2003-01-01

For over 28 years, the U.S. Geological Survey (USGS) has been acquiring seismic velocity and geologic data at a number of locations in California, many of which were chosen because strong ground motions from earthquakes were recorded at the sites. The method for all measurements involves picking first arrivals of P- and S-waves from a surface source recorded at various depths in a borehole (as opposed to noninvasive methods, such as the SASW method [e.g., Brown et al., 2002]). The results from most of the sites are contained in a series of U.S. Geological Survey Open-File Reports (see References). Until now, none of the results have been available as computer files, and before 1992 the interpretation of the arrival times was in terms of piecemeal interval velocities, with no attempt to derive a layered model that would fit the travel times in an overall sense (the one exception is Porcella, 1984). In this report I reanalyze all of the arrival times in terms of layered models for P- and for S-wave velocities at each site, and I provide the results as computer files. In addition to the measurements reported in the open-file reports, I also include some borehole results from other reports, as well as some results never before published. I include data for 277 boreholes (at the time of this writing; more will be added to the web site as they are obtained), all in California (I have data from boreholes in Washington and Utah, but these will be published separately). I am also in the process of interpreting travel time data obtained using a seismic cone penetrometer at hundreds of sites; these data can be interpreted in the same way of those obtained from surface-to-borehole logging. When available, the data will be added to the web site (see below for information on obtaining data from the World Wide Web (WWW)). In addition to the basic borehole data and results, I provide information concerning strong-motion stations that I judge to be close enough to the boreholes

Thermophysical parameters from laboratory measurements and tests in borehole heat exchangers

Science.gov (United States)

Pacetti, Chiara; Giuli, Gabriele; Invernizzi, Chiara; Chiozzi, Paolo; Verdoya, Massimo

2017-04-01

Besides the type of thermal regime, the performance of borehole heat exchangers relies on the overall thermal resistance of the borehole. This parameter strongly depends on the underground thermal conductivity, which accounts for most of the heat that can be extracted. The geometric configuration and the increase of thermal conductivity of the grout filling back the bore can yield a non-negligible enhancement in thermal performances. In this paper, we present a study on a pilot geothermal plant consisting of two borehole heat exchangers, 95 m deep and 9 m apart. Laboratory and in situ tests were carried out with the aim of investigating underground thermal properties, mechanisms of heat transfer and thermal characteristics of the filling grouts. Samples of grouting materials were analysed in the lab for assessing the thermal conductivity. An attempt to improve the thermal conductivity was made by doping grouts with alumina. Results showed that alumina large concentrations can increase the thermal conductivity by 25-30%. The in situ experiments included thermal logs under conditions of thermal equilibrium and thermal response tests (TRTs). The analysis of the temperature-depth profiles, based on the mass and energy balance in permeable horizons with uniform thermo-hydraulic and steady-state conditions, revealed that the underground thermal regime is dominated by conduction. TRTs were performed by injecting a constant heat rate per unit length into the boreholes for 60-90 hours. After TRTs, the temperature drop off (TDO) was recorded at 20-m-depth intervals for one week in both holes. The TRT time series were interpreted according to the classical model of the infinite line source (ILS), to infer the underground thermal conductivity. The TDO records allowed the inference of the underground thermal properties variation with depth. The results of thermal conductivity inferred with the ILS method are consistent with the values obtained from the TDO analysis.

Groundwater sampling and chemical characterisation of the Laxemar deep borehole KLX02

International Nuclear Information System (INIS)

Laaksoharju, M.; Skaarman, C.; Smellie, J.; Nilsson, A.C.

1995-02-01

The Laxemar deep borehole, KLX02 (1705 m depth), located close to the Aespoe Hard Rock Laboratory (HRL), has been investigated. Groundwater sampling was conducted on two occasions and using different methods. The first sampling was taken in the open borehole using the so-called Tube sampler; the second sampling carried out using the SKB-packer equipment to isolate pre-determined borehole sections. Groundwater compositions consist of two distinct groupings; one shallow to intermediate Sodium-Bicarbonate type (Na(Ca,K):HC 3 Cl(SO 4 )) to a depth of 1000 m, and the other of deep origin, a calcium-chloride type (Ca-Na(K):Cl-SO 4 (Br)), occurring below 1000 m. The deep brines contain up to 46000 mg of Cl per litre. The influence of borehole activities are seen in the tritium data which record significant tritium down to 1000 m, and even to 1420 m. Mixing modelling shows that water from the 1960's is the main source for this tritium. The high tritium values in the 1090-1096.2 m section are due to contamination of 1% shallow water from 1960 and 2% of modern shallow water. The upper 800 m of bedrock at Laxemar lies within a groundwater recharge area; the sub-vertical to moderate angled fracture zones facilitate groundwater circulation to considerable depths, at least to 800 m, thus accounting for some of the low saline brackish groundwaters in these conducting fracture zones. Below 1000 m the system is hydraulically and geochemically 'closed' such that highly saline brines exist in a near-stagnant environment. 30 refs, 22 figs, 8 tabs

Western Gas Sands Project. Status report, 1 August-31 August, 1979

Energy Technology Data Exchange (ETDEWEB)

None

1979-01-01

This status report summarizes progress of government-sponsored projects directed toward increasing gas production from the low-permeability gas sands of the western United States. Work on fracture conductivity, rock-fluid interaction, and log evaluation and interpretation techniques continued at Bartlesville. Work commenced on completing, testing and possible hydraulic fracturing of the Rio Blanco Natural Gas Company well No. 397-19-1 and on the evaluation of seismic data for stratigraphic studies of lenticular sands. LLL continued experimental and theoretical work on hydraulic fracturing mechanics and analysis of well test data. LASL worked on developing NMR methods to define fluid saturation, porosity, and permeability of western gas sands at in situ conditions. M.D. Wood, Inc. was involved in design and site preparation for two hydraulic fracture mapping jobs in the Cotton Valley Trend in Texas. Testing and analyses of the borehole seismic system and borehole hydrophone system continued at Sandia. Field tests and related activities for the WGSP progressed as scheduled in August. Cyclic injection of dehydrated natural gas and production in Colorado Interstate Gas Company's Miller No. 1 and Sprague No. 1 wells continued. The Gas Producing Enterprises, Inc. wells, Natural Buttes Units 9, 14, 18 and 20 flowed to sales. The Mitchell Energy Corporation Muse-Duke No. 1 was shut-in for a 15-day pressure buildup test. Hydraulic fracture containment experiments and activities in the multi-frac test series continued at the Nevada Test Site for Sandia Laboratories' mineback program.

Hydro-mechanical analysis of results acquired by video-observations and deformation measurements performed in boreholes in the Opalinus clay of the URL Mont Terri supported by laboratory investigations on the hydro-mechanical behaviour of Opalinus clay

International Nuclear Information System (INIS)

Seeska, R.; Rutenberg, M.; Lux, K.H.

2012-01-01

also be detected. Furthermore, a significant influence of the hydraulic behaviour on the load-bearing and deformation behaviour of the investigated boreholes was observed. Therefore, laboratory investigations regarding the hydraulic sensitivity of Opalinus Clay have been performed in the TUC rock mechanic laboratory on rock samples from the URL Mont Terri in addition to the in-situ observations. To investigate the hydraulic sensitivity and the hydro-mechanically coupled behaviour of the clay-stone samples, a series of uniaxial strength tests with precisely controlled relative humidity and temperature of the air surrounding the specimen inside the test rig has been performed. Eventually, an attempt has been made to hydro-mechanically model the observed borehole behaviour by using a three-dimensional model covering a drift section and a borehole within the near field of the drift. The numerical simulations have been performed using an elastoplastic constitutive model named ubiquitous joint. Implemented in the FLAC3D software code, the constitutive model ubiquitous joint is capable of modelling the mechanical behaviour of the rock matrix as well as the highly anisotropic mechanical behaviour of the bedding planes. Furthermore, effects like time dependent desaturation of the rock mass, a reduction of strength in the damaged zones around the drift and the borehole, and the increase of hydraulic permeability within the damaged zones have also been taken into consideration when performing the numerical simulations. Figure 2 exemplarily shows the calculated pore pressure distribution around the drift and the borehole in a cross section along the borehole's longitudinal axis. The presentation includes a brief discussion of the results obtained by the logging tool and the discussion of the borehole videos that were recorded by the axial borehole camera as well as a discussion of the laboratory results before in the concluding part the results of the numerical simulations will be

Seismic trapped modes in the oroville and san andreas fault zones.

Science.gov (United States)

Li, Y G; Leary, P; Aki, K; Malin, P

1990-08-17

Three-component borehole seismic profiling of the recently active Oroville, California, normal fault and microearthquake event recording with a near-fault three-component borehole seismometer on the San Andreas fault at Parkfield, California, have shown numerous instances of pronounced dispersive wave trains following the shear wave arrivals. These wave trains are interpreted as fault zone-trapped seismic modes. Parkfield earthquakes exciting trapped modes have been located as deep as 10 kilometers, as shallow as 4 kilometers, and extend 12 kilometers along the fault on either side of the recording station. Selected Oroville and Parkfield wave forms are modeled as the fundamental and first higher trapped SH modes of a narrow low-velocity layer at the fault. Modeling results suggest that the Oroville fault zone is 18 meters wide at depth and has a shear wave velocity of 1 kilometer per second, whereas at Parkfield, the fault gouge is 100 to 150 meters wide and has a shear wave velocity of 1.1 to 1.8 kilometers per second. These low-velocity layers are probably the rupture planes on which earthquakes occur.

On the development in digital engineering-seismic studies in Finland

International Nuclear Information System (INIS)

Okko, O.

1998-01-01

Shallow refraction and reflection seismic soundings were carried out in Finland using the newest portable digital seismographs. These improve the field investigation methods and introduce digital data processing techniques. New mechanical wave sources were developed to allow the conventional refraction soundings to be carried out in urban and industrial areas. The Finnish crystalline bedrock is covered by thin post-glacial overburden. With the present recording technology the bedrock refractions from the shots of a buffalo gun were recorded from shallow depths down to 15 - 20 meters. In the digital refraction records, reflected waves are also visible from depths of a few meters to the first hundred meters. In a combined interpretation of these sounding modes, the number of seismic layers in the soil sequence can be estimated from reflectors to avoid the well-known misinterpretations due to blind zones in the refraction survey. Digital recording was also introduced into a slim acoustic logging system. This makes it possible to record whole waveforms to analyze the travel times and amplitudes of body and surface waves along 56 mm diameter boreholes. The acoustic logging is very sensitive to microcracking along the hole, requiring inversion techniques to calculate the velocities and attenuation factors in the formation. The velocity and attenuation of the body waves is connected to mechanical weakness in the bedrock using the calculated log of Young's modulus. Furthermore, attenuation of the Stoneley-type surface waves can separate the water-bearing open fractures from the closed ones. Subhorizontal fracture zones in the bedrock were mapped by high frequency soundings carried out on bedrock outcrops. The sonic logs at the same sites showed that the required thickness of these reflective horizons has to be a few meters. Unfortunately, most of the fractures intersected by boreholes are thinner than 1 m at the intersections making them difficult targets. The logs also

An automated method to build groundwater model hydrostratigraphy from airborne electromagnetic data and lithological borehole logs

DEFF Research Database (Denmark)

Marker, Pernille Aabye; Foged, N.; He, X.

2015-01-01

of electrical resistivity and clay fraction are classified into hydrostratigraphic zones using k-means clustering. Hydraulic conductivity values of the zones are estimated by hydrological calibration using hydraulic head and stream discharge observations. The method is applied to a Danish case study......Large-scale integrated hydrological models are important decision support tools in water resources management. The largest source of uncertainty in such models is the hydrostratigraphic model. Geometry and configuration of hydrogeological units are often poorly determined from hydrogeological data......-scale groundwater models. We present a novel method to automatically integrate large AEM data-sets and lithological information into large-scale hydrological models. Clay-fraction maps are produced by translating geophysical resistivity into clay-fraction values using lithological borehole information. Voxel models...

Nine-component vertical seismic profiling at Yucca Mountain, Nevada

International Nuclear Information System (INIS)

Balch, A.H.; Erdemir, C.; Spengler, R.W.; Hunter, W.C.

1996-01-01

Nine-component vertical seismic profiling has been conducted at the UE-25 UZ No. 16 borehole at Yucca Mountain, Nevada, in support of investigation of the hydrologic significance of fault and fracture systems. A large data set from multi-component sources and receivers allows state-of-the-art advances in processing using polarization filtering and reverse time migration, for enhanced interpretation of geologic features

Optimal design of water supply networks for enhancing seismic reliability

International Nuclear Information System (INIS)

Yoo, Do Guen; Kang, Doosun; Kim, Joong Hoon

2016-01-01

The goal of the present study is to construct a reliability evaluation model of a water supply system taking seismic hazards and present techniques to enhance hydraulic reliability of the design into consideration. To maximize seismic reliability with limited budgets, an optimal design model is developed using an optimization technique called harmony search (HS). The model is applied to actual water supply systems to determine pipe diameters that can maximize seismic reliability. The reliabilities between the optimal design and existing designs were compared and analyzed. The optimal design would both enhance reliability by approximately 8.9% and have a construction cost of approximately 1.3% less than current pipe construction cost. In addition, the reinforcement of the durability of individual pipes without considering the system produced ineffective results in terms of both cost and reliability. Therefore, to increase the supply ability of the entire system, optimized pipe diameter combinations should be derived. Systems in which normal status hydraulic stability and abnormal status available demand could be maximally secured if configured through the optimal design. - Highlights: • We construct a seismic reliability evaluation model of water supply system. • We present technique to enhance hydraulic reliability in the aspect of design. • Harmony search algorithm is applied in optimal designs process. • The effects of the proposed optimal design are improved reliability about by 9%. • Optimized pipe diameter combinations should be derived indispensably.

Borehole television survey

International Nuclear Information System (INIS)

Lau, J.S.O.

1980-01-01

The borehole television survey can provide a measure of the orientation, depth, width and aperture of any planar discontinuity intersected by a borehole and a technique is in an advanced stage of development by the Geological Survey of Canada (GSC) to make such measurements. Much of its practical application to date has been in crystalline rocks (plutons) at research areas pertaining to the Nuclear Waste Disposal Program in Canada. It also has many other engineering applications where bedrock stability is of particular concern. The equipment required to carry out the survey can be readily transported by two panel trucks with trailers. The components consist of a camera probe, control unit, cable storage reel, cable drive, video-tape recorder, TV monitor and two electrical generators. An inclined planar structure intersected by a borehole appears as an elliptical trace on the wall of the borehole. Such an intersection line shows on the TV monitor as a sinusoidal curve with a high point and a low point as the camera rotates through an angle of 360 degrees. The azimuth of the low point, measured by a compass in the camera probe, represents the direction of the dip of the planar structure. The angle of dip is measured midway between the high and low points or is computed from the maximum-to-minimum distance of the sinusoid and the hole diameter. These observations provide the true orientation of the planar structure if the borehole is vertical. However, if the borehole is inclined, direct observations will only provide the apparent orientation. The true orientation must thus be obtained either by means of stereographic projection or spherical trigonometry. A computer program has been written to calculate the true orientation from the apparent orientation. In the field, observation data are recorded directly on a data record sheet for keypunching and input into the computer

Geophysical borehole logging

International Nuclear Information System (INIS)

McCann, D.; Barton, K.J.; Hearn, K.

1981-08-01

Most of the available literature on geophysical borehole logging refers to studies carried out in sedimentary rocks. It is only in recent years that any great interest has been shown in geophysical logging in boreholes in metamorphic and igneous rocks following the development of research programmes associated with geothermal energy and nuclear waste disposal. This report is concerned with the programme of geophysical logging carried out on the three deep boreholes at Altnabreac, Caithness, to examine the effectiveness of these methods in crystalline rock. Of particular importance is the assessment of the performance of the various geophysical sondes run in the boreholes in relation to the rock mass properties. The geophysical data can be used to provide additional in-situ information on the geological, hydrogeological and engineering properties of the rock mass. Fracturing and weathering in the rock mass have a considerable effect on both the design parameters for an engineering structure and the flow of water through the rock mass; hence, the relation between the geophysical properties and the degree of fracturing and weathering is examined in some detail. (author)

Geophysical investigations of the Romuvaara area, Finland

International Nuclear Information System (INIS)

Saksa, P.; Paananen, M.

1991-06-01

In the study area of Romuvaara, investigations have been carried out during 1987 - 90 with the aim of finding out whether the polyphasically deformed Precambrian gneiss complex is suitable for the final disposal of spent nuclear fuel. The bedrock has been studied by geological, geophysical, geohydrological and geochemical methods. Airborne, ground and borehole geophysical surveys were used in studying the rock type distribution, fracturing and hydraulic conductivity of the bedrock to a depth of one kilometre. Airborne surveys (magnetic, radiometric and two electromagnetic methods) and ground surveys (VLF and VLF-R, magnetic and soil radar methods) were useful in distinguishing the metadiabases, amphibolites and granodiorites from the less magnetized migmatites. The electromagnetic and seismic refraction surveys were used in locating crushed and fractured zones. The rock type distribution was studied by single-hole logging of susceptibility, natural γ radiation and radiometric γ-γ -density. Electrical and acoustic logging served the mapping of fractures and the interpretation of water injection tests. The flow conditions in the boreholes were studied by fluid logging and tube-wave sounding. The rock volume surrounding the boreholes was mapped by borehole radar with a frequency of 22 MHz. The upper parts of the boreholes were also studied by vertical radar profiling (VRP). Larger volumes of rock were mapped by vertical seismic profiling (VSP) using 4 - 5 transmitter shotholes per borehole

Key Factors to Determine the Borehole Spacing in a Deep Borehole Disposal for HLW

International Nuclear Information System (INIS)

Lee, Jongyoul; Choi, Heuijoo; Lee, Minsoo; Kim, Geonyoung; Kim, Kyeongsoo

2015-01-01

Deep fluids also resist vertical movement because they are density stratified and reducing conditions will sharply limit solubility of most dose critical radionuclides at the depth. Finally, high ionic strengths of deep fluids will prevent colloidal transport. Therefore, as an alternative disposal concept, i.e., deep borehole disposal technology is under consideration in number of countries in terms of its outstanding safety and cost effectiveness. In this paper, the general concept for deep borehole disposal of spent fuels or high level radioactive wastes which has been developed by some countries according to the rapid advance in the development of drilling technology, as an alternative method to the deep geological disposal method, was reviewed. After then an analysis on key factors for the distance between boreholes for the disposal of HLW was carried out. In this paper, the general concept for deep borehole disposal of spent fuels or HLW wastes, as an alternative method to the deep geological disposal method, were reviewed. After then an analysis on key factors for the determining the distance between boreholes for the disposal of HLW was carried out. These results can be used for the development of the HLW deep borehole disposal system

Key Factors to Determine the Borehole Spacing in a Deep Borehole Disposal for HLW

Energy Technology Data Exchange (ETDEWEB)

Lee, Jongyoul; Choi, Heuijoo; Lee, Minsoo; Kim, Geonyoung; Kim, Kyeongsoo [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2015-05-15

Deep fluids also resist vertical movement because they are density stratified and reducing conditions will sharply limit solubility of most dose critical radionuclides at the depth. Finally, high ionic strengths of deep fluids will prevent colloidal transport. Therefore, as an alternative disposal concept, i.e., deep borehole disposal technology is under consideration in number of countries in terms of its outstanding safety and cost effectiveness. In this paper, the general concept for deep borehole disposal of spent fuels or high level radioactive wastes which has been developed by some countries according to the rapid advance in the development of drilling technology, as an alternative method to the deep geological disposal method, was reviewed. After then an analysis on key factors for the distance between boreholes for the disposal of HLW was carried out. In this paper, the general concept for deep borehole disposal of spent fuels or HLW wastes, as an alternative method to the deep geological disposal method, were reviewed. After then an analysis on key factors for the determining the distance between boreholes for the disposal of HLW was carried out. These results can be used for the development of the HLW deep borehole disposal system.

BoreholeAR: A mobile tablet application for effective borehole database visualization using an augmented reality technology

Science.gov (United States)

Lee, Sangho; Suh, Jangwon; Park, Hyeong-Dong

2015-03-01

Boring logs are widely used in geological field studies since the data describes various attributes of underground and surface environments. However, it is difficult to manage multiple boring logs in the field as the conventional management and visualization methods are not suitable for integrating and combining large data sets. We developed an iPad application to enable its user to search the boring log rapidly and visualize them using the augmented reality (AR) technique. For the development of the application, a standard borehole database appropriate for a mobile-based borehole database management system was designed. The application consists of three modules: an AR module, a map module, and a database module. The AR module superimposes borehole data on camera imagery as viewed by the user and provides intuitive visualization of borehole locations. The map module shows the locations of corresponding borehole data on a 2D map with additional map layers. The database module provides data management functions for large borehole databases for other modules. Field survey was also carried out using more than 100,000 borehole data.

Borehole induction coil transmitter

Science.gov (United States)

Holladay, Gale; Wilt, Michael J.

2002-01-01

A borehole induction coil transmitter which is a part of a cross-borehole electromagnetic field system that is used for underground imaging applications. The transmitter consists of four major parts: 1) a wound ferrite or mu-metal core, 2) an array of tuning capacitors, 3) a current driver circuit board, and 4) a flux monitor. The core is wound with several hundred turns of wire and connected in series with the capacitor array, to produce a tuned coil. This tuned coil uses internal circuitry to generate sinusoidal signals that are transmitted through the earth to a receiver coil in another borehole. The transmitter can operate at frequencies from 1-200 kHz and supplies sufficient power to permit the field system to operate in boreholes separated by up to 400 meters.

Analyses of the deep borehole drilling status for a deep borehole disposal system

Energy Technology Data Exchange (ETDEWEB)

Lee, Jong Youl; Choi, Heui Joo; Lee, Min Soo; Kim, Geon Young; Kim, Kyung Su [KAERI, Daejeon (Korea, Republic of)

2016-05-15

The purpose of disposal for radioactive wastes is not only to isolate them from humans, but also to inhibit leakage of any radioactive materials into the accessible environment. Because of the extremely high level and long-time scale radioactivity of HLW(High-level radioactive waste), a mined deep geological disposal concept, the disposal depth is about 500 m below ground, is considered as the safest method to isolate the spent fuels or high-level radioactive waste from the human environment with the best available technology at present time. Therefore, as an alternative disposal concept, i.e., deep borehole disposal technology is under consideration in number of countries in terms of its outstanding safety and cost effectiveness. In this paper, the general status of deep drilling technologies was reviewed for deep borehole disposal of high level radioactive wastes. Based on the results of these review, very preliminary applicability of deep drilling technology for deep borehole disposal analyzed. In this paper, as one of key technologies of deep borehole disposal system, the general status of deep drilling technologies in oil industry, geothermal industry and geo scientific field was reviewed for deep borehole disposal of high level radioactive wastes. Based on the results of these review, the very preliminary applicability of deep drilling technology for deep borehole disposal such as relation between depth and diameter, drilling time and feasibility classification was analyzed.

Geological interpretation of borehole image and sonic logs. A case study from the North Sea

Energy Technology Data Exchange (ETDEWEB)

Vahle, C. [Eriksfiord GmbH, Walldorf (Germany)

2013-08-01

Borehole imagers and dipole sonic tools form the ideal pair of instruments for observation and evaluation of structural tilt, faulting and fracturing as well as sediment transport direction and depositional architecture. In addition, the stress field can be inverted in combination with rock mechanical data. The structural tilt and its variation along the well are evaluated in stereograms and projections along the well trace. Changes in structural tilt are attributed to fault block rotation as well as angular unconformities. Fault zones are usually easily recognised in borehole images by e.g. juxtaposition of different strata/facies and deformation of adjacent layering. Integration with micro-scale core data as well as macro-scale seismics, if available, is of vital importance. Furthermore, calibration against core observations is helpful for e.g. fracture characterisation. The stress field orientation is interpreted from breakout and drilling-induced fractures, which are usually easy to detect in borehole images. However, in case of slanted and highly deviated wells the full stress tensor including the stress magnitudes is necessary to evaluate the stress field orientation. The full stress tensor is inverted by utilising rock mechanical data from core measurement and/or from empirical relations with elastic properties such as Poission's ratio and Young's modulus with respect to breakout and drilling-induced fractures. In addition, the stress field can be simulated using numerical methods to match the current observations. Sedimentary features such as cross-beds or slumps may indicate sediment transport directions after the data set was corrected for structural tilt. Image facies and their stacking patterns in combination with standard petrophysical curves are interpreted with respect to the depositional environment and included in a sequence stratigraphic framework. A correlation with core observations provides important calibration of the image facies

Crosshole investigations - details of the construction and operation of the hydraulic testing system

International Nuclear Information System (INIS)

Holmes, D.; Sehlstedt, M.

1986-05-01

The Crosshole Programme, part of the international Stripa Project is designed to evaluate the effectiveness of various remote-sensing techniques in characterising a rock mass around a repository. A multidisciplinary approach has been adopted in which various geophysical, mapping and hydrogeological methods are used to determine the location and characteristics of significant features in the rock. The Programme utilises six boreholes drilled in a fan array from the 360 metre level in the Stripa Mine, Sweden. The hydrogeological component of the work uses single and crosshole testing methods, including sinusoidal pressure testing, to locate fractures and characterise groundwater movement within them. Crosshole methods use packers to isolate portions of two boreholes which both intersect a significant feature in the rock mass. Hydraulic signals are generated in one isolated section and received in the other borehole. This report describes the design and operation of the computer-controlled system which automatically performs the hydrogeological tests. (author) 3 refs., 13 figs

Crosshole investigations - Details of the construction and operation of the hydraulic testing system

International Nuclear Information System (INIS)

Holmes, D.; Sehlstedt, M.

1986-05-01

The Crosshole Programme, part of the international Stripa Project is designed to evaluate the effectiveness of various remote-sensing techniques in characterizing a rock mass around a repository. A multidisciplinary approach has been adopted in which various geophysical, mapping and hydrogeological methods are used to determine the location and characteristics of significant features in the rock. The Programme utilises six boreholes drilled in a fan array from the 360 metre level in the Stripa Mine, Sweden. The hydrogeological component of the work uses single and crosshole testing methods, including sinusoidal pressure testing, to locate fractures and characterize groundwater movement within them. Crosshole methods use packers to isolate portions of two boreholes which both intersect a significant feature in the rock mass. Hydraulic signals are generated in one isolated section and received in the other borehole. This report describes the design and operation of the computer-controlled system which automatically performs the hydrogeological tests. (authors)

Site characterization at Groningen gas field area through joint surface-borehole H/V analysis

Science.gov (United States)

Spica, Zack J.; Perton, Mathieu; Nakata, Nori; Liu, Xin; Beroza, Gregory C.

2018-01-01

A new interpretation of the horizontal to vertical (H/V) spectral ratio in terms of the Diffuse Field Assumption (DFA) has fuelled a resurgence of interest in that approach. The DFA links H/V measurements to Green's function retrieval through autocorrelation of the ambient seismic field. This naturally allows for estimation of layered velocity structure. In this contribution, we further explore the potential of H/V analysis. Our study is facilitated by a distributed array of surface and co-located borehole stations deployed at multiple depths, and by detailed prior information on velocity structure that is available due to development of the Groningen gas field. We use the vertical distribution of H/V spectra recorded at discrete depths inside boreholes to obtain shear wave velocity models of the shallow subsurface. We combine both joint H/V inversion and borehole interferometry to reduce the non-uniqueness of the problem and to allow faster convergence towards a reliable velocity model. The good agreement between our results and velocity models from an independent study validates the methodology, demonstrates the power of the method, but more importantly provides further constraints on the shallow velocity structure, which is an essential component of integrated hazard assessment in the area.

Borehole closure in salt

International Nuclear Information System (INIS)

Fuenkajorn, K.; Daemen, J.J.K.

1988-12-01

Constitutive law parameters are determined from salt behavior characterization experiments. The results are applied to predict creep (time-dependent) closure of boreholes in salt specimens subjected to various loading configurations. Rheological models (linear and nonlinear viscoelastic and viscoplastic models), empirical models, and physical theory models have been formulated from the results of uniaxial creep tests, strain and stress rate controlled uniaxial tests, constant strain rate triaxial tests, cyclic loading tests, and seismic velocity measurements. Analytical solutions for a thick-walled cylinder subjected to internal and external pressures and for a circular hole in an infinite plate subjected to a biaxial or uniaxial stressfield have been derived from each of the linear viscoelastic models and from one of the empirical laws. The experimental results indicate that the salt samples behave as an elastic-viscoplastic material. The elastic behavior tends to be linear and time-independent. The plastic deformation is time-dependent. The stress increment to strain rate increment ratio gradually decreases as the stress level increases. The transient potential creep law seems to give the simplest satisfactory governing equation describing the viscoplastic behavior of salt during the transient phase. 204 refs., 27 figs., 29 tabs

Characterization of crystalline rocks in deep boreholes. The Kola, Krivoy Rog and Tyrnauz boreholes

International Nuclear Information System (INIS)

1992-12-01

SKB studies, as one alternative, the feasibility of disposing of spent nuclear fuel in very deep boreholes. As a part of this work NEDRA has compiled geoscientific data from three superdeep boreholes within the former Soviet Union. The holes considered were: the Kola borehole, 12261 m deep and located on the Kola Peninsula, the Krivoy Rog borehole, 5000 m deep and located in Ukraine, and the Tyrnauz borehole, 4001 m deep and located between the Black Sea and the Caspian Sea. These boreholes all penetrate crystalline formations, but major differences are found when their tectonic environments are compared. Excluding the uppermost horizon affected by surface phenomena, data do not indicate any general correlation between depth and the state of rock fracturing, which is instead governed by site specific, lithological and tectonical factors. This applies also to fracture zones, which are found at similar frequencies at all depths. As opposed to the structural data, the hydrogeological and hydrochemical information reveals a vertical zonation, with clear similarities between the three boreholes. An upper zone with active circulation and fresh or slightly mineralized groundwaters reaches down 1000-2000 m. The interval from 1000-2000 m down to 4000-5000 m can be characterized as a transition zone with lower circulation rates and gradually increasing mineralisation. Below 4000-5000 m, strongly mineralized, stagnant, juvenile or metamorphogenic waters are found. Geothermal data verify the existence of this zonation. 28 figs, 30 tabs

Borehole Stability in High-Temperature Formations

Science.gov (United States)

Yan, Chuanliang; Deng, Jingen; Yu, Baohua; Li, Wenliang; Chen, Zijian; Hu, Lianbo; Li, Yang

2014-11-01

In oil and gas drilling or geothermal well drilling, the temperature difference between the drilling fluid and formation will lead to an apparent temperature change around the borehole, which will influence the stress state around the borehole and tend to cause borehole instability in high geothermal gradient formations. The thermal effect is usually not considered as a factor in most of the conventional borehole stability models. In this research, in order to solve the borehole instability in high-temperature formations, a calculation model of the temperature field around the borehole during drilling is established. The effects of drilling fluid circulation, drilling fluid density, and mud displacement on the temperature field are analyzed. Besides these effects, the effect of temperature change on the stress around the borehole is analyzed based on thermoelasticity theory. In addition, the relationships between temperature and strength of four types of rocks are respectively established based on experimental results, and thermal expansion coefficients are also tested. On this basis, a borehole stability model is established considering thermal effects and the effect of temperature change on borehole stability is also analyzed. The results show that the fracture pressure and collapse pressure will both increase as the temperature of borehole rises, and vice versa. The fracture pressure is more sensitive to temperature. Temperature has different effects on collapse pressures due to different lithological characters; however, the variation of fracture pressure is unrelated to lithology. The research results can provide a reference for the design of drilling fluid density in high-temperature wells.

Inferring Fault Frictional and Reservoir Hydraulic Properties From Injection-Induced Seismicity

Science.gov (United States)

Jagalur-Mohan, Jayanth; Jha, Birendra; Wang, Zheng; Juanes, Ruben; Marzouk, Youssef

2018-02-01

Characterizing the rheological properties of faults and the evolution of fault friction during seismic slip are fundamental problems in geology and seismology. Recent increases in the frequency of induced earthquakes have intensified the need for robust methods to estimate fault properties. Here we present a novel approach for estimation of aquifer and fault properties, which combines coupled multiphysics simulation of injection-induced seismicity with adaptive surrogate-based Bayesian inversion. In a synthetic 2-D model, we use aquifer pressure, ground displacements, and fault slip measurements during fluid injection to estimate the dynamic fault friction, the critical slip distance, and the aquifer permeability. Our forward model allows us to observe nonmonotonic evolutions of shear traction and slip on the fault resulting from the interplay of several physical mechanisms, including injection-induced aquifer expansion, stress transfer along the fault, and slip-induced stress relaxation. This interplay provides the basis for a successful joint inversion of induced seismicity, yielding well-informed Bayesian posterior distributions of dynamic friction and critical slip. We uncover an inverse relationship between dynamic friction and critical slip distance, which is in agreement with the small dynamic friction and large critical slip reported during seismicity on mature faults.

J-SHIS - an integrated system for knowing seismic hazard information in Japan

Science.gov (United States)

Azuma, H.; Fujiwara, H.; Kawai, S.; Hao, K. X.; Morikawa, N.

2015-12-01

An integrated system of Japan seismic hazard information station (J-SHIS) was established in 2005 for issuing and exchanging information of the National Seismic Hazard Maps for Japan that are based on seismic hazard assessment (SHA). A simplified app, also named J-SHIS, for smartphones is popularly used in Japan based on the integrated system of http://www.j-shis.bosai.go.jp/map/?lang=en. "Smartphone tells hazard" is realized on a cellphone, a tablet and/or a PC. At a given spot, the comprehensive information of SHA map can be easily obtained as below: 1) A SHA probability at given intensity (JMA=5-, 5+, 6-, 6+) within 30 years. 2) A site amplification factor varies within 0.5 ~ 3.0 and expectation is 1 based on surface geology map information. 3) A depth of seismic basement down to ~3,000m based on deeper borehole and geological structure. 4) Scenario earthquake maps: By choosing an active fault, one got the average case for different parameters of the modeling. Then choose a case, you got the shaking map of intensity with color scale. "Seismic Hazard Karte tells more hazard" is another app based on website of http://www.j-shis.bosai.go.jp/labs/karte/. (1) For every mesh of 250m x 250m, professional service SHA information is provided over national-world. (2) With five ranks for eight items, comprehensive SHA information could be delivered. (3) Site amplification factor with an average index is given. (4) Deeper geologic structure modeling is provided with borehole profiling. (5) A SHA probability is assessed within 30 and/or 50 years for the given site. (6) Seismic Hazard curves are given for earthquake sources from inland active fault, subduction zone, undetermined and their summarization. (7) The JMA seismic intensities are assessed in long-term averaged periods of 500-years to ~100,000 years. The app of J-SHIS can be downloaded freely from http://www.j-shis.bosai.go.jp/app-jshis.

Rock property estimates using multiple seismic attributes and neural networks; Pegasus Field, West Texas

Energy Technology Data Exchange (ETDEWEB)

Schuelke, J.S.; Quirein, J.A.; Sarg, J.F.

1998-12-31

This case study shows the benefit of using multiple seismic trace attributes and the pattern recognition capabilities of neural networks to predict reservoir architecture and porosity distribution in the Pegasus Field, West Texas. The study used the power of neural networks to integrate geologic, borehole and seismic data. Illustrated are the improvements between the new neural network approach and the more traditional method of seismic trace inversion for porosity estimation. Comprehensive statistical methods and interpretational/subjective measures are used in the prediction of porosity from seismic attributes. A 3-D volume of seismic derived porosity estimates for the Devonian reservoir provide a very detailed estimate of porosity, both spatially and vertically, for the field. The additional reservoir porosity detail provided, between the well control, allows for optimal placement of horizontal wells and improved field development. 6 refs., 2 figs.

Hydraulic Fracturing and the Environment

Science.gov (United States)

Ayatollahy Tafti, T.; Aminzadeh, F.; Jafarpour, B.; de Barros, F.

2013-12-01

In this presentation, we highlight two key environmental concerns of hydraulic fracturing (HF), namely induced seismicity and groundwater contamination (GC). We examine the induced seismicity (IS) associated with different subsurface fluid injection and production (SFIP) operations and the key operational parameters of SFIP impacting it. In addition we review the key potential sources for possible water contamination. Both in the case of IS and GC we propose modeling and data analysis methods to quantify the risk factors to be used for monitoring and risk reduction. SFIP include presents a risk in hydraulic fracturing, waste water injection, enhanced oil recovery as well as geothermal energy operations. Although a recent report (NRC 2012) documents that HF is not responsible for most of the induced seismicities, we primarily focus on HF here. We look into vaious operational parameters such as volume and rate of water injection, the direction of the well versus the natural fracture network, the depth of the target and the local stress field and fault system, as well as other geological features. The latter would determine the potential for triggering tectonic related events by small induced seismicity events. We provide the building blocks for IS risk assessment and monitoring. The system we propose will involve adequate layers of complexity based on mapped seismic attributes as well as results from ANN and probabilistic predictive modeling workflows. This leads to a set of guidelines which further defines 'safe operating conditions' and 'safe operating zones' which will be a valuable reference for future SFIP operations. We also illustrate how HF can lead to groundwater aquifer contamination. The source of aquifer contamination can be the hydrocarbon gas or the chemicals used in the injected liquid in the formation. We explore possible pathways of contamination within and discuss the likelihood of contamination from each source. Many of the chemical compounds used

Challenges in Microseismic Monitoring of Hydrualic Fracturing

Science.gov (United States)

Venkataraman, A.; Li, R.

2011-12-01

To enhance well productivity, hydraulic fractures are stimulated by injecting fluid and/or gas with proppant into the rock matrix. This results in stress perturbations that induce fractures in the formation releasing minor amounts of seismic energy as microseismic events. Microseismicity can be recorded by properly positioned geophones and is one of the indirect methods that allow us to determine the actual volume of rock that was impacted during and after hydraulic fracturing. Specifically, microseismic data is acquired during hydro-fracture treatments to validate and assist completions, assist in placing wells in the formation, identify frac barriers, and to illuminate faults and potential fault re-activation. In the industry, microseismic data is acquired using geophones deployed in borehole and/or surface arrays. Borehole arrays are more traditional and have been used for nearly 20 years. Event location using borehole data is fairly robust, but azimuth and aperture are limited. Moreover, having dedicated boreholes can be expensive. The newer method of acquiring data is the use of geophones deployed on the surface or in shallow boreholes. Since microseismic events are very small (-4 to -0.5), surface records have weak P and S arrivals that are buried in the noise and traditional event location methods which use arrival time picks cannot be used. Migration based approaches which rely on the power of stacking waveforms is the common approach. However, poor signal-to-noise data and polarity in seismic waves generated by micro-earthquakes can result in uncertainty in event location. In this paper, we will discuss the pros and cons of both arrays, the status of the technology, its limitations and challenges. Specifically, we will focus on applications where industry-academic collaborations could lead to step changes in our understanding of the controls on microseismicity.

Preliminary results of hydrologic testing: The composite Umtanum basalt flow top at borehole RRL-2 (3,568 - 3,781 feet)

International Nuclear Information System (INIS)

Strait, S.R.; Spane, F.A. Jr.

1982-11-01

This report presents preliminary results and description of hydrologic test activities for the composite Umtanum basalt flow top (3,568--3,781 feet) at Borehole RRL-2. Hydrologic tests conducted include two constant discharge air-lift and four slug tests. Preliminary results indicate an observed hydraulic head for the test interval of 405.7 feet above mean sea level. Transmissivity values determined from hydrologic tests performed, range between 244 to 481 ft 2 /day, with an assigned best estimate of 480 ft 2 /day. The best estimate of equivalent hydraulic conductivity, based on an effective test thickness of 157 feet, is 3.1 ft/day. 7 refs., 9 figs., 3 tabs

One Decade of Induced Seismicity in Basel, Switzerland: A Consistent High-Resolution Catalog Obtained by Template Matching

Science.gov (United States)

Herrmann, M.; Kraft, T.; Tormann, T.; Scarabello, L.; Wiemer, S.

2017-12-01

Induced seismicity at the site of the Basel Enhanced Geothermal System (EGS) continuously decayed for six years after injection had been stopped in December 2006. Starting in May 2012, the Swiss Seismological Service was detecting a renewed increase of induced seismicity in the EGS reservoir to levels last seen in 2007 and reaching magnitudes up to ML2.0. Seismic monitoring at this EGS site is running for more than ten years now, but the details of the long-term behavior of its induced seismicity remained unexplored because a seismic event catalog that is consistent in detection sensitivity and magnitude estimation did not exist.We have created such a catalog by applying our matched filter detector to the 11-year-long seismic recordings of a borehole station at 2.7km depth. Based on 3'600 located earthquakes of the operator's borehole-network catalog, we selected about 2'500 reasonably dissimilar templates using waveform clustering. This large template set ensures an adequate coverage of the diversity of event waveforms which is due to the reservoir's highly complex fault system and the close observation distance. To cope with the increased computational demand of scanning 11-years of data with 2'500 templates, we parallelized our detector to run on a high-performance computer of the Swiss National Supercomputing Centre.We detect more than 200'000 events down to ML-2.5 during the six-day-long stimulation in December 2006 alone. Previously, only 13'000 detections found by an amplitude-threshold-based detector were known for this period. The high temporal and spatial resolution of this new catalog allows us to analyze the statistics of the induced Basel earthquakes in great detail. We resolve spatio-temporal variations of the seismicity parameters (a- and b-value) that have not been identified before and derive the first high-resolution temporal evolution of the seismic hazard for the Basel EGS reservoir.In summer 2017, our detector monitored the 10-week pressure

Reflection and tubewave analysis of the seismic data from the Stripa crosshole site

International Nuclear Information System (INIS)

Cosma, C.; Baehler, S.; Hammarstroem, M.; Pihl, J.

1986-12-01

The data from the crosshole research program (radar, seismics and hydraulics) in the Stripa Phase II Project resulted in the construction of a model. The results from the present study were compared to this model. It was found that the existing data set used for tomographic analysis could only be used to a limited extent, as reflection analysis requires a more dense detector coverage. Nevertheless two reflectors were detected. The positions of the reflectors were compared to the existing crosshole model and proved to correlate well. For the tubewave analysis almost all crosshole seismic data could be used. By comparing the results with previous hydraulic tests, it was found that tubewave sources and hydraulically conductive zones are in concordance. All previously defined zones but one could be detected. (orig./HP)

New experiences in borehole dilution techniques

International Nuclear Information System (INIS)

Umesh Chandra

1977-01-01

A study of filtration rate and direction of groundwater flow was made at various depths in borehole using bromine-82 as groundwater tracer. The filtration rates were found to vary along the depth of borehole. Vertical flow in the borehole was observed in an alluvial aquifer even after sealing the borehole by rubber packers. The filtration rates, obtained without the packer at various depths, were much less than those obtained with packer. Microscopic hydrological information was obtained around the borehole which was useful in planning a drainage system in the area. A depth was located in the borehole where vertical flow was in opposite directions. At another depth a zone of horizontal flow was observed where vertical flow was in opposite directions. The improved instrumentation used rendered the field work extremely easy quick and readily reproducible. (author)

Deep borehole disposition of surplus fissile materials-The site selection process

International Nuclear Information System (INIS)

Heiken, G.; WoldeGabriel, G.; Morley, R.; Plannerer, H.

1996-01-01

One option for disposing of excess weapons plutonium is to place it near the base of deep boreholes in stable crystalline rocks. The technology exists to immediately begin the design of this means of disposition and there are many attractive sites available within the conterminous US. The borehole system utilizes mainly natural barriers to preven migration of Pu and U to the Earth's surface. Careful site selection ensures favorable geologic conditions that provide natural long-lived migration barriers; they include deep, extremely stable rock formations, strongly reducing brines that exhibit increasing salinity with depth, and most importantly, demonstrated isolation or non-communication of deep fluids with the biosphere for millions of years. This isolation is the most important characteristic, with the other conditions mainly being those that will enhance the potential of locating and maintaining the isolated zones. Candidate sites will probably be located on the craton in very old Precambrian crystalline rocks, most likely the center of a granitic pluton. The sites will be located in tectonically stable areas with no recent volcanic or seismic activity, and situated away from tectonic features that might become active in the near geologic future

Crosshole investigations - short and medium range seismic tomography

International Nuclear Information System (INIS)

Cosma, C.

1987-02-01

Seismic tomographic tests were conducted as a part of the Crosshole Investigations program of the Stripa Project. The aim has been to study if it is possible to detect by seismic tomography major fracture zones and determine their dimensions and orientation. The analysis was based on both compressional (P) and transversal (S) waves. The Young's modulus has been also calculated for a sub-set of measurements as a cross check for the P and S wave velocities. The experimental data was collected at the crosshole site in the Stripa mine during 1984-1985. A down-the-hole impact source was used together with triaxial detectors and a digital seismograph. Five tomographic sections were obtained. The number of records per section was appr. 250. Measurements were done down to 200 m depth in all boreholes. The main conclusion is that it is possible to detect major fracture zones by seismic tomography. Their position and orientation can also be estimated. (orig./HP)

The Effect of Loading Rate on Hydraulic Fracturing in Synthetic Granite - a Discrete Element Study

Science.gov (United States)

Tomac, I.; Gutierrez, M.

2015-12-01

Hydraulic fracture initiation and propagation from a borehole in hard synthetic rock is modeled using the two dimensional Discrete Element Method (DEM). DEM uses previously established procedure for modeling the strength and deformation parameters of quasi-brittle rocks with the Bonded Particle Model (Itasca, 2004). A series of simulations of laboratory tests on granite in DEM serve as a reference for synthetic rock behavior. Fracturing is enabled by breaking parallel bonds between DEM particles as a result of the local stress state. Subsequent bond breakage induces fracture propagation during a time-stepping procedure. Hydraulic fracturing occurs when pressurized fluid induces hoop stresses around the wellbore which cause rock fracturing and serves for geo-reservoir permeability enhancement in oil, gas and geothermal industries. In DEM, a network of fluid pipes and reservoirs is used for mathematical calculation of fluid flow through narrow channels between DEM particles, where the hydro-mechanical coupling is fully enabled. The fluid flow calculation is superimposed with DEM stress-strain calculation at each time step. As a result, the fluid pressures during borehole pressurization in hydraulic fracturing, as well as, during the fracture propagation from the borehole, can be simulated. The objective of this study is to investigate numerically a hypothesis that fluid pressurization rate, or the fluid flow rate, influences upon character, shape and velocity of fracture propagation in rock. The second objective is to better understand and define constraints which are important for successful fracture propagation in quasi-brittle rock from the perspective of flow rate, fluid density, viscosity and compressibility relative to the rock physical properties. Results from this study indicate that not only too high fluid flow rates cause fracture arrest and multiple fracture branching from the borehole, but also that the relative compressibility of fracturing fluid and

Effect of radon transport in groundwater upon gamma-ray borehole logs

International Nuclear Information System (INIS)

Nelson, P.H.; Rachiele, R.; Smith, A.

1980-09-01

Granitic rock at an experimental waste storage site at Stripa, Sweden, is unusually high in natural radioelements (40 ppM uranium) with higher concentrations occurring locally in thin chloritic zones and fractures. Groundwater seeping through fractures into open boreholes is consequently highly anomalous in its radon content, with activity as high as one microcurie per liter. When total count gamma-ray logs are run in boreholes where groundwater inflow is appreciable, the result is quite unusual: the radon daughter activity in the water adds considerably to the contribution from the rock, and in fact often dominates the log response. The total gamma activity increases where radon-charged groundwater enters a borehole, and remains at a high level as the water flows along the hole in response to the hydraulic gradient. As a consequence, the gamma log serves as a flow profile, locating zones of water entry (or loss) by an increase (or decrease) in the total gamma activity. A simple model has been developed for flow through a thin crack emanating radon at a rate E showing that the radon concentration of water entering a hole is E/Λh, where Λ is the radon decay rate and h the crack aperture, assuming that the flow rate and crack source area are such that an element of water resides within the source area for several radon half-lives or more. Concentration measurements can provide a measurement of the inflow rate. Data from the 127-mm holes in the time-scale drift behave in this fashion

Analysis of induced seismicity in geothermal reservoirs – An overview

Science.gov (United States)

Zang, Arno; Oye, Volker; Jousset, Philippe; Deichmann, Nicholas; Gritto, Roland; McGarr, Arthur F.; Majer, Ernest; Bruhn, David

2014-01-01

In this overview we report results of analysing induced seismicity in geothermal reservoirs in various tectonic settings within the framework of the European Geothermal Engineering Integrating Mitigation of Induced Seismicity in Reservoirs (GEISER) project. In the reconnaissance phase of a field, the subsurface fault mapping, in situ stress and the seismic network are of primary interest in order to help assess the geothermal resource. The hypocentres of the observed seismic events (seismic cloud) are dependent on the design of the installed network, the used velocity model and the applied location technique. During the stimulation phase, the attention is turned to reservoir hydraulics (e.g., fluid pressure, injection volume) and its relation to larger magnitude seismic events, their source characteristics and occurrence in space and time. A change in isotropic components of the full waveform moment tensor is observed for events close to the injection well (tensile character) as compared to events further away from the injection well (shear character). Tensile events coincide with high Gutenberg-Richter b-values and low Brune stress drop values. The stress regime in the reservoir controls the direction of the fracture growth at depth, as indicated by the extent of the seismic cloud detected. Stress magnitudes are important in multiple stimulation of wells, where little or no seismicity is observed until the previous maximum stress level is exceeded (Kaiser Effect). Prior to drilling, obtaining a 3D P-wave (Vp) and S-wave velocity (Vs) model down to reservoir depth is recommended. In the stimulation phase, we recommend to monitor and to locate seismicity with high precision (decametre) in real-time and to perform local 4D tomography for velocity ratio (Vp/Vs). During exploitation, one should use observed and model induced seismicity to forward estimate seismic hazard so that field operators are in a position to adjust well hydraulics (rate and volume of the

Drilling and the associated borehole measurements of the pilot hole ONK-PH3

International Nuclear Information System (INIS)

Oehberg, A.; Heikkinen, E.; Hirvonen, H.; Kemppainen, K.; Majapuro, J.; Niemonen, J.; Poellaenen, J.; Rouhiainen, P.

2006-03-01

The construction of the ONKALO access tunnel started in September 2004 at Olkiluoto. Most of the investigations related to the construction of the access tunnel aim to ensure successful excavations, reinforcement and sealing. Pilot holes are boreholes, which are core drilled along the tunnel profile. The length of the pilot holes typically varies from several tens of metres to a couple of hundred metres. The pilot holes will mostly aim to confirm the quality of the rock mass for tunnel construction, and in particular at identifying water conductive fractured zones and at providing information that could result in modifications of the existing construction plans. The pilot hole ONK-PH3 was drilled in September 2005. The length of the borehole is 145.04 metres. The aim during the drilling work was to orientate core samples as much as possible. The deviation of the borehole was measured during and after the drilling phase. Electric conductivity was measured from the collected returning water samples. Logging of the core samples included the following parameters: lithology, foliation, fracturing, fracture frequency, RQD, fractured zones, core loss and weathering. The rock mechanical logging was based on Q-classification. The tests to determine rock strength and deformation properties were made with a Rock Tester-equipment. Difference Flow method was used for the determination of hydraulic conductivity in fractures and fractured zones in the borehole. The overlapping i.e. the detailed flow logging mode was used. The flow logging was performed with 0.5 m section length and with 0.1 m depth increments. Water loss tests (Lugeon tests) and a pressure build-up test were used to give background information for the grouting design. Geophysical borehole logging and optical imaging surveys of the pilot hole PH3 included the field work of all the surveys, the integration of the data as well as interpretation of the acoustic and borehole radar data. One of the objectives of the

Crosshole investigations

International Nuclear Information System (INIS)

Olsson, O.; Pihl, J.

1987-09-01

The analysis of the radar and seismic data has given a consistent description of the fracture zones at the Crosshole site in agreement with geological and other geophysical observations made in the boreholes. The hydraulic investigations within the Crosshole project have yielded substantial progress in assessing the hydrogeology of fractured granitic rocks. The crosshole hydraulic testing concentrated on measuring the distribution of hydraulic properties within the extensive fractured zones identified by geophysics. A new analysis involving the 'dimension' of the flow test has been developed to analyse the results of the crosshole sinusoidal testing. The combined analysis of the geophysical and the hydraulic data set has shown that groundwater flow is concentrated within a few major features which have been identified by the geophysical methods. (orig./DG)

Seismic 2D reflection processing and interpretation of shallow refraction data

International Nuclear Information System (INIS)

Oehman, I.; Heikkinen, E.; Lehtimaeki, T.

2006-12-01

Posiva Oy takes care of the final disposal of spent nuclear fuel in Finland. In year 2001 Olkiluoto was selected for the site of final disposal. Currently construction of the underground research facility, ONKALO, is going on at the Olkiluoto site. The aim of this work was to use two-dimensional reflection seismic processing methods to refraction seismic data collected from the ONKALO area in year 2002, and to locate gently dipping reflectors from the stacked sections. Processing was done using mainly open source software Seismic Unix. After the processing, the most distinct two-dimensional reflectors were picked from seismic sections using visualization environment OpendTect. After picking the features from crossing lines were combined into three-dimensional surfaces. Special attention was given for the detection of possible faults and discontinuities. The surfaces were given coordinates and their orientation was adjusted using a geometric procedure, which corresponds roughly a 3D migration, transferred to 3D presentation utility and compared to available geological information. The advantage of this work is to be able to get three-dimensional reflection seismic results from existing data set at only processing costs. Survey lines are also partly located in ONKALO area where extensive surface seismic surveys may not be possible to perform. The applied processing method was successful in detecting the reflectors. Most significant steps were the refraction and residual statics, and deconvolution. Some distinct reflectors can be seen at times 20-200 ms (vertical depths 50-500 m). The signal gets noisier below 200 ms. Reflectors are best visible as coherent phase between the adjacent traces, but do not raise much above the surrounding noise level. Higher amount of traces to be stacked would emphasis the reflections and their continuity more. Reflectors picked on crossing lines match well to borehole observations (KR4, KR7, KR24 and KR38) of fracture zones, and get

Background noise model development for seismic stations of KMA

Science.gov (United States)

Jeon, Youngsoo

2010-05-01

The background noise recorded at seismometer is exist at any seismic signal due to the natural phenomena of the medium which the signal passed through. Reducing the seismic noise is very important to improve the data quality in seismic studies. But, the most important aspect of reducing seismic noise is to find the appropriate place before installing the seismometer. For this reason, NIMR(National Institution of Meteorological Researches) starts to develop a model of standard background noise for the broadband seismic stations of the KMA(Korea Meteorological Administration) using a continuous data set obtained from 13 broadband stations during the period of 2007 and 2008. We also developed the model using short period seismic data from 10 stations at the year of 2009. The method of Mcmara and Buland(2004) is applied to analyse background noise of Korean Peninsula. The fact that borehole seismometer records show low noise level at frequency range greater than 1 Hz compared with that of records at the surface indicate that the cultural noise of inland Korean Peninsula should be considered to process the seismic data set. Reducing Double Frequency peak also should be regarded because the Korean Peninsula surrounded by the seas from eastern, western and southern part. The development of KMA background model shows that the Peterson model(1993) is not applicable to fit the background noise signal generated from Korean Peninsula.

Estimating Hydraulic Conductivities in a Fractured Shale Formation from Pressure Pulse Testing and 3d Modeling

Science.gov (United States)

Courbet, C.; DICK, P.; Lefevre, M.; Wittebroodt, C.; Matray, J.; Barnichon, J.

2013-12-01

In the framework of its research on the deep disposal of radioactive waste in shale formations, the French Institute for Radiological Protection and Nuclear Safety (IRSN) has developed a large array of in situ programs concerning the confining properties of shales in their underground research laboratory at Tournemire (SW France). One of its aims is to evaluate the occurrence and processes controlling radionuclide migration through the host rock, from the disposal system to the biosphere. Past research programs carried out at Tournemire covered mechanical, hydro-mechanical and physico-chemical properties of the Tournemire shale as well as water chemistry and long-term behaviour of the host rock. Studies show that fluid circulations in the undisturbed matrix are very slow (hydraulic conductivity of 10-14 to 10-15 m.s-1). However, recent work related to the occurrence of small scale fractures and clay-rich fault gouges indicate that fluid circulations may have been significantly modified in the vicinity of such features. To assess the transport properties associated with such faults, IRSN designed a series of in situ and laboratory experiments to evaluate the contribution of both diffusive and advective process on water and solute flux through a clay-rich fault zone (fault core and damaged zone) and in an undisturbed shale formation. As part of these studies, Modular Mini-Packer System (MMPS) hydraulic testing was conducted in multiple boreholes to characterize hydraulic conductivities within the formation. Pressure data collected during the hydraulic tests were analyzed using the nSIGHTS (n-dimensional Statistical Inverse Graphical Hydraulic Test Simulator) code to estimate hydraulic conductivity and formation pressures of the tested intervals. Preliminary results indicate hydraulic conductivities of 5.10-12 m.s-1 in the fault core and damaged zone and 10-14 m.s-1 in the adjacent undisturbed shale. Furthermore, when compared with neutron porosity data from borehole

RELIABILITY AND ACCURACY ASSESSMENT OF INVASIVE AND NON- INVASIVE SEISMIC METHODS FOR SITE CHARACTERIZATION: FEEDBACK FROM THE INTERPACIFIC PROJECT

OpenAIRE

Garofalo , F.; Foti , S.; Hollender , F.; Bard , P.-Y.; Cornou , C.; Cox , B.R.; Dechamp , A.; Ohrnberger , M.; Sicilia , D.; Vergniault , C.

2017-01-01

International audience; The InterPacific project (Intercomparison of methods for site parameter and velocity profile characterization) aims to assess the reliability of seismic site characterization methods (borehole and surface wave methods) used for estimating shear wave velocity (VS) profiles and other related parameters (e.g., VS30). Three sites, representative of different geological conditions relevant for the evaluation of seismic site response effects, have been selected: (1) a hard r...

Preliminary results of hydrologic testing of the Umtanum Basalt Fracture Zone at borehole RRL-2 (3,781 to 3,827 ft)

International Nuclear Information System (INIS)

Strait, S.R.; Spane, F.A. Jr.

1983-02-01

This report presents preliminary results and description of hydrologic test activities for the Umtanum Basalt Fracture Zone at Borehole RRL-2, within the test interval 3,781 to 3,827 feet. Hydrologic tests conducted include two short-term, constant discharge pumping tests and two slug tests. Preliminary results indicate an observed hydraulic head for the test interval of 406.7 feet above mean sea level. Transmissivity values determined from hydrologic tests performed range between 205 and 881 ft 2 /day. The best estimate of equivalent hydraulic conductivity, based on an effective test thickness of 6 feet, is 147 ft/day. 8 refs., 6 figs., 3 tabs

Seismic considerations in sealing a potential high-level radioactive waste repository

International Nuclear Information System (INIS)

Fernandez, J.A.; Richardson, A.M.; Lin, Ming

1992-01-01

The potential repository system is intended to isolate high-level radioactive waste at Yucca Mountain. One subsystem that may contribute to achieving this objective is the sealing subsystem. This subsystem is comprised of sealing components in the shafts, ramps, underground network of drifts, and the exploratory boreholes. Sealing components can be rigid, as in the case of a shaft seal, or can be more compressible, as in the case of drift fill comprised of mined rockfill. This paper presents the preliminary seismic response of discrete sealing components in welded and nonwelded tuff. Special consideration is given to evaluating the stress in the seal, and the behavior of the interface between the seal and the rock. The seismic responses are computed using both static and dynamic analyses. Also presented is an evaluation of the maximum seismic response encountered by a drift seal with respect to the angle of incidence of the seismic wave. Mitigation strategies and seismic design considerations are proposed which can potentially enhance the overall response of the sealing component and subsequently, the performance of the overall repository system

Stepwise hydrogeological modeling and groundwater flow analysis on site scale (The former part of the step 3)

International Nuclear Information System (INIS)

Onoe, Hironori; Saegusa, Hiromitsu; Endo, Yoshinobu

2005-07-01

One of the main goals of the Mizunami Underground Research Laboratory Project is to establish comprehensive techniques for investigation, analysis, and assessment of the deep geological environment. To achieve this goal, a variety of investigations are being conducted using an iterative approach. In this study, hydrogeological modeling and groundwater flow analyses have been carried out using the data from surface-based investigations at the former part of Step 3 (deep borehole investigations without vertical seismic profiling investigations), in order to synthesize the investigation results, to evaluate the uncertainty of the hydrogeological model, and to specify items for further investigation. The results of this study are summarized as follows: 1) The uncertainty of hydrogeological model of the site scale is decreased as stepwise research; 2) Borehole investigations combined with hydraulic monitoring are useful for decreasing the uncertainty of hydrogeological model; The main items specified for further investigations are summarized as follows: 1) Trend, length, and hydraulic parameters of faults confirmed in the MIU construction site; 2) Shape of boundary of geological layer, and hydraulic parameters of rock; 3) Hydraulic head distribution of deep underground. (author)

High-resolution 3D seismic reflection imaging across active faults and its impact on seismic hazard estimation in the Tokyo metropolitan area

Science.gov (United States)

Ishiyama, Tatsuya; Sato, Hiroshi; Abe, Susumu; Kawasaki, Shinji; Kato, Naoko

2016-10-01

We collected and interpreted high-resolution 3D seismic reflection data across a hypothesized fault scarp, along the largest active fault that could generate hazardous earthquakes in the Tokyo metropolitan area. The processed and interpreted 3D seismic cube, linked with nearby borehole stratigraphy, suggests that a monocline that deforms lower Pleistocene units is unconformably overlain by middle Pleistocene conglomerates. Judging from structural patterns and vertical separation on the lower-middle Pleistocene units and the ground surface, the hypothesized scarp was interpreted as a terrace riser rather than as a manifestation of late Pleistocene structural growth resulting from repeated fault activity. Devastating earthquake scenarios had been predicted along the fault in question based on its proximity to the metropolitan area, however our new results lead to a significant decrease in estimated fault length and consequently in the estimated magnitude of future earthquakes associated with reactivation. This suggests a greatly reduced seismic hazard in the Tokyo metropolitan area from earthquakes generated by active intraplate crustal faults.

Deep Borehole Field Test Research Activities at LBNL

Energy Technology Data Exchange (ETDEWEB)

Dobson, Patrick [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Tsang, Chin-Fu [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Kneafsey, Timothy [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Borglin, Sharon [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Piceno, Yvette [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Andersen, Gary [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Nakagawa, Seiji [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Nihei, Kurt [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Rutqvist, Jonny [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Doughty, Christine [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Reagan, Matthew [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2016-08-19

The goal of the U.S. Department of Energy Used Fuel Disposition’s (UFD) Deep Borehole Field Test is to drill two 5 km large-diameter boreholes: a characterization borehole with a bottom-hole diameter of 8.5 inches and a field test borehole with a bottom-hole diameter of 17 inches. These boreholes will be used to demonstrate the ability to drill such holes in crystalline rocks, effectively characterize the bedrock repository system using geophysical, geochemical, and hydrological techniques, and emplace and retrieve test waste packages. These studies will be used to test the deep borehole disposal concept, which requires a hydrologically isolated environment characterized by low permeability, stable fluid density, reducing fluid chemistry conditions, and an effective borehole seal. During FY16, Lawrence Berkeley National Laboratory scientists conducted a number of research studies to support the UFD Deep Borehole Field Test effort. This work included providing supporting data for the Los Alamos National Laboratory geologic framework model for the proposed deep borehole site, conducting an analog study using an extensive suite of geoscience data and samples from a deep (2.5 km) research borehole in Sweden, conducting laboratory experiments and coupled process modeling related to borehole seals, and developing a suite of potential techniques that could be applied to the characterization and monitoring of the deep borehole environment. The results of these studies are presented in this report.

Deep Borehole Field Test Research Activities at LBNL

International Nuclear Information System (INIS)

Dobson, Patrick; Tsang, Chin-Fu; Kneafsey, Timothy; Borglin, Sharon; Piceno, Yvette; Andersen, Gary; Nakagawa, Seiji; Nihei, Kurt; Rutqvist, Jonny; Doughty, Christine; Reagan, Matthew

2016-01-01

The goal of the U.S. Department of Energy Used Fuel Disposition's (UFD) Deep Borehole Field Test is to drill two 5 km large-diameter boreholes: a characterization borehole with a bottom-hole diameter of 8.5 inches and a field test borehole with a bottom-hole diameter of 17 inches. These boreholes will be used to demonstrate the ability to drill such holes in crystalline rocks, effectively characterize the bedrock repository system using geophysical, geochemical, and hydrological techniques, and emplace and retrieve test waste packages. These studies will be used to test the deep borehole disposal concept, which requires a hydrologically isolated environment characterized by low permeability, stable fluid density, reducing fluid chemistry conditions, and an effective borehole seal. During FY16, Lawrence Berkeley National Laboratory scientists conducted a number of research studies to support the UFD Deep Borehole Field Test effort. This work included providing supporting data for the Los Alamos National Laboratory geologic framework model for the proposed deep borehole site, conducting an analog study using an extensive suite of geoscience data and samples from a deep (2.5 km) research borehole in Sweden, conducting laboratory experiments and coupled process modeling related to borehole seals, and developing a suite of potential techniques that could be applied to the characterization and monitoring of the deep borehole environment. The results of these studies are presented in this report.

Cement thickness measurements in cased boreholes

International Nuclear Information System (INIS)

Wahl, J.S.; Schuster, N.A.

1978-01-01

Methods and apparatus are provided for logging a borehole having solid matter along at least a portion of the wall thereof. Gamma radiation is emitted from the borehole into the surrounding media, and the amount of radiation which returns to the borehole is measured by three detectors located at different distances from the source of radiation, so as to be primarily sensitive to radiation which has respectively penetrated to three different depths in the surrounding media. The thickness of the solid matter on the borehole wall is then determined from the three gamma radiation measurements

The Global Seismographic Network (GSN): Deployment of Next Generation VBB Borehole Sensors and Improving Overall Network Noise Performance

Science.gov (United States)

Hafner, K.; Davis, P.; Wilson, D.; Sumy, D.

2017-12-01

The Global Seismographic Network (GSN) recently received delivery of the next generation Very Broadband (VBB) borehole sensors purchased through funding from the DOE. Deployment of these sensors will be underway during the end of summer and fall of 2017 and they will eventually replace the aging KS54000 sensors at approximately one-third of the GSN network stations. We will present the latest methods of deploying these sensors in the existing deep boreholes. To achieve lower noise performance at some sites, emplacement in shallow boreholes might result in lower noise performance for the existing site conditions. In some cases shallow borehole installations may be adapted to vault stations (which make up two thirds of the network), as a means of reducing tilt-induced signals on the horizontal components. The GSN is creating a prioritized list of equipment upgrades at selected stations with the ultimate goal of optimizing overall network data availability and noise performance. For an overview of the performance of the current GSN relative to selected set of metrics, we are utilizing data quality metrics and Probability Density Functions (PDFs)) generated by the IRIS Data Management Centers' (DMC) MUSTANG (Modular Utility for Statistical Knowledge Gathering) and LASSO (Latest Assessment of Seismic Station Observations) tools. We will present our metric analysis of GSN performance in 2016, and show the improvements at GSN sites resulting from recent instrumentation and infrastructure upgrades.

Geogas transport in fractured hard rock – Correlations with mining seismicity at 3.54 km depth, TauTona gold mine, South Africa

International Nuclear Information System (INIS)

Lippmann-Pipke, Johanna; Erzinger, Jörg; Zimmer, Martin; Kujawa, Christian; Boettcher, Margaret; Heerden, Esta Van; Bester, Armand; Moller, Hannes; Stroncik, Nicole A.; Reches, Zeev

2011-01-01

An on-site gas monitoring study has been conducted in the framework of an earthquake laboratory (The International NELSAM–DAFGAS projects) at the TauTona gold mine, South Africa. Five boreholes up to 60 m long were drilled at 3.54 km depth into the highly fractured Pretorius Fault Zone and instruments for chemical and seismic monitoring installed therein. Over the span of 4 years sensitive gas monitoring devices were continuously improved to enable the direct observation of geogas concentration variations in the DAFGAS borehole. The major gas concentrations are constant and air-like with about 78% N 2 , 21% O 2 , 1% Ar. The geogas components CO 2 , CH 4 , He and H 2 show the most interesting trends and variations on the minute-by-minute basis and significantly correlate with seismic data, while the 222 Rn activity remains constant. Time series and cross correlation analysis allow the identification of different gas components (geogas and tunnel air) and the identification of two processes influencing the borehole gas composition: (1) pumping-induced tunnel air breakthrough through networks of initially water-saturated fault fractures; and (2) seismicity induced permeability enhancement of fault fractures to above ∼5 × 10 -10 m 2 . The current set-up of the gas monitoring system is sensitive enough to quantify the resulting geogas transport during periods of intense blasting activities (including recorded blasts with seismic moment ⩽1 × 10 9 Nm, located within 1000 m of the cubby) and, it is suggested, also during induced earthquakes, a final goal of the project.

Borehole logging in uranium exploration

International Nuclear Information System (INIS)

Kulkarni, N.H.

1992-01-01

The ultimate objective of exploration by drilling as far as Atomic Minerals Division is concerned is to locate the ore zone in the subsurface, draw samples and analyze them for their metal content. The presence of the ore zone is also indicated by gamma-ray logging of the borehole. A gamma-ray detector is lowered in the borehole and precise depth and grade of the ore zone is established. This helps the geologist in correlating the ore horizon with the surface outcrop or the ore zone intercepted in adjoining boreholes and in deciding about further drilling and location of boreholes. Most commonly, total gamma measurements are made although some units capable of measuring the gamma-ray spectrum are also in use. It is possible to know if the mineralization is due to uranium without waiting for the laboratory results. The present write up gives a brief account of the principles, equipment and methods of borehole gamma-ray logging including density and self-potential logging. (author). 8 refs., 5 figs

Instantaneous Attributes Applied to Full Waveform Sonic Log and Seismic Data in Integration of Elastic Properties of Shale Gas Formations in Poland

Science.gov (United States)

Wawrzyniak-Guz, Kamila

2018-03-01

Seismic attributes calculated from full waveform sonic log were proposed as a method that may enhance the interpretation the data acquired at log and seismic scales. Though attributes calculated in the study were the mathematical transformations of amplitude, frequency, phase or time of the acoustic full waveforms and seismic traces, they could be related to the geological factors and/or petrophysical properties of rock formations. Attributes calculated from acoustic full waveforms were combined with selected attributes obtained for seismic traces recorded in the vicinity of the borehole and with petrophysical parameters. Such relations may be helpful in elastic and reservoir properties estimation over the area covered by the seismic survey.

Seismic Fracture Characterization Methodologies for Enhanced Geothermal Systems

Energy Technology Data Exchange (ETDEWEB)

Queen, John H. [Hi-Geophysical, Inc., Ponca, OK (United States)

2016-05-09

Executive Summary The overall objective of this work was the development of surface and borehole seismic methodologies using both compressional and shear waves for characterizing faults and fractures in Enhanced Geothermal Systems. We used both surface seismic and vertical seismic profile (VSP) methods. We adapted these methods to the unique conditions encountered in Enhanced Geothermal Systems (EGS) creation. These conditions include geological environments with volcanic cover, highly altered rocks, severe structure, extreme near surface velocity contrasts and lack of distinct velocity contrasts at depth. One of the objectives was the development of methods for identifying more appropriate seismic acquisition parameters for overcoming problems associated with these geological factors. Because temperatures up to 300º C are often encountered in these systems, another objective was the testing of VSP borehole tools capable of operating at depths in excess of 1,000 m and at temperatures in excess of 200º C. A final objective was the development of new processing and interpretation techniques based on scattering and time-frequency analysis, as well as the application of modern seismic migration imaging algorithms to seismic data acquired over geothermal areas. The use of surface seismic reflection data at Brady's Hot Springs was found useful in building a geological model, but only when combined with other extensive geological and geophysical data. The use of fine source and geophone spacing was critical in producing useful images. The surface seismic reflection data gave no information about the internal structure (extent, thickness and filling) of faults and fractures, and modeling suggests that they are unlikely to do so. Time-frequency analysis was applied to these data, but was not found to be significantly useful in their interpretation. Modeling does indicate that VSP and other seismic methods with sensors located at depth in wells will be the most

Magmatic processes evidenced by borehole dilatometer data at Campi Flegrei, Italy.

Science.gov (United States)

Di Lieto, Bellina; Romano, Pierdomenico; Scarpa, Roberto; Orazi, Massimo

2017-04-01

Since spring 2004 a joint research project (AMRA, UniSa, INGV) has been developed in Italy to install borehole strainmeters aimed at enhanced INGV monitoring systems. Six Sacks-Evertson dilatometers were installed around Campi Flegrei and Vesuvius during 2004-2005, and in 2008 these were supplemented by two arrays of long-baseline underground water tube tiltmeters. Renewed activity started since 2004-2005, characterized by a low rate of vertical displacement, amounting initially to a few cm/year. Recent deformation in the Campi Flegrei caldera is dominated by aseismic inflation, interrupted by minor transient aseismic reversals in rate. These are typically below the noise level or are poorly sampled by the low sampling frequency of most geodetic techniques, but can be quantified relatively easily using high sensitivity strainmeters and tiltmeters. These instruments provide coherent views of deformation at several different time scales capturing reversals in rate with periods from minutes to months. Monotonic uplift episodes have been recorded with durations of several weeks to a few years. During the summer of 2006 a long term strain episode related to an increase of CO2 emission, evidenced by borehole tiltmeters and continuous GPS sensors, has been observed by the borehole dilatometers array. This strain episode preceded caldera microseismic activity by few months, as was also observed during the 1982 period of unrest. Other aseismic slip episodes were recorded in October 2006 and in March 2010, several minutes before the most significant seismic swarms (VT and/or LP events) occurred after the 1982-1984 uplift. The time scale of these transient strain events lasted less than one hour, putting further constraints on the origin of ground uplifts at Campi Flegrei. Their locations are compatible with the source inferred from long term deformation signals, at about 4 km depth beneath Pozzuoli. The current array provides us with a glimpse of the potential utility of a

Identification Of Rippability And Bedrock Depth Using Seismic Refraction

Science.gov (United States)

Ismail, Nur Azwin; Saad, Rosli; Nawawi, M. N. M.; Muztaza, Nordiana Mohd; El Hidayah Ismail, Noer; Mohamad, Edy Tonizam

2010-12-01

Spatial variability of the bedrock with reference to the ground surface is vital for many applications in geotechnical engineering to decide the type of foundation of a structure. A study was done within the development area of Mutiara Damansara utilising the seismic refraction method using ABEM MK8 24 channel seismograph. The geological features of the subsurface were investigated and velocities, depth to the underlying layers were determined. The seismic velocities were correlated with rippability characteristics and borehole records. Seismic sections generally show a three layer case. The first layer with velocity 400-600 m/s predominantly consists of soil mix with gravel. The second layer with velocity 1600-2000 m/s is suggested to be saturated and weathered area. Both layers forms an overburden and generally rippable. The third layer represents granite bedrock with average depth and velocity 10-30 m and >3000 m/s respectively and it is non-rippable. Steep slope on the bedrock are probably the results of shear zones.

Identification Of Rippability And Bedrock Depth Using Seismic Refraction

International Nuclear Information System (INIS)

Ismail, Nur Azwin; Saad, Rosli; Nawawi, M. N. M; Muztaza, Nordiana Mohd; El Hidayah Ismail, Noer; Mohamad, Edy Tonizam

2010-01-01

Spatial variability of the bedrock with reference to the ground surface is vital for many applications in geotechnical engineering to decide the type of foundation of a structure. A study was done within the development area of Mutiara Damansara utilising the seismic refraction method using ABEM MK8 24 channel seismograph. The geological features of the subsurface were investigated and velocities, depth to the underlying layers were determined. The seismic velocities were correlated with rippability characteristics and borehole records. Seismic sections generally show a three layer case. The first layer with velocity 400-600 m/s predominantly consists of soil mix with gravel. The second layer with velocity 1600-2000 m/s is suggested to be saturated and weathered area. Both layers forms an overburden and generally rippable. The third layer represents granite bedrock with average depth and velocity 10-30 m and >3000 m/s respectively and it is non-rippable. Steep slope on the bedrock are probably the results of shear zones.

a Borehole-Dilution Method for Quantifying Vertical Darcy Fluxes in the Hyporheic Zone

Science.gov (United States)

Augustine, S. D.; Annable, M. D.; Cho, J.

2017-12-01

The borehole dilution method has consistently and successfully been used for estimating local water fluxes, however, this method can be relatively labor intensive and expensive. The focus of this research is aimed at developing a low-cost, borehole dilution method for quantifying vertical water fluxes in the hyporheic zone at the surface-groundwater interface. This would allow for the deployment of multiple units within a targeted surface water body and thus produce high-resolution, spatially distributed data on the infiltration rates over a short period of time with minimal set-up requirements. The device consists of a 2-inch, inner diameter PVC pipe containing short, screened sections in its upper and lower segments. The working unit is driven into the sediment and acts as a continuous flow reactor creating a pathway between the subsurface pore-water and the overlying surface water where the presence of a hydraulic gradient facilitates vertical movement. We developed a simple electrode and tracer-injection system housed within the unit to inject and measure salt tracer concentrations at the desired intervals while monitoring and storing those measurements using open-source Arduino technology. Preliminary lab and field scale trials provided data that was fit to both zero and first order reaction rate functions for analysis. The field test was conducted over approximately one day within a wet retention basin. The initial results estimated a vertical Darcy flux of 113.5 cm/d. Additional testing over a range of expected Darcy fluxes will be presented along with an evaluation considering enhanced water flow due to the high hydraulic conductivity of the device.

Classifying zones of suitability for manual drilling using textural and hydraulic parameters of shallow aquifers: a case study in northwestern Senegal

Science.gov (United States)

Fussi, F. Fabio; Fumagalli, Letizia; Fava, Francesco; Di Mauro, Biagio; Kane, Cheik Hamidou; Niang, Magatte; Wade, Souleye; Hamidou, Barry; Colombo, Roberto; Bonomi, Tullia

2017-12-01

A method is proposed that uses analysis of borehole stratigraphic logs for the characterization of shallow aquifers and for the assessment of areas suitable for manual drilling. The model is based on available borehole-log parameters: depth to hard rock, depth to water, thickness of laterite and hydraulic transmissivity of the shallow aquifer. The model is applied to a study area in northwestern Senegal. A dataset of boreholes logs has been processed using a software package (TANGAFRIC) developed during the research. After a manual procedure to assign a standard category describing the lithological characteristics, the next step is the automated extraction of different textural parameters and the estimation of hydraulic conductivity using reference values available in the literature. The hydraulic conductivity values estimated from stratigraphic data have been partially validated, by comparing them with measured values from a series of pumping tests carried out in large-diameter wells. The results show that this method is able to produce a reliable interpretation of the shallow hydrogeological context using information generally available in the region. The research contributes to improving the identification of areas where conditions are suitable for manual drilling. This is achieved by applying the described method, based on a structured and semi-quantitative approach, to classify the zones of suitability for given manual drilling techniques using data available in most African countries. Ultimately, this work will support proposed international programs aimed at promoting low-cost water supply in Africa and enhancing access to safe drinking water for the population.

An optimization procedure for borehole emplacement in fractured media

International Nuclear Information System (INIS)

Billaux, D.; Guerin, F.

1998-01-01

Specifying the position and orientation of the 'next borehole(s)' in a fractured medium, from prior incomplete knowledge of the fracture field and depending on the objectives assigned to this new borehole(s), is a crucial point in the iterative process of site characterization. The work described here explicitly includes site knowledge and specific objectives in a tractable procedure that checks possible borehole characteristics, and rates all trial boreholes according to their compliance with objectives. The procedure is based on the following ideas : Firstly, the optimization problem is strongly constrained, since feasible borehole head locations and borehole dips are generally limited. Secondly, a borehole is an 'access point' to the fracture network. Finally, when performing a flow or tracer test, the information obtained through the monitoring system will be best if this system detects the largest possible share of the flow induced by the test, and if it cuts the most 'interesting' flow paths. The optimization is carried out in four steps. 1) All possible borehole configurations are defined and stored. Typically, several hundred possible boreholes are created. Existing boreholes are also specified. 2) Stochastic fracture networks reproducing known site characteristics are generated. 3) A purely geometrical rating of all boreholes is used to select the 'geometrically best' boreholes or groups of boreholes. 4) Among the boreholes selected by the geometrical rating, the best one(s) is chosen by simulating the experiment for which it will be used and checking flowrates through possible boreholes. This method is applied to study the emplacement of a set of five monitoring boreholes prior to the sinking of a shaft for a planned underground laboratory in a granite massif in France (Vienne site). Twelve geometrical parameters are considered for each possible borehole. A detailed statistical study helps decide on the shape of a minimization function. This is then used

Induced Seismicity Monitoring System

Science.gov (United States)

Taylor, S. R.; Jarpe, S.; Harben, P.

2014-12-01

There are many seismological aspects associated with monitoring of permanent storage of carbon dioxide (CO2) in geologic formations. Many of these include monitoring underground gas migration through detailed tomographic studies of rock properties, integrity of the cap rock and micro seismicity with time. These types of studies require expensive deployments of surface and borehole sensors in the vicinity of the CO2 injection wells. Another problem that may exist in CO2 sequestration fields is the potential for damaging induced seismicity associated with fluid injection into the geologic reservoir. Seismic hazard monitoring in CO2 sequestration fields requires a seismic network over a spatially larger region possibly having stations in remote settings. Expensive observatory-grade seismic systems are not necessary for seismic hazard deployments or small-scale tomographic studies. Hazard monitoring requires accurate location of induced seismicity to magnitude levels only slightly less than that which can be felt at the surface (e.g. magnitude 1), and the frequencies of interest for tomographic analysis are ~1 Hz and greater. We have developed a seismo/acoustic smart sensor system that can achieve the goals necessary for induced seismicity monitoring in CO2 sequestration fields. The unit is inexpensive, lightweight, easy to deploy, can operate remotely under harsh conditions and features 9 channels of recording (currently 3C 4.5 Hz geophone, MEMS accelerometer and microphone). An on-board processor allows for satellite transmission of parameter data to a processing center. Continuous or event-detected data is kept on two removable flash SD cards of up to 64+ Gbytes each. If available, data can be transmitted via cell phone modem or picked up via site visits. Low-power consumption allows for autonomous operation using only a 10 watt solar panel and a gel-cell battery. The system has been successfully tested for long-term (> 6 months) remote operations over a wide range

Uncertainty analysis of depth predictions from seismic reflection data using Bayesian statistics

Science.gov (United States)

Michelioudakis, Dimitrios G.; Hobbs, Richard W.; Caiado, Camila C. S.

2018-03-01

Estimating the depths of target horizons from seismic reflection data is an important task in exploration geophysics. To constrain these depths we need a reliable and accurate velocity model. Here, we build an optimum 2D seismic reflection data processing flow focused on pre - stack deghosting filters and velocity model building and apply Bayesian methods, including Gaussian process emulation and Bayesian History Matching (BHM), to estimate the uncertainties of the depths of key horizons near the borehole DSDP-258 located in the Mentelle Basin, south west of Australia, and compare the results with the drilled core from that well. Following this strategy, the tie between the modelled and observed depths from DSDP-258 core was in accordance with the ± 2σ posterior credibility intervals and predictions for depths to key horizons were made for the two new drill sites, adjacent the existing borehole of the area. The probabilistic analysis allowed us to generate multiple realizations of pre-stack depth migrated images, these can be directly used to better constrain interpretation and identify potential risk at drill sites. The method will be applied to constrain the drilling targets for the upcoming International Ocean Discovery Program (IODP), leg 369.

Comparison between results of detailed tectonic studies on borehole core vs microresistivity images of borehole wall from gas-bearing shale complexes, Baltic Basin, Poland.

Science.gov (United States)

Bobek, Kinga; Jarosiński, Marek; Pachytel, Radomir

2017-04-01

Structural analysis of borehole core and microresistivity images yield an information about geometry of natural fracture network and their potential importance for reservoir stimulation. Density of natural fractures and their orientation in respect to the maximum horizontal stress has crucial meaning for hydraulic fractures propagation in unconventional reservoirs. We have investigated several hundred meters of continuous borehole core and corresponding microresistivity images (mostly XRMI) from six boreholes in the Pomeranian part of the Early Paleozoic Baltic Basin. In general, our results challenge the question about representatives of statistics based on structural analyses on a small shale volume represented by borehole core or borehole wall images and credibility of different sets of data. Most frequently, fractures observed in both XRMI and cores are steep, small strata-bound fractures and veins with minor mechanical aperture (0,1 mm in average). These veins create an orthogonal joint system, locally disturbed by fractures associated with normal or by gently dipping thrust faults. Mean fractures' height keeps in a range between 30-50 cm. Fracture density differs significantly among boreholes and Consistent Lithological Units (CLUs) but the most frequent means falls in a range 2-4 m-1. We have also payed an attention to bedding planes due to their expected coupling with natural fractures and their role as structural barriers for vertical fracture propagation. We aimed in construction for each CLU the so-called "mean brick", which size is limited by an average distance between two principal joint sets and between bedding fractures. In our study we have found out a discrepancy between structural profiles based on XRMI and core interpretation. For some CLUs joint fractures densities, are higher in cores than in XRMI. In this case, numerous small fractures were not recorded due to the limits of XRMI resolution. However, the most veins with aperture 0,1 mm

Hydrocarbon Induced Seismicity in Northern Netherlands

Science.gov (United States)

Dost, B.; Spetzler, J.; Kraaijpoel, D.; Caccavale, M.

2015-12-01

The northern Netherlands has been regarded aseismic until the first earthquakes started in 1986, after more than 25 years of gas production from the one of the largest on-shore gas-fields in the World, the Groningen field, and accompanying smaller gas fields. Due to the shallow sources, at approximately 3 km depth, even small magnitude events cause considerable damage to buildings in the region. Since the largest recorded event in the Groningen field in 2012 with ML= 3,6, more than 30.000 damage claims were received by the mining company. Since 1995 a seismic monitoring network is operational in the region, consisting of 8 200m deep boreholes with 4 levels of 3C 4,5 Hz geophones. The network was designed for a location threshold of ML=1,5 over a 40x 80 km region. Average station separation was 20 km. At the end of 2014, 245 events have been recorded with ML ≥ 1,5, out of a total of 1100. Since 2003 a new mining law is in place in the Netherlands, which requires for each gas field in production a seismic risk analysis. Initially, due to the small number of events for specific fields, a general hazard (PSHA) was calculated for all gas-fields and a maximum magnitude was estimated at ML = 3,9. Since 2003 an increase in the activity rate is observed for the Groningen field, leading to the development of new models and a re-assessment of parameters like the maximum magnitude. More recently these models are extended to seismic risk, where also the fragility of the regional buildings is taken into account. Understanding the earthquake process is essential in taking mitigation measures. Continued research is focused on reducing the uncertainties in the hazard and risk models and is accompanied by an upgrade of the monitoring network. In 2014 a new dense network was designed to monitor the Groningen gas field in this region (30*40 km) with an average separation of 4 km. This allows an improved location threshold (M>0,5) and location accuracy (50-100m). A detailed P- and S

Borehole DC-12 hydrostratigraphic chart

International Nuclear Information System (INIS)

Gephart, R.E.

1981-09-01

This hydrostratigraphic chart identifies the basic stratigraphy and preliminary hydrologic testing results for Borehole DC-12. This borehole was cored through the Saddle Mountains and Wanapum basalt formations and into the Grande Ronde. Selected zones were hydrologically tested during coring

Borehole DC-14 hydrostratigraphic chart

International Nuclear Information System (INIS)

Gephart, R.E.

1981-09-01

This hydrostratigraphic chart identifies the basic stratigraphy and preliminary hydrologic testing results for Borehole DC-14. This borehole was cored through the Saddle Mountains and Wanapum basalt formations and into the Grande Ronde. Selected zones were hydrologically tested during coring

Borehole DC-15 hydrostratigraphic chart

International Nuclear Information System (INIS)

Gephart, R.E.

1981-09-01

This hydrostratigraphic chart identifies the basic stratigraphy and preliminary hydrologic testing results for Borehole DC-15. This borehole was cored through the Saddle Mountains and Wanapum basalt formations and into the Grande Ronde. Selected zones were hydrologically tested during coring

Geophysical and transport properties of reservoir rocks. Final report for task 4: Measurements and analysis of seismic properties

Energy Technology Data Exchange (ETDEWEB)

Cook, N.G.W.

1993-05-01

The principal objective of research on the seismic properties of reservoir rocks is to develop a basic understanding of the effects of rock microstructure and its contained pore fluids on seismic velocities and attenuation. Ultimately, this knowledge would be used to extract reservoir properties information such as the porosity, permeability, clay content, fluid saturation, and fluid type from borehole, cross-borehole, and surface seismic measurements to improve the planning and control of oil and gas recovery. This thesis presents laboratory ultrasonic measurements for three granular materials and attempts to relate the microstructural properties and the properties of the pore fluids to P- and S-wave velocities and attenuation. These experimental results show that artificial porous materials with sintered grains and a sandstone with partially cemented grains exhibit complexities in P- and S-wave attenuation that cannot be adequately explained by existing micromechanical theories. It is likely that some of the complexity observed in the seismic attenuation is controlled by details of the rock microstructure, such as the grain contact area and grain shape, and by the arrangement of the grain packing. To examine these effects, a numerical method was developed for analyzing wave propagation in a grain packing. The method is based on a dynamic boundary integral equation and incorporates generalized stiffness boundary conditions between individual grains to account for viscous losses and grain contact scattering.

Development of technical means for directional hydraulic fracturing with shearing loading of borehole walls

Science.gov (United States)

Rybalkin, LA; Patutin, AV; Patutin, DV

2018-03-01

During the process of mineral deposits’ mining one of the most important conditions for safe and economically profitable work of a mining enterprise is obtaining timely information on the stress state of the developed massif. One of the most common methods of remote study of the geomechanical state of the rock massif is hydraulic fracturing of the formation. Directional hydraulic fracturing is a type of the method employed to form cracks across production wells. This technology was most widely used in the gas industry to extract gas from shale formations. In mining, this technology is used to set up filtration screens, to integrate degassing, to soften the hard roof of coal seams. Possible practical appliance is the expansion of the application field of this technology to intensify the production of viscous oil, to leach non-ferrous metals, to create in the rock massif anti-filtration screens for various purposes, as well as to measure stresses acting along the wells.

Study of iron deposit using seismic refraction and resistivity in Carajás Mineral Province, Brazil

Science.gov (United States)

Nogueira, Pedro Vencovsky; Rocha, Marcelo Peres; Borges, Welitom Rodrigues; Silva, Adalene Moreira; Assis, Luciano Mozer de

2016-10-01

This work comprises the acquisition, processing and interpretation of 2D seismic shallow refraction (P-wave) and resistivity profiles located in the iron ore deposit of N4WS, Carajás Mineral Province (CMP), northern Brazil. The geophysical methods were used to identify the boundaries of the iron ore deposit. Another objective was to evaluate the potentiality of these geophysical methods in that geological context. In order to validate the results, the geophysical lines were located to match a geological borehole line. For the seismic refraction, we used 120 channels, spaced by 10 m, in a line of 1190 m, with seven shot points. The resistivity method used in the acquisition was the electrical resistivity imaging, with pole-pole array, in order to reach greater depths. The resistivity line had a length of 1430 m, with 10 m spacing between electrodes. The seismic results produced a model with two distinct layers. Based on the velocities values, the first layer was interpreted as altered rocks, and the second layer as more preserved rocks. It was not possible to discriminate different lithologies with the seismic method inside each layer. From the resistivity results, a zone of higher resistivity (> 3937 Ω·m) was interpreted as iron ore, and a region of intermediate resistivity (from 816 to 2330 Ω·m) as altered rocks. These two regions represent the first seismic layer. On the second seismic layer, an area with intermediated resistivity values (from 483 to 2330 Ω·m) was interpreted as mafic rocks, and the area with lower resistivity (boreholes and show reasonable correlation, suggesting that the geophysical anomalies correspond to the main variations in composition and physical properties of rocks.

Dual hydraulic behaviour of the Chalk in the Netherlands North Sea

NARCIS (Netherlands)

Verweij, H.

2006-01-01

Information on the sedimentary development, seismic stratigraphy and burial compaction of the Chalk Group in the Netherlands North Sea was combined with pressure data and basin modelling to investigate the hydraulic behaviour of the Chalk Group in the Central Graben and Schill Grund High. The

Characteristics of vertical seismic motions and qp-values in sedimentary layers

International Nuclear Information System (INIS)

Tohdo, Masanobu; Hatori, Toshiaki; Chiba, Osamu; Takahashi, Katsuya; Takemura, Masayuki; Tanaka, Hideo.

1995-01-01

Using seismic records observed in 4 borehole arrays, characteristics of vertical seismic motions in sedimentary layers are investigated. The results are as follows. 1) P-waves having intensive effect to vertical component are propagating within sedimentary layers even after the S-wave onset time (S-wave part). 2) Frequency dependent Q-values for P-waves (Qp) in Tertiary sediment layers obtained from the optimal analyses to spectral ratios have the tendency to be identical with Q-values for S-waves (Qs) with the same wavelength. 3) Observed vertical motions in upper ground can be simulated by the multiple reflection theory of P-waves based on the optimized velocities and Q-values. (author)

Conductive fracture mapping. A study on the correlation between borehole TV- and radar images and difference flow logging results in borehole KLX02

International Nuclear Information System (INIS)

Carlsten, S.; Straahle, A.; Ludvigson, Jan-Erik

2001-10-01

the recorded borehole length were used as the most important parameters. The accuracy of the recorded length (depth) of the interpreted radar reflectors is rather poor compared to the BIPS-logging. A total number of 6 radar reflectors (of the 12 identified) could be correlated with BIPS-features and DIFF-flow anomalies. As above, the correlated BIPS-features were classified as open fractures or in some cases as veins in the rock. The correlation study indicates that the number of features mapped as 'open fractures' together with 'fractures with cavities' in the BIPS characterisation, correspond to almost 70% of the total number of interpreted flow anomalies from the DIFF-logging in this borehole interval. This figure increases to almost 80% if uncertain flow anomalies below the measurement limit are excluded. The remainder of the flow anomalies correspond to features mapped as 'altered fractures or veins' and 'dull fractures or veins 'in the BIPS- characterisation. The estimated lateral extent of the correlated radar reflectors is about 10-30 m. The latter figure corresponds to the estimated persistence (depth of penetration)of the radar images in this case. The dominant strike of the interpreted flow anomalies is towards WNW-NW as determined from the BIPS- and radar characterisation. This result is in good agreement with previous investigations of the orientation of water-conductive fractures at Aespoe. Thus, it is concluded that the interpreted flow anomalies from the DIFF-log are representative for the dominating hydraulic conditions in the rock. The accuracy of the depth recording is one of the most important parameter and also the one that, in this study, contributes to the largest error when comparing different methods. One of the conclusions of this study is to diminish the error by using efficient measuring wheels in order to avoid sliding of the cable during logging. A new method for making length registration is at present under development. Also, certainty

Instantaneous Attributes Applied to Full Waveform Sonic Log and Seismic Data in Integration of Elastic Properties of Shale Gas Formations in Poland

Directory of Open Access Journals (Sweden)

Wawrzyniak-Guz Kamila

2018-01-01

Full Text Available Seismic attributes calculated from full waveform sonic log were proposed as a method that may enhance the interpretation the data acquired at log and seismic scales. Though attributes calculated in the study were the mathematical transformations of amplitude, frequency, phase or time of the acoustic full waveforms and seismic traces, they could be related to the geological factors and/or petrophysical properties of rock formations. Attributes calculated from acoustic full waveforms were combined with selected attributes obtained for seismic traces recorded in the vicinity of the borehole and with petrophysical parameters. Such relations may be helpful in elastic and reservoir properties estimation over the area covered by the seismic survey.

Borehole Breakout Growth and In-Situ Stress Orientation in the Central Scandinavian Caledonides: Results from the Cosc-1 Borehole

Science.gov (United States)

Wenning, Q.; Zappone, A.; Berthet, T.; Ask, M. V. S.; Rosberg, J. E.; Almqvist, B. S. G.

2017-12-01

Borehole breakouts are often assumed to form near instantaneously due to stress perturbations around boreholes after the rock mass was removed. Recent observations in sediments [e.g., Moore et al., 2011] and crystalline rocks [e.g., Berard and Cornet, 2003], as well as numerical modelling results [e.g., Schoenball et al., 2014], suggest that there are cases in which borehole breakout grows radially over time, forcing us to reconsider subsurface stress estimation. These observations are rare due to drilling difficulties (i.e., cementing and casing the borehole after drilling), often only allowing a single image logging campaign. In 2014, the Collisional Orogeny in the Scandinavian Caledonides deep scientific borehole (COSC-1) was drilled to a depth of 2.5 km. To date the borehole is open and uncased, allowing two acoustic televiewer logging campaigns, with more than one year between campaigns. The borehole is still available for supplementary data collactions. These logs provide detailed images along the full length of the 2.5 km deep borehole with 1.6 km of overlapping logs for breakout and drilling induced tensile fracture analysis. The results show from the sparse occurrence of breakouts and drilling induced tensile fractures a NW-SE average maximum horizontal stress direction, consistent with the general trend in Scandinavia. The unique acquisition of image logs in two successions allows for analysis of time-dependent borehole deformation, indicating that six breakout zones have crept, both along the borehole axis and radially (up to 20° growth) around the borehole. While some breakouts have grown, the formation of new breakouts has not occurred. The occurrence of breakouts and their growth appear to be independent of lithology. The observed growth after the second logging campaign suggests that under conditions where the stress exceeded the strength of the rock, the resulting breakout causes perturbations in the stresses around the borehole in the near

底板巷水力冲孔卸压增透技术的研究与应用%Study and Application on Pressure Releasing and Permeability Improved Technology with Hydraulic Flushing in Floor Gateway

Institute of Scientific and Technical Information of China (English)

徐东方; 黄渊跃; 罗治顺; 杨献东

2013-01-01

In order to investigate the effect of the pressure releasing and permeability improved technology with hydraulic flushing in floor gateway to improve the seam permeability and to improve the gas drainage rate, a trial was conducted on the pressure releasing and permeability improved technology with hydraulic flushing in No. 1259(3) floor gateway of Puxijing.The results showed that the radius of the pressure releasing and permeability improvement with the hydraulic flushing borehole could reach 4~5 m and would be 1.6~2.0 times higher than the influence radius of the gas drainage with a conventional borehole. Within half month after the hydraulic flushing measures conducted, the average gas drainage concentration of the borehole was 2.77 times higher than the conventional borehole,the average gas flow value was 3.43 times higher than the conventional borehole,the effect of the pressure releasing and permeability improvement was relatively remarkable , the seam permeability was improved and the outburst danger was reduced.%为了考察底板巷水力冲孔卸压增透技术对增加煤层透气性,提高瓦斯抽采效果,在浦溪井1259(3)底板巷实施水力冲孔卸压增透技术试验.结果表明:水力冲孔卸压增透半径达到4～5m,为普通钻孔抽采影响半径的1.6～2.0倍；采取水力冲孔措施的半个月内,钻孔的平均瓦斯抽采浓度是普通钻孔的2.77倍,平均瓦斯流量是普通钻孔的3.43倍,卸压增透效果比较明显,提高了煤层透气性,降低了突出危险性.

Seismic considerations in sealing a potential high-level radioactive waste repository

International Nuclear Information System (INIS)

Fernandez, J.A.; Richardson, A.M.; Lin, Ming

1993-01-01

The potential repository system is intended to isolate high-level radioactive waste at Yucca Mountain according the performance objective--10 CFR 60.112. One subsystem that may contribute to achieving this objective is the sealing subsystem. This subsystem is comprised of sealing components in the shafts, ramps, underground network of drifts, and the exploratory boreholes. Sealing components can be rigid, as in the case of a shaft seal, or can be more compressible, as in the case of drift fill comprised of mined rockfill. This paper presents the preliminary seismic response of discrete sealing components in welded and nonwelded tuff. Special consideration is given to evaluating the stress in the seal, and the behavior of the interface between the seal and the rock. The seismic responses are computed using both static and dynamic analyses. Also presented is an evaluation of the maximum seismic response encountered by a drift seal with respect to the angle of incidence of the seismic wave. Mitigation strategies and seismic design considerations are proposed which can potentially enhance the overall response of the sealing component and subsequently, the performance of the overall repository system

Geomechanical Considerations for the Deep Borehole Field Test

Science.gov (United States)

Park, B. Y.

2015-12-01

Deep borehole disposal of high-level radioactive waste is under consideration as a potential alternative to shallower mined repositories. The disposal concept consists of drilling a borehole into crystalline basement rocks to a depth of 5 km, emplacement of canisters containing solid waste in the lower 2 km, and plugging and sealing the upper 3 km of the borehole. Crystalline rocks such as granites are particularly attractive for borehole emplacement because of their low permeability and porosity at depth, and high mechanical strength to resist borehole deformation. In addition, high overburden pressures contribute to sealing of some of the fractures that provide transport pathways. We present geomechanical considerations during construction (e.g., borehole breakouts, disturbed rock zone development, and creep closure), relevant to both the smaller-diameter characterization borehole (8.5") and the larger-diameter field test borehole (17"). Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

Fracture Modes and Identification of Fault Zones in Wenchuan Earthquake Fault Scientific Drilling Boreholes

Science.gov (United States)

Deng, C.; Pan, H.; Zhao, P.; Qin, R.; Peng, L.

2017-12-01

After suffering from the disaster of Wenchuan earthquake on May 12th, 2008, scientists are eager to figure out the structure of formation, the geodynamic processes of faults and the mechanism of earthquake in Wenchuan by drilling five holes into the Yingxiu-Beichuan fault zone and Anxian-Guanxian fault zone. Fractures identification and in-situ stress determination can provide abundant information for formation evaluation and earthquake study. This study describe all the fracture modes in the five boreholes on the basis of cores and image logs, and summarize the response characteristics of fractures in conventional logs. The results indicate that the WFSD boreholes encounter enormous fractures, including natural fractures and induced fractures, and high dip-angle conductive fractures are the most common fractures. The maximum horizontal stress trends along the borehole are deduced as NWW-SEE according to orientations of borehole breakouts and drilling-induced fractures, which is nearly parallel to the strikes of the younger natural fracture sets. Minor positive deviations of AC (acoustic log) and negative deviation of DEN (density log) demonstrate their responses to fracture, followed by CNL (neutron log), resistivity logs and GR (gamma ray log) at different extent of intensity. Besides, considering the fact that the reliable methods for identifying fracture zone, like seismic, core recovery and image logs, can often be hampered by their high cost and limited application, this study propose a method by using conventional logs, which are low-cost and available in even old wells. We employ wavelet decomposition to extract the high frequency information of conventional logs and reconstruction a new log in special format of enhance fracture responses and eliminate nonfracture influence. Results reveal that the new log shows obvious deviations in fault zones, which confirm the potential of conventional logs in fracture zone identification.

Borehole imaging tool detects well bore fractures

International Nuclear Information System (INIS)

Ma, T.A.; Bigelow, E.L.

1993-01-01

This paper reports on borehole imaging data which can provide high quality geological and petrophysical information to improve fracture identification, dip computations, and lithology determinations in a well bore. The ability to visually quantify the area of a borehole wall occupied by fractures and vugs enhances reservoir characterization and well completion operations. The circumferential borehole imaging log (CBIL) instrument is an acoustic logging device designed to produce a map of the entire borehole wall. The visual images can confirm computed dips and the geological features related to dip. Borehole geometry, including breakout, are accurately described by complete circumferential caliper measurements, which is important information for drilling and completion engineers. In may reservoirs, the images can identify porosity type, bedding characteristics, and petrophysical parameters

Borehole DC-6 hydrostratigraphic chart

International Nuclear Information System (INIS)

Gephart, R.E.

1981-09-01

This hydrostratigraphic chart for Borehole DC-6 identifies the basic stratigraphy and preliminary hydrologic test results. This borehole was cored for obtaining stratigraphic data and only that portion within the Grande Ronde formation remains open for hydrologic testing. The upper two formations were cased and cemented off

Did you smooth your well logs the right way for seismic interpretation?

International Nuclear Information System (INIS)

Duchesne, Mathieu J; Gaillot, Philippe

2011-01-01

Correlations between physical properties and seismic reflection data are useful to determine the geological nature of seismic reflections and the lateral extent of geological strata. The difference in resolution between well logs and seismic data is a major hurdle faced by seismic interpreters when tying both data sets. In general, log data have a resolution of at least two orders of magnitude greater than seismic data. Smoothing physical property logs improves correlation at the seismic scale. Three different approaches were used and compared to smooth a density log: binomial filtering, seismic wavelet filtering and discrete wavelet transform (DWT) filtering. Regression plots between the density logs and the acoustic impedance show that the data smoothed with the DWT is the only method that preserves the original relationship between the raw density data and the acoustic impedance. Smoothed logs were then used to generate synthetic seismograms that were tied to seismic data at the borehole site. Best ties were achieved using the synthetic seismogram computed with the density log processed with the DWT. The good performance of the DWT is explained by its adaptive multi-scale characteristic which preserved significant local changes of density on the high-resolution data series that were also pictured at the seismic scale. Since synthetic seismograms are generated using smoothed logs, the choice of the smoothing method impacts on the quality of seismic-to-well ties. This ultimately can have economical implications during hydrocarbon exploration or exploitation phases

Experimental perforation of tubing with a hydraulic sand jet

Energy Technology Data Exchange (ETDEWEB)

Semenov, Yu V

1970-01-01

A series of field tests has shown that perforation with a hydraulic sand jet improves the quality of well completion. The sand jet does not crack the cement sheath or the casing, and the perforations are larger and deeper than perforations formed by explosive charges. Fluid circulation during sand jet perforation can safely be stopped for at least 10 min. Water containing a surfactant can be used as a sand carrier. Sand jet perforation allows successful completion of wells cased by 2 tubing strings. Sand jet perforation can be used to clean the borehole well and to remove foreign objects from the well.

Analytical Data Report for Sediment Samples Collected From 116-KE-3 and UPR-100-K-1; Boreholes C8796 and C8796

Energy Technology Data Exchange (ETDEWEB)

Snyder, Michelle M.V. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Last, George V. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Stephenson, John R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Clayton, Ray E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2016-03-01

CH2M Hill Plateau Remediation Company (CHPRC) requested the services of the Pacific Northwest National Laboratory (PNNL) to perform contaminant leach testing on samples from two boreholes, C8796 and C8797, installed near the 105-KE reactor. These tests consisted of field texture column tests, <2 mm repacked column tests, batch desorption tests, and ion exchange experiments. In addition, hydraulic and physical property characterization was performed.

Visualization of volumetric seismic data

Science.gov (United States)

Spickermann, Dela; Böttinger, Michael; Ashfaq Ahmed, Khawar; Gajewski, Dirk

2015-04-01

Mostly driven by demands of high quality subsurface imaging, highly specialized tools and methods have been developed to support the processing, visualization and interpretation of seismic data. 3D seismic data acquisition and 4D time-lapse seismic monitoring are well-established techniques in academia and industry, producing large amounts of data to be processed, visualized and interpreted. In this context, interactive 3D visualization methods proved to be valuable for the analysis of 3D seismic data cubes - especially for sedimentary environments with continuous horizons. In crystalline and hard rock environments, where hydraulic stimulation techniques may be applied to produce geothermal energy, interpretation of the seismic data is a more challenging problem. Instead of continuous reflection horizons, the imaging targets are often steep dipping faults, causing a lot of diffractions. Without further preprocessing these geological structures are often hidden behind the noise in the data. In this PICO presentation we will present a workflow consisting of data processing steps, which enhance the signal-to-noise ratio, followed by a visualization step based on the use the commercially available general purpose 3D visualization system Avizo. Specifically, we have used Avizo Earth, an extension to Avizo, which supports the import of seismic data in SEG-Y format and offers easy access to state-of-the-art 3D visualization methods at interactive frame rates, even for large seismic data cubes. In seismic interpretation using visualization, interactivity is a key requirement for understanding complex 3D structures. In order to enable an easy communication of the insights gained during the interactive visualization process, animations of the visualized data were created which support the spatial understanding of the data.

Borehole Data

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Records of past temperature derived from boreholes drilled into the Earth crust. Parameter keywords describe what was measured in this data set. Additional summary...

Evaluation of geophysical borehole studies

International Nuclear Information System (INIS)

Brotzen, O.; Duran, O.; Magnusson, K.Aa.

Four studies concerning geophysical investigations and TV inspection in boreholes in connection with KBS studies at Finnsjoe, Karlshamn, Kraakemaala and Stripa and PRAV's studies at Studsvik have been evaluated. This has led to proposals concerning the choice of instruments and methods for future studies and a review of future work required. The evaluation has shown that the following borehole measurements are of primary interest in the continued work: Determinations of temperature and resistivity of the borehole liquid, resistance and resistivity measurements, SP, Sonic, Caliper and VLF. TV inspection, IP and gamma-gamma should also be included in the arsenal of available test methods.(author)

Lithology, hydro-dynamism and thermicity in the multi-layer sedimentary system intersected by the Andra deep borehole of Montiers-sur-Saulx (Meuse, France)

International Nuclear Information System (INIS)

Landrein, Philippe; Vigneron, Georges; Delay, Jacques; Lebon, Patrick; Pagel, Maurice

2013-01-01

their own sampling on cores dedicated to the Andra studies as well as on cores that were positioned to suit their own research themes. The Callovo-Oxfordian and the upper part of the Dogger were cored continuously from 526 m to 770 m in depth. The method used for the lower part, from 770 to 2001 m (MD),was percussion air drilling with punctual core extraction for certain horizons. Numerous logs were carried out during drilling, others were differed, and two thermal logs were performed 9 months after drilling: These logs and the cores helped to establish a stratigraphic log consistent with previous Andra drilling results in the Dogger and the Malm, as well as the Chevillon 1 drilling for the Liassic and Triassic units. Information obtained from the deep borehole confirmed the progressive northeasterly thickening of the Callovo-Oxfordian layer as well as its lithological vertical and horizontal consistency. The measurements of hydraulic transmissivity in Callovo-Oxfordian formation show the same range than in other places in the Transposition zone. In the Dogger, a clear link between the permeability of certain levels and the depositional environments was brought to light. For the deep formations (Lias and Trias), the series is consistent with the one deduced from previous drillings. Only the formation of the lower Keuper 'Marnes irisees' is thicker than expected. The reconstruction of the thickness of the formations, achieved thanks to the seismic campaign and nearest oil drillings, shows that the EST433 borehole is located in a hollow area where the Keuper formations are thicker. The borehole results show that the upper and middle Lias and Trias facies have a very low porosity and that only the lower Trias contains aquiferous levels. Thus, a series of a thousand meters with no significant porosity separates the Dogger aquifer from that of the lower Trias. Interpretation of the seismic profiles reveals the existence of faults, mainly in the western part of the zone, but

Oman Drilling Project Phase I Borehole Geophysical Survey

Science.gov (United States)

Matter, J. M.; Pezard, P. A.; Henry, G.; Brun, L.; Célérier, B.; Lods, G.; Robert, P.; Benchikh, A. M.; Al Shukaili, M.; Al Qassabi, A.

2017-12-01

The Oman Drilling Project (OmanDP) drilled six holes at six sites in the Samail ophiolite in the southern Samail and Tayin massifs. 1500-m of igneous and metamorphic rocks were recovered at four sites (GT1, GT2, GT3 and BT1) using wireline diamond core drilling and drill cuttings at two sites (BA1, BA2) using air rotary drilling, respectively. OmanDP is an international collaboration supported by the International Continental Scientific Drilling Program, the Deep Carbon Observatory, NSF, NASA, IODP, JAMSTEC, and the European, Japanese, German and Swiss Science Foundations, and with in-kind support in Oman from Ministry of Regional Municipalities and Water Resources, Public Authority of Mining, Sultan Qaboos University and the German University of Technology. A comprehensive borehole geophysical survey was conducted in all the OmanDP Phase I boreholes shortly after drilling in April 2017. Following geophysical wireline logs, using slim-hole borehole logging equipment provided and run by the Centre National De La Recherche Scientifique (CNRS) and the Université de Montpellier/ Géosciences Montpellier, and logging trucks from the Ministry of Regional Municipalities and Water Resources, were collected in most of the holes: electrical resistivity (dual laterolog resistivity, LLd and LLs), spectral gamma ray (K, U, and Th contents), magnetic susceptibility, total natural gamma ray, full waveform sonic (Vp and Vs), acoustic borehole wall imaging, optical borehole wall imaging, borehole fluid parameters (pressure, temperature, electrical conductivity, dissolved oxygen, pH, redox potential, non-polarized spontaneous electrical potential), and caliper (borehole diameter). In addition, spinner flowmeter (downhole fluid flow rate along borehole axis) and heatpulse flow meter logs (dowhole fluid flow rate along borehole axis) were collected in BA1 to characterize downhole fluid flow rates along borehole axis. Unfortuantely, only incomplete wireline logs are available for

Rippability Assessment of Weathered Sedimentary Rock Mass using Seismic Refraction Methods

Science.gov (United States)

Ismail, M. A. M.; Kumar, N. S.; Abidin, M. H. Z.; Madun, A.

2018-04-01

Rippability or ease of excavation in sedimentary rocks is a significant aspect of the preliminary work of any civil engineering project. Rippability assessment was performed in this study to select an available ripping machine to rip off earth materials using the seismic velocity chart provided by Caterpillar. The research area is located at the proposed construction site for the development of a water reservoir and related infrastructure in Kampus Pauh Putra, Universiti Malaysia Perlis. The research was aimed at obtaining seismic velocity, P-wave (Vp) using a seismic refraction method to produce a 2D tomography model. A 2D seismic model was used to delineate the layers into the velocity profile. The conventional geotechnical method of using a borehole was integrated with the seismic velocity method to provide appropriate correlation. The correlated data can be used to categorize machineries for excavation activities based on the available systematic analysis procedure to predict rock rippability. The seismic velocity profile obtained was used to interpret rock layers within the ranges labelled as rippable, marginal, and non-rippable. Based on the seismic velocity method the site can be classified into loose sand stone to moderately weathered rock. Laboratory test results shows that the site’s rock material falls between low strength and high strength. Results suggest that Caterpillar’s smallest ripper, namely, D8R, can successfully excavate materials based on the test results integration from seismic velocity method and laboratory test.

Borehole disposal design concept in Madagascar

International Nuclear Information System (INIS)

Randriamarolahy, J.N.; Randriantseheno, H.F.; Andriambololona, Raoelina

2008-01-01