WorldWideScience

Sample records for mono-diameter wellbore casing

  1. Quantifying drag on wellbore casings in moving salt sheets

    Science.gov (United States)

    Weijermars, R.; Jackson, M. P. A.; Dooley, T. P.

    2014-08-01

    Frontier hydrocarbon development projects in the deepwater slopes of the Gulf of Mexico Basin, Santos Basin and Lower Congo Basin all require wells to cross ductile layers of autochthonous or allochthonous salt moving at peak rates of 100 mm yr-1. The Couette-Poiseuille number is introduced here to help pinpoint the depth of shear stress reversal in such salt layers. For any well-planned through salt, the probable range of creep forces of moving salt needs to be taken into account when designing safety margins and load-factor tolerance of the well casing. Drag forces increase with wellbore diameter, but more significantly with effective viscosity and speed of the creeping salt layer. The potential drag forces on cased wellbores in moving salt sheets are estimated analytically using a range of salt viscosities (1015-1019 Pa s) and creep rates (0-10 mm yr-1). Drag on perfectly rigid casing of infinite strength may reach up to 13 Giga Newton per meter wellbore length in salt having a viscosity of 1019 Pa s. Well designers may delay stress accumulations due to salt drag when flexible casing accommodates some of the early displacement and strain. However, all creeping salt could displace, fracture and disconnect well casing, eventually. The shear strength of typical heavy duty well casing (about 1000 MPa) can be reached due to drag by moving salt. Internal flow of salt will then fracture the casing near salt entry and exit points, but the structural damage is likely to remain unnoticed early in the well-life when the horizontal shift of the wellbore is still negligibly small (at less than 1 cm yr-1). Disruption of casing and production flow lines within the anticipated service lifetime of a well remains a significant risk factor within distinct zones of low-viscosity salt which may reach ultrafast creep rates of 100 mm yr-1.

  2. High-energy gas fracturing in cased and perforated wellbores

    Energy Technology Data Exchange (ETDEWEB)

    Cuderman, J.F.

    1986-06-01

    A propellant-based technology, High-Energy Gas Fracturing (HEGF), has been applied to fracturing through perforations in cased boreholes. HEGF is a tailored-pulse fracturing technique originally developed by Sandia National Laboratories for application in uncased, liquid-free gas wells in Appalachian Devonian shales. Because most oil and gas wells are liquid filled as well as cased and perforated, the potential impact of present research is significantly broader. A number of commercial tailored-pulse fracturing services, using a variety of explosives or propellants, are currently available. Present research provides valuable insight into phenomena that occur in those stimulations. The use of propellants that deflagrate or burn rather than detonate, as do high-order explosives, permits controlled buildup of pressure in the wellbore. The key to successful stimulation in cased and perforated wellbores is to control the pressure buildup of the combustion gases to maximize fracturing without destroying the casing. Eight experiments using cased and perforated wellbore were conducted in a tunnel complex at the Department of Energy's Nevada Test Site, which provides a realistic in situ stress environment (4 to 10 MPa (600 to 1500 psi)) and provides access for mineback to directly observe fracturing obtained. Primary variables in the experiments include propellant burn rate and amount of propellant used, presence or absence of liquid in the wellbore, in situ stress orientation, and perforation diameter, density, and phasing. In general, the presence of liquid in the borehole results in a much faster pressure risetime and a lower peak pressure for the same propellant charge. Fracture surfaces proceed outward along lines of perforations as determined by phasing, then gradually turn toward the hydraulic fracture direction. 8 refs., 23 figs., 3 tabs.

  3. Numerical Simulation on Open Wellbore Shrinkage and Casing Equivalent Stress in Bedded Salt Rock Stratum

    Directory of Open Access Journals (Sweden)

    Jianjun Liu

    2013-01-01

    Full Text Available Most salt rock has interbed of mudstone in China. Owing to the enormous difference of mechanical properties between the mudstone interbed and salt rock, the stress-strain and creep behaviors of salt rock are significantly influenced by neighboring mudstone interbed. In order to identify the rules of wellbore shrinkage and casings equivalent stress in bedded salt rock stratum, three-dimensional finite difference models were established. The effects of thickness and elasticity modulus of mudstone interbed on the open wellbore shrinkage and equivalent stress of casing after cementing operation were studied, respectively. The results indicate that the shrinkage of open wellbore and equivalent stress of casings decreases with the increase of mudstone interbed thickness. The increasing of elasticity modulus will reduce the shrinkage of open wellbore and casing equivalent stress. Research results can provide the scientific basis for the design of mud density and casing strength.

  4. Numerical simulation on open wellbore shrinkage and casing equivalent stress in bedded salt rock stratum.

    Science.gov (United States)

    Liu, Jianjun; Zhang, Linzhi; Zhao, Jinzhou

    2013-01-01

    Most salt rock has interbed of mudstone in China. Owing to the enormous difference of mechanical properties between the mudstone interbed and salt rock, the stress-strain and creep behaviors of salt rock are significantly influenced by neighboring mudstone interbed. In order to identify the rules of wellbore shrinkage and casings equivalent stress in bedded salt rock stratum, three-dimensional finite difference models were established. The effects of thickness and elasticity modulus of mudstone interbed on the open wellbore shrinkage and equivalent stress of casing after cementing operation were studied, respectively. The results indicate that the shrinkage of open wellbore and equivalent stress of casings decreases with the increase of mudstone interbed thickness. The increasing of elasticity modulus will reduce the shrinkage of open wellbore and casing equivalent stress. Research results can provide the scientific basis for the design of mud density and casing strength.

  5. The Mechanism of Wellbore Weakening in Worn Casing-Cement-Formation System

    Directory of Open Access Journals (Sweden)

    Zheng Shen

    2014-01-01

    Full Text Available Maintaining casing integrity, in terms of downhole zonal isolations and well stability, is extremely important in oil/gas wells. Casing wear occurs not only in directional drilling, but also in vertical drilling with a slight deviation angle. In most hydrocarbon wells, deteriorated casing was reported from the onset of casing wear by the presence of friction force during the rotation of drillpipe. The friction force against the casing wall causes the reduction of casing strength. Furthermore, the rotation of drillpipe combined with corrosive drilling fluids could dramatically degrade the casing strength. We used a finite element analysis to focus on the stress evolution in worn casings. Comparison study between worn casing and perfect casing was conducted. Our study showed that the thermal load significantly increases the stress concentration of the worn casing in the wellbore. Finite element solutions indicated that the radial stress of the worn casing is not affected as much as the hoop stress. Along with the increased burst pressure or the elevated temperature, the unworn portion of the casing also suffers from severe compression stress. This work is important to broadening the understanding of well engineers through addressing the true stress profile of worn casing in cemented wellbore.

  6. Wellbore Integrity Network

    Energy Technology Data Exchange (ETDEWEB)

    Carey, James W. [Los Alamos National Laboratory; Bachu, Stefan [Alberta Innovates

    2012-06-21

    In this presentation, we review the current state of knowledge on wellbore integrity as developed in the IEA Greenhouse Gas Programme's Wellbore Integrity Network. Wells are one of the primary risks to the successful implementation of CO{sub 2} storage programs. Experimental studies show that wellbore materials react with CO{sub 2} (carbonation of cement and corrosion of steel) but the impact on zonal isolation is unclear. Field studies of wells in CO{sub 2}-bearing fields show that CO{sub 2} does migrate external to casing. However, rates and amounts of CO{sub 2} have not been quantified. At the decade time scale, wellbore integrity is driven by construction quality and geomechanical processes. Over longer time-scales (> 100 years), chemical processes (cement degradation and corrosion) become more important, but competing geomechanical processes may preserve wellbore integrity.

  7. Reaction and transport in wellbore interfaces under CO2 storage conditions: Experiments simulating debonded cement-casing interfaces

    NARCIS (Netherlands)

    Wolterbeek, T.K.T.; Peach, C.J.; Spiers, C.J.

    2013-01-01

    Debonding-defects at the interfaces between wellbore casing and cement are widely recognized as providing potential pathways for CO2 escape from geological storage systems. This study addresses how chemical reaction between CO2, cement and steel may affect the transport properties of such defects un

  8. Optimisation of the Near-Wellbore Geometry of Hydraulic Fractures Propagating from Cased Perforated Completions

    NARCIS (Netherlands)

    van de Ketterij, R.G.

    2001-01-01

    Hydraulic fracturing is a technique frequently used to stimulate the production of an oil or gas well by creating a fracture in the porous rock around the wellbore. The success of a hydraulic fracture treatment depends heavily on the created fracture geometry. The optimum situation arises when a sin

  9. Wellbore pressure transducer

    Science.gov (United States)

    Shuck, Lowell Z.

    1979-01-01

    Subterranean earth formations containing energy values are subjected to hydraulic fracturing procedures to enhance the recovery of the energy values. These fractures are induced in the earth formation by pumping liquid into the wellbore penetrating the earth formation until the pressure of the liquid is sufficient to fracture the earth formation adjacent to the wellbore. The present invention is directed to a transducer which is positionable within the wellbore to generate a signal indicative of the fracture initiation useful for providing a timing signal to equipment for seismic mapping of the fracture as it occurs and for providing a measurement of the pressure at which the fracture is initiated.

  10. Wellbore Seal Repair Using Nanocomposite Materials

    Energy Technology Data Exchange (ETDEWEB)

    Stormont, John [Univ. of New Mexico, Albuquerque, NM (United States)

    2016-08-31

    Nanocomposite wellbore repair materials have been developed, tested, and modeled through an integrated program of laboratory testing and numerical modeling. Numerous polymer-cement nanocomposites were synthesized as candidate wellbore repair materials using various combinations of base polymers and nanoparticles. Based on tests of bond strength to steel and cement, ductility, stability, flowability, and penetrability in opening of 50 microns and less, we identified Novolac epoxy reinforced with multi-walled carbon nanotubes and/or alumina nanoparticles to be a superior wellbore seal material compared to conventional microfine cements. A system was developed for testing damaged and repaired wellbore specimens comprised of a cement sheath cast on a steel casing. The system allows independent application of confining pressures and casing pressures while gas flow is measured through the specimens along the wellbore axis. Repair with the nanocomposite epoxy base material was successful in dramatically reducing the flow through flaws of various sizes and types, and restoring the specimen comparable to an intact condition. In contrast, repair of damaged specimens with microfine cement was less effective, and the repair degraded with application of stress. Post-test observations confirm the complete penetration and sealing of flaws using the nanocomposite epoxy base material. A number of modeling efforts have supported the material development and testing efforts. We have modeled the steel-repair material interface behavior in detail during slant shear tests, which we used to characterize bond strength of candidate repair materials. A numerical model of the laboratory testing of damaged wellbore specimens was developed. This investigation found that microannulus permeability can satisfactorily be described by a joint model. Finally, a wellbore model has been developed that can be used to evaluate the response of the wellbore system (casing, cement, and microannulus

  11. Effect of wellbore storage on the analysis of multiphase-flow-pressure data

    Energy Technology Data Exchange (ETDEWEB)

    Hatzignatiou, D.G. (Univ. of Alaska, Fairbanks, AK (United States)); Peres, A.M.M. (Petrobras S.A., Rio de Janeiro (Brazil)); Reynolds, A.C. (Univ. of Tulsa, OK (United States))

    1994-09-01

    This paper investigates the effect of wellbore storage on the analysis of pressure drawdown data obtained at a well producing a solution-gas-drive reservoir. Wellbore storage effects are incorporated by specifying a sandface oil flow rate that increases exponentially from zero to the specified constant value of the oil flow rate at the surface. Use of new computational equations derived here shows that effective oil permeability as a pointwise function of pressure can be computed directly from the measured values of the flowing wellbore pressure, provided the sandface oil flow rate is measured and incorporated into the analysis. If the sandface flow rate is unknown, effective permeability can be computed only after wellbore storage effects become negligible. In all cases, a semilog plot of wellbore pressure squared vs. time is shown to be a viable method for estimating effective oil permeability at initial conditions, effective oil permeability at the final flowing wellbore pressure value, and mechanical skin factor.

  12. Geomechanical analyses to investigate wellbore/mine interactions in the Potash Enclave of Southeastern New Mexico.

    Energy Technology Data Exchange (ETDEWEB)

    Ehgartner, Brian L.; Bean, James E. (Sandia Staffing Alliance, LLC, Albuquerque, NM); Arguello, Jose Guadalupe, Jr.; Stone, Charles Michael

    2010-04-01

    Geomechanical analyses have been performed to investigate potential mine interactions with wellbores that could occur in the Potash Enclave of Southeastern New Mexico. Two basic models were used in the study; (1) a global model that simulates the mechanics associated with mining and subsidence and (2) a wellbore model that examines the resulting interaction impacts on the wellbore casing. The first model is a 2D approximation of a potash mine using a plane strain idealization for mine depths of 304.8 m (1000 ft) and 609.6 m (2000 ft). A 3D wellbore model then considers the impact of bedding plane slippage across single and double cased wells cemented through the Salado formation. The wellbore model establishes allowable slippage to prevent casing yield.

  13. Rate Gyroscopic Wellbore Survey System

    Institute of Scientific and Technical Information of China (English)

    Sheng Limin

    1997-01-01

    @@ The rate gyroscopic wellbore survey system as a new type of survey instruments adopts the inertial-grade rate gyro and quartz flexible accelerometers to compose a gyrocompassing system, transiting data to surface instrument by single core cable. The azimuth, inclination and tool-face angle can be computed from these data by surface computer.

  14. Heating production fluids in a wellbore

    Science.gov (United States)

    Orrego, Yamila; Jankowski, Todd A.

    2016-07-12

    A method for heating a production fluid in a wellbore. The method can include heating, using a packer fluid, a working fluid flowing through a first medium disposed in a first section of the wellbore, where the first medium transfers heat from the packer fluid to the working fluid. The method can also include circulating the working fluid into a second section of the wellbore through a second medium, where the second medium transfers heat from the working fluid to the production fluid. The method can further include returning the working fluid to the first section of the wellbore through the first medium.

  15. Wellbore integrity analysis of a natural CO2 producer

    KAUST Repository

    Crow, Walter

    2010-03-01

    Long-term integrity of existing wells in a CO2-rich environment is essential for ensuring that geological sequestration of CO2 will be an effective technology for mitigating greenhouse gas-induced climate change. The potential for wellbore leakage depends in part on the quality of the original construction as well as geochemical and geomechanical stresses that occur over its life-cycle. Field data are essential for assessing the integrated effect of these factors and their impact on wellbore integrity, defined as the maintenance of isolation between subsurface intervals. In this report, we investigate a 30-year-old well from a natural CO2 production reservoir using a suite of downhole and laboratory tests to characterize isolation performance. These tests included mineralogical and hydrological characterization of 10 core samples of casing/cement/formation, wireline surveys to evaluate well conditions, fluid samples and an in situ permeability test. We find evidence for CO2 migration in the occurrence of carbonated cement and calculate that the effective permeability of an 11′-region of the wellbore barrier system was between 0.5 and 1 milliDarcy. Despite these observations, we find that the amount of fluid migration along the wellbore was probably small because of several factors: the amount of carbonation decreased with distance from the reservoir, cement permeability was low (0.3-30 microDarcy), the cement-casing and cement-formation interfaces were tight, the casing was not corroded, fluid samples lacked CO2, and the pressure gradient between reservoir and caprock was maintained. We conclude that the barrier system has ultimately performed well over the last 3 decades. These results will be used as part of a broader effort to develop a long-term predictive simulation tool to assess wellbore integrity performance in CO2 storage sites. © 2009 Elsevier Ltd. All rights reserved.

  16. Wellbore Wall Stress Analysis around Failure Casing in Consideration of Fluid Seepage%考虑渗流作用的套管错断口井壁围岩应力场分析

    Institute of Scientific and Technical Information of China (English)

    艾池; 刘国勇; 刘顺利; 隋杨; 赵万春

    2011-01-01

    考虑井壁周围岩体中流体的渗流作用,建立了套管错断口井壁岩体的平衡微分方程.然后按照损伤程度的不同将错断口井壁岩体划分为不同的区域(失稳破坏区、损伤区、弹性区),考虑不同区域内岩石材料参数的不同,分析了错断口周围岩体各个区域内的应力分布规律,确定了失稳破坏区和损伤区的半径,并在此基础上得到了岩体发生失稳破坏和损伤时的临界应力条件,从而为套管错断后井壁稳定性的研究和错断口吐岩块现象的预防提供了理论依据.%The balanced differential equation of wellbore wall is built around failure casing considering fluid seepage. The area around failure casing is divided into different areas (unstable failure zone, damaged zone, elastic zone) according to the degree of damage, their stress distribution were obtained with consideration of variations of rock properties in different areas. The radius of unstable failure zone and damaged zone are determined. Critical stresses of rock failure and damage are obtained which provides a theoretical basis for the wellbore stability investigation and casing failure prevention.

  17. Drilling subsurface wellbores with cutting structures

    Science.gov (United States)

    Mansure, Arthur James; Guimerans, Rosalvina Ramona

    2010-11-30

    A system for forming a wellbore includes a drill tubular. A drill bit is coupled to the drill tubular. One or more cutting structures are coupled to the drill tubular above the drill bit. The cutting structures remove at least a portion of formation that extends into the wellbore formed by the drill bit.

  18. Geomechanical analysis to predict the oil leak at the wellbores in Big Hill Strategic Petroleum Reserve

    Energy Technology Data Exchange (ETDEWEB)

    Park, Byoung Yoon

    2014-02-01

    Oil leaks were found in wellbores of Caverns 105 and 109 at the Big Hill Strategic Petroleum Reserve site. According to the field observations, two instances of casing damage occurred at the depth of the interbed between the caprock bottom and salt top. A three dimensional finite element model, which contains wellbore element blocks and allows each cavern to be configured individually, is constructed to investigate the wellbore damage mechanism. The model also contains element blocks to represent interface between each lithology and a shear zone to examine the interbed behavior in a realistic manner. The causes of the damaged casing segments are a result of vertical and horizontal movements of the interbed between the caprock and salt dome. The salt top subsides because the volume of caverns below the salt top decrease with time due to salt creep closure, while the caprock subsides at a slower rate because the caprock is thick and stiffer. This discrepancy yields a deformation of the well. The deformed wellbore may fail at some time. An oil leak occurs when the wellbore fails. A possible oil leak date of each well is determined using the equivalent plastic strain failure criterion. A well grading system for a remediation plan is developed based on the predicted leak dates of each wellbore.

  19. Equilibrium equations for nonlinear buckling analysis of drill-strings in 3D curved well-bores

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    With the development of drilling technology, the oil/gas well has evolved from its early vertical straight form to the inclined, horizontal, plane curved, or even 3D curved well-bore. Understanding of the buck- ling behavior of a drill-string in a well-bore is crucial for the success of a drilling operation. Therefore, equilibrium equations for analyzing the buckling behavior of a drill-string in a 3D curved well-bore are required. Based on Love’s equilibrium equations for a curved and twisted rod in space, a set of equi- librium equations for the nonlinear buckling analysis of a drill-string in a 3D curved well-bore are de- rived by introducing a radial constraint of the well-bore. The proposed formulae can account for the well curvature and tortuosity. Thus, it can be used to analyze the buckling behaviors of a drill-string constrained in a well-bore and subjected to axial compression, torsion at its upper end, and gravity simultaneously. It is worth noting that the existing equations in the literature for a drill-string in a straight and plane curved well-bore with a constant curvature are a special case of the proposed model. Thus, the present model can provide a theoretical basis for the nonlinear buckling analysis of a drill-string constrained in a 3D curved well-bore.

  20. Equilibrium equations for nonlinear buckling analysis of drill-strings in 3D curved well-bores

    Institute of Scientific and Technical Information of China (English)

    TAN MeiLan; GAN LiFei

    2009-01-01

    With the development of drilling technology, the oil/gas well has evolved from its early vertical straight form to the inclined, horizontal, plane curved, or even 3D curved well-bore. Understanding of the buck-ling behavior of a drill-string in a well-bore is crucial for the success of a drilling operation. Therefore, equilibrium equations for analyzing the buckling behavior of a drill-string in a 3D curved well-bore are required. Based on Love's equilibrium equations for a curved and twisted rod in space, s set of equi-librium equations for the nonlinear buckling analysis of a drill-string in a 3D curved well-bore are de-rived by introducing a radial constraint of the well-bore. The proposed formulae can account for the well curvature and tortuosity. Thus, it can be used to analyze the buckling behaviors of a drill-string constrained in a well-bore and subjected to axial compression, torsion at its upper end, and gravity simultaneously. It is worth noting that the existing equations in the literature for a drill-string in a straight and plane curved well-bore with a constant curvature are a special case of the proposed model. Thus, the present model can provide s theoretical basis for the nonlinear buckling analysis of a drill-string constrained in a 3D curved well-bore.

  1. Advanced wellbore thermal simulator GEOTEMP2 user manual

    Energy Technology Data Exchange (ETDEWEB)

    Mondy, L.A.; Duda, L.E.

    1984-11-01

    GEOTEMP2 is a wellbore thermal simulator computer code designed for geothermal drilling and production applications. The code treats natural and forced convection and conduction within the wellbore and heat conduction within the surrounding rock matrix. A variety of well operations can be modeled including injection, production, forward, and reverse circulation with gas or liquid, gas or liquid drilling, and two-phase steam injection and production. Well completion with several different casing sizes and cement intervals can be modeled. The code allows variables suchas flow rate to change with time enabling a realistic treatment of well operations. This user manual describes the input required to properly operate the code. Ten sample problems are included which illustrate all the code options. Complete listings of the code and the output of each sample problem are provided.

  2. Estimation of Wellbore and Formation Temperatures during the Drilling Process under Lost Circulation Conditions

    Directory of Open Access Journals (Sweden)

    Mou Yang

    2013-01-01

    Full Text Available Significant change of wellbore and surrounding formation temperatures during the whole drilling process for oil and gas resources often leads by annulus fluid fluxes into formation and may pose a threat to operational security of drilling and completion process. Based on energy exchange mechanisms of wellbore and formation systems during circulation and shut-in stages under lost circulation conditions, a set of partial differential equations were developed to account for the transient heat exchange process between wellbore and formation. A finite difference method was used to solve the transient heat transfer models, which enables the wellbore and formation temperature profiles to be accurately predicted. Moreover, heat exchange generated by heat convection due to circulation losses to the rock surrounding a well was also considered in the mathematical model. The results indicated that the lost circulation zone and the casing programme had significant effects on the temperature distributions of wellbore and formation. The disturbance distance of formation temperature was influenced by circulation and shut-in stages. A comparative perfection theoretical basis for temperature distribution of wellbore-formation system in a deep well drilling was developed in presence of lost circulation.

  3. On the analysis of well test data influenced by wellbore storage, skin, asnd bottomwater drive

    Energy Technology Data Exchange (ETDEWEB)

    Chu, W.C.; Chen, J.C.; Raghavan, R.; Reynolds, A.C.

    1984-11-01

    The combined influence of wellbore storage, wellbore damage, and partial penetration on the analysis of pressure data is discussed. The effect of a gas cap or bottomwater aquifer (constant pressure boundary) also is documented. The authors demonstrate that the magnitude of the wellbore storage constant dictates the type and amount of information that can be gleaned from a pressure test during the storage dominated period. For small values of the dimensionless storage constant and large values of dimensionless well length, the flow capacity of the perforated (open) interval and the skin factor, which reflects impediments to flow around the sand face, can be determined from data affected by wellbore storage. This information can be obtained from the wellbore storage type curves (the complete penetration solutions) available in the literature. Values of the dimensionless well length and storage constant for which this information can be obtained are specified in the paper. For other cases, the flow capacity of the entire interval and the total skin factor can be estimated. Again, storage type curves for the complete penetration solutions can be used to obtain this information if both boundaries are sealed. If one of the boundaries is at a constant pressure (water drive or gas cap), then the new solution presented in this paper should be used.

  4. Proceedings of the wellbore sampling workshop

    Energy Technology Data Exchange (ETDEWEB)

    Traeger, R.K. (ed.); Harding, B.W.

    1987-11-01

    Representatives from academia, industry and research laboratories participated in an intensive two-day review to identify major technological limitations in obtaining solid and fluid samples from wellbores. Top priorities identified for further development include: coring of hard and unconsolidated materials; flow through fluid samplers with borehole measurements T, P and pH; and nonintrusive interrogation of pressure cores.

  5. Geomechanics of fracture caging in wellbores

    NARCIS (Netherlands)

    Weijermars, R.; Zhang, X.; Schultz-Ela, D.

    2013-01-01

    This study highlights the occurrence of so-called ‘fracture cages’ around underbalanced wellbores, where fractures cannot propagate outwards due to unfavourable principal stress orientations. The existence of such cages is demonstrated here by independent analytical and numerical methods. We explain

  6. Geomechanics of fracture caging in wellbores

    NARCIS (Netherlands)

    Weijermars, R.; Zhang, X.; Schultz-Ela, D.

    2013-01-01

    This study highlights the occurrence of so-called ‘fracture cages’ around underbalanced wellbores, where fractures cannot propagate outwards due to unfavourable principal stress orientations. The existence of such cages is demonstrated here by independent analytical and numerical methods. We explain

  7. Cementing a wellbore using cementing material encapsulated in a shell

    Energy Technology Data Exchange (ETDEWEB)

    Aines, Roger D.; Bourcier, William L.; Duoss, Eric B.; Floyd, III, William C.; Spadaccini, Christopher M.; Vericella, John J.; Cowan, Kenneth Michael

    2017-03-14

    A system for cementing a wellbore penetrating an earth formation into which a pipe extends. A cement material is positioned in the space between the wellbore and the pipe by circulated capsules containing the cement material through the pipe into the space between the wellbore and the pipe. The capsules contain the cementing material encapsulated in a shell. The capsules are added to a fluid and the fluid with capsules is circulated through the pipe into the space between the wellbore and the pipe. The shell is breached once the capsules contain the cementing material are in position in the space between the wellbore and the pipe.

  8. Cementing a wellbore using cementing material encapsulated in a shell

    Science.gov (United States)

    Aines, Roger D.; Bourcier, William L.; Duoss, Eric B.; Spadaccini, Christopher M.; Cowan, Kenneth Michael

    2016-08-16

    A system for cementing a wellbore penetrating an earth formation into which a pipe extends. A cement material is positioned in the space between the wellbore and the pipe by circulated capsules containing the cement material through the pipe into the space between the wellbore and the pipe. The capsules contain the cementing material encapsulated in a shell. The capsules are added to a fluid and the fluid with capsules is circulated through the pipe into the space between the wellbore and the pipe. The shell is breached once the capsules contain the cementing material are in position in the space between the wellbore and the pipe.

  9. Cementing a wellbore using cementing material encapsulated in a shell

    Energy Technology Data Exchange (ETDEWEB)

    Aines, Roger D.; Bourcier, William L.; Duoss, Eric B.; Spadaccini, Christopher M.; Cowan, Kenneth Michael

    2016-08-16

    A system for cementing a wellbore penetrating an earth formation into which a pipe extends. A cement material is positioned in the space between the wellbore and the pipe by circulated capsules containing the cement material through the pipe into the space between the wellbore and the pipe. The capsules contain the cementing material encapsulated in a shell. The capsules are added to a fluid and the fluid with capsules is circulated through the pipe into the space between the wellbore and the pipe. The shell is breached once the capsules contain the cementing material are in position in the space between the wellbore and the pipe.

  10. Wellbore enlargement investigation: Potential analogs to the Waste Isolation Pilot Plant during inadvertent intrusion of the repository

    Energy Technology Data Exchange (ETDEWEB)

    Boak, D.M.; Dotson, L.; Aguilar, R. [and others

    1997-01-01

    This study involved the evaluation and documentation of cases in which petroleum wellbores were enlarged beyond the nominal hole diameter as a consequence of erosion during exploratory drilling, particularly as a function of gas flow into the wellbore during blowout conditions. A primary objective was to identify analogs to potential wellbore enlargement at the Waste Isolation Pilot Plant (WIPP) during inadvertent human intrusion. Secondary objectives were to identify drilling scenarios associated with enlargement, determine the physical extent of enlargement, and establish the physical properties of the formation in which the enlargement occurred. No analogs of sufficient quality to establish quantitative limits on wellbore enlargement at the WIPP disposal system were identified. However, some information was obtained regarding the frequency of petroleum well blowouts and the likelihood that such blowouts would bridge downhole, self-limiting the surface release of disposal-system material. Further work would be necessary, however, to determine the conditions under which bridging could occur and the extent to which the bridging might be applicable to WIPP. In addition, data on casing sizes of petroleum boreholes in the WIPP vicinity support the use of a 12-{1/4} inch borehole size in WIPP performance assessment calculations. Finally, although data are limited, there was no evidence of significant wellbore enlargement in any of three blowouts that occur-red in wellbores in the Delaware Basin (South Culebra Bluff Unit No. 1, Energy Research and Development Administration (ERDA) 6, and WIPP 12).

  11. A 3-D wellbore simulator (WELLTHER-SIM) to determine the thermal diffusivity of rock-formations

    Science.gov (United States)

    Wong-Loya, J. A.; Santoyo, E.; Andaverde, J.

    2017-06-01

    Acquiring thermophysical properties of rock-formations in geothermal systems is an essential task required for the well drilling and completion. Wellbore thermal simulators require such properties for predicting the thermal behavior of a wellbore and the formation under drilling and shut-in conditions. The estimation of static formation temperatures also needs the use of these properties for the wellbore and formation materials (drilling fluids and pipes, cements, casings, and rocks). A numerical simulator (WELLTHER-SIM) has been developed for modeling the drilling fluid circulation and shut-in processes of geothermal wellbores, and for the in-situ determination of thermal diffusivities of rocks. Bottomhole temperatures logged under shut-in conditions (BHTm), and thermophysical and transport properties of drilling fluids were used as main input data. To model the thermal disturbance and recovery processes in the wellbore and rock-formation, initial drilling fluid and static formation temperatures were used as initial and boundary conditions. WELLTHER-SIM uses these temperatures together with an initial thermal diffusivity for the rock-formation to solve the governing equations of the heat transfer model. WELLTHER-SIM was programmed using the finite volume technique to solve the heat conduction equations under 3-D and transient conditions. Thermal diffusivities of rock-formations were inversely computed by using an iterative and efficient numerical simulation, where simulated thermal recovery data sets (BHTs) were statistically compared with those temperature measurements (BHTm) logged in some geothermal wellbores. The simulator was validated using a well-documented case reported in the literature, where the thermophysical properties of the rock-formation are known with accuracy. The new numerical simulator has been successfully applied to two wellbores drilled in geothermal fields of Japan and Mexico. Details of the physical conceptual model, the numerical

  12. Problems in the wellbore integrity of a shale gas horizontal well and corresponding countermeasures

    Directory of Open Access Journals (Sweden)

    Zhonglan Tian

    2015-12-01

    Full Text Available In the Changning–Weiyuan national shale gas demonstration area, SW Sichuan Basin, the wellbore integrity damage occurs in some shale gas wells and has direct effect on the gas production rate of single shale gas horizontal well. After statistics analysis was performed on the problems related with wellbore integrity, such as casing damage, casing running difficulty and cement sheath blow-by, the multi-factor coupling casing stress calculation and evaluation mode laws established. Then study was conducted on the influential mechanism of multi-factor coupling (temperature effect, casing bending and axial pressure on casing damage. The shale slip mechanism and its relationship with casing sheared formation were analyzed by using the Mohr–Coulomb criterion. Inversion analysis was performed on the main controlling factors of casing friction by using the developed casing hook load prediction and friction analysis software. And finally, based on the characteristics of shale gas horizontal wells, wellbore integrity control measures were proposed in terms of design and construction process, so as to improve the drilling quality (DQ. More specifically, shale gas well casing design calculation method and check standard were modified, well structure and full bore hole trajectory design were optimized, drilling quality was improved, cement properties were optimized and cement sealing integrity during fracturing process was checked. These research findings are significant in the design and management of future shale gas borehole integrity.

  13. A multi-feedzone geothermal wellbore simulator

    Energy Technology Data Exchange (ETDEWEB)

    Bjornsson, G.

    1987-05-01

    The main objective of this work is to develop a multiple feedzone wellbore model for single- or two-phase flow in vertical wells. It has been demonstrated in various fields (e.g., oil and gas and geothermal) that multiple feedzones with different pressure potentials can significantly effect the well performance in the long run. Very little work in this subject has been done to date, but the importance of the subject is becoming more and more evident. 55 refs., 33 figs., 4 tabs.

  14. Closure of open wellbores in creeping salt sheets

    NARCIS (Netherlands)

    Weijermars, R.; Jackson, M.P.A.; Van Harmelen, A.

    2013-01-01

    Safe exploration and production of pre-salt (or subsalt) hydrocarbons require that drilling operations be optimized. We introduce analytical models of wellbore closure, accounting for variations in both the wellbore net pressure and far-field flow rate of an autochthonous or allochthonous salt sheet

  15. Investigation of wellbore cooling by circulation and fluid penetration into the formation using a wellbore thermal simulator computer code

    Energy Technology Data Exchange (ETDEWEB)

    Duda, L.E.

    1985-01-01

    The high temperatures of geothermal wells present severe problems for drilling, logging, and developing these reservoirs. Cooling the wellbore is perhaps the most common method to solve these problems. However, it is usually not clear what may be the most effective wellbore cooling mechanism for a given well. In this paper, wellbore cooling by the use of circulation or by fluid injection into the surrounding rock is investigated using a wellbore thermal simulator computer code. Short circulation times offer no prolonged cooling of fluid in the wellbore, but long circulation times (greater than ten or twenty days) greatly reduce the warming rate after shut-in. The dependence of the warming rate on the penetration distance of cooler temperatures into the rock formation (as by fluid injection) is investigated. Penetration distances of greater than 0.6 m appear to offer a substantial reduction in the warming rate. Several plots are shown which demonstrate these effects. 16 refs., 6 figs.

  16. AnalyzeHOLE - An Integrated Wellbore Flow Analysis Tool

    Science.gov (United States)

    Halford, Keith

    2009-01-01

    Conventional interpretation of flow logs assumes that hydraulic conductivity is directly proportional to flow change with depth. However, well construction can significantly alter the expected relation between changes in fluid velocity and hydraulic conductivity. Strong hydraulic conductivity contrasts between lithologic intervals can be masked in continuously screened wells. Alternating intervals of screen and blank casing also can greatly complicate the relation between flow and hydraulic properties. More permeable units are not necessarily associated with rapid fluid-velocity increases. Thin, highly permeable units can be misinterpreted as thick and less permeable intervals or not identified at all. These conditions compromise standard flow-log interpretation because vertical flow fields are induced near the wellbore. AnalyzeHOLE, an integrated wellbore analysis tool for simulating flow and transport in wells and aquifer systems, provides a better alternative for simulating and evaluating complex well-aquifer system interaction. A pumping well and adjacent aquifer system are simulated with an axisymmetric, radial geometry in a two-dimensional MODFLOW model. Hydraulic conductivities are distributed by depth and estimated with PEST by minimizing squared differences between simulated and measured flows and drawdowns. Hydraulic conductivity can vary within a lithology but variance is limited with regularization. Transmissivity of the simulated system also can be constrained to estimates from single-well, pumping tests. Water-quality changes in the pumping well are simulated with simple mixing models between zones of differing water quality. These zones are differentiated by backtracking thousands of particles from the well screens with MODPATH. An Excel spreadsheet is used to interface the various components of AnalyzeHOLE by (1) creating model input files, (2) executing MODFLOW, MODPATH, PEST, and supporting FORTRAN routines, and (3) importing and graphically

  17. AnalyzeHOLE: An Integrated Wellbore Flow Analysis Tool

    Energy Technology Data Exchange (ETDEWEB)

    Keith J. Halford

    2009-10-01

    Conventional interpretation of flow logs assumes that hydraulic conductivity is directly proportional to flow change with depth. However, well construction can significantly alter the expected relation between changes in fluid velocity and hydraulic conductivity. Strong hydraulic conductivity contrasts between lithologic intervals can be masked in continuously screened wells. Alternating intervals of screen and blank casing also can greatly complicate the relation between flow and hydraulic properties. More permeable units are not necessarily associated with rapid fluid-velocity increases. Thin, highly permeable units can be misinterpreted as thick and less permeable intervals or not identified at all. These conditions compromise standard flow-log interpretation because vertical flow fields are induced near the wellbore. AnalyzeHOLE, an integrated wellbore analysis tool for simulating flow and transport in wells and aquifer systems, provides a better alternative for simulating and evaluating complex well-aquifer system interaction. A pumping well and adjacent aquifer system are simulated with an axisymmetric, radial geometry in a two-dimensional MODFLOW model. Hydraulic conductivities are distributed by depth and estimated with PEST by minimizing squared differences between simulated and measured flows and drawdowns. Hydraulic conductivity can vary within a lithology but variance is limited with regularization. Transmissivity of the simulated system also can be constrained to estimates from single-well, pumping tests. Water-quality changes in the pumping well are simulated with simple mixing models between zones of differing water quality. These zones are differentiated by backtracking thousands of particles from the well screens with MODPATH. An Excel spreadsheet is used to interface the various components of AnalyzeHOLE by (1) creating model input files, (2) executing MODFLOW, MODPATH, PEST, and supporting FORTRAN routines, and (3) importing and graphically

  18. Final Research Performance Progress Report: Geothermal Resource Development with Zero Mass Withdrawal, Engineered Convection, and Wellbore Energy Conversion

    Energy Technology Data Exchange (ETDEWEB)

    Hughes, Richard [Louisiana State Univ., Baton Rouge, LA (United States); Tyagi, Mayank [Louisiana State Univ., Baton Rouge, LA (United States); Radonjic, Mileva [Louisiana State Univ., Baton Rouge, LA (United States); Dahi, Arash [Louisiana State Univ., Baton Rouge, LA (United States); Wang, Fahui [Louisiana State Univ., Baton Rouge, LA (United States); John, Chacko [Louisiana State Univ., Baton Rouge, LA (United States); Kaiser, Mark [Louisiana State Univ., Baton Rouge, LA (United States); Snyder, Brian [Louisiana State Univ., Baton Rouge, LA (United States); Sears, Stephen [Louisiana State Univ., Baton Rouge, LA (United States)

    2017-07-07

    This project is intended to demonstrate the technical and economic feasibility, and environmental and social attractiveness of a novel method of heat extraction from geothermal reservoirs. The emphasis is on assessing the potential for a heat extraction method that couples forced and free convection to maximize extraction efficiency. The heat extraction concept is enhanced by considering wellbore energy conversion, which may include only a boiler for a working fluid, or perhaps a complete boiler, turbine, and condenser cycle within the wellbore. The feasibility of this system depends on maintaining mechanical and hydraulic integrity of the wellbore, so the material properties of the casing-cement system are examined both experimentally and with well design calculations. The attractiveness depends on mitigation of seismic and subsidence risks, economic performance, environmental impact, and social impact – all of which are assessed as components of this study.

  19. Numerical simulation on streaming potentials in a wellbore; Koseinai no ryudo den`i ni kansuru suchi simulation

    Energy Technology Data Exchange (ETDEWEB)

    Ikeda, N. [Kyushu University, Fukuoka (Japan)

    1996-05-01

    This paper reports numerical computation of streaming potentials which are generated by transient pressure waves propagating the vicinity of wellbore wall immediately after a mud cake formed on the wellbore wall has been removed. One existing analysis solution on heat conduction was utilized upon changing the parameters in order to derive fluid pressure inside the ground bed. Calculations were carried out by using the existing three-dimensional finite difference method (partly re-written) based on the relationship constituted between the fluid pressure and the streaming potential. This paper presents results of calculating the streaming potentials in wellbores on models having wellbores filled with mud water in a cubic ground bed existing with ground bed water at saturation of 100%. The calculations have been conducted on the following cases: a case where permeability of the ground bed is small with the fluid under two conditions of low electric resistivity and high electric resistivity, a case where the permeability is large with the fluid under the above conditions, and a case where a small area of bore wall is covered with a rubber pad having high electric resistivity under a low electric resistivity condition. 8 refs., 5 figs.

  20. Wellbore stability in shales considering chemo-poroelastic effects

    Energy Technology Data Exchange (ETDEWEB)

    Araujo, Ewerton M.P.; Pastor, Jorge A.S.C.; Fontoura, Sergio A.B.; Rabe, Claudio [Pontificia Univ. Catolica do Rio de Janeiro (PUC-Rio), RJ (Brazil). Dept. de Engenharia Civil. Grupo de Tecnologia e Engenharia de Petroleo

    2004-07-01

    Under compaction and low geothermal gradients are deep water characteristics. Both under compaction and low geothermal gradients generate considerable thickness of smectite-rich shales. These rocks are the major source of wellbore stability problems, because they are susceptible to adverse physico-chemical reactions when in contact with inadequate drilling fluids. Due shales are low permeability rocks diffusion processes dominate the changes of pore pressure around wellbore. Diffusion of fluids, ions and temperature occurs in shales during drilling and demand a fully coupled modelling taking account these factors. Despite temperature importance, in this paper wellbore stability in shales is analyzed through a model that considers only the coupling between poroelastic and physico-chemical effects. The coupled equations are solved analytically and have been implemented in a computational simulator with user-friendly interface. Time-dependent simulations of wellbore stability in shales are presented for a typical deep water scenario. The results show that physico-chemical effects change pore pressure around wellbore and have high impact on the wellbore stability. (author)

  1. Probabilistic Approach in Wellbore Stability Analysis during Drilling

    Directory of Open Access Journals (Sweden)

    Mahmood R. Al-Khayari

    2016-01-01

    Full Text Available In oil industry, wellbore instability is the most costly problem that a well drilling operation may encounter. One reason for wellbore failure can be related to ignoring rock mechanics effects. A solution to overcome this problem is to adopt in situ stresses in conjunction with a failure criterion to end up with a deterministic model that calculates collapse pressure. However, the uncertainty in input parameters can make this model misleading and useless. In this paper, a new probabilistic wellbore stability model is presented to predict the critical drilling fluid pressure before the onset of a wellbore collapse. The model runs Monte Carlo simulation to capture the effects of uncertainty in in situ stresses, drilling trajectories, and rock properties. The developed model was applied to different in situ stress regimes: normal faulting, strike slip, and reverse faulting. Sensitivity analysis was applied to all carried out simulations and found that well trajectories have the biggest impact factor in wellbore instability followed by rock properties. The developed model improves risk management of wellbore stability. It helps petroleum engineers and field planners to make right decisions during drilling and fields’ development.

  2. Offshore wellbore stability analysis based on fully coupled poro-thermo-elastic theory

    Science.gov (United States)

    Cao, Wenke; Deng, Jingen; Yu, Baohua; Liu, Wei; Tan, Qiang

    2017-03-01

    Drilling-induced tensile fractures are usually caused when the weight of mud is too high, and the effective tangential stress becomes tensile. It is thus hard to explain why tensile fractures are distributed along the lower part of a hole in an offshore exploration well when the mud weight is low. According to analysis, the reason could be the thermal effect, which cannot be ignored because of the drilling fluid and the cooling action of sea water during circulation. A heat transfer model is set up to obtain the temperature distribution of the wellbore and its formation by the finite difference method. Then, fully coupled poro-thermo-elastic theory is used to study the pore pressure and effective stress around the wellbore. By comparing it with both poroelastic and elastic models, it is indicated that the poroelastic effect is dominant at the beginning of circulation and inhibits tensile fractures from forming; then, the thermal effect becomes more important and decreases the effective tangential stress with the passing of time, so the drilling fluid and the cooling effect of sea water can cause tensile fractures to happen. Meanwhile, tensile fractures are shallow and not likely to lead to mud leakage with lower mud weight, which agrees with the actual drilling process. On the other hand, the fluid cooling effect could increase the strength of the rock and reduce the likelihood of shear failure, which would be beneficial for wellbore stability. So, the thermal effect cannot be neglected in offshore wellbore stability analysis, and mud weight and borehole exposure time should be controlled in the case of mud loss.

  3. Application of inertial navigation to wellbore positional surveying

    Energy Technology Data Exchange (ETDEWEB)

    Watts, A.C.

    1982-06-01

    There is an increasing need for higher accuracy in wellbore directional and positional surveying than is currently available using conventional techniques. Among the factors contributing to this need are closed interspacing of wells particularly from offshore platforms, deeper and more highly deviated wells, smaller target formations and the requirement for rapid drilling of relief wells in the case of blowouts. The application of inertial navigation system (INS) of suitable size and cost for this type of application is not inherently accurate enough to offer significant improvements in well-surveying accuracy. Techniques to improve accuracy are, in general, based on the fact that the dynamics associated with the propagation of the navigator errors are very well known. Inertial systems are routinely aided using external data from a number of sources. Such aiding may take the form of an external position or velocity measurement which is compared to the position or velocity indicated by the navigator. Kalman filter theory provides a convenient formulation for generation of a minimum variance estimate of the state vector of a linear system. The theory may be extended to the nonlinear case through the use of linearization about a state trajectory. This approach is currently seeing wide use in aiding of inertial navigation systems. The approach proposed here would use the Kalman filter formulation for estimation of the INS errors and updating of the navigator. This formulation also provides a structure for estimation of various instrument parameters which should improve system performance.

  4. Investigation of Possible Wellbore Cement Failures During Hydraulic Fracturing Operations

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jihoon; Moridis, George

    2014-11-01

    We model and assess the possibility of shear failure, using the Mohr-Coulomb model ? along the vertical well by employing a rigorous coupled flow-geomechanic analysis. To this end, we vary the values of cohesion between the well casing and the surrounding cement to representing different quality levels of the cementing operation (low cohesion corresponds to low-quality cement and/or incomplete cementing). The simulation results show that there is very little fracturing when the cement is of high quality.. Conversely, incomplete cementing and/or weak cement can causes significant shear failure and the evolution of long fractures/cracks along the vertical well. Specifically, low cohesion between the well and cemented areas can cause significant shear failure along the well, but the same cohesion as the cemented zone does not cause shear failure. When the hydraulic fracturing pressure is high, low cohesion of the cement can causes fast propagation of shear failure and of the resulting fracture/crack, but a high-quality cement with no weak zones exhibits limited shear failure that is concentrated near the bottom of the vertical part of the well. Thus, high-quality cement and complete cementing along the vertical well appears to be the strongest protection against shear failure of the wellbore cement and, consequently, against contamination hazards to drinking water aquifers during hydraulic fracturing operations.

  5. Model based monitoring of wellbore hydraulics for abnormal event detection

    Energy Technology Data Exchange (ETDEWEB)

    Todorov, Dimitar; Fruhwirth, Rudolf K. [Thonhauser Data Engineering GmbH, Leoben (Austria); Thonhauser, Gerhard [Montanuniversitaet Leoben (Austria)

    2013-03-15

    With the increasing demand for energy in the last decades, the petroleum industry was forced to push the limits to levels that have never been reached before. Exploring very deep waters, drilling under varying conditions of extreme pressure and temperature and dealing with issues, which involve a new level of understanding, are challenges, which need to be overcome in order to safely and successfully accomplish the planned goals. Operating under such circumstances obligates the driller to be extremely precise in his actions. Even with the driller's extensive experience and training, the possible reaction time is in some cases extremely short. This article discusses the reasons for automatic trouble event recognition systems in the drilling process and how these affect the drilling operations and optimization processes. In this respect a concept of a real time hydraulic monitor will be developed helping the driller to visualize calculations in a plot, showing the pump limitations, the limitations due to the formation fracture gradient and the hole cleaning requirements. Additionally, taking into account the complete wellbore hydraulics and introducing various well behavior models and different algorithms, the system is capable of operating as a real-time indicator for undesired downhole events. (orig.)

  6. Experimental and Computational Studies of Coupled Geomechanical and Hydrologic Processes in Wellbore Systems (Invited)

    Science.gov (United States)

    Carey, J. W.; Mori, H.; Porter, M. L.; Lewis, K. C.; Kelkar, S.

    2013-12-01

    Potential leakage from wells is an important issue in the protection of groundwater resources, CO2 sequestration, and hydraulic fracturing. The first defense in all of these applications is a properly constructed well with adequate Portland cement that effectively isolates the subsurface. The chief threat for such wells is mechanical disruption of the cement, cement/steel, or cement/caprock interfaces. This can occur through wellbore operations that pressurize/depressurize the steel tubing or create temperature transients (e.g., injection, production, hydraulic fracturing, and mechanical testing) as well as reservoir-scale stresses (e.g., filling or depletion of the reservoir) and tectonic stresses (e.g., the mobility of salt). However, there is relatively limited information available on the hydrologic consequences of such processes. Toward this end, we discuss recent experiments and computational models of coupled geomechanical and hydrologic processes in wellbore systems. Triaxial coreflood experiments with tomography were conducted on synthetic wellbore systems including cement-steel, rock-cement and rock-cement-steel composites. The aim of the experiments was to induce stresses through application of axial loads in order to create defects within the cement or at the cement/steel or cement/rock interface. High injection fluid pressures (supercritical CO2 × brine) were applied to the base of the initially impermeable composites. Mechanical failure resulted in creation of permeability, which was measured as a function of time (allowing for the possibility of Portland cement to deform and modify permeability). In addition, fracture patterns were characterized using x-ray tomography. We used the computer code FEHM to study coupled hydrologic and mechanical processes in the near-wellbore environment. The wellbore model was developed as a wedge within a radially symmetric 3D volume. The grid elements consist of the steel casing, the casing-cement interface, the

  7. Modeling Methane Leakage from Faulty Wellbores in the Denver-Julesburg Basin, Colorado

    Science.gov (United States)

    Lackey, G.; Rajaram, H.; Karra, S.; Sherwood, O.; Burke, T. L.

    2015-12-01

    Regulations in the state of Colorado mandate that all oil and gas wells be constructed with surface casings that extend 50 feet below the depth of the deepest potable aquifer, and production casings that are cemented to at least 200 feet above the shallowest producing formation. Building wells in accordance with the minimum regulations leaves an uncemented annulus between the production casing and the surrounding rock matrix, extending from the bottom of the surface casing to the top of the production casing cement. In Colorado, this annulus is sealed at the ground surface by the "bradenhead valve". Stray methane can enter the uncemented annulus through faulty cement in the producing formation or an intermediate gas-bearing zone and migrate upwards along the production casing. The gas dissolves into the annular fluid and accumulates below the bradenhead valve building pressure. Data from the Colorado Oil and Gas Conservation Commission (COGCC) indicates that 1,492 wells in the Denver-Julesburg (DJ) Basin have recorded bradenhead pressures greater than 20 psi since 2007. A leak of this kind creates the potential for both the single-phase transport of dissolved methane and the multiphase transport of methane gas away from the well. The degree to which methane transport occurs depends not only on the size of the leak but also the construction of the wellbore. In Colorado, the definition of potable groundwater has changed with time. To meet increasing demands for water, drinking water wells have been drilled deeper. As a result, there are potentially 4,144 wells in the DJ Basin with surface casings too shallow to protect the deepest potable aquifer. In this work, we investigate how a methane leak into the open annulus of an oil and gas wellbore, could result in the transport of dissolved and gas phase methane into a nearby drinking water aquifer. We construct a multiphase wellbore model that computes the pressure distribution and gas fraction along the uncemented

  8. Hydro-mechanical simulations of well abandonment at the Ketzin pilot site for CO2 storage verify wellbore system integrity

    Science.gov (United States)

    Unger, Victoria; Kempka, Thomas

    2015-04-01

    In geological underground utilisation, operating and abandoned wells have been identified as a main potential leakage pathways for reservoir fluids. In the scope of the well abandonment procedure currently carried out at the Ketzin pilot site for CO2 storage in Germany, a hydro-mechanical model was built to carry out a coupled analysis of the integrity in the entire wellbore system. The main aim of the present study was to assess the impacts of stress changes associated with CO2 injection as well as the cement backfill undertaken in the scope of well abandonment. A numerical model comprising cement sheaths, steel casings, tubing, multiple packers and wellbore annuli was implemented to enable a detailed representation of the entire wellbore system. The numerical model grid has a horizontal discretisation of 5 m x 5 m to focus on near wellbore effects, whereby element sizes increase with increasing distance from the wellbore. Vertical grid discretisation uses a tartan grid type over the entire model thickness of 1,500 m to ensure a sufficient discretisation of all wellbore system elements as well as of the reservoir unit. The total number of elements amounts to 210,672. Mechanical model parameters were taken from geological, drilling, logging and laboratory test data based on Ketzin pilot site-specific information as well as related literature (Kempka et al., 2014). The coupled calculations were performed using an elasto-plastic constitutive law, whereby an initial simulation run ensured a static mechanical equilibrium to represent the initial state before the start of CO2 injection. Thereto, gravitational load of the overburden rocks and pore pressure distribution following available well logs were integrated for initial model parameterisation including a normal faulting stress regime defined by a horizontal to vertical total stress ratio of 0.85. A correction accounting for the temperature and pressure dependent CO2 density was carried out in advance of each

  9. Advanced wellbore thermal simulator GEOTEMP2. Appendix. Computer program listing

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, R.F.

    1982-02-01

    This appendix gives the program listing of GEOTEMP2 with comments and discussion to make the program organization more understandable. This appendix is divided into an introduction and four main blocks of code: main program, program initiation, wellbore flow, and wellbore heat transfer. The purpose and use of each subprogram is discussed and the program listing is given. Flowcharts will be included to clarify code organization when needed. GEOTEMP2 was written in FORTRAN IV. Efforts have been made to keep the programing as conventional as possible so that GEOTEMP2 will run without modification on most computers.

  10. The Framework Dedicated to Three Phase Flows Wellbore Modelling

    Directory of Open Access Journals (Sweden)

    Bartlomiej Bielecki

    2015-01-01

    Full Text Available To predict physical properties in a wellbore during oil and gas production, scientists use empirical correlations or mechanistic approach algorithms. The typical research in this field is concentrated on a single property analysis as heat transfer, pressure, temperature, and so forth. Here the most proper correlations, regarding the subject, are presented. And the authors studied how to join all correlations into the full framework which returns all production parameters at every depth in a wellbore. Additionally, the presented simulation results are studied here. Based on presented algorithms, the proper tool has been applied and the results shown in this paper are taken from this application.

  11. Shale-Gas Experience as an Analog for Potential Wellbore Integrity Issues in CO2 Sequestration

    Energy Technology Data Exchange (ETDEWEB)

    Carey, James W. [Los Alamos National Laboratory; Simpson, Wendy S. [Los Alamos National Laboratory; Ziock, Hans-Joachim [Los Alamos National Laboratory

    2011-01-01

    Shale-gas development in Pennsylvania since 2003 has resulted in about 19 documented cases of methane migration from the deep subsurface (7,0000) to drinking water aquifers, soils, domestic water wells, and buildings, including one explosion. In all documented cases, the methane leakage was due to inadequate wellbore integrity, possibly aggravated by hydrofracking. The leakage of methane is instructive on the potential for CO{sub 2} leakage from sequestration operations. Although there are important differences between the two systems, both involve migrating, buoyant gas with wells being a primary leakage pathway. The shale-gas experience demonstrates that gas migration from faulty wells can be rapid and can have significant impacts on water quality and human health and safety. Approximately 1.4% of the 2,200 wells drilled into Pennsylvania's Marcellus Formation for shale gas have been implicated in methane leakage. These have resulted in damage to over 30 domestic water supplies and have required significant remediation via well repair and homeowner compensation. The majority of the wellbore integrity problems are a result of over-pressurization of the wells, meaning that high-pressure gas has migrated into an improperly protected wellbore annulus. The pressurized gas leaks from the wellbore into the shallow subsurface, contaminating drinking water or entering structures. The effects are localized to a few thousands of feet to perhaps two-three miles. The degree of mixing between the drinking water and methane is sufficient that significant chemical impacts are created in terms of elevated Fe and Mn and the formation of black precipitates (metal sulfides) as well as effervescing in tap water. Thus it appears likely that leaking CO{sub 2} could also result in deteriorated water quality by a similar mixing process. The problems in Pennsylvania highlight the critical importance of obtaining background data on water quality as well as on problems associated with

  12. Wellbore stability analysis in chemically active shale formations

    Directory of Open Access Journals (Sweden)

    Shi Xiang-Chao

    2016-01-01

    Full Text Available Maintaining wellbore stability involves significant challenges when drilling in low-permeability reactive shale formations. In the present study, a non-linear thermo-chemo-poroelastic model is provided to investigate the effect of chemical, thermal, and hydraulic gradients on pore pressure and stress distributions near the wellbores. The analysis indicates that when the solute concentration of the drilling mud is higher than that of the formation fluid, the pore pressure and the effective radial and tangential stresses decrease, and v. v. Cooling of the lower salinity formation decreases the pore pressure, radial and tangential stresses. Hole enlargement is the combined effect of shear and tensile failure when drilling in high-temperature shale formations. The shear and tensile damage indexes reveal that hole enlargement occurs in the vicinity of the wellbore at an early stage of drilling. This study also demonstrates that shale wellbore stability exhibits a time-delay effect due to changes in the pore pressure and stress. The delay time computed with consideration of the strength degradation is far less than that without strength degradation.

  13. Optimization of SAGD wellbore completions : short production tubing string sensitivities

    Energy Technology Data Exchange (ETDEWEB)

    Cokar, M.; Graham, J. [Society of Petroleum Engineers, Canadian Section, Calgary, AB (Canada)]|[Petro-Canada, Calgary, AB (Canada)

    2008-10-15

    This study investigated the effects of changing the landing position of short production tubing strings near the heel of steam assisted gravity drainage (SAGD) production wells. A homogenous discretized wellbore model was used to model the reservoir and wellbore simultaneously in order to study wellbore and reservoir interactions. The aim of the study was to develop a method of optimizing bitumen production and determining the most economical position for wellbore strings. Simulations were conducted to examine the effect of shortening the production tubing string and examine the impact of extending the tubing string beyond the heel of the well on bitumen bitumen production rates and the steam oil ratio (SOR). Results of the study showed that a shortened string decreased bitumen production rates, while the amounts of steam produced through the tubing string increased. When the tubing string was extended past the heel of the well, bitumen production rates remained the same, but steam injection rates and SOR decreased. A lower pressure differential between the injector and producer wells was also observed. The study showed that SAGD producers can re-position production tubing strings in order to determine ratios of liquid production. It was concluded that although placing the short production tubing string close to the heel increased oil production, a longer tubing string improved production rates while lowering operating costs. 3 refs., 3 tabs., 35 figs.

  14. Non-ferromagnetic overburden casing

    Energy Technology Data Exchange (ETDEWEB)

    Vinegar, Harold J. (Bellaire, TX); Harris, Christopher Kelvin (Houston, TX); Mason, Stanley Leroy (Allen, TX)

    2010-09-14

    Systems, methods, and heaters for treating a subsurface formation are described herein. At least one system for electrically insulating an overburden portion of a heater wellbore is described. The system may include a heater wellbore located in a subsurface formation and an electrically insulating casing located in the overburden portion of the heater wellbore. The casing may include at least one non-ferromagnetic material such that ferromagnetic effects are inhibited in the casing.

  15. Impacts of shaking Bengkulus seismicity to subsurface Wellbore in the XX area

    Science.gov (United States)

    Rusli, Saifatur; Pratama, M. Ardian; Mardiyan, Hilman; Mirza, Finisha, Brian

    2016-05-01

    Bengkulu earthquake was happened on Wednesday, May 5th 2010 at 23:29:03 WIB (UTC-7) with magnitude 6.5 Richter scale. The Epicentrum was very close to Mentawai Fault System located on latitude 4.063°S and longitude 101.085°E with depth subsurface 27 kms. It was occurred the result of the Indian Ocean Plate-Australia's activity with low angled-subducted beneath the island of Sumatra. Shaking Bengkulus seismicity impacted subsurface in the XX Area which situated on South Palembang Sub-Basin part of South Sumatra Basin (SSB) about 200 kms far away from the epicentrum. Due to XX Area has some producing wells so that the seismicity activities as hypothetically impacts to Subsurface Wellbore which has caused some wells casing problems in the same depth. The wells casing problem shown after conducted routine sand bailer by Sand Line Unit, it was a downhole device used to remove debris sands or similar small particles around the fishingnecks of downhole tools or equipment in the wellbore, and then Sand Bailer tools got scratch at one side body. Similarly, Sand Bailer tools couldnt lowered until Total Depth and got samples sands slightly. At the end, it has impacted to well performance to produce oil in the XX Area.

  16. Prediction of Dynamic Wellbore Pressure in Gasified Fluid Drilling

    Institute of Scientific and Technical Information of China (English)

    Wang Zhiming; Ping Liqiu; Zou Ke

    2007-01-01

    The basis of designing gasified drilling is to understand the behavior of gas/liquid two-phase flow in the wellbore. The equations of mass and momentum conservation and equation of fluid flow in porous media were used to establish a dynamic model to predict weIlbore pressure according to the study results of Ansari and Beggs-Brill on gas-liquid two-phase flow. The dynamic model was solved by the finite difference approach combined with the mechanistic steady state model. The mechanistic dynamic model was numerically implemented into a FORTRAN 90 computer program and could simulate the coupled flow of fluid in wellbore and reservoir. The dynamic model revealed the effects of wellhead back pressure and injection rate of gas/liquid on bottomhole pressure. The model was validated against full-scale experimental data, and its 5.0% of average relative error could satisfy the accuracy requirements in engineering design.

  17. Analysis of pressure buildup data influenced by wellbore phase redistribution

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, L.G.; Jones, J.R.; Reynolds, A.C.

    1986-10-01

    This work considers the influence of wellbore phase redistribution effects on the analysis of pressure buildup data. First, the authors show that the pressure responses observed when phase redistribution effects exist consist of three distinct types and delineate the conditions under which each type exists. Second, they investigate the reliability of Fair's type curves for analyzing pressure data. Third, for each type of pressure response, they provide rules for determining when the conventional semilog straight line will begin on a semilog plot of pressure data vs. time. They also consider general procedures that are based on Duhamel's principle for analyzing pressure data when sandface flow rates are also available. They discuss the application of these methods to analyze pressure data influenced by wellbore storage effects and investigate the effect that errors in the measured sandface rate have on the analysis.

  18. Wellbore Surveying While Drilling Based on Kalman Filtering

    Directory of Open Access Journals (Sweden)

    Mahmoud ElGizawy

    2010-01-01

    Full Text Available Problem statement: Oil and gas are global fuels obtained primarily from drilling wells in underground terrestrial reservoirs. Vertical drilling is preferred because of its simplicity and therefore low cost, but subsurface targets can often be procured only by directing the wellbore along predefined non-vertical trajectories. For instance, directional drilling must be employed to reach locations inaccessible to the drilling rig, to side track an existing well (multilateral drilling, or to drill multiple wells from the same offshore platform (horizontal drilling. Approach: A complete knowledge of the wellbore direction and orientation during the drilling process is essential to guarantee proper directional drilling procedure. Results: Thus, besides the conventional drilling assembly, directional drilling operations require sensors to provide azimuth, inclination and toolface angles of the drill. These sensors are part of the Measurement-While-Drilling (MWD tool, which in current technology is installed several feet behind the drill bit. In such systems, values for inclination and toolface angles are determined from accelerometer measurements at predetermined stationary surveying stations; these values are then incorporated with magnetometer measurements to deliver the azimuth angle. Values for inclination and azimuth angles at the current surveying station are combined with those from the previous station to compute the position of the probe. However, there is no accurate information about the wellbore trajectory between survey stations. Additionally, the magnetic field of the magnetometers has deleterious effect on the overall accuracy of surveying measurements. Conclusion: A method to provide continuous information about the wellbore trajectory has been developed in this study. The module developed integrates a Rotary Steerable System (RSS and MWD tool into one drilling probe utilizing Inertial Navigation System (INS technology. This is achieved

  19. Application of Cement Science to Improved Wellbore Infrastructures Mileva Radonjic and Darko Kupresan Craft & Hawkins Department of Petroleum Engineering, Louisiana State University, USA Corresponding author: mileva@lsu.edu Key words: micro-annular gas flow, nano-properties of wellbore cements, micro-porosity

    Science.gov (United States)

    Radonjic, M.

    2015-12-01

    Recent focus on carbon emission from cement industry inspired researchers to improve CSH properties by reducing Ca/Si ratio at the nanoscale, and lower porosity (permeability) of hydrated cement at micro scale. If implemented in wellbore cement technology, both of these efforts could provide advanced properties for wellbore infrastructure. These advancements would further reduce the issue of leaky wellbores in fluid injections, hydraulic fracturing and subsurface storage for existing operating wells. Numerous inadequately abandoned wells, however, pose more complex engineering problems, primarily due to the difficulty in locating fluid flow pathways along the wellbore structure. In order to appreciate the difficulty of this problem, we need to remind ourselves that: a typical 30,000-ft. wellbore with an average production casing of 8 inches in diameter can be presented in scale by a 6-m long human hair of 150 μm these structures are placed in the subsurface, often not just vertical in geometry but deviated close to 90° tangent where monitoring and remediation becomes demanding and if we consider that wellbore cement is not continuously placed along the wellbore and it is approximately 1/10 of a wellbore diameter, we can see that the properties of these materials demand application of nano-science and a different scale phenomena than perhaps previously acknowledged. The key concept behind Ca/Si reduction associated with improved mechanical properties is traditionally achieved chemically, by addition of supplemental cementitious materials. In our study we have tried to evaluate CSH alterations due to mechanically induced phase transformation. The data suggest that confined compression-extrusion of hydrated wellbore cement and the consequent propagation of pore water can change cement composition by dissolving and removing Ca, therefore reducing Ca/Si of cement phases. The advantage of this approach is that the process is less impacted by pressure

  20. Exploring the hole cleaning parameters of horizontal wellbore using two-phase Eulerian CFD approach

    Directory of Open Access Journals (Sweden)

    Satish K Dewangan

    2016-03-01

    Full Text Available The present investigation deals with the flow through concentric annulus with the inner cylinder in rotation. This work has got its importance in the petroleum industries in relation to the wellbore drilling. In wellbore drilling, the issue of the hole-cleaning is very serious problem especially in case of the horizontal drilling process. The effect of the various parameters like slurry flow velocity, inner cylinder rotational speed, inlet solid concentration which affect hole cleaning was discussed. Their effect on the pressure drop, wall shear stress, mixture turbulence kinetic energy, and solid-phase velocity and slip velocity were analyzed, which are responsible for solid-phase distribution. Flow was considered to be steady, incompressible and two-phase slurry flow with water as carrier fluid and silica sand as the secondary phase. Eulerian approach was used for modeling the slurry flow. Silica sand was considered of spherical shape with particle size of 180 µm. ANSYS FLUENT software was used for modeling and solution. Plotting was done using Tecplot software and Microsoft Office.

  1. Hydraulic fracturing model featuring initiation beyond the wellbore wall for directional well in coal bed

    Science.gov (United States)

    Li, Yuwei; Jia, Dan; Wang, Meng; Liu, Jia; Fu, Chunkai; Yang, Xinliang; Ai, Chi

    2016-08-01

    In developing internal fracture systems in coal beds, the initiation mechanism differs greatly from that of conventional ones and initiations may be produced beyond the wellbore wall. This paper describes the features of the internal structure of coal beds and RFPA2D simulation is used to attest the possible occurrence of initiation beyond the wellbore wall in coal bed hydraulic fracturing. Using the theory of elasticity and fracture mechanics, we analyse the stress distribution in the vicinal coal rock. Then by taking into consideration the effects of the spatial relationship between coal bed cleats and the wellbore, we establish a model for calculating both tensile and shear initiation pressure that occur along cleats beyond the wellbore wall. The simulation in this paper indicates that for shear initiations that happen along coal cleats, the pressure required to initiate fracture for cleats beyond the wellbore wall is evidently lower than that on the wellbore wall, thus it is easier to initiate shear fractures for cleats beyond the wellbore wall. For tensile failure, the pressure required to initiate tensile fracture for cleats beyond the wellbore wall is obviously higher than that for cleats at the wellbore wall, thus it is easier to initiate tensile fractures for cleats at the wellbore wall. On the one hand, this paper has proved the possible occurrence of initiations beyond the wellbore wall and has changed the current assumption that hydraulic fractures can only occur at the wellbore wall. On the other hand, the established theoretical model provides a new approach to calculating the initiation pressure in hydraulic fracturing.

  2. Study on temperature distribution along wellbore of fracturing horizontal wells in oil reservoir

    Directory of Open Access Journals (Sweden)

    Junjun Cai

    2015-12-01

    Full Text Available The application of distributed temperature sensors (DTS to monitor producing zones of horizontal well through a real-time measurement of a temperature profile is becoming increasingly popular. Those parameters, such as flow rate along wellbore, well completion method, skin factor, are potentially related to the information from DTS. Based on mass-, momentum-, and energy-balance equations, this paper established a coupled model to study on temperature distribution along wellbore of fracturing horizontal wells by considering skin factor in order to predict wellbore temperature distribution and analyze the factors influencing the wellbore temperature profile. The models presented in this paper account for heat convective, fluid expansion, heat conduction, and viscous dissipative heating. Arriving temperature and wellbore temperature curves are plotted by computer iterative calculation. The non-perforated and perforated sections show different temperature distribution along wellbore. Through the study on the sensitivity analysis of skin factor and flow rate, we come to the conclusion that the higher skin factor generates larger temperature increase near the wellbore, besides, temperature along wellbore is related to both skin factors and flow rate. Temperature response type curves show that the larger skin factor we set, the less temperature augmenter from toe to heel could be. In addition, larger flow rate may generate higher wellbore temperature.

  3. Optimization of Integrated Reservoir, Wellbore, and Power Plant Models for Enhanced Geothermal Systems

    Science.gov (United States)

    Peluchette, Jason

    Geothermal energy has the potential to become a substantially greater contributor to the U.S. energy market. An adequate investment in Enhanced Geothermal Systems (EGS) technology will be necessary in order to realize the potential of geothermal energy. This study presents an optimization of a waterbased Enhanced Geothermal System (EGS) modeled for AltaRock Energy's Newberry EGS Demonstration location. The optimization successfully integrates all three components of the geothermal system: (1) the present wellbore design, (2) the reservoir design, and (3) the surface plant design. Since the Newberry EGS Demonstration will use an existing well (NWG 55-29), there is no optimization of the wellbore design, and the aim of the study for this component is to replicate the present wellbore conditions and design. An in-house wellbore model is used to accurately reflect the temperature and pressure changes that occur in the wellbore fluid and the surrounding casing, cement, and earth during injection and production. For the reservoir design, the existing conditions, such as temperature and pressure at depth and rock density, are incorporated into the model, and several design variables are investigated. The engineered reservoir is modeled using the reservoir simulator TOUGH2 while using the graphical interface PetraSim for visualization. Several fracture networks are investigated with the goal of determining which fracture network yields the greatest electrical output when optimized jointly with the surface plant. A topological optimization of the surface is completed to determine what type of power plant is best suited for this location, and a parametric optimization of the surface plant is completed to determine the optimal operating conditions. The conditions present at the Newberry, Oregon EGS project site are the basis for this optimization. The subsurface conditions are favorable for the production of electricity from geothermal energy with rock temperatures exceeding

  4. Wellbore inertial navigation system (WINS) software development and test results

    Energy Technology Data Exchange (ETDEWEB)

    Wardlaw, R. Jr.

    1982-09-01

    The structure and operation of the real-time software developed for the Wellbore Inertial Navigation System (WINS) application are described. The procedure and results of a field test held in a 7000-ft well in the Nevada Test Site are discussed. Calibration and instrumentation error compensation are outlined, as are design improvement areas requiring further test and development. Notes on Kalman filtering and complete program listings of the real-time software are included in the Appendices. Reference is made to a companion document which describes the downhole instrumentation package.

  5. Characteristics of mechanical wellbore failure and damage: Insights of discrete element modelling and application to CO2 storage

    NARCIS (Netherlands)

    Heege, J.H. ter; Orlic, B.; Hoedeman, G.C.

    2015-01-01

    Wellbore zonal isolation is particularly important for subsurface storage of CO2, where well integrity must be ensured for very long time spans. In this study, three dimensional discrete element models of wellbore systems have been used to simulate failure and damage of wellbore cement and surroundi

  6. Development of an Ultrasonic Phased Array System for Wellbore Integrity Evaluation and Near-Wellbore Fracture Network Mapping of Injection and Production Wells in Geothermal Energy Systems

    Energy Technology Data Exchange (ETDEWEB)

    Almansouri, Hani [Purdue University; Foster, Benjamin [Purdue University; Kisner, Roger A [ORNL; Polsky, Yarom [ORNL; Bouman, Charlie [Purdue University

    2016-01-01

    This paper documents our progress developing an ultrasound phased array system in combination with a model-based iterative reconstruction (MBIR) algorithm to inspect the health of and characterize the composition of the near-wellbore region for geothermal reservoirs. The main goal for this system is to provide a near-wellbore in-situ characterization capability that will significantly improve wellbore integrity evaluation and near well-bore fracture network mapping. A more detailed image of the fracture network near the wellbore in particular will enable the selection of optimal locations for stimulation along the wellbore, provide critical data that can be used to improve stimulation design, and provide a means for measuring evolution of the fracture network to support long term management of reservoir operations. Development of such a measurement capability supports current hydrothermal operations as well as the successful demonstration of Engineered Geothermal Systems (EGS). The paper will include the design of the phased array system, the performance specifications, and characterization methodology. In addition, we will describe the MBIR forward model derived for the phased array system and the propagation of compressional waves through a pseudo-homogenous medium.

  7. Stress State Analysis in Aspect of Wellbore Drilling Direction

    Science.gov (United States)

    Knez, Dariusz

    2014-03-01

    Drilling directional wells challenges designers. Apart from known problems until now they face exact description of stress distribution in near wellbore region issue. Paper presents analysis of stress state taking into account drilling direction. The transposed in-situ stress state relative to the borehole coordinate system (Cartesian borehole coordinate system) and the total stress component at the borehole wall (cylindrical coordinate system) exhibits cyclic behaviour with respect to drilling direction of borehole. It allows to find optimal wellbore path Wiercenie otworów kierunkowych stanowi duże wyzwanie dla projektantów. Poza problemami typowymi obecnie staja oni w obliczu zagadnienia dokładnego opisu rozkładu naprężeń w strefie przyotworowej. Artykuł przedstawia analizę stanu naprężeń w aspekcie kierunku wiercenia. Rozkład naprężeń transponowany do układu odniesienia związanego z otworem wiertniczym (kartezjański układ współrzędnych zgodny z kierunkiem otworu wiertniczego) oraz składowe naprężenia na ścianie otworu wiertniczego (w cylindrycznym układzie odniesienia) wykazują cykliczną zmienność zależną od kierunku wiercenia. Pozwala to na określenie optymalnej trajektorii osi otworu wiertniczego

  8. Systematic assessment of wellbore integrity for geologic carbon storage projects using regulatory and industry information

    Energy Technology Data Exchange (ETDEWEB)

    Moody, Mark [Battelle Memorial Institute, Columbus, OH (United States); Sminchak, J.R. [Battelle Memorial Institute, Columbus, OH (United States)

    2015-11-01

    Under this three year project, the condition of legacy oil and gas wells in the Midwest United States was evaluated through analysis of well records, well plugging information, CBL evaluation, sustained casing pressure (SCP) field testing, and analysis of hypothetical CO2 test areas to provide a realistic description of wellbore integrity factors. The research included a state-wide review of oil and gas well records for Ohio and Michigan, along with more detailed testing of wells in Ohio. Results concluded that oil and gas wells are clustered along fields in areas. Well records vary in quality, and there may be wells that have not been identified in records, but there are options for surveying unknown wells. Many of the deep saline formations being considered for CO2 storage have few wells that penetrate the storage zone or confining layers. Research suggests that a variety of well construction and plugging approaches have been used over time in the region. The project concluded that wellbore integrity is an important issue for CO2 storage applications in the Midwest United States. Realistic CO2 storage projects may cover an area in the subsurface with several hundred legacy oil and gas wells. However, closer inspection may often establish that most of the wells do not penetrate the confining layers or storage zone. Therefore, addressing well integrity may be manageable. Field monitoring of SCP also indicated that tested wells provided zonal isolation of the reservoirs they were designed to isolate. Most of these wells appeared to exhibit gas pressure originating from intermediate zones. Based on these results, more flexibility in terms of cementing wells to surface, allowing well testing, and monitoring wells may aid operators in completing CO2 storage project. Several useful products were developed under this project for examining wellbore integrity for CO2 storage applications including, a

  9. A Graph Theoretic Approach for Hydraulic Fracturing and Wellbore Leakage Risk Modeling

    Science.gov (United States)

    Glosser, D.; Rose, K.; Bauer, J. R.; Warner, T.

    2016-12-01

    Recent large scale development of unconventional formations for fossil energy has raised concerns over the potential for fluid leakage between subsurface systems and wellbores. This is particularly true in regions with extensive drilling history, where spatial densities of wellbores are higher, and where significant uncertainties in the location and mechanical integrity of such wellbores exist. The generation of induced fracture networks during hydraulic fracturing may increase subsurface connectivity, and create the potential for unwanted fluid migration between operational and legacy wellbores and subsurface fracture networks. We present a graph theoretic approach for identifying geospatial regions and wellbores at increased risk for subsurface connectivity based on wellbore proximity and local geologic characteristics. The algorithm transforms user inputted geospatial data (geologic and wellbore x,y,z) to graph structure, where wellbores are represented as nodes, and where potential overlapping fracture network zones are represented as edges. The algorithm can be used to complement existing fracture models to better account for the reach of induced fractures, and to identify spatial extents at increased risk for unwanted subsurface connectivity. Additionally, the model can be used to identify regions in need of geophysical detection methods for locating undocumented wells. As a result, the method can be part of a cumulative strategy to reduce uncertainty inherent to combined geologic and engineered systems. The algorithm has been successfully tested against a known leakage scenario in Pennsylvania. In addition to identifying wells associated with the leakage event, the algorithm identified two other higher risk networks in the region. The algorithm output provides valuable information for industry to develop environmentally safe drilling and injection plans; and for regulators to identify specific wellbores at greater risk for leakage, and to develop targeted

  10. Effective Permeability Change in Wellbore Cement with Carbon Dioxide Reaction

    Energy Technology Data Exchange (ETDEWEB)

    Um, Wooyong; Jung, Hun Bok; Martin, Paul F.; McGrail, B. Peter

    2011-11-01

    Portland cement, a common sealing material for wellbores for geological carbon sequestration was reacted with CO{sub 2} in supercritical, gaseous, and aqueous phases at various pressure and temperature conditions to simulate cement-CO{sub 2} reaction along the wellbore from carbon injection depth to the near-surface. Hydrated Portland cement columns (14 mm diameter x 90 mm length; water-to-cement ratio = 0.33) including additives such as steel coupons and Wallula basalt fragments were reacted with CO{sub 2} in the wet supercritical (the top half) and dissolved (the bottom half) phases under carbon sequestration condition with high pressure (10 MPa) and temperature (50 C) for 5 months, while small-sized hydrated Portland cement columns (7 mm diameter x 20 mm length; water-to-cement ratio = 0.38) were reacted with CO{sub 2} in dissolved phase at high pressure (10 MPa) and temperature (50 C) for 1 month or with wet CO{sub 2} in gaseous phase at low pressure (0.2 MPa) and temperature (20 C) for 3 months. XMT images reveal that the cement reacted with CO{sub 2} saturated groundwater had degradation depth of {approx}1 mm for 1 month and {approx}3.5 mm for 5 month, whereas the degradation was minor with cement exposure to supercritical CO{sub 2}. SEM-EDS analysis showed that the carbonated cement was comprised of three distinct zones; the innermost less degraded zone with Ca atom % > C atom %, the inner degraded zone with Ca atom % {approx} C atom % due to precipitation of calcite, the outer degraded zone with C atom % > Ca atom % due to dissolution of calcite and C-S-H, as well as adsorption of carbon to cement matrix. The outer degraded zone of carbonated cement was porous and fractured because of dissolution-dominated reaction by carbonic acid exposure, which resulted in the increase in BJH pore volume and BET surface area. In contrast, cement-wet CO{sub 2}(g) reaction at low P (0.2 MPa)-T (20 C) conditions for 1 to 3 months was dominated by precipitation of micron

  11. Numerical assessment of the mechanical stability in vertical, directional and horizontal wellbores

    Institute of Scientific and Technical Information of China (English)

    Kamran Goshtasbi; Ayub Elyasi; Ali Naeimipour

    2013-01-01

    In this research the stability of wellbore is evaluated in seven different stress regimes and diverse orien-tations using FLAC3D software. The normalized yielded zone area (NYZA, i.e., the ratio of surrounding yielded cross-sectional area to initial area of wellbore) is determined for different mud pressures as well as diverse orientations of wellbore. By means of MATLAB software the best curve is fitted to the recorded points and then the optimized mud pressure is calculated using these plots. The optimized orientation is selected considering these data. Finally the mud pressure resulted from this method was compared with the mud pressure obtained from the Mogi-Coulomb criterion and then with the fields data. The minimum allowable mud pressure obtained from the NYZA criterion is close to actual data and the value obtained from the Mogi-Coulomb criterion. Hence, the NYZA is considered to be an appropriate criterion for well-bore stability analysis.

  12. A review of the shale wellbore stability mechanism based on mechanical–chemical coupling theories

    Directory of Open Access Journals (Sweden)

    Qiangui Zhang

    2015-06-01

    Full Text Available Wellbore instability in hard brittle shale is a critical topic related to the effective exploitation of shale gas resources. This review first introduces the physical–chemical coupling theories applied in shale wellbore stability research, including total water absorption method, equivalent pore pressure method, elasticity incremental method of total water potential and non-equilibrium thermodynamic method. Second, the influences of water activity, membrane efficiency, clay content and drilling fluid on shale wellbore instability are summarized. Results demonstrate that shale and drilling fluid interactions can be the critical factors affecting shale wellbore stability. The effects of thermodynamics and electrochemistry may also be considered in the future, especially the microscopic reaction of shale and drilling fluid interactions. An example of this reaction is the chemical reaction between shale components and drilling fluid.

  13. Pulse testing in the presence of wellbore storage and skin effects

    Energy Technology Data Exchange (ETDEWEB)

    Ogbe, D.O.; Brigham, W.E.

    1984-08-01

    A pulse test is conducted by creating a series of short-time pressure transients in an active (pulsing) well and recording the observed pressure response at an observation (responding) well. Using the pressure response and flow rate data, the transmissivity and storativity of the tested formation can be determined. Like any other pressure transient data, the pulse-test response is significantly influenced by wellbore storage and skin effects. The purpose of this research is to examine the influence of wellbore storage and skin effects on interference testing in general and on pulse-testing in particular, and to present the type curves and procedures for designing and analyzing pulse-test data when wellbore storage and skin effects are active at either the responding well or the pulsing well. A mathematical model for interference testing was developed by solving the diffusivity equation for radial flow of a single-phase, slightly compressible fluid in an infinitely large, homogeneous reservoir. When wellbore storage and skin effects are present in a pulse test, the observed response amplitude is attenuated and the time lag is inflated. Consequently, neglecting wellbore storage and skin effects in a pulse test causes the calculated storativity to be over-estimated and the transmissivity to be under-estimated. The error can be as high as 30%. New correlations and procedures are developed for correcting the pulse response amplitude and time lag for wellbore storage effects. Using these correlations, it is possible to correct the wellbore storage-dominated response amplitude and time lag to within 3% of their expected values without wellbore storage, and in turn to calculate the corresponding transmissivity and storativity. Worked examples are presented to illustrate how to use the new correction techniques. 45 references.

  14. Imaging wellbore cement degradation by carbon dioxide under geologic sequestration conditions using X-ray computed microtomography.

    Science.gov (United States)

    Jung, Hun Bok; Jansik, Danielle; Um, Wooyong

    2013-01-02

    X-ray microtomography (XMT), a nondestructive three-dimensional imaging technique, was applied to demonstrate its capability to visualize the mineralogical alteration and microstructure changes in hydrated Portland cement exposed to carbon dioxide under geologic sequestration conditions. Steel coupons and basalt fragments were added to the cement paste in order to simulate cement-steel and cement-rock interfaces. XMT image analysis showed the changes of material density and porosity in the degradation front (density: 1.98 g/cm(3), porosity: 40%) and the carbonated zone (density: 2.27 g/cm(3), porosity: 23%) after reaction with CO(2)-saturated water for 5 months compared to unaltered cement (density: 2.15 g/cm(3), porosity: 30%). Three-dimensional XMT imaging was capable of displaying spatially heterogeneous alteration in cement pores, calcium carbonate precipitation in cement cracks, and preferential cement alteration along the cement-steel and cement-rock interfaces. This result also indicates that the interface between cement and host rock or steel casing is likely more vulnerable to a CO(2) attack than the cement matrix in a wellbore environment. It is shown here that XMT imaging can potentially provide a new insight into the physical and chemical degradation of wellbore cement by CO(2) leakage.

  15. Fluid-solid coupling model for studying wellbore instability in drilling of gas hydrate bearing sediments

    Institute of Scientific and Technical Information of China (English)

    程远方; 李令东; 崔青

    2013-01-01

    As the oil or gas exploration and development activities in deep and ultra-deep waters become more and more, encountering gas hydrate bearing sediments (HBS) is almost inevitable. The variation in temperature and pressure can destabilize gas hydrate in nearby formation around the borehole, which may reduce the strength of the formation and result in wellbore instability. A non-isothermal, transient, two-phase, and fluid-solid coupling mathematical model is proposed to simulate the complex stability performance of a wellbore drilled in HBS. In the model, the phase transition of hydrate dissociation, the heat exchange between drilling fluid and formation, the change of mechanical and petrophysical properties, the gas-water two-phase seepage, and its interaction with rock deformation are considered. A finite element simulator is developed, and the impact of drilling mud on wellbore instability in HBS is simulated. Results indicate that the re-duction in pressure and the increase in temperature of the drilling fluid can accelerate hydrate decomposition and lead to mechanical properties getting worse tremendously. The cohesion decreases by 25% when the hydrate totally dissociates in HBS. This easily causes the wellbore instability accordingly. In the first two hours after the formation is drilled, the regions of hydrate dissociation and wellbore instability extend quickly. Then, with the soaking time of drilling fluid increasing, the regions enlarge little. Choosing the low temperature drilling fluid and increasing the drilling mud pressure appropriately can benefit the wellbore stability of HBS. The established model turns out to be an efficient tool in numerical studies of the hydrate dissociation behavior and wellbore stability of HBS.

  16. Montney unconventional gas : next generation, an integrated approach to optimizing wellbore completions technology

    Energy Technology Data Exchange (ETDEWEB)

    Tapper, N.; Schnell, R. [Talisman Energy Inc., Calgary, AB (Canada)

    2009-07-01

    The Montney Formation is a prolific tight gas reservoir located in the western Canadian Sedimentary Basin in British Columbia and Alberta. The key to achieving economic success in the Peace River Arch area lies with horizontal wells with multiple fractures. The driver for the next generation of completions involves using various area drilling and completion techniques as a starting point to lower the installation cost without affecting the completion or production results. This presentation discussed unconventional gas in the Montney Formation and a next generation, integrated approach to optimizing wellbore completions technology. In order to address the need to change from cemented liners with pump down plugs and perforations completions, the presentation provided background information on swellable packers that could take the place of cement. Swellpacker completion bottom hole assembly and design considerations were presented. A solution for reducing costs was presented along with 6 case histories. It was concluded that new technology is the key to reducing costs in the Montney. Technology must be thoroughly vetted by drilling and completion experts and properly applied. figs.

  17. Computational studies of two-phase cement-CO2-brine interaction in wellbore environments

    Energy Technology Data Exchange (ETDEWEB)

    Carey, James William [Los Alamos National Laboratory; Lichtner, Peter C [Los Alamos National Laboratory

    2009-01-01

    Wellbore integrity is essential to ensuring long-term isolation of buoyant supercritical CO{sub 2} during geologic sequestration of CO{sub 2}. In this report, we summarize recent progress in numerical simulations of cement-brine-CO{sub 2} interactions with respect to migration of CO{sub 2} outside of casing. Using typical values for the hydrologic properties of cement, caprock (shale) and reservoir materials, we show that the capillary properties of good quality cement will prevent flow of CO{sub 2} into and through cement. Rather, CO{sub 2}, if present, is likely to be confined to the casing-cement or cement-formation interfaces. CO{sub 2} does react with the cement by diffusion from the interface into the cement, in which case it produces distinct carbonation fronts within the cement. This is consistent with observations of cement performance at the CO{sub 2}-enhanced oil recovery SACROC Unit in West Texas (Carey et al. 2007). For poor quality cement, flow through cement may occur and would produce a pattern of uniform carbonation without reaction fronts. We also consider an alternative explanation for cement carbonation reactions as due to CO{sub 2} derived from caprock. We show that carbonation reactions in cement are limited to surficial reactions when CO{sub 2} pressure is low (< 10 bars) as might be expected in many caprock environments. For the case of caprock overlying natural CO{sub 2} reservoirs for millions of years, we consider Scherer and Huet's (2009) hypothesis of diffusive steady-state between CO{sub 2} in the reservoir and in the caprock. We find that in this case, the aqueous CO{sub 2} concentration would differ little from the reservoir and would be expected to produce carbonation reaction fronts in cements that are relatively uniform as a function of depth.

  18. A Wellbore Stability Model for a Deviated Well in a Transversely Isotropic Formation Considering Poroelastic Effects

    Science.gov (United States)

    Liu, Ming; Jin, Yan; Lu, Yunhu; Chen, Mian; Hou, Bing; Chen, Wenyi; Wen, Xin; Yu, Xiaoning

    2016-09-01

    To analyse wellbore stability phenomena when drilling through a transversely isotropic formation such as shale, a wellbore stability model is developed based on the coordinate transformation method and complex variable elasticity theory. In order to comprehensively consider the anisotropies in the transversely isotropic formation, the model includes the followings: 1. the elastic anisotropy due to the sedimentation effect and naturally developed fractures and 2. the strength anisotropy due to the poor cementation between bedding planes and natural fractures. The model is further generalized by accounting for an arbitrary wellbore trajectory under an arbitrary in situ stress orientation. Next, the model is used in a parametric study that includes factors such as elastic anisotropy, strength anisotropy, multiple weak planes, in situ stress anisotropy, and poroelastic anisotropy, all of which can have a great influence on wellbore stability. Finally, a correction for a frequently used failure criterion has been made to ensure that the newly developed model is comprehensive and accurate for wellbore stability analyses in highly heterogeneous formations.

  19. Simulation of a SAGD well blowout using a reservoir-wellbore coupled simulator

    Energy Technology Data Exchange (ETDEWEB)

    Walter, J.; Vanegas, P.; Cunha, L.B. [Alberta Univ., Edmonton, AB (Canada); Worth, D.J. [C-FER Technologies, Edmonton, AB (Canada); Crepin, S. [Petrocedeno, Caracas (Venezuela)

    2008-10-15

    Single barrier completion systems are typically used in SAGD projects due to the lack of equipment suitable for high temperature SAGD downhole environments. This study used a wellbore and reservoir coupled thermal simulator tool to investigate the blowout behaviour of a steam assisted gravity drainage (SAGD) well pair when the safety barrier has failed. Fluid flow pressure drop through the wellbore and heat losses between the wellbore and the reservoir were modelled using a discretized wellbore option and a semi-analytical model. The fully coupled mechanistic model accounted for the simultaneous transient pressure and temperature variations along the wellbore and the reservoir. The simulations were used to predict flowing potential and fluid compositions of both wells in a SAGD well pair under various flowing conditions. Blowout scenarios were created for 3 different points in the well pair's life. Three flow paths during the blowout were evaluated for both the production and injection wells. Results of the study were used to conduct a comparative risk assessment between a double barrier and a single barrier completion. The modelling study confirmed that both the injection and production wells had the potential for blowouts lasting significant periods of time, with liquid rates over 50 times the normal production liquid rates. The model successfully predicted the blowout flow potential of the SAGD well pairs. 8 refs., 3 tabs., 18 figs.

  20. Subsurface fracture mapping from geothermal wellbores. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Hartenbaum, B.A.; Rawson, G.

    1983-08-01

    To advance the state-of-the-art in Hot Dry Rock technology, and evaluation is made of (1) the use of both electromagnetic and acoustic radar to map far-field fractures, (2) the use of more than twenty different conventional well logging tools to map borehole-fracture intercepts, (3) the use of magnetic dipole ranging to determine the relative positions of the injection well and the production well within the fractured zone, (4) the use of passive microseismic methods to determine the orientation and extent of hydraulic fractures, and (5) the application of signal processing techniques to fracture mapping including tomography, holography, synthetic aperture, image reconstruction, and the relative importance of phase and amplitude information. It is found that according to calculations, VHF backscatter radar has the potential for mapping fractures within a distance of 50 +- 20 meters from the wellbore. A new technique for improving fracture identification is presented. The range of acoustic radar is five to seven times greater than that of VHF radar when compared on the basis of equal resolution, i.e., equal wavelengths. Analyses of extant data indicate that when used synergistically the (1) caliper, (2) resistivity dipmeter, (3) televiewer, (4) television, (5) impression packer, and (6) acoustic transmission are useful for mapping borehole-fracture intercepts. A new model of hydraulic fracturing is presented which indicates that a hydraulic fracture is dynamically unstable; consequently, improvements in locating the crack tip may be possible. The importance of phase in signal processing is stressed and those techniques which employ phase data are emphasized for field use.

  1. The wellbore pressure response in naturally fractured reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Reynolds, A.C.; Chang, W.L.

    1983-10-01

    Recently a new flow regime has been identified for pressure drawdown or buildup data obtained from a well producing a naturally fractured reservoir. During the time period corresponding to this new flow regime, a semilog plot of pressure versus time exhibits a semilog straight line with slope equal to m/2, where m is the slope of both the ''early and late time'' semilog straight lines predicted by the Warren and Root model. The identification of this intermediate time semilog straight line means that pressure data may exhibit as many as three semilog straight lines. A virtually complete analysis of well test pressure data is possible when the data exhibits two or more of the three possible straight lines. In this work we present type curves which can be used to obtain a virtually complete analysis of pressure data when only one of the three semilog straight lines is reflected by the data. Analytical work on the pressure response in a naturally fractured reservoir requires the assumption of a matrix-fracture geometry. One model that has frequently been used assumes that a naturally fractured reservoir is equivalent to a system of plane horizontal fractures. The use of this model suggests that the pressure response should be similar to the pressure response in a two-layer reservoir. In this work, the authors establish the conditions under which the pressure response in a two-layer reservoir with crossflow between the layers will be identical to the pressure response in a naturally fractured reservoir. The twolayer analogue provides information on the well response when the matrix feeds directly into the wellbore. In addition, the authors consider the economic feasibility of stimulating the ''matrix layer''.

  2. Improving the accuracy and reliability of MWD/magnetic-Wellbore-Directional surveying in the barents sea

    DEFF Research Database (Denmark)

    Edvardsen, I.; Nyrnes, E.; Johnsen, M. G.;

    2014-01-01

    , and the effect of the latter is increased because of diminished value of the magnetic horizontal component. Wellbore directional surveying for operations on the continental shelf in the North Sea and the Norwegian Sea rely on wellestablishedprocedures for near-real-time magnetic monitoring by use of onshore...... of nonmagnetic steel in the bottomhole assembly (BHA). To maintain azimuth uncertaintyat an acceptable level in northern areas, it is crucial that wellbore-directional-surveying requirements are given high priority and considered early during well planning. During the development phase of an oil and gas field......, the planned wells must be assigned adequate positional-uncertainty models and, if possible, be designed in a direction that minimizes the wellbore directional uncertainty. ©2014 Society of Petroleum Engineers....

  3. A feedback-based inverse heat transfer method to estimate unperturbed temperatures in wellbores

    Energy Technology Data Exchange (ETDEWEB)

    Espinosa-Paredes, Gilberto [Area de Ingenieria en Recursos Energeticos, Universidad Autonoma Metropolitana-Iztapalapa, Apartado Postal 55-534, Mexico D.F. 09340 (Mexico); Espinosa-Martinez, Erick G. [Retorno Quebec 6, Col. Burgos de Cuernavaca 62580, Temixco, Mor. (Mexico)

    2009-01-15

    This paper presents a feedback-based strategy to solve an inverse heat transfer problem for the estimation of unperturbed formation temperatures (UFT) from measured temperatures in wellbores. The feedback function uses the error between the measured and estimated temperatures during the shut-in process. Thus, an inverse heat transfer problem was solved in this way since the UFT represents the unknown initial conditions and the measured temperatures in the wellbore represents the particular solution of the PDE'S governing the heat transfer process in the formation and in the wellbore system. The performance of the method is illustrated via numerical simulations of two wells: (a) oil well FE-1227 from the Gulf of Mexico maritime zone and (b) well CP-0512 from Cerro Prieto Mexican geothermal field. (author)

  4. Experimental determination of wellbore diameter and shape (4D imaging of wellbore) by using ultrasonic caliper within different fluids for real-time drilling application

    Energy Technology Data Exchange (ETDEWEB)

    Elahifar, Behzad; Esmaeili, Abdolali; Thonhauser, Gerhard [Montanuniversitaet Leoben (Austria); Fruhwirth, Rudolf K. [TDE Thonhauser Data Engineering GmbH, Leoben (Austria)

    2013-03-15

    Drilling programs continue to push into new and more complicated environments. As a result, accurate measurement, interpretation and analysis of drilling data in real time are becoming more critical. One of the key measurement devices for drilling, cementing and formation evaluation is the borehole caliper. An ultrasonic sensor caliper tool is thereby a key measurement device for determining the borehole diameter in MWD or LWD tools. Another use of ultrasonic caliper tools is to offer a method for calculating borehole volumes. Real-time application of ultrasonic caliper tools can also support the early detection of borehole instability. This paper describes the experiments related to the accuracy of the ultrasonic sensor for measuring wellbore diameter by performing the tests in different fluids, comparing the results and determining the weak points of the sensor for detecting echoes. In addition the wellbore profiles were simulated and the simulated results were compared with the recorded data. Different tests related to the position of the caliper tool inside the wellbore were performed as well as the evaluation of the accuracy of the ultrasonic sensor by simulating dog-legs and latches. (orig.)

  5. Fracture healing and transport properties of wellbore cement in the presence of supercritical CO2

    NARCIS (Netherlands)

    Liteanu, E.; Spiers, C.J.

    2011-01-01

    This paper investigates the process and rate of carbonation reaction of Class A wellbore cement exposed to CO2-saturated solution at confined conditions similar to those employed in geological storage of CO2. The main goal was to investigate whether reaction improves or degrades the sealing/healing

  6. Effect of CO2-induced reactions on the mechanical behaviour of fractured wellbore cement

    NARCIS (Netherlands)

    Wolterbeek, T.K.T.; Hangx, S.J.T.; Spiers, C.J.

    2016-01-01

    Geomechanical damage, such as fracturing of wellbore cement, can severely impact well integrity in CO2 storage fields. Chemical reactions between the cement and CO2-bearing fluids may subsequently alter the cement’s mechanical properties, either enhancing or inhibiting damage accumulation during ong

  7. Wellbore Models GWELL, GWNACL, and HOLA User's Guide

    Energy Technology Data Exchange (ETDEWEB)

    Aunzo, Z.P.; Bjornsson, G.; Bodvarsson, G.S.

    1991-10-01

    This report describes three multi-component, multi-feedzone geothermal wellbore simulators developed. These simulators reproduce the measured flowing temperature and pressure profiles in flowing wells and determine the relative contribution, fluid properties (e.g. enthalpy, temperature) and fluid composition (e.g. CO{sub 2}, NaCl) of each feedzone for a given discharge condition. The three related wellbore simulators that will be discussed here are HOLA, GWELL and GWNACL. HOLA is a multi-feedzone geothermal wellbore simulator for pure water, modified after the wellbore simulator developed by Bjornsson, 1987 and can now handle deviated wells. The other two simulators GWELL (see also Aunzo, 1990) and GWNACL are modified versions of HOLA that can handle H{sub 2}O-CO{sub 2} and H{sub 2}O-NaCl systems, respectively. These simulators can handle both single and two-phase flows in vertical and inclined pipes and calculate the flowing temperature and pressure profiles in the well. The simulators solve numerically the differential equations that describe the steady-state energy, mass and momentum flow in a pipe. The codes allow for multiple feedzones, variable grid spacing and well radius. These codes were developed using FORTRAN language on the UNIX system.

  8. Wellbore models GWELL, GWNACL, and HOLA: User's guide

    Energy Technology Data Exchange (ETDEWEB)

    Aunzo, Z.P. (PNOC Energy Development Corp., Metro Manila (Philippines). Geothermal Div.); Bjornsson, G. (Icelandic National Energy Authority, Reykjavik (Iceland)); Bodvarsson, G.S. (Lawrence Berkeley Lab., CA (United States))

    1991-10-01

    This report describes three multi-component, multi-feedzone geothermal wellbore simulators developed. These simulators reproduce the measured flowing temperature and pressure profiles in flowing wells and determine the relative contribution, fluid properties (e.g., enthalpy, temperature) and fluid composition (e.g. CO{sub 2}, NaCl) of each feedzone for a given discharge condition. The three related wellbore simulators that will be discussed here are HOLA, GWELL and GWNACL. HOLA is a multi-feedzone geothermal wellbore simulator for pure water, modified after the wellbore simulator developed by Bjornsson, 1987 and can now handle deviated wells. The other two simulators GWELL and GWNACL are modified versions of HOLO that can handle H{sub 2}O CO{sub 2} and H{sub 2}O-NaCl systems, respectively. These simulators can handle both single and two-phase flows in vertical and inclined pipes and calculate the flowing temperature and pressure profiles in the well. The simulators solve numerically the differential equations that describe the steady-state energy, mass and momentum flow in a pipe. The codes allow for multiple feedzones, variable grid spacing and well radius. Theses codes were developed using FORTRAN language on the UNIX system.

  9. Trajectory Control:Directional MWD Inversely New Wellbore Positioning Accuracy Prediction Method

    Institute of Scientific and Technical Information of China (English)

    Ahmed Abd Alaziz Ibrahim; Tagwa Ahmed Musa

    2004-01-01

    The deviation control of directional drilling is essentially the controlling of two angles of the wellbore actually drilled, namely, the inclination and azimuth. In directional drilling the bit trajectory never coincides exactly with the planned path, which is usually a plane curve with straight, building, holding, and dropping sections in succession. The drilling direction is of course dependant on the direction of the resultant forces acting on the bit and it is quite a tough job to hit the optimum target at the hole bottom as required. The traditional passive methods for correcting the drilling path have not met the demand to improve the techniques of deviation control. A method for combining wellbore surveys to obtain a composite, more accurate well position relies on accepting the position of the well from the most accurate survey instrument used in a given section of the wellbore. The error in each position measurement is the sum of many independent root sources of error effects. The relationship between surveys and other influential factors is considered, along with an analysis of different points of view. The collaborative work describes, establishes a common starting point of wellbore position uncertainty model, definition of what constitutes an error model, mathematics of position uncertainty calculation and an error model for basic directional service.

  10. Groundwater-Quality Impacts from Natural-Gas Wellbore Leakage: Numerical Sensitivity Analysis of Hydrogeologic, Geostatistical, and Source-Term Parameterization at Varying Depths

    Science.gov (United States)

    Rice, A. K.; McCray, J. E.; Singha, K.

    2016-12-01

    The development of directional drilling and stimulation of reservoirs by hydraulic fracturing has transformed the energy landscape in the U.S. by making recovery of hydrocarbons from shale formations not only possible but economically viable. Activities associated with hydraulic fracturing present a set of water-quality challenges, including the potential for impaired groundwater quality. In this project, we use a three-dimensional, multiphase, multicomponent numerical model to investigate hydrogeologic conditions that could lead to groundwater contamination from natural gas wellbore leakage. This work explores the fate of methane that enters a well annulus, possibly from an intermediate formation or from the production zone via a flawed cement seal, and leaves the annulus at one of two depths: at the elevation of groundwater or below a freshwater aquifer. The latter leakage scenario is largely ignored in the current scientific literature, where focus has been on leakage directly into freshwater aquifers, despite modern regulations requiring steel casings and cement sheaths at these depths. We perform a three-stage sensitivity analysis, examining (1) hydrogeologic parameters of media surrounding a methane leakage source zone, (2) geostatistical variations in intrinsic permeability, and (3) methane source zone pressurization. Results indicate that in all cases methane reaches groundwater within the first year of leakage. To our knowledge, this is the first study to consider natural gas wellbore leakage in the context of multiphase flow through heterogeneous permeable media; advantages of multiphase modeling include more realistic analysis of methane vapor-phase relative permeability as compared to single-phase models. These results can be used to inform assessment of aquifer vulnerability to hydrocarbon wellbore leakage at varying depths.

  11. Prediction of natural gas hydrate formation region in wellbore during deep- water gas well testing

    Institute of Scientific and Technical Information of China (English)

    WANG Zhi-yuan; SUN Bao-jiang; WANG Xue-rui; ZHANG Zhen-nan

    2014-01-01

    Wellbore temperature field equations are established with considerations of the enthalpy changes of the natural gas during the deep-water gas well testing. A prediction method for the natural gas hydrate formation region during the deep-water gas well testing is proposed, which combines the wellbore temperature field equations, the phase equilibrium conditions of the natural gas hydrate formation and the calculation methods for the pressure field. Through the sensitivity analysis of the parameters that affect the hydrate formation region, it can be concluded that during the deep-water gas well testing, with the reduction of the gas production rate and the decrease of the geothermal gradient, along with the increase of the depth of water, the hydrate formation region in the wellbore enlarges, the hydrate formation regions differ with different component contents of natural gases, as compared with the pure methane gas, with the increase of ethane and propane, the hydrate formation region expands, the admixture of inhibitors, the type and the concentrations of which can be optimized through the method proposed in the paper, will reduce the hydrate formation region, the throttling effect will lead to the abrupt changes of temperature and pressure, which results in a variation of the hydrate formation region, if the throttling occurs in the shallow part of the wellbore, the temperature will drop too much, which enlarges the hydrate formation region, otherwise, if the throttling occurs in the deep part of the wellbore, the hydrate formation region will be reduced due to the decrease of the pressure.

  12. Determination of Diffusion Profiles in Altered Wellbore Cement Using X-ray Computed Tomography Methods

    Energy Technology Data Exchange (ETDEWEB)

    Mason, Harris E. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Walsh, Stuart D. C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); DuFrane, Wyatt L. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Carroll, Susan A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2014-06-17

    The development of accurate, predictive models for use in determining wellbore integrity requires detailed information about the chemical and mechanical changes occurring in hardened Portland cements. X-ray computed tomography (XRCT) provides a method that can nondestructively probe these changes in three dimensions. Here, we describe a method for extracting subvoxel mineralogical and chemical information from synchrotron XRCT images by combining advanced image segmentation with geochemical models of cement alteration. The method relies on determining “effective linear activity coefficients” (ELAC) for the white light source to generate calibration curves that relate the image grayscales to material composition. The resulting data set supports the modeling of cement alteration by CO2-rich brine with discrete increases in calcium concentration at reaction boundaries. The results of these XRCT analyses can be used to further improve coupled geochemical and mechanical models of cement alteration in the wellbore environment.

  13. U.S. Geological Survey Combined Well-Bore Flow and Depth-Dependent Water Sampler

    Science.gov (United States)

    Izbicki, John A.; Christensen, Allen H.; Hanson, Randall T.; Martin, Peter; Crawford, Steven M.; Smith, Gregory A.

    1999-01-01

    The U.S. Geological Survey has developed a combined well-bore flow and depth-dependent sample collection tool. It is suitable for use in existing production wells having limited access and clearances as small as 1 inch. The combination of well-bore flow and depth-dependent water-quality data is especially effective in assessing changes in aquifer properties and water quality with depth. These are direct measures of changes in well yield and ground-water quality with depth under actual operating conditions. Combinations of other geophysical tools capable of making these measurements, such as vertical-axis current meters used with wire-line samplers, are commercially available but these tools are large and can not easily enter existing production wells.

  14. Wellbore Stability in Oil and Gas Drilling with Chemical-Mechanical Coupling

    Directory of Open Access Journals (Sweden)

    Chuanliang Yan

    2013-01-01

    Full Text Available Wellbore instability in oil and gas drilling is resulted from both mechanical and chemical factors. Hydration is produced in shale formation owing to the influence of the chemical property of drilling fluid. A new experimental method to measure diffusion coefficient of shale hydration is given, and the calculation method of experimental results is introduced. The diffusion coefficient of shale hydration is measured with the downhole temperature and pressure condition, then the penetration migrate law of drilling fluid filtrate around the wellbore is calculated. Furthermore, the changing rules of shale mechanical properties affected by hydration and water absorption are studied through experiments. The relationships between shale mechanical parameters and the water content are established. The wellbore stability model chemical-mechanical coupling is obtained based on the experimental results. Under the action of drilling fluid, hydration makes the shale formation softened and produced the swelling strain after drilling. This will lead to the collapse pressure increases after drilling. The study results provide a reference for studying hydration collapse period of shale.

  15. Coalbed Methane Production System Simulation and Deliverability Forecasting: Coupled Surface Network/Wellbore/Reservoir Calculation

    Directory of Open Access Journals (Sweden)

    Jun Zhou

    2017-01-01

    Full Text Available As an unconventional energy, coalbed methane (CBM mainly exists in coal bed with adsorption, whose productivity is different from conventional gas reservoir. This paper explains the wellbore pressure drop, surface pipeline network simulation, and reservoir calculation model of CBM. A coupled surface/wellbore/reservoir calculation architecture was presented, to coordinate the gas production in each calculation period until the balance of surface/wellbore/reservoir. This coupled calculation method was applied to a CBM field for predicting production. The daily gas production increased year by year at the first time and then decreased gradually after several years, while the daily water production was reduced all the time with the successive decline of the formation pressure. The production of gas and water in each well is almost the same when the structure is a star. When system structure is a dendritic surface system, the daily gas production ranked highest at the well which is the nearest to the surface system collection point and lowest at the well which is the farthest to the surface system collection point. This coupled calculation method could be used to predict the water production, gas production, and formation pressure of a CBM field during a period of time.

  16. Dynamic alterations in wellbore cement integrity due to geochemical reactions in CO2-rich environments

    Science.gov (United States)

    Cao, Peilin; Karpyn, Zuleima T.; Li, Li

    2013-07-01

    The interaction between wellbore cement and CO2 has the potential to alter cement properties and form preferential leakage pathways during geological carbon sequestration. This work investigates changes in wellbore cement integrity during continuous flooding of CO2-saturated brine. We created composite cement-sandstone core samples with a continuous gap in the cement zone in order to represent defects such as fractures and voids in wellbore cement. Volumetric and structural changes in the cement zone were monitored and quantified using X-ray Micro-Computed Tomography imaging. During an 8 day dynamic flow-through period, the fracture/void aperture increased significantly, whereas the host sandstone remained unaltered. The void volume increased at a faster rate in the early stage of the flow-through period than it did toward the end of the period. Compared to the apertures close to the core outlet, those located near the core inlet experienced more severe cement degradation, accompanied by a decrease in specific surface area, constituting evidence of a smoothing effect. Contrary to previous observations of the self-healing behavior of cement fractures, the in situ permeability on a parallel experiment increased by a factor of 8 after 10 days of flooding. Findings from this work will provide valuable insights applicable to the development of predictive models and for risk assessment under conditions relevant to CO2 sequestration.

  17. Quasi-steady model for predicting temperature of aqueous foams circulating in geothermal wellbores

    Energy Technology Data Exchange (ETDEWEB)

    Blackwell, B.F.; Ortega, A.

    1983-01-01

    A quasi-steady model has been developed for predicting the temperature profiles of aqueous foams circulating in geothermal wellbores. The model assumes steady one-dimensional incompressible flow in the wellbore; heat transfer by conduction from the geologic formation to the foam is one-dimensional radially and time-dependent. The vertical temperature distribution in the undisturbed geologic formation is assumed to be composed of two linear segments. For constant values of the convective heat-transfer coefficient, a closed-form analytical solution is obtained. It is demonstrated that the Prandtl number of aqueous foams is large (1000 to 5000); hence, a fully developed temperature profile may not exist for representative drilling applications. Existing convective heat-transfer-coefficient solutions are adapted to aqueous foams. The simplified quasi-steady model is successfully compared with a more-sophisticated finite-difference computer code. Sample temperature-profile calculations are presented for representative values of the primary parameters. For a 5000-ft wellbore with a bottom hole temperature of 375{sup 0}F, the maximum foam temperature can be as high as 300{sup 0}F.

  18. A Simple Data Analysis Method for a Pumping Test with Skin and Wellbore Storage Effects

    Directory of Open Access Journals (Sweden)

    Chia-Shyun Chen and Chuan-Gui Lan

    2009-01-01

    Full Text Available In a pumping test conducted in a con fined aquifer in northern Taiwan, drawdown in the observation well was subject to wellbore storage of its own and the combined effect of wellbore storage and skin of the nearby pumping well. For such a complicated pumping test condition, the appropriate well hydraulics solutions are complicated in mathematics and involve five unknown a priori parameters; namely, the aquifer transmissivity, the aquifer storage coefficient, the skin factor of the pumping well, and the wellbore storage co efficients of the pumping and observation wells. The conventional trial-and-er ror procedure for a simul taneous determination of these five parameters is not easy to apply. Here, a simple data analysis method is de veloped, which takes advantage of the late-time characteristics of drawdown data and the late-time asymptotic behavior of the appropriate wellhy draulics solutions. As a re sult, some currently available graphic techniques are proven us ful for the determination of these parameters. Validity of this approach is verified by the excellent agree ment between the calculated drawdown using the appropriate well hydraulics solutions with the parameter estimates obtained from the field drawdown data.

  19. Reduced-Order Model for Leakage Through an Open Wellbore from the Reservoir due to Carbon Dioxide Injection

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Lehua [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Oldenburg, Curtis M. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2017-07-26

    Potential CO2 leakage through existing open wellbores is one of the most significant hazards that need to be addressed in geologic carbon sequestration (GCS) projects. In the framework of the National Risk Assessment Partnership (NRAP) which requires fast computations for uncertainty analysis, rigorous simulation of the coupled wellbore-reservoir system is not practical. We have developed a 7,200-point look-up table reduced-order model (ROM) for estimating the potential leakage rate up open wellbores in response to CO2 injection nearby. The ROM is based on coupled simulations using T2Well/ECO2H which was run repeatedly for representative conditions relevant to NRAP to create a look-up table response-surface ROM. The ROM applies to a wellbore that fully penetrates a 20-m thick reservoir that is used for CO2 storage. The radially symmetric reservoir is assumed to have initially uniform pressure, temperature, gas saturation, and brine salinity, and it is assumed these conditions are held constant at the far-field boundary (100 m away from the wellbore). In such a system, the leakage can quickly reach quasi-steady state. The ROM table can be used to estimate both the free-phase CO2 and brine leakage rates through an open well as a function of wellbore and reservoir conditions. Results show that injection-induced pressure and reservoir gas saturation play important roles in controlling leakage. Caution must be used in the application of this ROM because well leakage is formally transient and the ROM lookup table was populated using quasi-steady simulation output after 1000 time steps which may correspond to different physical times for the various parameter combinations of the coupled wellbore-reservoir system.

  20. Mechanical Behavior and Permeability Evolution of Reconstituted Coal Samples under Various Unloading Confining Pressures—Implications for Wellbore Stability Analysis

    Directory of Open Access Journals (Sweden)

    Qiangui Zhang

    2017-03-01

    Full Text Available Low pressure, low permeability, and low saturation of Chinese coal-bed methane (CBM reservoirs make underbalanced drilling (UBD widely used for mining CBM in China. In this study, mechanical behavior and permeability of coal rock were investigated under different degrees of unloading confining pressure (UCP-reloading axial stress (RAS by a triaxial experimental apparatus. These tests revealed that: (1 peak deviatoric stress of coal rock in UCP-RAS is lower than that in a conventional triaxial compression (CTC test, and the peak deviatoric stress linearly relates the degree of unloading confining pressure. The deformation modulus of coal in UCP-RAS is lower than that in CTC, while the lateral expansion ratio is larger than that in CTC; (2 higher UCP leads to a faster increase of permeability during RAS until the failure of coal; (3 the cohesion and internal friction angle tested by UCP-RAS are lower by 4.57% and 15.18% than those tested by CTC. In addition, a field case (Zhaozhuang well, Qinshui Basin, China of a well collapse problem validates the higher probability of wellbore collapse due to the increase of equivalent collapse fluid density, which is calculated by using coal rock parameters tested by UCP-RAS rather than by CTC.

  1. Chemical and Physical Reactions of Wellbore Cement under CO2 Storage Conditions: Effects of Cement Additives

    Science.gov (United States)

    Kutchko, B. G.; Strazisar, B. R.; Huerta, N.; Lowry, G. V.; Dzombak, D. A.; Thaulow, N.

    2008-12-01

    Sequestration of CO2 into geologic formations requires long-term storage and low leakage rates to be effective. Active and abandoned wells in candidate storage formations must be evaluated as potential leakage points. Wellbore integrity is an important part of an overall integrated assessment program being developed at NETL to assess potential risks at CO2 storage sites. Such a program is needed for ongoing policy and regulatory decisions for geologic carbon sequestration. The permeability and integrity of the cement in the well is a primary factor affecting its ability to prevent leakage. Cement must be able to maintain low permeability over lengthy exposure to reservoir conditions in a CO2 injection and storage scenario. Although it is known that cement may be altered by exposure to CO2, the results of ongoing research indicate that cement curing conditions, fluid properties, and cement additives play a significant role in the rate of alteration and reaction. The objective of this study is to improve understanding of the factors affecting wellbore cement integrity for large-scale geologic carbon sequestration projects. Due to the high frequency use of additives (pozzolan) in wellbore cement, it is also essential to understand the reaction of these cement-pozzolan systems upon exposure to CO2 under sequestration conditions (15.5 MPa and 50°C). Laboratory experiments were performed to determine the physical and chemical changes, as well as the rate of alteration of commonly used pozzolan-cement systems under simulated sequestration reservoir conditions, including both supercritical CO2 and CO2-saturated brine. The rate of alteration of the cement-pozzolan systems is considerably faster than with neat cement. However, the alteration of physical properties is much less significant with the pozzolanic blends. Permeability of a carbonated pozzolanic cement paste remains sufficiently small to block significant vertical migration of CO2 in a wellbore. All of the

  2. Final Scientific/Technical Report for "Nanite" for Better Well-Bore Integrity and Zonal Isolation

    Energy Technology Data Exchange (ETDEWEB)

    Veedu, Vinod [Oceanit Laboratories, Inc., Honolulu, HI (United States); Hadmack, Michael [Oceanit Laboratories, Inc., Honolulu, HI (United States); Pollock, Jacob [Oceanit Laboratories, Inc., Honolulu, HI (United States); Pernambuco-Wise, Paul [Oceanit Laboratories, Inc., Honolulu, HI (United States); Ah Yo, Derek [Oceanit Laboratories, Inc., Honolulu, HI (United States)

    2017-05-30

    Nanite™ is a cementitious material that contains a proprietary formulation of functionalized nanomaterial additive to transform conventional cement into a smart material responsive to pressure (or stress), temperature, and any intrinsic changes in composition. This project has identified optimal sensing modalities of smart well cement and demonstrated how real-time sensing of Nanite™ can improve long-term wellbore integrity and zonal isolation in shale gas and applicable oil and gas operations. Oceanit has explored Nanite’s electrical sensing properties in depth and has advanced the technology from laboratory proof-of-concept to sub-scale testing in preparation for field trials.

  3. A multibody dynamics model of contact between the drillstring and the wellbore and the rock penetration process

    Directory of Open Access Journals (Sweden)

    Ningyu Wang

    2015-05-01

    Full Text Available This article models the contact between the drillstring with large slenderness ratio and the extending rigid wellbore based on the multibody dynamics method. The drillstring is modeled as absolute nodal coordinate formulation beams with contact detection points. An algorithm is developed to locate the contact points and calculate the contact forces when the drillstring is sliding and rotating in the wellbore. This provides support force and friction for the moving drillstring and effectively confines it inside the wellbore. A rock penetration model is established based on the rock-breaking velocity equation. The governing equation for the full-hole drilling system including the drillstring and the contact model is established and solved. A rock penetration correction method is proposed to stabilize the computation and to model and simulate the slide drilling process. A field drilling process is modeled and simulated. The simulation result fits the experimental result well.

  4. Explaining Spatial Variability in Wellbore Impairment Risk for Pennsylvania Oil and Gas Wells, 2000-2014

    Science.gov (United States)

    Santoro, R.; Ingraffea, A. R.

    2015-12-01

    Previous modeling (ingraffea et al. PNAS, 2014) indicated roughly two-times higher cumulative risk for wellbore impairment in unconventional wells, relative to conventional wells, and large spatial variation in risk for oil and gas wells drilled in the state of Pennsylvania. Impairment risk for wells in the northeast portion of the state were found to be 8.5-times greater than that of wells drilled in the rest of the state. Here, we set out to explain this apparent regional variability through Boosted Regression Tree (BRT) analysis of geographic, developmental, and general well attributes. We find that regional variability is largely driven by the nature of the development, i.e. whether conventional or unconventional development is dominant. Oil and natural gas market prices and total well depths present as major influences in wellbore impairment, with moderate influences from well densities and geologic factors. The figure depicts influence paths for predictors of impairments for the state (top left), SW region (top right), unconventional/NE region (bottom left) and conventional/NW region (bottom right) models. Influences are scaled to reflect percent contributions in explaining variability in the model.

  5. Incorporating electrokinetic effects in the porochemoelastic inclined wellbore formulation and solution.

    Science.gov (United States)

    Nguyen, Vinh X; Abousleiman, Youname N

    2010-03-01

    The porochemoelectroelastic analytical models and solutions have been used to describe the response of chemically active and electrically charged saturated porous media such as clays, shales, and biological tissues. However, these attempts have been restricted to one-dimensional consolidation problems, which are very limited in practice and not general enough to serve as benchmark solutions for numerical validation. This work summarizes the general linear porochemoelectroelastic formulation and presents the solution of an inclined wellbore drilled in a fluid-saturated chemically active and ionized formation, such as shale, and subjected to a three-dimensional in-situ state of stress. The analytical solution to this geometry incorporates the coupled solid deformation and simultaneous fluid/ion flows induced by the combined influences of pore pressure, chemical potential, and electrical potential gradients under isothermal conditions. The formation pore fluid is modeled as an electrolyte solution comprised of a solvent and one type of dissolved cation and anion. The analytical approach also integrates into the solution the quantitative use of the cation exchange capacity (CEC) commonly obtained from laboratory measurements on shale samples. The results for stresses and pore pressure distributions due to the coupled electrochemical effects are illustrated and plotted in the vicinity of the inclined wellbore and compared with the classical porochemoelastic and poroelastic solutions.

  6. ANALYSIS OF EFFECT FACTOR IN SHALE WELLBORE STABILITY%泥页岩井壁稳定影响因素分析

    Institute of Scientific and Technical Information of China (English)

    王倩; 周英操; 唐玉林; 姜智博

    2012-01-01

    考虑泥页岩钻井液体系中电化势渗透产生的流体流动和离子运移以及与固体变形的联合作用,提出泥页岩井壁稳定耦合新模型.通过有限元计算泥页岩井壁周围孔隙压力场和应力场,分析泥页岩及钻井液性能参数对井壁周围地层坍塌破坏系数和坍塌压力的影响.研究结果表明,泥页岩渗透率增大,溶质扩散系数增大,泥页岩单位表面电荷数减小有利于泥页岩井壁稳定.通过使用高浓度、高反射系数的钻井液能够提高泥页岩井壁的稳定性,对于泥页岩地层使用过高的钻井液密度反而会导致井壁不稳定.泥页岩钻井液体系膨胀系数减小,泥页岩水化程度能够减轻.在钻井液浓度大于泥页岩孔隙流体浓度的情况下化学反渗透可能使泥页岩失水,与大尺寸井眼相比,小尺寸井眼坍塌破坏指数随时间变化较显著.%A new shale wellbore stability model considering fluid flow and ion transmission induced by shale-drilling fluid system electrochemical potential osmosis, and solid deformation resulted by solute diffusion, ion transmission and hydrate expansion is proposed. Pore pressure and stress field around the wellbore wall is computed by finite element method, and the effect of shale and drilling fluid parameters on collapse index and caving pressure is analyzed. The research results demonstrate that large shale permeability, large solute diffusion coefficient and small shale per unit surface charge are favour of shale stability. Drilling fluid with high concentration and reflection coefficient is beneficial for shale stability. High mud weight can sometimes result in instability for shale formation. While the swelling coefficient of shale-drilling fluid system decreases, the shale hydration can be alleviated. Especially for the case that the drilling fluid concentration is larger than the shale pore fluid, the chemical reverse osmosis may cause shale dehydration. The collapse index

  7. Adaptive forward-inverse modeling of reservoir fluids away from wellbores

    Energy Technology Data Exchange (ETDEWEB)

    Ziagos, J P; Gelinas, R J; Doss, S K; Nelson, R G

    1999-07-30

    This Final Report contains the deliverables of the DeepLook Phase I project entitled, ''Adaptive Forward-Inverse Modeling of Reservoir Fluids Away from Wellbores''. The deliverables are: (i) a description of 2-D test problem results, analyses, and technical descriptions of the techniques used, (ii) a listing of program setup commands that construct and execute the codes for selected test problems (these commands are in mathematical terminology, which reinforces technical descriptions in the text), and (iii) an evaluation and recommendation regarding continuance of this project, including considerations of possible extensions to 3-D codes, additional technical scope, and budget for the out-years. The far-market objective in this project is to develop advanced technologies that can help locate and enhance the recovery of oil from heterogeneous rock formations. The specific technical objective in Phase I was to develop proof-of-concept of new forward and inverse (F-I) modeling techniques [Gelinas et al, 1998] that seek to enhance estimates (images) of formation permeability distributions and fluid motion away from wellbore volumes. This goes to the heart of improving industry's ability to jointly image reservoir permeability and flow predictions of trapped and recovered oil versus time. The estimation of formation permeability away from borehole measurements is an ''inverse'' problem. It is an inseparable part of modeling fluid flows throughout the reservoir in efforts to increase the efficiency of oil recovery at minimum cost. Classic issues of non-uniqueness, mathematical instability, noise effects, and inadequate numerical solution techniques have historically impeded progress in reservoir parameter estimations. Because information pertaining to fluid and rock properties is always sampled sparsely by wellbore measurements, a successful method for interpolating permeability and fluid data between the measurements must be

  8. Monetizing Leakage Risk of Geologic CO2 Storage using Wellbore Permeability Frequency Distributions

    Science.gov (United States)

    Bielicki, Jeffrey; Fitts, Jeffrey; Peters, Catherine; Wilson, Elizabeth

    2013-04-01

    Carbon dioxide (CO2) may be captured from large point sources (e.g., coal-fired power plants, oil refineries, cement manufacturers) and injected into deep sedimentary basins for storage, or sequestration, from the atmosphere. This technology—CO2 Capture and Storage (CCS)—may be a significant component of the portfolio of technologies deployed to mitigate climate change. But injected CO2, or the brine it displaces, may leak from the storage reservoir through a variety of natural and manmade pathways, including existing wells and wellbores. Such leakage will incur costs to a variety of stakeholders, which may affect the desirability of potential CO2 injection locations as well as the feasibility of the CCS approach writ large. Consequently, analyzing and monetizing leakage risk is necessary to develop CCS as a viable technological option to mitigate climate change. Risk is the product of the probability of an outcome and the impact of that outcome. Assessment of leakage risk from geologic CO2 storage reservoirs requires an analysis of the probabilities and magnitudes of leakage, identification of the outcomes that may result from leakage, and an assessment of the expected economic costs of those outcomes. One critical uncertainty regarding the rate and magnitude of leakage is determined by the leakiness of the well leakage pathway. This leakiness is characterized by a leakage permeability for the pathway, and recent work has sought to determine frequency distributions for the leakage permeabilities of wells and wellbores. We conduct a probabilistic analysis of leakage and monetized leakage risk for CO2 injection locations in the Michigan Sedimentary Basin (USA) using empirically derived frequency distributions for wellbore leakage permeabilities. To conduct this probabilistic risk analysis, we apply the RISCS (Risk Interference of Subsurface CO2 Storage) model (Bielicki et al, 2013a, 2012b) to injection into the Mt. Simon Sandstone. RISCS monetizes leakage risk

  9. Permeability Changes on Wellbore Cement Fractures Modified by Geochemical and Geomechanical Processes

    Science.gov (United States)

    Rod, K. A.; Um, W.

    2015-12-01

    Experimental studies were conducted using batch reactors, X-ray microtomography (XMT), and computational fluid dynamics (CFD) modeling to determine changes in cement fracture surfaces, fluid flow pathways and permeability, and cement fracture propagation with geochemical and geomechanical processes. Portland cement-basalt interface sample with artificial fractures was prepared to study the geochemical and geomechanical effects on the integrity of wellbores containing defects caused by subsurface activities. Cement-basalt interface sample was subjected to mechanical stress at 2.7 MPa before the chemical reaction. CFD modeling was performed to simulate flow of supercritical CO2 within the fractures before and after the application of mechanical stress. The model results highlighted the complex flow characteristics within the fracture and also changes in flow patterns due to application of geomechanical stress. The CFD model predicted ~45% increase in permeability after the application of geomechanical force, which increases the fracture aperture. The same sample was reacted with CO2-saturated groundwater with impurity H2S (1 wt.%) at 50°C and 10 MPa for 3 to 3.5 months under static conditions. XMT provided three-dimensional (3-D) visualization of the opening and interconnection of cement fractures due to mechanical stress. Even after a 3.5-month reaction with CO2-H2S-saturated groundwater at 50°C and 10 MPa, CaCO3 (s) precipitation occurred more extensively within the cement fracture rather than along the cement-basalt interfaces. Micro X-ray diffraction analysis also showed that major cement carbonation products of CO2-saturated groundwater reacting with impurity H2S were calcite, aragonite, and vaterite, consistent with cement carbonation by pure CO2-saturated groundwater, while pyrite was not identified due to low H2S content. The experimental results imply that the wellbore cement with fractures is likely to be healed during exposure to CO2-saturated

  10. Open hole packer for high pressure service in a five hundred degree fahrenheit precambrian wellbore

    Energy Technology Data Exchange (ETDEWEB)

    Dreesen, D.S.; Miller, J.R.; Halbardier, F.A.; Nicholson, R.W.

    1985-01-01

    Massive hydraulic fracturing (MHF) from a lower wellbore (EE-2) created a large man-made reservoir which did not intersect the upper well (EE-3). To create a heat extraction flow loop, the upper well was sidetracked and redrilled (EE-3A) down into a microseismic cloud around EE-2 mapped during the MHF. The potential to intersect numerous fracture zones in the redrilled bore was apparent from seismicity. To economically and effectively isolate and test these microseismic zones required that a functional open hole packer be developed. The packer would be exposed to soak temperatures as high as 500/sup 0/F (260/sup 0/C) with cool down to 100/sup 0/F (40/sup 0/C) at differential pressures exceeding 5000 psi (35 Mpa). A functional packer has been designed, manufactured, and successfully used for the creation of a hot dry rock (HDR) reservoir. 5 figs., 1 tab.

  11. Development of a thermal resistance model to evaluate wellbore heat exchange efficiency

    Directory of Open Access Journals (Sweden)

    Albert A. Koenig, Martin F. Helmke

    2014-01-01

    Full Text Available A new model is proposed to simulate conduction of heat between a pipe loop in a geoexchange system and the ground. The approach employs the thermal resistor technique coupled with a conduction shape factor modified by an occultation factor. The model is compared to available data and demonstrates suitable agreement with previous studies. The model facilitates a parametric study of borehole resistance as a function of geometry and thermal conductivity of the components. By spacing the legs of the loop against the borehole and increasing the pipe size, the study shows that one can maximize the wellbore heat transfer using a moderate (1.2 W/mK thermal conductivity grout. This study further demonstrates that improved well construction techniques could increase the efficiency of most closed-loop geothermal systems by 10 percent.

  12. A systematic approach for wellbore drilling and placement of SAGD well pairs and infill wells

    Energy Technology Data Exchange (ETDEWEB)

    Illfelder, H.; Forbes, E.; McElhinney, G.; Rennie, A. [PathFinder, A Schlumberger Company (Canada); Schaepsmeyer, H.; Krawchuk, A. [Cenovus Energy Incorporated (Canada)

    2011-07-01

    In Alberta, Canada, steam assisted gravity drainage (SAGD) is used to enhance oil recovery in heavy oil reservoirs. This process requires the drilling of producer and injector wells which is usually done using standard techniques. These techniques lead to sub-optimal well-placement and thus this paper aims to define a systematic approach for the drilling process. Several methods to improve the drilling process are demonstrated including careful control of the directional drilling process, borehole tortuosity minimization and producer and injector wellbore placement. The paper also presents the real-time analysis of the drilling and advanced ranging (RADAR) system, a service brand and platform developed for implementing the improved methods while drilling is in progress. This paper develops a systematic approach to placing SAGD wells in an improved manner and presents the RADAR system which allows the application of these methods.

  13. Third-order elastic solution of the stress field around a wellbore

    Energy Technology Data Exchange (ETDEWEB)

    Elata, D.

    1996-04-01

    Within a certain range of strain, consolidated granular materials may be characterized as nonlinear elastic solids. The nonlinearity can be easily observed by examining the effect of stress on the acoustical properties of the material. Ignoring damage evolution and failure that occur in higher strains and the hysteretic behavior due to intercyranular friction, the material can be modeled as a nonlinear hyperelastic solid. A simple example of such a model is formulating the strain energy as a third-order polynomial of the strain invariants. This model is limited in the sense that the material is assumed to be isotropic with respect to the stress free state, and that the mechanical response of the material is described by only five material constants. Nevertheless, this model is appealing because it naturally exhibits stress dependent stiffness and stress induced anisotropy, and it allows a different mechanical response to positive and negative volume changes. In this work, this model is used to calculate the stress field around a wellbore. Many well logging tools use acoustics (e.g., tube, surface, torsion, and flexural waves) to detect pore fluids and ore in the surrounding granular rock. By modeling the rock as an isotropic third-order elastic material the effects of the inhomogeneous stiffness and the stress induced anisotropy may be examined. Analysis of the tangential stress around a wellbore in an isotropic third-order elastic (TOE) material yields different results than the same analysis in the related isotropic linear elastic (LE) material (i.e., both materials have the same stiffness tensor at the stress free state). This difference modifies the far-field stress that is interpreted of from hydraulic fracturing data. The analysis in the present work is static and pore fluid effects are ignored.

  14. A cleaner cut : oilfield service firm claims its rotary steerable cuts a cleaner wellbore at a faster clip than competitors

    Energy Technology Data Exchange (ETDEWEB)

    Mahony, J.

    2010-03-15

    Rotary steerable tools that use push-the-bit technology have a higher tendency to cut scored spiral wellbores than point-and-hit tools. This article described the Revolution rotary-steerable system (RSS) that was marketed in Canada by Houston-based Weatherford. The article outlined the benefits of the RSS including how it provides speed and a smoother wellbore to long-reach directional wells as well as an overall lower cost. Revolution RSS has drilled almost two million feet of wells worldwide and over one million feet onshore North America, primarily in the United States. Users of the Revolution RSS also claim that another advantage is its high rate-of-penetration. The Revolution RSS is available in 4 different bottomhole assembly sizes, ranging from 4 and three quarter inches to 6 and three quarter inches to the widest at 8 and three quarter inches. 1 ref., 1 fig.

  15. Thermal effects on fluid flow and hydraulic fracturing from wellbores and cavities in low-permeability formations

    Energy Technology Data Exchange (ETDEWEB)

    Yarlong Wang [Petro-Geotech Inc., Calgary, AB (Canada); Papamichos, Euripides [IKU Petroleum Research, Trondheim (Norway)

    1999-07-01

    The coupled heat-fluid-stress problem of circular wellbore or spherical cavity subjected to a constant temperature change and a constant fluid flow rate is considered. Transient analytical solutions for temperature, pore pressure and stress are developed by coupling conductive heat transfer with Darcy fluid flow in a poroelastic medium. They are applicable to lower permeability porous media suitable for liquid-waste disposal and also simulating reservoir for enhanced oil recovery, where conduction dominates the heat transfer process. A full range of solutions is presented showing separately the effects of temperature and fluid flow on pore pressure and stress development. It is shown that injection of warm fluid can be used to restrict fracture development around wellbores and cavities and generally to optimise a fluid injection operation. Both the limitations of the solutions and the convective flow effect are addressed. (Author)

  16. Comprehensive database of wellbore temperatures and drilling mud weight pressures by depth for Judge Digby field, Louisiana

    Science.gov (United States)

    Burke, Lauri

    2010-01-01

    This document serves as the repository for the unprocessed data used in the investigation of temperature and overpressure relations within the deep Tuscaloosa Formation in Judge Digby field. It is a compilation of all the publicly accessible wellbore temperature and pressure data for Judge Digby field, a prolific natural gas field producing from the Upper Cretaceous lower part of the Tuscaloosa Formation in the Gulf Coast region. This natural gas field is in Pointe Coupee Parish in the southern part of onshore Louisiana.

  17. Relative permeability of fractured wellbore cement: an experimental investigation using electrical resistivity monitoring for moisture content

    Science.gov (United States)

    Um, W.; Rod, K. A.; Strickland, C. E.

    2016-12-01

    Permeability is a critical parameter needed to understand flow in subsurface environments; it is particularly important in deep subsurface reservoirs where multiphase fluid flow is common, such as carbon sequestration and geothermal reservoirs. Cement is used in the annulus of wellbores due to its low permeable properties to seal aquifers, reducing leaks to adjacent strata. Extreme subsurface environments of CO2 storage and geothermal production conditions will eventually reduce the cement integrity, propagating fracture networks and increasing the permeability for air and/or water. To date, there have been no reproducible experimental investigations of relative permeability in fractured wellbore cement published. To address this gap, we conducted a series of experiments using fractured Portland cement monoliths with increasing fracture networks. The monolith cylinder sides were jacketed with heavy-duty moisture-seal heat-shrink tubing, then fractured using shear force applied via a hydraulic press. Fractures were generated with different severity for each of three monoliths. Stainless steel endcaps were fixed to the monoliths using the same shrink-wrapped jacket. Fracture characteristics were determined using X-ray microtomography and image analysis. Flow controllers were used to control flow of water and air to supply continuous water or water plus air, both of which were delivered through the influent end cap. Effluent air flow was monitored using a flow meter, and water flow was measured gravimetrically. To monitor the effective saturation of the fractures, a RCON2 concrete bulk electrical resistivity test device was attached across both endcaps and a 0.1M NaNO3 brine was used as the transport fluid to improve resistivity measurements. Water content correlated to resistivity measurements with a r2 > 0.96. Data from the experiments was evaluated using two relative permeability models, the Corey-curve, often used for modeling relative permeability in porous media

  18. A comprehensive mathematical model for estimating oil drainage rate in SAGD process considering wellbore/formation coupling effect

    Science.gov (United States)

    Cheng, Linsong; Gu, Hao; Huang, Shijun

    2016-11-01

    The aim of this work is to present a comprehensive mathematical model for estimating oil drainage rate in Steam-assisted gravity drainage (SAGD) process, more importantly, wellbore/formation coupling effect is considered. Firstly, mass and heat transfer in vertical and horizontal wellbores are described briefly. Then, a function of steam chamber height is introduced and the expressions for oil drainage rate in rising and expanding steam chamber stages are derived in detail. Next, a calculation flowchart is provided and an example is given to introduce how to use the proposed method. Finally, after the mathematical model is validated, the effects of wellhead steam injection rate on simulated results are further analyzed. The results indicate that heat injection power per meter reduces gradually along the horizontal wellbore, which affects both steam chamber height and oil drainage rate in the SAGD process. In addition, when production time is the same, the calculated oil drainage rate from the new method is lower than that from Butler's method. Moreover, the paper shows that when wellhead steam injection rate is low enough, the steam chamber is not formed at the horizontal well's toe position and enhancing the wellhead steam injection rate can increase the oil drainage rate.

  19. The Development of a Gas-Liquid Two-Phase Flow Sensor Applicable to CBM Wellbore Annulus.

    Science.gov (United States)

    Wu, Chuan; Wen, Guojun; Han, Lei; Wu, Xiaoming

    2016-11-18

    The measurement of wellbore annulus gas-liquid two-phase flow in CBM (coalbed methane) wells is of great significance for reasonably developing gas drainage and extraction processes, estimating CBM output, judging the operating conditions of CBM wells and analyzing stratum conditions. Hence, a specially designed sensor is urgently needed for real-time measurement of gas-liquid two-phase flow in CBM wellbore annulus. Existing flow sensors fail to meet the requirements of the operating conditions of CBM wellbore annulus due to such factors as an inapplicable measurement principle, larger size, poor sealability, high installation accuracy, and higher requirements for fluid media. Therefore, based on the principle of a target flowmeter, this paper designs a new two-phase flow sensor that can identify and automatically calibrate different flow patterns of two-phase flows. Upon the successful development of the new flow sensor, lab and field tests were carried out, and the results show that the newly designed sensor, with a measurement accuracy of ±2.5%, can adapt to the operating conditions of CBM wells and is reliable for long-term work.

  20. Application of Neutron imaging in pore structure of hydrated wellbore cement: comparison of hydration of H20 with D2O based Portland cements

    Science.gov (United States)

    Dussenova, D.; Bilheux, H.; Radonjic, M.

    2012-12-01

    Wellbore Cement studies have been ongoing for decades. The studies vary from efforts to reduce permeability and resistance to corrosive environment to issues with gas migration also known as Sustained Casing Pressure (SCP). These practical issues often lead to health and safety problems as well as huge economic loss in oil and gas industry. Several techniques have been employed to reduce the impact of gas leakage. In this study we purely focus on expandable liners, which are introduced as part of oil well reconstruction and work-overs and as well abandonment procedures that help in prevention of SCP. Expandable liner is a tube that after application of a certain tool can increase its diameter. The increase in diameter creates extra force on hydrated cement that results in reducing width of interface fractures and cement-tube de-bonding. Moreover, this also causes cement to change its microstructure and other porous medium properties, primarily hydraulic conductivity. In order to examine changes before and after operations, cement pore structure must be well characterized and correlated to cement slurry design as well as chemical and physical environmental conditions. As modern oil well pipes and tubes contain iron, it is difficult to perform X-ray tomography of a bulk measurement of the cement in its wellbore conditions, which are tube wall-cement-tube wall. Neutron imaging is a complementary technique to x-ray imaging and is well suited for detection of light elements imbedded in metallic containers. Thus, Neutron Imaging (NI) is investigated as a tool for the detection of pore structure of hydrated wellbore cement. Recent measurements were conducted at the Oak Ridge National Laboratory (ORNL) High Flux Isotope Reactor (HFIR) neutron imaging facility. NI is is highly sensitive to light elements such as Hydrogen (H). Oil well cements that have undergone a full hydration contain on average 30%-40% of free water in its pore structure. The unreacted water is the main

  1. Implementation of Bounding Surface Model into ABAQUS and Its Application to Wellbore Stability Analysis

    Science.gov (United States)

    Chen, S.; Al-Muntasheri, G.; Abousleiman, Y. N.

    2014-12-01

    The critical state concept based bounding surface model is one of the most widely used elastoplastic constitutive models for geomaterials, attributed mainly to its essential feature of allowing plastic deformation to occur for stress points within the bounding surface and thus the capability to represent the realistic non-recoverable behaviour of soils and rocks observed under the cyclic loading. This paper develops an implicit integration algorithm for the bounding surface model, using the standard return mapping approach (elastic predictor-plastic corrector), to obtain the updated stresses for the given strain increments. The formulation of the constitutive integration requires the derivation of a supplementary differential equation to describe the evolution of a key variable, i.e., the ratio between the image stress and the current stress quantities. It is essentially an extension of the integration scheme presented in an earlier work used for the simple bounding surface version of modified Cam Clay associated with a substantially simplified hardening rule. The integration algorithm for the bounding surface model is implemented into the finite element analysis commercial program, ABAQUS, through the material interface of UMAT (user defined material subroutine), and then used for the analysis of wellbore stability problem. The predictions from the ABAQUS simulations are generally in excellent agreement with the available analytical solutions, thus demonstrating the accuracy and robustness of the proposed integration scheme.

  2. Calculations of Gas-liquid Equilibrium in Wellbore with High Carbon dioxide Flow

    Science.gov (United States)

    Zhang, Jiaming; Wu, Xiaodong; Wang, Bo; Liu, Kai; Gao, Yue

    2014-05-01

    Carbon dioxide injection not only enhances the oil recovery dramatically, but also it will reduce the greenhouse effect, therefore, Carbon dioxide injection technique is applied extensively. During the process of carbon dioxide displacement, when carbon dioxide breaks though into oil production wells, carbon dioxide content will impacts the phase state and physical properties of the mixed liquor in the wellbore, as a result, it will affect the calculation of temperature and pressure in oil production wells. Applying the conventional black-oil model to calculate the phase state of the miscible fluids is unacceptable. To tackle the problem, this paper uses the gas-liquid flash theory and component model to program software, so that the phase state (gas, liquid or gas-liquid) and physical properties of the mixed liquor (including hydrogen sulfide, carbon dioxide and hydrocarbon) under initial conditions is calculated, moreover, the impact of carbon dioxide content on the physical properties(mainly including density, viscosity, specific heat at const pressure, surface tension, etc) of mixed liquor in oil production wells is analyzed in this paper. The comparison of the results shows that this model can meet the engineering needs with high accuracy.

  3. Rapid computation of directional wellbore drawdown in a confined aquifer via Poisson resummation

    Science.gov (United States)

    Blumenthal, Benjamin J.; Zhan, Hongbin

    2016-08-01

    We have derived a rapidly computed analytical solution for drawdown caused by a partially or fully penetrating directional wellbore (vertical, horizontal, or slant) via Green's function method. The mathematical model assumes an anisotropic, homogeneous, confined, box-shaped aquifer. Any dimension of the box can have one of six possible boundary conditions: 1) both sides no-flux; 2) one side no-flux - one side constant-head; 3) both sides constant-head; 4) one side no-flux; 5) one side constant-head; 6) free boundary conditions. The solution has been optimized for rapid computation via Poisson Resummation, derivation of convergence rates, and numerical optimization of integration techniques. Upon application of the Poisson Resummation method, we were able to derive two sets of solutions with inverse convergence rates, namely an early-time rapidly convergent series (solution-A) and a late-time rapidly convergent series (solution-B). From this work we were able to link Green's function method (solution-B) back to image well theory (solution-A). We then derived an equation defining when the convergence rate between solution-A and solution-B is the same, which we termed the switch time. Utilizing the more rapidly convergent solution at the appropriate time, we obtained rapid convergence at all times. We have also shown that one may simplify each of the three infinite series for the three-dimensional solution to 11 terms and still maintain a maximum relative error of less than 10-14.

  4. Hydrocarbons Emissions Due to Wellbore and other Subsurface Leakage in the Uintah Basin, Utah

    Science.gov (United States)

    Watkins, C.; Lyman, S. N.

    2015-12-01

    The explosive growth of oil and gas production in the United States has focused public and regulatory attention on environmental impacts of hydrocarbon extraction, including air quality and climate impacts. One potentially important emissions source is subsurface leakage of natural gas. Better understanding of wellbore and other subsurface leaks are important in providing ways to decrease pollution while increasing the efficiency of oil and gas production. Soil gas measurements carried out by USGS over the last several years in Utah's oil and gas fields have shown that, while concentrations of methane in soils near wells are typically low, soil gas near some wells can contain more than 50% methane. In the summers of 2013-2015 we carried out campaigns to measure the emission rate of methane and other hydrocarbons from soils near wells in the Uintah Basin, Utah. We also measured emissions at several locations on individual well pads and determined that concentrations of hydrocarbons tend to decrease with distance from the well head. Soil emissions were also measured at non-well sites in the same area to determine background emission rates. Emissions from exposed coal, oil shale, gilsonite, and fault zone surfaces were also measured. Relationships of emissions with soil gas concentrations, meteorological conditions, and soil properties were also investigated.

  5. Modeling the key factors that could influence the diffusion of CO2 from a wellbore blowout in the Ordos Basin, China.

    Science.gov (United States)

    Li, Qi; Shi, Hui; Yang, Duoxing; Wei, Xiaochen

    2016-11-26

    Carbon dioxide (CO2) blowout from a wellbore is regarded as a potential environment risk of a CO2 capture and storage (CCS) project. In this paper, an assumed blowout of a wellbore was examined for China's Shenhua CCS demonstration project. The significant factors that influenced the diffusion of CO2 were identified by using a response surface method with the Box-Behnken experiment design. The numerical simulations showed that the mass emission rate of CO2 from the source and the ambient wind speed have significant influence on the area of interest (the area of high CO2 concentration above 30,000 ppm). There is a strong positive correlation between the mass emission rate and the area of interest, but there is a strong negative correlation between the ambient wind speed and the area of interest. Several other variables have very little influence on the area of interest, e.g., the temperature of CO2, ambient temperature, relative humidity, and stability class values. Due to the weather conditions at the Shenhua CCS demonstration site at the time of the modeled CO2 blowout, the largest diffusion distance of CO2 in the downwind direction did not exceed 200 m along the centerline. When the ambient wind speed is in the range of 0.1-2.0 m/s and the mass emission rate is in the range of 60-120 kg/s, the range of the diffusion of CO2 is at the most dangerous level (i.e., almost all Grade Four marks in the risk matrix). Therefore, if the injection of CO2 takes place in a region that has relatively low perennial wind speed, special attention should be paid to the formulation of pre-planned, emergency measures in case there is a leakage accident. The proposed risk matrix that classifies and grades blowout risks can be used as a reference for the development of appropriate regulations. This work may offer some indicators in developing risk profiles and emergency responses for CO2 blowouts.

  6. Incorporating electrokinetic effects in the porochemoelastic inclined wellbore formulation and solution

    Directory of Open Access Journals (Sweden)

    Vinh X. Nguyen

    2010-03-01

    Full Text Available The porochemoelectroelastic analytical models and solutions have been used to describe the response of chemically active and electrically charged saturated porous media such as clays, shales, and biological tissues. However, these attempts have been restricted to one-dimensional consolidation problems, which are very limited in practice and not general enough to serve as benchmark solutions for numerical validation. This work summarizes the general linear porochemoelectroelastic formulation and presents the solution of an inclined wellbore drilled in a fluid-saturated chemically active and ionized formation, such as shale, and subjected to a three-dimensional in-situ state of stress. The analytical solution to this geometry incorporates the coupled solid deformation and simultaneous fluid/ion flows induced by the combined influences of pore pressure, chemical potential, and electrical potential gradients under isothermal conditions. The formation pore fluid is modeled as an electrolyte solution comprised of a solvent and one type of dissolved cation and anion. The analytical approach also integrates into the solution the quantitative use of the cation exchange capacity (CEC commonly obtained from laboratory measurements on shale samples. The results for stresses and pore pressure distributions due to the coupled electrochemical effects are illustrated and plotted in the vicinity of the inclined wellbore and compared with the classical porochemoelastic and poroelastic solutions.Modelos analíticos poroelásticos incluindo acoplamento químico e elétrico e soluções têm sido utilizados paradescrever a resposta de meios porosos saturados ativos química e eletricamente tais como argilas, folhelhos e tecidos biológicos. Entretanto tais tentativas têm sido restritas a problemas de consolidação unidimensional os quais exibem limitações na prática não constituindo exemplos realistas para validação de soluções numéricas. Este trabalho

  7. Numerical simulation in steam injection wellbores by mechanistic approach; Simulacao numerica do escoamento de vapor em pocos por uma abordagem mecanicista

    Energy Technology Data Exchange (ETDEWEB)

    Souza Junior, J.C. de; Campos, W.; Lopes, D.; Moura, L.S.S. [PETROBRAS, Rio de Janeiro, RJ (Brazil); Thomas, A. Clecio F. [Universidade Estadual do Ceara (UECE), CE (Brazil)

    2008-07-01

    This work addresses to the development of a hydrodynamic and heat transfer mechanistic model for steam flow in injection wellbores. The problem of two-phase steam flow in wellbores has been solved recently by using available empirical correlations from petroleum industry (Lopes, 1986) and nuclear industry (Moura, 1991).The good performance achieved by mechanistic models developed by Ansari (1994), Hasan (1995), Gomez (2000) and Kaya (2001) supports the importance of the mechanistic approach for the steam flow problem in injection wellbores. In this study, the methodology to solve the problem consists in the application of a numerical method to the governing equations of steam flow and a marching algorithm to determine the distribution of the pressure and temperature along the wellbore. So, a computer code has been formulated to get numerical results, which provides a comparative study to the main models found in the literature. Finally, when compared to available field data, the mechanistic model for downward vertical steam flow in wellbores gave better results than the empirical correlations. (author)

  8. Wellbore cement fracture evolution at the cement–basalt caprock interface during geologic carbon sequestration

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Hun Bok; Kabilan, Senthil; Carson, James P.; Kuprat, Andrew P.; Um, Wooyong; Martin, Paul F.; Dahl, Michael E.; Kafentzis, Tyler A.; Varga, Tamas; Stephens, Sean A.; Arey, Bruce W.; Carroll, KC; Bonneville, Alain; Fernandez, Carlos A.

    2014-08-07

    Composite Portland cement-basalt caprock cores with fractures, as well as neat Portland cement columns, were prepared to understand the geochemical and geomechanical effects on the integrity of wellbores with defects during geologic carbon sequestration. The samples were reacted with CO2-saturated groundwater at 50 ºC and 10 MPa for 3 months under static conditions, while one cement-basalt core was subjected to mechanical stress at 2.7 MPa before the CO2 reaction. Micro-XRD and SEM-EDS data collected along the cement-basalt interface after 3-month reaction with CO2-saturated groundwater indicate that carbonation of cement matrix was extensive with the precipitation of calcite, aragonite, and vaterite, whereas the alteration of basalt caprock was minor. X-ray microtomography (XMT) provided three-dimensional (3-D) visualization of the opening and interconnection of cement fractures due to mechanical stress. Computational fluid dynamics (CFD) modeling further revealed that this stress led to the increase in fluid flow and hence permeability. After the CO2-reaction, XMT images displayed that calcium carbonate precipitation occurred extensively within the fractures in the cement matrix, but only partially along the fracture located at the cement-basalt interface. The 3-D visualization and CFD modeling also showed that the precipitation of calcium carbonate within the cement fractures after the CO2-reaction resulted in the disconnection of cement fractures and permeability decrease. The permeability calculated based on CFD modeling was in agreement with the experimentally determined permeability. This study demonstrates that XMT imaging coupled with CFD modeling represent a powerful tool to visualize and quantify fracture evolution and permeability change in geologic materials and to predict their behavior during geologic carbon sequestration or hydraulic fracturing for shale gas production and enhanced geothermal systems.

  9. 分支水平井稳态渗流理论及最优井长%The time-invariant seepage theory and optimal wellbore length of multi-lateral horizontal wells

    Institute of Scientific and Technical Information of China (English)

    曾晓晶; 同登科

    2011-01-01

    针对油藏中分支水平井的稳态渗流问题,基于渗流力学理论,采用全三维方法,导出了油藏稳态渗流与分支水平井井筒流的耦合模型.用改进的Su方法以及一种新方法计算了裸眼完井分支水平井井筒内的压降,分析和比较了井筒内压力和采油指的分布情况;同时,给出了考虑经济因素的分支水平井水平段最优长度的计算方法.结果表明,分支水平井的单个分支内的流动况和水平井近似;由于摩擦因素的影响,分支水平井的水平分支不是越长越好,而是有一个最优值.这些结论可用于实际油藏中支水平井的设计和产能预测.%In terms of the time-invariant seepage of multi-lateral horizontal wells in oil reservoirs, a coupled model of the time-invariant seepage in reservoirs and the wellbore flow in multi-lateral horizontal wells was deduced with the full 3D analytical method based on the filtration mechanic theory. The pressure drop in barefoot completion multi-lateral horizontal wellbores was calculated using the improved Su method and a new approach, and distributions of pressure and productive indices in wellbores were analyzed and compared. At the same time, a computing method with the consideration of economic factors was proposed to optimize the length of the horizontal section for multi-lateral horizontal wells. The results derived from calculations and analyses of some real cases indicated that the flowing status within an individual branch of multi-lateral horizontal wells was similar to that in horizontal wells, the length of lateral branches of multi-lateral horizontal wells is not the longer, the better, but instead, it has an optimal value due to the friction effect. These conclusions are available for designing multi-lateral horizontal wells and forecasting the productivity of this kind of wells.

  10. The wellbore simulator SIMU1999; El simulador de pozos SIMU1999

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez Upton, Pedro [Comision Federal de Electricidad, Morelia, Michoacan (Mexico)

    1999-08-01

    This work presents a brief description of the architecture and scope of the wellbore simulator SIMU1999. Its prime application involves the representation of the different flow types and thermodynamic conditions found in geothermal wells. The simulator utilizes a homogeneous flow model which incorporates the fundamental theories of fluid mechanics and allows the handling of two-phase three component mixtures (H{sub 2}O-NaCl-CO{sub 2}), which represent the main constituents appearing in the production of geothermal fluids. SIMU1999 uses a two-phase friction factor developed on the basis of 64 production test carried out on 45 different wells. There were recovered more than 324 pressure drop data and 628 temperature measurements from the inner of the wells. Mechanical log recorders (Kuster) were mainly used but some electronic logs (Hot Hole and Pruett) were carried out, too. The friction factor is calculated using the Reynolds number, steam quality, and fluid pressure, therefore, it is independent of any previous flow pattern identification. Production data included specific enthalpies from 650 to 2 780 kj/kg, fluid pressures between 0.4 and 14 MPa, and fluid temperatures from 110 to 340 Celsius degrees. The computer code of SIMU 1999 is written in Fortran 90 and generates and executable file a little bit greater than 1 Mb. The program is divided in four parts, these are: the wellbore simulator; a graphical output to analyze the results on the screen; a separated subroutine to evaluate the mass flow rate of three component flows discharging to the atmosphere at the speed of sound; and an independent thermodynamic module which could be utilized to make estimations to be used in manual analysis. The code incorporates an efficient algorithm to solve the fluid transport phenomena problem, based on a numerical method of successive approaches. The simulator uses the International System of Units, for data input and for results (outcomes) generation. Everything is realized

  11. 1:1 scale wellbore experiment and associated modeling for a better understanding of well integrity in the context of CO2 geological storage

    NARCIS (Netherlands)

    Manceau, J.C.; Trémosa, J.; Audigane, P.; Claret, F.; Wasch, L.J.; Gherardi, F.; Ukelis, O.; Dimier, A.; Nussbaum, C.; Lettry, Y.; Fierz, T.

    2014-01-01

    In this study, we present a new experiment for following the evolution of the well integrity over time due to different changes in well conditions (pressure, temperature and fluids in contact with the well) in the context of CO2 geological storage. A small section of a wellbore is reproduced in the

  12. Hydrated Ordinary Portland Cement as a Carbonic Cement: The Mechanisms, Dynamics, and Implications of Self-Sealing and CO2 Resistance in Wellbore Cements

    Energy Technology Data Exchange (ETDEWEB)

    Guthrie, George Drake Jr. [Los Alamos National Laboratory; Pawar, Rajesh J. [Los Alamos National Laboratory; Carey, James William [Los Alamos National Laboratory; Karra, Satish [Los Alamos National Laboratory; Harp, Dylan Robert [Los Alamos National Laboratory; Viswanathan, Hari S. [Los Alamos National Laboratory

    2017-07-28

    This report analyzes the dynamics and mechanisms of the interactions of carbonated brine with hydrated Portland cement. The analysis is based on a recent set of comprehensive reactive-transport simulations, and it relies heavily on the synthesis of the body of work on wellbore integrity that we have conducted for the Carbon Storage Program over the past decade.

  13. T2Well/ECO2N Version 1.0: Multiphase and Non-Isothermal Model for Coupled Wellbore-Reservoir Flow of Carbon Dioxide and Variable Salinity Water

    Energy Technology Data Exchange (ETDEWEB)

    Pan, L.; Oldenburg, C.M.; Wu, Y.-S.; Pruess, K.

    2011-02-14

    At its most basic level, the injection of CO{sub 2} into geologic CO{sub 2} storage sites involves a system comprising the wellbore and the target reservoir. The wellbore is the only conduit available to emplace CO{sub 2} into reservoirs for long-term storage. At the same time, wellbores in general have been identified as the most likely conduit for CO{sub 2} and brine leakage from geologic carbon sequestration (GCS) sites, especially those in sedimentary basins with historical hydrocarbon production. We have developed a coupled wellbore and reservoir model for simulating the dynamics of CO{sub 2} injection and leakage through wellbores. The model describes the following processes: (1) upward or downward wellbore flow of CO{sub 2} and variable salinity water with transition from supercritical to gaseous CO{sub 2} including Joule-Thomson cooling, (2) exsolution of CO{sub 2} from the aqueous phase as pressure drops, and (3) cross flow into or interaction with layers of surrounding rock (reservoirs). We use the Drift-Flux Model and related conservation equations for describing transient two-phase non-isothermal wellbore flow of CO{sub 2}-water mixtures under different flow regimes and interacting with surrounding rock. The mass and thermal energy balance equations are solved numerically by a finite difference scheme with wellbore heat transmission to the surrounding rock handled either semi-analytically or numerically. The momentum balance equation for the flow in the wellbore is solved numerically with a semi-explicit scheme. This manual provides instructions for compilation and use of the new model, and presents some example problems to demonstrate its use.

  14. Measuring water quality from individual fractures in open wellbores using hydraulic isolation and the dissolved oxygen alteration method

    Science.gov (United States)

    Vitale, Sarah A.; Robbins, Gary A.

    2017-08-01

    This study describes a low-cost method for sampling individual fractures in open wellbores in crystalline bedrock utilizing naturally occurring flow conditions in the well. The method entails using the dissolved oxygen alteration method (DOAM) to identify transmissive fractures and vertical flow direction. After obtaining information about relative hydraulic gradients, flow direction in the well is modified using a single control pump to isolate fractures of interest for sampling. Additional dissolved oxygen, injected during the DOAM procedure, serves as a tracer to ensure the water quality in the sampling zone is characteristic of the fracture of interest by requiring a tracer-free zone prior to sampling. Sampling procedures are described conceptually for nine bedrock wells with varying flow conditions containing one, two, or three transmissive inflowing fractures. The method was demonstrated in two crystalline bedrock wells containing one and two transmissive inflowing fractures.

  15. Large Diameter Freeze Shaft Single Wellbore Grouting Plugging Technology Research%大直径冻结井筒单层井壁注浆堵水技术研究

    Institute of Scientific and Technical Information of China (English)

    陈德明; 段安新

    2014-01-01

    To study the freezing of large diameter single wellbore wall grouting technology for large amount of leakage problems wellbore door grams celebrate mine shaft began to thaw vice combining technical features wellbore wall hydrogeological conditions and parameters of the wellbore after the walls ,curtains and wall impermeable microcracks take phased ,focused carried grouting .The results show that:the amount of leakage from the wellbore 233 m3/h reduced to 4.5 m3/h,reaching the amount of wellbore leakage specifications .%为研究大直径冻结井筒单层井壁注浆堵水技术,针对门克庆矿副立井开始解冻后井筒漏水量较大的问题,结合井筒的技术特征、水文地质情况和井壁参数,对井筒壁后、隔水帷幕及井壁微裂纹采取分阶段、分重点进行注浆堵水。结果表明:井筒漏水量由233 m3/h降低为4.5 m3/h,达到井筒漏水量规范要求。

  16. Casing pull tests for directionally drilled environmental wells

    Energy Technology Data Exchange (ETDEWEB)

    Staller, G.E.; Wemple, R.P. [Sandia National Labs., Albuquerque, NM (United States); Layne, R.R. [Charles Machine Works, Inc., Perry, OK (United States)

    1994-11-01

    A series of tests to evaluate several types of environmental well casings have been conducted by Sandia National Laboratories (SNL) and it`s industrial partner, The Charles Machine Works, Inc. (CMW). A test bed was constructed at the CMW test range to model a typical shallow, horizontal, directionally drilled wellbore. Four different types of casings were pulled through this test bed. The loads required to pull the casings through the test bed and the condition of the casing material were documented during the pulling operations. An additional test was conducted to make a comparison of test bed vs actual wellbore casing pull loads. A directionally drilled well was emplaced by CMW to closely match the test bed. An instrumented casing was installed in the well and the pull loads recorded. The completed tests are reviewed and the results reported.

  17. 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.

  18. On the feasibility of inducing oil mobilization in existing reservoirs via wellbore harmonic fluid action

    KAUST Repository

    Jeong, Chanseok

    2011-03-01

    Although vibration-based mobilization of oil remaining in mature reservoirs is a promising low-cost method of enhanced oil recovery (EOR), research on its applicability at the reservoir scale is still at an early stage. In this paper, we use simplified models to study the potential for oil mobilization in homogeneous and fractured reservoirs, when harmonically oscillating fluids are injected/produced within a well. To this end, we investigate first whether waves, induced by fluid pressure oscillations at the well site, and propagating radially and away from the source in a homogeneous reservoir, could lead to oil droplet mobilization in the reservoir pore-space. We discuss both the fluid pore-pressure wave and the matrix elastic wave cases, as potential agents for increasing oil mobility. We then discuss the more realistic case of a fractured reservoir, where we study the fluid pore-pressure wave motion, while taking into account the leakage effect on the fracture wall. Numerical results show that, in homogeneous reservoirs, the rock-stress wave is a better energy-delivery agent than the fluid pore-pressure wave. However, neither the rock-stress wave nor the pore-pressure wave is likely to result in any significant residual oil mobilization at the reservoir scale. On the other hand, enhanced oil production from the fractured reservoir\\'s matrix zone, induced by cross-flow vibrations, appears to be feasible. In the fractured reservoir, the fluid pore-pressure wave is only weakly attenuated through the fractures, and thus could induce fluid exchange between the rock formation and the fracture space. The vibration-induced cross-flow is likely to improve the imbibition of water into the matrix zone and the expulsion of oil from it. © 2011 Elsevier B.V.

  19. PREDICTING METHOD OF THE WELLBORE STABILITY OF INCLINED WELL BY WELL LOGGING%斜井井壁稳定的测井预测方法

    Institute of Scientific and Technical Information of China (English)

    陈科贵; 夏亚良; 高成军; 张歧安

    2011-01-01

    从影响井壁稳定的力学因素出发,通过井壁围岩应力分析提取影响斜井井壁稳定的主应力,结合岩石破坏的强度准则建立地层坍塌压力和破裂压力的测井预测模型.针对研究工区地质情况对模型进行适当修正,建立了该区安全钻井液密度窗口.通过精细解释测井资料预测的井壁稳定情况表明,测井资料能够较好地预测井壁的稳定性,为防止井漏、井塌等工程事故提供了重要依据.%Starting from the mechanic factors that influence wellbore stability, the main stress that influences well stability of inclined well is determined through borehole wall surrounding rock stress analysis, and combining with the intensity principle of rock damage, logging prediction model of formation caving pressure and fracture pressure is established. Certain modification is made to the model considering the geological conditions of the studied area, and density window of safe drilling fluid is established. The wellbore stability predicted by the fine interpretation of logging data shows that logging data can predict wellbore stability and provide criteria for the prevention of engineering accident, such as circulation loss, hole collapse, etc.

  20. The Mechanism of Radial Separation of Cement Sheath and Casing during Temperature Cycling

    Institute of Scientific and Technical Information of China (English)

    Gao Baokui; Gao Deli

    2006-01-01

    An axisymmetrical-plane-strain model, simulating a perfect casing-cement-formation wellbore section, was developed to study its structural integrity during temperature cycling. Constitutive equations of elastoplasticity and the finite element method were used in the model study. Thermal stresses and deformation were calculated in order to reveal the mechanism of the cement sheath separating from the casing by radial residual stress. It was found that when the temperature increased high enough, the casing deformed plastically, the casing inner surface contracted while outer surface expanded. When the temperature decreased, radial residual stress in the casing-cement sheath interface was tensile which would separate cement sheath from the casing. The wellbore structural integrity was destroyed by the interface separation, providing the chance for inflow of the fluids outside the casing. The impact of the separation on casing collapse was discussed and the probability of the separation extending in the axial direction was predicted.

  1. Impact of Thermal Stresses on Wellbore Integrity during CO2 Injection

    Science.gov (United States)

    Roy, P.; Walsh, S.; Morris, J.; Carroll, S.; Hao, Y.; Iyer, J.; Torsater, M.; Gawel, K.; Todorovic, J.

    2015-12-01

    Thermal stresses caused by injection of cold CO2 into warmer storage reservoirs could create leakage pathways out of the storage reservoir. Although few studies have been conducted to investigate the well bore integrity subjected to thermal cycling during CO2injection, a systematic investigation on thermally induced expansion and contraction affecting the debonding and cracking of the well barrier materials has not yet been performed. In this work, we have analyzed the thermo-mechanical characteristics of the well barrier materials undergoing repeated thermal cycling using a multiscale, multiphysics platform named GEOS. More specifically, we model the modes of failure during thermal cycling to assess the temperature range for minimal impact on well integrity. A finite element solver was used for the geomechanics and a finite volume solver was used for the thermal diffusion. Results of the initiation and propagation of fractures due to temperature variations in the cement sheath are presented. Preliminary results suggest that radial fracture develops as the cement is heated while debonding occurs in the casing-cement and cement-rock interfaces during the cooling period. The effects of different confinement conditions based on in-situ stresses were also analyzed. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under the Contract DE-AC52-07NA27344. This work has been produced with support from the BIGCCS Centre, performed under the Norwegian research program Centres for Environment-friendly Energy Research (FME) and the KPN project "Ensuring well integrity during CO2 injection". The authors acknowledge the following partners for their contributions: Gassco, Shell, Statoil, TOTAL, GDF SUEZ and the Research Council of Norway (193816/S60 and 23389).

  2. Quantification of Wellbore Leakage Risk Using Non-destructive Borehole Logging Techniques

    Energy Technology Data Exchange (ETDEWEB)

    Duguid, Andrew; Butsch, Robert; Cary, J.; Celia, Michael; Chugunov, Nikita; Gasda, Sarah; Hovorka, Susan; Ramakrishnan, T. S.; Stamp, Vicki; Thingelstad, Rebecca; Wang, James

    2014-08-29

    estimate the flow properties modeling of point pressure tests, modeling of vertical interference tests, and laboratory measurement of cased-hole sidewall cores The wells were in sufficiently good shape to allow the development of the characterization methods while still having enough defects to study differences in results as they relate to well integrity. Samples and tests analyzed from three of five wells studied in showed the cements were largely intact and had not degraded from exposure native brines. Log results taken in conjunction with the core measurements indicate that interfaces and/or problems with cement placement due to eccentering provide preferential flow paths for fluids, which can increase the effective permeability of the barrier several orders of magnitude above the permeability of intact cement. The results of the maps created using logging tools indicating that the cement condition and bond are generally good identify a need for more research to understand how logs can be used to predicteffective well permeabilities such as those measured by the VITs in this study.

  3. Influence of Chemical, Mechanical, and Transport Processes on Wellbore Leakage from Geologic CO2 Storage Reservoirs.

    Science.gov (United States)

    Carroll, Susan A; Iyer, Jaisree; Walsh, Stuart D C

    2017-08-15

    Wells are considered to be high-risk pathways for fluid leakage from geologic CO2 storage reservoirs, because breaches in this engineered system have the potential to connect the reservoir to groundwater resources and the atmosphere. Given these concerns, a few studies have assessed leakage risk by evaluating regulatory records, often self-reported, documenting leakage in gas fields. Leakage is thought to be governed largely by initial well-construction quality and the method of well abandonment. The geologic carbon storage community has raised further concerns because acidic fluids in the CO2 storage reservoir, alkaline cement meant to isolate the reservoir fluids from the overlying strata, and steel casings in wells are inherently reactive systems. This is of particular concern for storage of CO2 in depleted oil and gas reservoirs with numerous legacy wells engineered to variable standards. Research suggests that leakage risks are not as great as initially perceived because chemical and mechanical alteration of cement has the capacity to seal damaged zones. Our work centers on defining the coupled chemical and mechanical processes governing flow in damaged zones in wells. We have developed process-based models, constrained by experiments, to better understand and forecast leakage risk. Leakage pathways can be sealed by precipitation of carbonate minerals in the fractures and deformation of the reacted cement. High reactivity of cement hydroxides releases excess calcium that can precipitate as carbonate solids in the fracture network under low brine flow rates. If the flow is fast, then the brine remains undersaturated with respect to the solubility of calcium carbonate minerals, and zones depleted in calcium hydroxides, enriched in calcium carbonate precipitates, and made of amorphous silicates leached of original cement minerals are formed. Under confining pressure, the reacted cement is compressed, which reduces permeability and lowers leakage risks. The

  4. Determining the mechanical strength of CO2-induced reaction zones in wellbore cement: is it worth it?

    Science.gov (United States)

    Hangx, Suzanne; Marcelis, Fons; van der Linden, Arjan; Liteanu, Emilia

    2015-04-01

    CO2 injection, either for long-term CO2 storage (CCS) or Enhanced Oil Recovery (EOR), strongly hinges on maintaining storage integrity. Injection and legacy wells penetrating the caprock pose one of the most likely points of leakage. In order to be able to predict the long-term integrity of such wellbores, it's important to understand their chemical, hydrological and mechanical behaviour, and how it may change due to CO2 exposure. Generally, in response to CO2/brine/cement interactions, a number of different reaction zones are observed, each with their own chemical, and hence mechanical, signature. To aid mechanical modelling efforts, assessing the risk of cement failure caused by stress and temperature changes, knowledge is required of the strength of each of these zones. We performed experiments on Class G Portland cement to investigate the chemical-mechanical coupling due to CO2-exposure. Batch reaction experiments, in the presence of CO2-rich brine, were performed under typical storage conditions (T = 65° C, PCO2 = 8 MPa) for various periods of time (1, 2, 3, 4, 5 and 6 months). After exposure, mechanical tests were performed on the observed reaction zones, using the so-called core scratching technique, to evaluate the unconfined compressive strength (UCS) as a function of exposure time. Chemical analyses (CT-imaging, SEM microscopy, EDX chemical analysis) showed the formation of three reaction zones, similarly to what has been observed in other studies. Measurements of the mechanical strength of these different zones showed highly variable results. Such variations have also been observed in other studies, using different measurement techniques. The large variability in strength measurements is most likely an inherent result of the heterogenic nature of cement, which affects the extent and location of reaction throughout the sample. This begs the question: is it worth studying the mechanical strength of reaction-induced zones in cement? Or will it suffice to

  5. AREA 2: Novel Materials for Robust Repair of Leaky Wellbores in CO2 Storage Formations

    Energy Technology Data Exchange (ETDEWEB)

    Balhoff, Matthew [Univ. of Texas, Austin, TX (United States); Tavassoli, Shayan [Univ. of Texas, Austin, TX (United States); Fei Ho, Jostine [Univ. of Texas, Austin, TX (United States)

    2016-01-31

    cement cores to remove calcium and prevent syneresis during polymer placement. A chelating agent, sodium triphosphate (Na5P3O10), was found to successfully eliminate syneresis without compromising the injectivity of polymer solution during placement. Polymer gel strength is determined by recording the maximum holdback pressure gradients during liquid breakthrough tests after various periods of pretreatment and polymer shut-in time. Cores pretreated with Na5P3O10 successfully held up to an average of 80 psi/ft, which is significantly greater than the expected threshold value of about 0.1-5 psi/ft required to prevent flow in a typical CO2 leakage scenario. The use of such inexpensive, pH-triggered poly-acrylic acid polymer allows long-term robust seal of leaky wellbores under high pH conditions.

  6. Iron and Sulfur Geochemistry in Class H Wellbore Cements Exposed to CO2 and H2S

    Science.gov (United States)

    Lopano, C. L.; Webb, S. M.; Kutchko, B. G.; Strazisar, B. R.; Hawthorne, S. B.; Miller, D. J.; Guthrie, G.; Hakala, A.

    2013-12-01

    The effects of CO2 & co-constituents (such as H2S) sequestration on cement seal integrity are not well understood in the context of wellbore integrity for CO2 storage. This study evaluates the redox effects that co-contaminants such as H2S present to the CO2-cement reaction system via synchrotron X-ray XANES mapping specific to the iron and sulfur edge energies. Portland Class H cement was exposed to various proportions of H2S:CO2 in 1% NaCl saturated brine (1%, 21 mol%, and 40% H2S) under supercritical conditions (50°C and 15MPa). The reaction of cement with H2S-CO2 results in the formation of pyrite associated with the Fe-rich cement clinker phase, brownmillerite (also termed ferrite). Ferrite has not reacted in previous exposures to CO2 alone, which was confirmed by synchrotron spectroscopic analysis of cement exposed to supercritical CO2 alone. Thus it is hypothesized that the reaction is a result of redox conditions introduced by H2S. The synchrotron X-ray microprobe fluorescence (μXRF) imaging and spectroscopy capabilities at beamlines 2-3 and 14-3 at SSRL were used to collect multiple energy (ME) maps for both Fe and S in order to evaluate reaction fronts in the cement matrix and to monitor the chemical changes in the cement associated with exposure to CO2 (and H2S) at sequestration conditions. The use of this micro-spectroscopy technique allows for in-situ identification of any reaction intermediates (including amorphous materials) for the Fe and S phases in the cement. The coupled μXANES and μXRF data were used to generate iron and S speciation maps of the cement cores. Synchrotron microprobe capabilities at 2-3 were used to collected ME maps of Fe, and show differences in Fe oxidation between the rims (Fe2+) and cores (Fe3+) of the cement thin section. Analysis of Fe XANES indicates that there are potentially 4+ distinct coordination environments for the Fe in the cement cores studied: pyrite, ferrihydrite, brownmillerite (Fe3+, and/or Fe2+) and

  7. 重力热管自吸地热改善热采井井筒热损失研究%A Study of Reducing Heat Loss of Thermal Recovery Wellbore by Gravity Heatpipe Technology through Absorbing Geothermal Energy

    Institute of Scientific and Technical Information of China (English)

    李龙; 李春生; 朱兰

    2011-01-01

    On the basis of the principle of gravity heat pipe decreasing heat loss in wellbore during thermal re covery and heat transfer of wellbore during oil production, calculation models of thermal energy engineering and heat transfer loss of wellbore were established and were used to calculate an example of testing well. The results show that the measured temperature of produced liquid is close to the calculated one, fractional error of which is 5.52%. The temperature of produced liquid inceases by 10℃ with gravity heatpipe in comparison with that of the regular wellbore, which could prove that gravity heatpipe is able to change the temperature distribution of fluids in wellbore. Gravity heatpipe absorbing geothermal energy is a new technology in oil production and can be applied to an extended extent in thermal recovery wells of heavy oil.%在深入探讨重力热管改善抽油井井筒热损失原理的基础上,结合井筒传热模型,建立了稠油热采井重力热管自吸热过程的热工计算及井筒热损失的计算模型.并结合矿场应用实例进行了计算.结果表明,井口产出液实测温度与计算值相对误差为5.52%,符合工程要求.热管正常工作后能将井口流体温度提高近10℃,在井筒中起到了平衡流体温场的作用.重力热管自吸地热采油技术是采油工程领域一项全新的探索,在稠油热采中有着广泛的应用前景.

  8. IMPACT OF PHYSICAL AND CHEMICAL MUD CONTAMINATION ON WELLBORE CEMENT- FORMATION SHEAR BOND STRENGTH Authors: Arome Oyibo1 and Mileva Radonjic1 * 1. Craft and Hawkins Department of Petroleum Engineering, 2131 Patrick F. Taylor Hall, Louisiana State University, Baton Rouge, LA 70803, aoyibo1@tigers.lsu.edu, mileva@lsu.edu

    Science.gov (United States)

    Oyibo, A. E.

    2013-12-01

    Wellbore cement has been used to provide well integrity through zonal isolation in oil & gas wells and geothermal wells. Cementing is also used to provide mechanical support for the casing and protect the casing from corrosive fluids. Failure of cement could be caused by several factors ranging from poor cementing, failure to completely displace the drilling fluids to failure on the path of the casing. A failed cement job could result in creation of cracks and micro annulus through which produced fluids could migrate to the surface which could lead to sustained casing pressure, contamination of fresh water aquifer and blow out in some cases. In addition, cement failures could risk the release of chemicals substances from hydraulic fracturing into fresh water aquifer during the injection process. To achieve proper cementing, the drilling fluid should be completely displaced by the cement slurry. However, this is hard to achieve in practice, some mud is usually left on the wellbore which ends up contaminating the cement afterwards. The purpose of this experimental study is to investigate the impact of both physical and chemical mud contaminations on cement-formation bond strength for different types of formations. Physical contamination occurs when drilling fluids (mud) dries on the surface of the formation forming a mud cake. Chemical contamination on the other hand occurs when the drilling fluids which is still in the liquid form interacts chemically with the cement during a cementing job. We investigated the impact of the contamination on the shear bond strength and the changes in the mineralogy of the cement at the cement-formation interface to ascertain the impact of the contamination on the cement-formation bond strength. Berea sandstone and clay rich shale cores were bonded with cement cores with the cement-formation contaminated either physically or chemically. For the physically contaminated composite cores, we have 3 different sample designs: clean

  9. 泥页岩井壁稳定流固化耦合模型%A fluid-solid-chemistry coupling model for shale wellbore stability

    Institute of Scientific and Technical Information of China (English)

    王倩; 周英操; 王刚; 蒋宏伟; 刘玉石

    2012-01-01

    A fluid-solid-chemistry coupling model is built considering fluid flow and ion transmission induced by shale-drilling fluid system electrochemical potential osmosis, nonlinearity of flow and solute diffusion in shale-drilling fluid system, and solid deformation resulted from fluid flow and ion transmission. The model is used to compute the time-varying pore pressure, stress and damage index in formations around the wellbore of a well. The result shows that the pore pressure and stress are lower without consideration of the diffusion potential induced by ion selective character of shale membrane. The linear model overestimates the pore pressure and stress fields around the sidewall. The damage index reveals that collapse first occurs in formations near the wellbore, the caving pressure increases and changes obviously with time, the fracture pressure reduces but doesn't change significantly with time, and the drilling fluid density window narrows down with time.%考虑泥页岩-钻井液体系电化势渗透产生的流体流动和离子运移、泥页岩-钻井液体系中流体流动和溶质扩散过程的非线性、流体流动和离子运移对固体变形的影响,建立泥页岩井壁稳定流-固-化耦合模型.应用建立的模型计算实例井井眼周围地层随时间变化的孔隙压力、应力以及破坏指数.结果表明,若不考虑泥页岩膜离子选择性形成的扩散电势,计算的孔隙压力和应力偏小,而线性模型过高地预测了井壁周围的孔隙压力场和应力场.根据破坏指数可以看出,坍塌破坏首先发生在井壁附近地层,坍塌压力随时间延长增大且变化较明显,破裂压力随时间延长减小但变化不显著,钻井液密度窗口随时间变窄.

  10. Finite-element analysis of thermal-induced stresses around a cased injection well

    Energy Technology Data Exchange (ETDEWEB)

    Ferla, A [Department of Civil Engineering, Catholic University of Leuven, Kasteelpark Arenberg 40, 3001 Heverlee (Belgium); Lavrov, A; Fjaer, E, E-mail: andries_ferla@hotmail.co [Formation Physics Department, SINTEF Petroleum Research, 7465 Trondheim (Norway)

    2009-08-01

    Injection of surface fluids (sea water, CO{sub 2}, steam) into hydrocarbon reservoirs induces thermal stresses in the wellbore structures and in the near-well area. These stresses may endanger the integrity of the casing, the cement and the surrounding formation. Therefore, an accurate assessment of injection-induced thermal stresses and the associated risk of failure are of utmost importance for a safe and environmentally secure oil production. A coupled finite-element model has been developed and tested as a tool for assessing the probability and extent of failure caused by thermal-induced stresses around a cased wellbore. A feature of the model is an option for an automatic mesh refinement using Nikishkov elements and a quad-tree data structure. The refinement is automatically provided in the regions of rapid change of the nodal variables (displacements, temperature).

  11. Topical report on subsurface fracture mapping from geothermal wellbores. Phase I. Pulsed radar techniques. Phase II. Conventional logging methods. Phase III. Magnetic borehole ranging

    Energy Technology Data Exchange (ETDEWEB)

    Hartenbaum, B.A.; Rawson, G.

    1980-09-01

    To advance the state-of-the-art in Hot Dry Rock technology, an evaluation is made of (i) the use of radar to map far-field fractures, (ii) the use of more than twenty different conventional well logging tools to map borehole-fracture intercepts, and (iii) the use of magnetic dipole ranging to determine the relative positions of the injection well and the production well within the fractured zone. It is found that according to calculations, VHF backscatter radar has the potential for mapping fractures within a distance of 50 +- 20 meters from the wellbore. A new technique for improving fracture identification is presented. Analyses of extant data indicate that when used synergistically the (1) caliper, (2) resistivity dipmeter, (3) televiewer, (4) television, (5) impression packer, and (6) acoustic transmission are useful for mapping borehole-fracture intercepts. Improvements in both data interpretation techniques and high temperature operation are required. The surveying of one borehole from another appears feasible at ranges of up to 200 to 500 meters by using a low frequency magnetic field generated by a moderately strong dipole source (a solenoid) located in one borehole, a sensitive B field detector that traverses part of the second borehole, narrow band filtering, and special data inversion techniques.

  12. Hydraulic fracturing and wellbore completion of coalbed methane wells in the Powder River Basin, Wyoming: Implications for water and gas production

    Energy Technology Data Exchange (ETDEWEB)

    Colmenares, L.B.; Zoback, M.D. [Stanford University, Stanford, CA (United States). Dept. of Geophysics

    2007-01-15

    Excessive water production (more than 7000 bbl/month per well) from many coalbed methane (CBM) wells in the Powder River Basin of Wyoming is also associated with significant delays in the time it takes for gas production to begin. Analysis of about 550 water-enhancement activities carried out during well completion demonstrates that such activities result in hydraulic fracturing of the coal. Water-enhancement activities, consists of pumping 60 bbl of water/min into the coal seam during approximately 15 min. This is done to clean the well-bore and to enhance CBM production. Hydraulic fracturing is of concern because vertical hydraulic fracture growth could extend into adjacent formations and potentially result in excess CBM water production and inefficient depressurization of coals. Analysis of the pressure-time records of the water-enhancement tests enabled us to determine the magnitude of the least principal stress (S{sub 3}) in the coal seams of 372 wells. These data reveal that because S{sub 3} switches between the minimum horizontal stress and the overburden at different locations, both vertical and horizontal hydraulic fracture growth is inferred to occur in the basin, depending on the exact location and coal layer. Relatively low water production is observed for wells with inferred horizontal fractures, whereas all of the wells associated with excessive water production are characterized by inferred vertical hydraulic fractures. The reason wells with exceptionally high water production show delays in gas production appears to be inefficient depressurization of the coal caused by water production from the formations outside the coal. To minimize CBM water production, we recommend that in areas of known vertical fracture propagation, the injection rate during the water-enhancement tests should be reduced to prevent the propagation of induced fractures into adjacent water-bearing formations.

  13. Casing While Drilling "Smear Effect" Improves Wellbore Stability%随钻下套管的"覆盖效应"增强了井眼的稳定性

    Institute of Scientific and Technical Information of China (English)

    郭振山; 张言; 王龙

    2007-01-01

    自1997年以来,ConocoPhillips大陆石油公司在Lobo地区有一项多用途钻机研发的长远计划,现已在Webb和Zapata郡钻了120多口井,进尺487 681 m.这项开发计划要求在6年多的时间里钻900多口井.到2001年为止,实践证明用常规的方法难以进一步提高效率,必须提高钻进效率来拓展开发的潜力.建井成本受三个关键问题的影响:井漏、卡钻和下套管的时间,随钻下套管允许在钻进的同时下套管,此设计无需将钻柱起出井眼.5口随钻下套管井的试验成功,致使Conoco Phillips大陆石油公司在南得克萨斯广泛应用这项技术.其他作业者也在此区域开展了此技术的应用.

  14. Investigation of casing connection failure mechanisms in thermal wells

    Energy Technology Data Exchange (ETDEWEB)

    Xie, J. [C-FER Technologies, Edmonton, AB (Canada)

    2009-07-01

    Thermal well technologies use casing strings that consist of casing joints linked by threaded connections that are cemented over the wellbore's length in order to provide structural support and hydraulic isolation to the wellbore. Studies have demonstrated that over 80 per cent of uphole casing failures occur at the casing joint connections, and are caused by thread rupture or structural damage. This study discussed thermal well failures related to casing connection damage. Finite element analyses (FEA) were then conducted to consider various critical load conditions with a generic premium casing connection. The study considered structural integrity losses, fatigue, and leakage during connection installation. Results of the study were then used to optimize casing connection designs. The study showed that thermal cycle and curvature loading can have an impact on the structural and sealing performance of premium connections. Connection structural performance should be evaluated in order to determine appropriate designs for thermal well applications. It was concluded that the connection shoulder region is a critical area for material fatigue failure. 12 refs., 9 figs.

  15. Heat Transfer in Tubing-Casing Annulus during Production Process of Geothermal Systems

    Institute of Scientific and Technical Information of China (English)

    Fuzong Zhou; Xiuhua Zheng

    2015-01-01

    In geothermal systems, the temperature distribution of heat flow in the wellbore is de-pendent on the well structure and the geological conditions of the surrounding formation. Under-standing of heat transfer in the tubing-casing annulus can reduce the heat losses of wellbore fluid during the production process. The present study discusses the possible means of heat transfer in the annulus, and develops a piecewise equation for estimating the convective heat transfer coefficient with a wider valid condition of 0wellbore. Additionally, the contribution of radiation will increase to occupy a majority proportion in the total thermal conductivity when the annular size increases and the materials have high emissivity. Otherwise, thermal radiation is just the second fac-tor.

  16. Reaction of CO2 and brine at the interface between Portland cement and casing steel: Application to CO2 sequestration

    Science.gov (United States)

    Carey, J. W.; Zhang, J.; Lichtner, P. C.; Grigg, R.; Svec, B.; Pawar, R.

    2008-12-01

    Prediction of CO2 leakage through wellbore systems is a multiscale problem in geologic sequestration. In order for wellbore leakage to occur, km-scale processes must deliver CO2 from the point of injection to the wellbore. But, in order for the wellbore to actually leak, μm-scale processes must operate to allow CO2 to flow up the wellbore. In this study, we describe experiments and modeling of microscale processes accompanying CO2 leakage along the cement-casing interface. This work fits within a broader predictive study of CO2 sequestration performance (Viswanathan et al. 2008, Env Sci and Tech, in press) that includes calculation of CO2-migration times to wellbores. Experiments carried out in this report consisted of synthetic wellbore systems constructed of Portland cement and casing-grade steel in which a mixture of CO2 and brine were forced along the cement-casing interface at in situ sequestration conditions (40 °C and 14 MPa). The CO2-brine mixture was pre- equilibrated by flow through limestone before encountering the cement-casing composite. (The limestone- equilibrated fluid was calculated to be strongly out of equilibrium with both cement and the casing.) We used a high CO2-brine flux (10-20 ml/hour along the interface) and hypothesized that the interface would widen with time due to dissolution of either or both cement and steel. In addition to experiments, we conducted reactive transport modeling of cement reactivity using FLOTRAN, which was modified to allow representation of solid solution in the dominant cement phase, calcium-silicate-hydrate. We also developed a corrosion model for the steel. The experimental results showed that the steel was more reactive than the Portland cement. Extensive deposits or oxidation products of FeCO3-rich material developed at the interface and in some places led to an apparent closure of the interface despite the large flux through the system. In contrast, alteration of the cement appeared to be limited by

  17. Research on the Principles of Wellbore Multiphase Flow During Sour Gas Influx%酸性天然气侵入井筒多相流动规律研究

    Institute of Scientific and Technical Information of China (English)

    万立夫; 李根生; 迟焕鹏; 宋先知; 王海柱

    2012-01-01

    The mathematics model of wellbore multiphase flow after sour gas influx is established. The paper is comprehensively based on the application of pressure drop model and heat transfer model for two phases flow in wellbore, coupling the wellbore unsteady flow and formation seepage, and the mutual reaction ( chemical reaction and solubility) between sour gas and water-based drilling fluid into consideration. The pressure distribution in wellbore is calculated by numerical method with different components ( methane + carbon dioxide, methane + hydrogen sulfide) when drilling the same formation. The results indicates that the chemical reaction can be ignored. The solubility of carbon dioxide or hydrogen sulfide in the water-based drilling fluid is very remarkable. When the sour gas is near the wellhead, the solubility is decreased sharply. The density of sour gas has a sharp change near the wellhead. The higher he mole fraction of carbon dioxide and hydrogen sulfide of sour gas is, the shorter of distance near the wellhead is. The higher he mole fraction of carbon dioxide and hydrogen sulfide of sour gas is, the smaller change of pressure in the bottom hole pressure is. So that we shouldn' t judge the overflow lever according to the drop of bottom hole pressure.%在综合应用井筒两相流压降和传热模型的基础上,考虑地层渗流与井筒耦合,考虑了钻井液和侵入酸性流体的基本物性参数与井筒温度压力的耦合作用,酸性天然气与水基钻井液间的相互作用(化学反应和溶解),建立酸性天然气侵入井筒多相流计算模型.通过数值计算分析,钻遇相同地层条件下,不同组分(甲烷+二氧化碳,甲烷+硫化氢)两类酸性天然气藏的环空压力等变化规律.结果表明,酸性天然气与水基钻井液化学反应消耗酸性天然气质量流量很小,可忽略.而井筒内溶解度较大,酸性天然气在近井口处由于溶解度迅速降低,气体密度发生突变,且二氧化碳和

  18. Casing drilling - first experience in Brazil; Casing drilling - primeira experiencia no Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Placido, Joao Carlos Ribeiro; Medeiros, Fernando; Lucena, Humberto; Medeiros, Joao Carlos Martins de; Costa, Vicente Abel Soares Rosa da; Silva, Paulo Roberto Correa da [PETROBRAS, Rio de Janeiro, RJ (Brazil); Alves, Renato J.M. [Tesco, London (United Kingdom)

    2004-07-01

    This paper describes the 'Casing Drilling' technology and its first experience in Brazil. This new process of casing while drilling was first developed to reduce costs. This system integrates the drilling process and casing running in one operation, promoting a more efficient well construction system, reducing trip time and costs of drill pipes and their transportation. Besides, this methodology intends to eliminate hole problems related to trouble zones with abnormal pressure with loss circulation, to overcome zones with wellbore instabilities, and to facilitate well control. Two companies have been identified using this technology: Tesco and Weatherford. However, there are differences between the techniques used by these companies, which are described in this paper. In the first experience in Brazil, it was decided to field test the technology developed by Tesco. This paper describes the preparation, the operation and the results of this first test. (author)

  19. Research on Wellbore Stability of Shale Gas Based on Hoek-Brown Criterion%基于霍克-布朗准则评价页岩气井井壁稳定性

    Institute of Scientific and Technical Information of China (English)

    梁利喜; 刘向君

    2014-01-01

    The wellbore stability is one of the key technologies in order to achieve rule horizontal wellbore in shale with low cost. Due to the occurrence and the difficulty in obtaining mechanical parameters of the underground structural planes,the evaluation method of borehole stability by weak surface theory and Mohr-Coulomb criterion has not yet been applied in engineering,and was only studied in theory. In this paper,wellbore stability has been evaluated by using Hoek-Brown criterion. The core numerical model with different fractures has been created,and the tri-axial compression test with different confine pressures has been carried out by means of the numerical simulation. Relationship between the parameters mb ,S and rock mass structure has been analyzed using the result of the numerical simulation. And the method to determine the parameters mb ,S has been established with fracture development index. The analysis of engineering example shows that collapse pressure obtained with the theory are consistent with the actual drilling performance in shale formation and a new method for evaluating borehole stability of shale gas wells has been provided.%井壁稳定是实现页岩气水平井低成本、安全、高效钻井的核心技术之一,科学的井壁稳定性评价理论及方法是保障井壁稳定的前提与基础。页岩储层力学性能取决于结构面的发育程度、几何形态、组合特征及其力学性质等因素;受结构面产状及其力学参数获取困难的制约,目前普遍采用的弱面理论与莫尔-库仑准则相结合的井壁稳定性评价方法,仅局限于理论研究,尚未得到有效工程应用。鉴于此,开展了基于霍克-布朗强度理论的页岩地层井壁稳定性评价研究。通过构建含有不同裂隙的数值模型,进行不同围压下的三轴压缩数值仿真模拟,分析了参数mb、S 与岩体结构的关系,建立了基于结构面发育指数J的mb、S 量化方法。分析

  20. Kinetic mechanism of inorganic scale plugging removal at near wellbore zone by high power ultrasonic technology%大功率超声波近井无机垢解堵的动力学机理

    Institute of Scientific and Technical Information of China (English)

    蒲春生; 饶鹏; 许洪星; 吴飞鹏

    2011-01-01

    Based on the theory of solid and liquid coupling wave mechanics, the micro-dynamical characteristics caused by the transport of ultrasonic in porous media at near wellbore zone, including the elastic deformation of rock, the elastic crossflow of pore fluid and frame solid, and fluid squirt-flow produced by pore elastic deformation, are analyzed. Analysis of kinetics of peristaltic difference of porosity radius in porous media is presented. The characteristics of the removal of inorganic scale particle in porous media by using ultrasonic technology are also studied. Besides, by applying high power ultrasonic technology, the acoustic energy gathering in porous media at near wellbore zone leading to fracture of part rocks is illustrated. According to these analyses, the micro-dynamical mechanisms, such as inorganic scale fragmentation, ultrasonic cavitations, ultrasonic friction, ultrasonic peristaltic transport and ultrasonic fracture-making, occurred in inorganic scale plugging removal by high power ultrasonic technology are proposed.%利用超声波在含流体储层多孔介质中传播的固/液耦合波动力学理论,大功率超声波解除近井带地层堵塞过程中,超声波在近井储层多孔介质中传播引起岩石骨架弹性形变、孔隙流体与骨架固体弹性错流和孔隙弹性变形引起流体挤压喷射流动等微观动力学特性;超声波作用引起储层多孔介质孔隙半径蠕动变化的动力学特征;超声波作用解除储层多孔介质中无机垢颗粒微观动力学特征;分析了大功率超声波作用下,近井带储层多孔介质中声能聚集引起岩石局部起裂的动力学特征.在此基础上,提出了大功率超声波解除无机结垢堵塞的无机垢体破碎作用、超声空化作用、超声摩擦作用、超声蠕动输运作用以及超声造缝作用等微观动力学机理.

  1. 地层H2S侵入时井筒压力变化规律及控制研究%Principles of Wellbore Pressure Variation and Control during Formation H2S Influx

    Institute of Scientific and Technical Information of China (English)

    窦亮彬; 李根生; 沈忠厚; 田守嶒; 吴春方

    2013-01-01

    随着我国酸性油气藏勘探开发的深入,处于对并控安全的考虑,需对酸性气体侵入后并筒多相流动及相态转变规律进行研究.针对H2S特殊的物理性质,并考虑其在井筒内相态变化,建立了钻井过程中H2S侵入时井筒流动与传热的数学模型.将井筒传热、压力与H2S物性参数耦合迭代计算,给出了求解方法并编写程序进行数值计算.计算结果表明:井口回压较小时,H2S在环空上升过程中由液态转化为气态,相态转变点上部为气液两相流,其压力梯度较小,下部为井简单相流,其压力梯度较大.H2S侵入速度对环空压力和相交井深均有影响.随着侵入量增大,井底压力先急剧减小,后基本保持不变,而相变井深先增大后减小.井口回压对井底压力影响较大.随着井口回压增大,井底压力增大,但影响程度逐渐减小.井口回压不仅可以控制井筒是否发生相变,而且对相变井深位置影响十分大.对是否考虑传热对相变井深和井底压力的影响进行了对比分析.研究对提高酸性油气藏开发勘探安全具有一定指导意义.%The growing number of acid reservoirs were explored and developed in the China and the increasing necessity for well control safety has been forcing the oil and gas industry to study the principles of wellbore multiphase flow and phase transition of drilling during acid fluid invasion. Based on the theories of pressure drop and heat transfer for liquid-gas two phases flow in wellbore, a mathematical model for wellbore flow and heat transfer, in which the special physical properties of supercritical fluid (SC-F) and its phase transition were considered in the wellbore, was established during formation SC-F influx, and a solution method of the model was proposed and program was compiled for the numerical calculation. The results indicate that H2S transforms from liquid to gas state during its rising in the annulus when backpressure is small

  2. Geo Mechanical Analysis of Casing Failure in Bedded Rock Salt Formation

    Directory of Open Access Journals (Sweden)

    Tongtao Wang

    2012-08-01

    Full Text Available There are many bedded rock salt resources in China which are serviced as the hosts of underground natural gas storages. For the relatively thin nature of bedded rock salt and the local presence of other sedimentary rock formations, the design and safety evaluation of well completion casing take greater challenges to the engineers than that of casing in other type formations, i.e., limestone and carbonatite. The 2D and 3D geomechanical models of casing-cement sheath-rock salt are established in the paper based on the field data to obtain the creep loads in casing and find the main reasons causing casing failure. In addition, the effects of non-salt layer dip angle, friction factor between salt and non-salt layers and non-salt layer thickness, etc., on the stresses and deformations of casing are studied. The comprehensive results show hoop creep loads are the main reasons causing casing failure rather than radial creep loads. The cement sheath can improve the safety and optimize force state of casing even in perfect wellbore, which disagrees with Willson’s view that the cement sheath can be neglected in a salt formation wellbore with high quality. The non-uniform factor of radial creep loads in cement sheath is slightly smaller than that of original in-situ stresses, while that of radial creep loads in casing is greatly smaller than it. The stresses and deformations of casing increase with increasing thickness of non-salt layer and decrease with the increase of friction factor. When the non-salt layer dip angle is with a value of 50 deg, the stresses and deformations achieve the max and subsequently decrease.

  3. Flow and heat transfer regulation of multi-thermal fluids injection in wellbore%多元热流体在井筒中的流动与传热规律

    Institute of Scientific and Technical Information of China (English)

    李兆敏; 张丁涌; 衣怀峰; 杜文军; 薛兴昌; 麻涛

    2012-01-01

    建立高温烟气与水的热交换模型以及多元热流体在井筒内流动传热的温度场、压力场计算模型,计算含过热蒸汽和两相流状态的多元热流体在不同井深时的温度、压力以及其他参数.结果表明:随着井筒深度的增加,多元热流体的温度、压力均有所降低,并在某一深度多元热流体中水蒸气开始凝结,进入两相流状态,与纯蒸汽注入相比,其热损失量小,干度下降慢,在井底干度较大;井口注入温度越高、压力越小、流量越大,多元热流体的压降、温降幅度越大,热损失量越小;随着注入温度的降低,环空介质导热系数和注汽流量的增大,多元热流体干度的变化越早或过热度降幅越大,而注入压力对干度的影响有一个最优点,此时蒸汽在井底干度最大.%A heat transfer model between high temperature gas and water was established, and the wellbore temperature and pressure models calculating the temperature field, pressure field and other parameters of multi-thermal fluids single phase flow and two phase flow were developed. The results show that the temperature and pressure of multi-thermal fluids reduce with the increase of the wellbore depth. And at a certain depth, the water vapor of multi-thermal fluids condenses into two phase flow state, and compared with the pure steam injection, the heat loss is small, dryness descends slowly and the bottom-hole dryness is high. The influence of annulus media on the decrease of temperature and pressure is small. The higher inject temperature, the smaller pressure and greater flow rate lead to the faster temperature and pressure declining, and the smaller heat loss. At the same time, the dryness of multi-thermal fluids changes earlier or degree of superheat drops greatly with the diminution of injection temperature, the increase of the annulus media heat conductivity and injection flow, but the influence of pressure on dryness has a best point, and the

  4. A comprehensive prediction model of wellbore temperature, pressure and accumulated liquid for gas wells%气井井筒温度、压力与积液综合预测模型

    Institute of Scientific and Technical Information of China (English)

    李波; 王军磊; 宁波; 苏海洋

    2014-01-01

    气井积液是产水气藏开发设计和气井生产管理面临的重要问题,但目前对气井流动机理与携液预测还存在争议。从气液两相流的基本流动机理出发,建立了考虑液滴变形和井斜影响下气井井筒的流型、温度、压力与携液综合预测模型,并用实际井数据对模型进行了验证。结果表明,所建模型可用于直井、斜井和水平井的产水气井井筒温度压力预测,预测误差小于5%;在环雾状流动情况下,井筒内液体以液滴和液膜的形式被完全带出井口,不会出现井筒积液;对常规垂直气井,利用井口数据便能判断气井积液情况,Turner 模型计算气井携液临界值较实际值偏大,李闽模型计算结果明显偏小,建议采用彭朝阳模型计算气井携液临界值;对斜井和水平井,则需要同时考虑液滴变形和井斜的影响,水平井近水平段携液临界流速和流量明显较垂直井段小,而造斜井段携液临界流速和临界流量随井斜角的增大先增大后减小,在井斜角为30°~60°之间达到最大值,因此造斜井段是气井积液判断的重点部位。%Accumulated fluid in gas well is a key issue confronted in development design of water-producing gas pools and pro-duction management of gas wells, but at present, there are controversies on flow mechanism and water carrying prediction in gas wells. From the basic flow mechanism of two-phase flow of gas and liquid, a comprehensive prediction model was built to predict the flow pattern, temperature, pressure and water-carrying in gas wells, and this model was verified using actual well data. The result shows that the model so built can be used to predict the wellbore temperature and pressure of water-producing vertical wells, deviated wells and horizontal wells, and the prediction error is less than 5%. Under condition of annular mist flow, the fluid in the wellbore is carried out of the wellhead

  5. 钻井液径向温度梯度与轴向导热对井筒温度分布影响%Effects of the radial temperature gradient and axial conduction of drilling fluid on the wellbore temperature distribution∗

    Institute of Scientific and Technical Information of China (English)

    杨谋; 孟英峰; 李皋; 邓建民; 张林; 唐思洪

    2013-01-01

    Therefore, in this study, based on energy balance principle between wellbore and formation, a temperature model of drilling fluid layers was established under different grid units of wellbore condition. Meanwhile, the axial thermal conductivity temperature model of drilling fluid was established by introducing axial conduction items of drilling fluid, followed by using discrete and solving of implicit finite difference method to these mathematical models. The calculation results indicated that the error temperature of the radial and axial of drilling fluid wellbore temperature which was caused of radial temperature gradient were 0.15 and 0.2 ◦C respectively, whereas axis thermal conductivity of drilling fluid has little effect on wellbore temperature distribution. Therefore, the above results confirmed that it can ignore both of them to influence wellbore temperature distribution by established the wellbore-formation coupled transient heat transfer model. Moreover, it is the first proved the correctness of model assumptions from previous scholars based on the mathematical modeling methods, and then further provides the reliable theoretical basis for down-hole temperature distribution of oil and gas well and geothermal well.%  本文基于井筒与地层间能量平衡原理,将井筒钻井液划分成不同径向单元网格,建立了考虑径向温度梯度条件下钻井液层间温度模型;同时引入钻井液轴向导热项,建立了钻井液轴向导热温度模型,将数学模型应用隐式有限差分法离散与求解.计算结果表明:钻井液径向温度梯度对井筒径向与轴向温度产生的误差分别为0.15◦C和0.2◦C左右;而钻井液轴向导热对井筒温度分布几乎不产生影响.因此,通过建立的数学模型进行系统分析表明,在建立井筒-地层耦合瞬态传热模型时可忽略两者对井筒温度分布的影响.基于数学建模方法验证了以前学者模型

  6. 陆梁油田薄层底水油藏水平井井筒模拟研究%Study on the Horizontal Wellbore Model of Thin-layered Bottom-water Reservoir in Luliang Oilfield

    Institute of Scientific and Technical Information of China (English)

    许维娜; 石军; 颜江; 范赛华; 何长坡

    2013-01-01

      新疆陆梁油田呼图壁河组油藏发育一类特殊的薄层底水型油藏,其特点是油层厚度薄,构造幅度低,底水能量大,利用水平井开采,表现出无水采油期短、含水率上升速度快、产量递减大的特点。针对这些问题,采用水平井数值模拟方法,建立了考虑摩擦压力损失的水平井井筒模型,明确了摩擦压力损失对水平井的压力分布以及水平段产量的影响,在此基础上,分析研究了水平井底水锥进的水脊特征,判断了水平井出水位置,提出了封堵出水井段并结合油藏工程方法确定了水平井合理产液量,从而达到抑制底水快速锥进,减小压力损失,降低含水率上升速度的目的。%A special thin layer of bottom water reservoir has developed in Hutubi River Layer in Luliang Oilfield of Xinjiang. This kind of reservoir has thin thickness,small sand body amplitude and large bottom-water energy. Drilled with horizontal well,this kind of reservoir has possessed some characteristics such as short water free production period and water-cut with faster ascending velocity and big decline production. Aiming at solving these problems,we established the horizontal well-bore model which takes the pressure loss into consideration with the numerical simulation method,and obtained the pressure distribution of horizontal wells and the influence of horizontal section production due to the pressure loss. On this basis,we analyzed the features of water cresting characteristic of the horizontal well bottom water coning,and judged the location of water breakthrough in horizontal section. Finally,the paper suggests that the reasonable liquid production can be achieved by plugging the location of water breakthrough and using pump which has smaller diameter. Such method will control bottom water coning and decrease the pressure loss and reduce the water cut increasing rate.

  7. Wellbore pressure response in naturally fractured reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Reynolds, A.C. Jr.; Chang, W.; Raghavan, R.

    1983-01-01

    Recently a new flow regime has been identified for pressure drawdown or buildup data obtained from a well producing a naturally fractured reservoir. During the time period corresponding to this new flow regime, a semilog plot of pressure vs. time exhibits a semilog straight line with slope equal to m/2, where m is the slope of both the early and late time semilog straight lines predicted by the Warren and Root model. The identification of this intermediate time semilog straight line means that pressure data may exhibit as many as 3 semilog straight lines. A virtually complete analysis of well test pressure data is possible when the data exhibits 2 or more of the 3 possible straight lines. This work presents type curves which can be used to obtain a virtually complete analysis of pressure data when only one of the 3 semilog straight lines is reflected by the data. 13 references.

  8. A wellbore flow model of CO2 separate injection with concentric dual tubes and its affecting factors%同心双管分注CO2井筒流动模型及影响因素

    Institute of Scientific and Technical Information of China (English)

    吴晗; 吴晓东; 王庆; 朱明; 方越

    2011-01-01

    In view of issues of the low efficiency and poor effect in the process of commingled CO2 injection, a CO2 separate injection with concentric dual tubes was proposed. On the basis of the heat transfer principle and fluid flow theory, a mathematical model considering CO2 phase change as flowing along the wellbore of concentric dual tubes and heat transfer was established, with which temperature and pressure distributions of CO2 along the annulus between inner and outer tubes and in the inner tubing string were calculated. Moreover, effects brought about by various factors, such as injection rate, injection temperature, injection pressure, assemblage of inner and outer tubes, interval of injection layers etc. , on the pressure and temperature of CO2 flowing both in the annulus between inner and outer tubes and in the inner tubing string were investigated as well. The results indicate that on condition that wellhead injection parameters of inner and outer tubes are the same, the bigger the diameter of the outer tube, the higher the temperature of the annulus between inner and outer tubes. If the diameter of the outer tube keeps constant, the pressure of the annulus will increase with decreasing the diameter of the inner tube that has a small influence on the temperature of the annulus. When inner and outer tubes have definite diameters, the wellhead injection rate, injection temperature and intervals of injection layers may all have significant effects on temperature and pressure distributions of the annulus and the inner tube, while the wellhead injection pressure affects them a little.%针对CO2笼统注入过程中效率低、效果差等问题,提出了同心双管分注CO2技术.根据热量传递原理和流体流动理论,建立了考虑CO2相态变化的同心双管井筒流动与传热的数学模型,利用该模型研究了CO2沿内外管环空和内油管的温度和压力分布规律,分析了井口注入量、注入温度、注入压力、内外管

  9. Invisible casing : new density logging tool measures rock properties through steel and cement

    Energy Technology Data Exchange (ETDEWEB)

    Ross, E.

    2009-03-15

    This article described an open hole and cased hole logging tool developed by Calgary-based RECON Petrotechnologies Ltd. The geological interpretation tool has helped oil and gas producers in North America to maximize value from their drilling investment. The advanced tool provides geologists with a high definition view of the wellbore and formation in real-time. It has the ability to capture more samples per foot than any other system available. As such, it provides better information for accurate identification of pay zones and more complete reservoir and production evaluations. The tool has been used successfully to correlate well logs and map horizons in oil and gas fields in western Canada as well as the Barnett Shale in the United States. 1 ref., 1 fig.

  10. Case histories : implementation of new liner hanger technology in south central Venezuela significantly improves operations in complex wells

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez, C.; Soto, S.; Leon, A. [PDVSA Petroleos de Venezuela SA, Caracas (Venezuela, Bolivarian Republic of); Marval, P.; Schoener-Scott, M. [Halliburton, Houston, TX (United States)

    2009-07-01

    Liner hangers are used in deep drilling operations to eliminate the need for full casing strings. However, conventional liner-hanger system do not always permit tool rotation, and liner-hanger failures can result in the complete loss of the wellbore. This study discussed an expandable liner hanger designed to withstand aggressive reaming as well as drilling to depths. Three case histories of wells located in southern Venezuela were used to compare the use of traditional and expandable liner hanger systems. The studies considered liner weight, and the pressure differentials caused by the use of positive seals. The study showed that conventional liner systems are not suited to the extreme environments of the Venezuelan heavy oil reserves. Multiple leak paths were observed. The expandable liner system provided a gas-tight seal, improved flow paths, and reduced the need for remedial cement jobs. It was concluded that use of the expandable systems also increased worker safety. 6 refs., 13 figs.

  11. Geochemical and Geomechanical Effects on Wellbore Cement Fractures: Data Information for Wellbore Reduced Order Model

    Energy Technology Data Exchange (ETDEWEB)

    Um, Wooyong; Jung, Hun Bok; Kabilan, Senthil; Suh, Dong-Myung; Fernandez, Carlos A.

    2014-01-01

    The primary objective of the National Risk Assessment Partnership (NRAP) program is to develop a defensible, generalized, and science-based methodology and platform for quantifying risk profiles at CO2 injection and storage sites. The methodology must incorporate and define the scientific basis for assessing residual risks associated with long-term stewardship and help guide site operational decision-making and risk management. Development of an integrated and risk-based protocol will help minimize uncertainty in the predicted long-term behavior of the CO2 storage site and thereby increase confidence in storage integrity. The risk profile concept has proven useful in conveying the qualitative evolution of risks for CO2 injection and storage site. However, qualitative risk profiles are not sufficient for specifying long-term liability for CO2 storage sites. Because there has been no science-based defensible and robust methodology developed for quantification of risk profiles for CO2 injection and storage, NRAP has been focused on developing a science-based methodology for quantifying risk profiles for various risk proxies.

  12. Geomechanical and Numerical Studies of Casing Damages in a Reservoir with Solid Production

    Science.gov (United States)

    Gholami, Raoof; Rasouli, Vamegh; Aadnoy, Bernt; Mohammadnejad, Mojtaba

    2016-04-01

    Casings damage is a usually reported incident during production in many fields. This incident is conventionally induced by compressional, tensional, burst or collapse forces applied to the casing string. Excessive anisotropic and non-uniform stresses, causing shear failure in unconsolidated reservoirs, are one of the main reasons reported for the casing failure. In this paper, geomechanical and finite element numerical analysis was applied to model hydraulic and mechanical interactions between casing, cement sheath and formations in a carbonate reservoir located in Southern of Iran. The geomechanical analysis indicated that significant in situ stresses induced as a result of the fault reactivation and pore pressure reduction due to reservoir depletion could be the potential reasons for the casing damage experienced in this field. To assess this, numerical analysis was carried out to simulate the casing in the presence of existing forces during drilling, completion and production phases. It was found that excessive and non-uniform stresses surrounding the wellbore together with pore pressure reduction caused the formation to loss its strength and fail. This shear failure results in solid production, creation of the cavities and deformation of the casing because of the excessive buckling force. In addition, a new empirical equation for prediction of ultimate strength of the casing was developed according to the parameters introduced by sensitivity analysis.

  13. Swelling packer technology : case histories in open hole

    Energy Technology Data Exchange (ETDEWEB)

    Wilkens, A. [Easywell, Woodlands, TX (United States)

    2005-07-01

    This paper presented case histories of swelling packer technology open hole innovations. Challenges such as fluid flow management and the restriction of solids entering the well bore were discussed. Other challenges included the need to reduce well construction costs, long-term reliability, production optimization methods and positive economic returns. In order to simplify production methods, minimize pay zone damage and eliminate moving parts, it is advisable to return to the simpler open hole well-bore method. Zonal isolation issues were discussed. The role of oil swelling packer was described with reference to its flexibility attributes such as the fact that rubber swells in hydrocarbons, activates in oil but not pure water, and creates an effective seal in open hole. Swell packer for oil-based mud was examined, along with details of successful applications. Functionality issues were discussed. The advantages of swell pack for oil-based mud is that it is rugged, self-repairing and has no environmental impact. It also has a good track record and is more flexible than concrete, more durable than Hydrogenated Nitrile Butadiene Rubber (HNBR) and regains integrity after failure. Various well construction advances, completion advances and global installations were discussed. Reservoir, well construction and completion challenges were reviewed. Economic challenges were discussed. Various features of the Constrictor swell packer, which enables annular fluid flow management, were presented. The Oil Selector, a product that enables automatic water control, was also reviewed. 7 figs.

  14. Using open hole and cased-hole resistivity logs to monitor gas hydrate dissociation during a thermal test in the mallik 5L-38 research well, Mackenzie Delta, Canada

    Science.gov (United States)

    Anderson, B.I.; Collett, T.S.; Lewis, R.E.; Dubourg, I.

    2008-01-01

    Gas hydrates, which are naturally occurring ice-like combinations of gas and water, have the potential to provide vast amounts of natural gas from the world's oceans and polar regions. However, producing gas economically from hydrates entails major technical challenges. Proposed recovery methods such as dissociating or melting gas hydrates by heating or depressurization are currently being tested. One such test was conducted in northern Canada by the partners in the Mallik 2002 Gas Hydrate Production Research Well Program. This paper describes how resistivity logs were used to determine the size of the annular region of gas hydrate dissociation that occurred around the wellbore during the thermal test in the Mallik 5L-38 well. An open-hole logging suite, run prior to the thermal test, included array induction, array laterolog, nuclear magnetic resonance and 1.1-GHz electromagnetic propagation logs. The reservoir saturation tool was run both before and after the thermal test to monitor formation changes. A cased-hole formation resistivity log was run after the test.Baseline resistivity values in each formation layer (Rt) were established from the deep laterolog data. The resistivity in the region of gas hydrate dissociation near the wellbore (Rxo) was determined from electromagnetic propagation and reservoir saturation tool measurements. The radius of hydrate dissociation as a function of depth was then determined by means of iterative forward modeling of cased-hole formation resistivity tool response. The solution was obtained by varying the modeled dissociation radius until the modeled log overlaid the field log. Pretest gas hydrate production computer simulations had predicted that dissociation would take place at a uniform radius over the 13-ft test interval. However, the post-test resistivity modeling showed that this was not the case. The resistivity-derived dissociation radius was greatest near the outlet of the pipe that circulated hot water in the wellbore

  15. The effect of various deformation processes on the corrosion behavior of casing and tubing carbon steels in sweet environment

    Science.gov (United States)

    Elramady, Alyaa Gamal

    The aim of this research project is to correlate the plastic deformation and mechanical instability of casing steel materials with corrosion behavior and surface change, in order to identify a tolerable degree of deformation for casing steel materials. While the corrosion of pipeline and casing steels has been investigated extensively, corrosion of these steels in sweet environments with respect to plastic deformation due to bending, rolling, autofrettage, or handling needs more investigation. Downhole tubular expansion of pipes (casings) is becoming standard practice in the petroleum industry to repair damaged casings, shutdown perforations, and ultimately achieve mono-diameter wells. Tubular expansion is a cold-drawing metal forming process, which consists of running conical mandrels through casings either mechanically using a piston or hydraulically by applying a back pressure. This mechanism subjects the pipes to large radial plastic deformations of up to 30 pct. of the inner diameter. It is known that cold-working is a way of strengthening materials such as low carbon steel, but given that this material will be subjected to corrosive environments, susceptibility to stress corrosion cracking (SCC) should be investigated. This research studies the effect of cold-work, in the form of cold-rolling and cold-expansion, on the surface behavior of API 5CT steels when it is exposed to a CO2-containing environment. Cold-work has a pronounced influence on the corrosion behavior of both API 5CT K55 and P110 grade steels. The lowest strength grade steel, API 5CT K55, performed poorly in a corrosive environment in the slow strain rate test. The ductile material exhibited the highest loss in strength and highest susceptibility to stress corrosion cracking in a CO 2-containing environment. The loss in strength declined with cold-rolling, which can be ascribed to the surface compressive stresses induced by cold-work. On the other hand, API 5CT P110 grade steels showed higher

  16. Design, build, develop, and test a fieldworthy spiral tool and packer for casing repair

    Energy Technology Data Exchange (ETDEWEB)

    Koster, C.

    1992-01-01

    A new method for sealing casing is currently under development by Nu-Bore Systems. The method involves internally lining a section of the wellbore with a multi-layer spiral wrapping of a high strength, corrosion resistant metal interleaved with a high bond strength, resilient epoxy. The high strength metal is preferably a copper based alloy hardened to a very high strength in order to resist the internal and external pressures of downhole environments. The epoxy adhesive formulation is one that forms a bond between the steel inner wall of the casing and copper alloy strip. The copper alloy strip spiral wraps are interleaved with epoxy, and the whole system provides a high level of outward directed spring force and, thus, resists both internal and externally directed forces. This method has been assessed by the Department of Energy, and the magnitude of the oilfield need and the technology are described in a DoE report entitled, Downhole Casing Repair System'' (OERI Number 013152). In this report, the cost savings to the nation's energy program was estimated to be in the range of hundreds of millions of dollars per year, and the method was judged technically feasible once certain well defined engineering obstacles are overcome.

  17. Case Report Case Report

    African Journals Online (AJOL)

    User

    2013-03-26

    Mar 26, 2013 ... at the time of diagnosis try various complementary and and palliation. ... c Medicine and Palliative Cancer Care: A Case Report ... us complementary and alternative therapies for treatment about the .... in nature. Upper GI ...

  18. Low temperature barrier wellbores formed using water flushing

    Science.gov (United States)

    McKinzie, II; John, Billy [Houston, TX; Keltner, Thomas Joseph [Spring, TX

    2009-03-10

    A method of forming an opening for a low temperature well is described. The method includes drilling an opening in a formation. Water is introduced into the opening to displace drilling fluid or indigenous gas in the formation adjacent to a portion of the opening. Water is produced from the opening. A low temperature fluid is applied to the opening.

  19. CNLC Provides Well-Bore Technical Services Worldwide

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    @@ BRIEF INTRODUCTION of CNLC China National Logging Corporation (CNLC), a subsidiary of CNPC Services & Engineering Ltd.,which provides well bore technical services at international market solely on behalf of CNPC, is a specialized service company mainly engaged in: 1. Wire-line logging, mud logging, well testing,well completion, perforating and other relevant engineering services.

  20. Investigation of possible wellbore cement failures during hydraulic fracturing operations

    Science.gov (United States)

    Researchers used the peer-reviewed TOUGH+ geomechanics computational software and simulation system to investigate the possibility of fractures and shear failure along vertical wells during hydraulic fracturing operations.

  1. Wellbore manufacturing processes for in situ heat treatment processes

    Science.gov (United States)

    Davidson, Ian Alexander; Geddes, Cameron James; Rudolf, Randall Lynn; Selby, Bruce Allen; MacDonald, Duncan Charles

    2012-12-11

    A method includes making coiled tubing at a coiled tubing manufacturing unit coupled to a coiled tubing transportation system. One or more coiled tubing reels are transported from the coiled tubing manufacturing unit to one or more moveable well drilling systems using the coiled tubing transportation system. The coiled tubing transportation system runs from the tubing manufacturing unit to one or more movable well drilling systems, and then back to the coiled tubing manufacturing unit.

  2. Apparatus for advancing a wellbore using high power laser energy

    Science.gov (United States)

    Zediker, Mark S.; Land, Mark S.; Rinzler, Charles C.; Faircloth, Brian O.; Koblick, Yeshaya; Moxley, Joel F.

    2014-09-02

    Delivering high power laser energy to form a borehole deep into the earth using laser energy. Down hole laser tools, laser systems and laser delivery techniques for advancement, workover and completion activities. A laser bottom hole assembly (LBHA) for the delivery of high power laser energy to the surfaces of a borehole, which assembly may have laser optics, a fluid path for debris removal and a mechanical means to remove earth.

  3. A Fully Analytical Solution of the Wellbore Stability Problem under Undrained Conditions Using a Linearised Cam-Clay Model Solution analytique au problème de stabilité de puits en conditions non drainées utilisant un modèle de Cam-Clay linéarisé

    Directory of Open Access Journals (Sweden)

    Charlez P. A.

    2006-12-01

    Full Text Available This paper presents a linearised version of the Cam-Clay model fully integrated in the scope of the general theory of poroplasticity. The constitutive law which is developed in the scope of the effective plastic stress concept, only contains two plastic parameters (hardening modulus and slope of the critical state line. To be validated, the model is integrated over homogeneous stress paths (hydrostatic, drained triaxial and undrained triaxal then compared with experimental data issued from conventional laboratory triaxial tests. In the second part, a simplified version of the model is applied to the wellbore boundary problem (vertical well in an axisymmetric horizontal stress field and under undrained conditions. Given the linearity of the constitutive law and the a priori knowledge of the shape of the plastic region, the solution (stress, strain and pore pressure is fully analytical. The solution shows that for an overconsolidated material (overconsolidation degree less than 2 the hoop stress is strongly relaxed in the plastic zone. The higher the compressibility of the saturating fluid, the larger the relaxation of the hoop stress. In terms of stability, the more compressible the fluid saturating the porous medium is, the more stable the well will be. Finally the larger the overconsolidation ratio is, the less stable the well will be. Cet article présente une version linéarisée du modèle de Cam-Clay intégré dans le cadre général de la théorie de la poroplasticité isotherme. La loi de comportement développée à partir du concept des contraintes effectives plastiques ne contient que deux paramètres plastiques (module d'écrouissage et pente de la droite critique. Le modèle est validé sur des chemins de contrainte homogènes (hydrostatique, triaxial drainé et triaxial non drainé et comparé à des essais expérimentaux obtenus à partir d'essais conventionnels de laboratoire. Ensuite, une version simplifiée du modèle est

  4. Design, build, develop, and test a fieldworthy spiral tool and packer for casing repair. Quarterly report, June 16, 1992--September 15, 1992

    Energy Technology Data Exchange (ETDEWEB)

    Koster, C.

    1992-10-01

    A new method for sealing casing is currently under development by Nu-Bore Systems. The method involves internally lining a section of the wellbore with a multi-layer spiral wrapping of a high strength, corrosion resistant metal interleaved with a high bond strength, resilient epoxy. The high strength metal is preferably a copper based alloy hardened to a very high strength in order to resist the internal and external pressures of downhole environments. The epoxy adhesive formulation is one that forms a bond between the steel inner wall of the casing and copper alloy strip. The copper alloy strip spiral wraps are interleaved with epoxy, and the whole system provides a high level of outward directed spring force and, thus, resists both internal and externally directed forces. This method has been assessed by the Department of Energy, and the magnitude of the oilfield need and the technology are described in a DoE report entitled, ``Downhole Casing Repair System`` (OERI Number 013152). In this report, the cost savings to the nation`s energy program was estimated to be in the range of hundreds of millions of dollars per year, and the method was judged technically feasible once certain well defined engineering obstacles are overcome.

  5. Case series

    African Journals Online (AJOL)

    abp

    30 janv. 2017 ... Clinical symptoms were mainly cough (32.8% of cases), dyspnea (23.7% of ... of cases, sarcomas in 7.8% of cases, renal cancers in 5.2% of cases, bladder ..... Prognosis of osteosarcoma with pulmonary metastases at initial.

  6. Assessing the effect of cement-steel interface on well casing corrosion in aqueous CO2 environments

    Energy Technology Data Exchange (ETDEWEB)

    Han, Jiabin [Los Alamos National Laboratory; Carey, James W [Los Alamos National Laboratory; Zhang, Jinsuo [Los Alamos National Laboratory

    2010-01-01

    CO{sub 2} leakage is a critical safety concern for geologic storage. In wellbore environments, important leakage paths include the rock-cement and cement-casing interfaces. If the cement-casing interface is filled with escaping CO{sub 2}, the well casing directly contacts the CO{sub 2}. This can cause severe corrosion in the presence of water. This paper studies the effect of steel-cement interface gaps, ranging from 1 mm to 0 um, on casing corrosion. Corrosion kinetics were measured employing electrochemical techniques including linear polarization resistance, open circuit potential and electrochemical impedance spectroscopy. The experimental results showed that the corrosion of steel is not significant where the gap between steel and cement is small ({le} 100 {micro}m). Corrosion rates are controlled by the diffusion of corrosive species (H{sub 2}CO{sub 3} and H{sup +}) along the interface. In contrast, steel corrosion is severe in a broad gap where the corrosion process is limited only by the reaction kinetics of steel and corrosive species. The threshold leading to severe corrosion in terms of the cement-steel interface size (100 {micro}m) was determined. Our research clarifies a corrosion scenario at the cement-steel interface. Casing steel corrosion is initiated when attacked by corrosive species at the cement-steel interface. For relatively tight interfaces, this results in a slow thinning of the casing and expansion of the interface width. If the gap increases beyond the critical threshold size, the corrosion rate increases significantly, and a potentially damaging cycle of corrosion and interface expansion is developed.

  7. Case study : evaluation of oilfield and water well disposal well designs for oil sands facility in northern Alberta, Canada

    Energy Technology Data Exchange (ETDEWEB)

    Champollion, Y.; Gleixner, M.R.; Wozniewicz, J. [Golder Associates Ltd., Calgary, AB (Canada); MacFarlane, W.D.; Skulski, L. [Nexen Canada Ltd., Calgary, AB (Canada)

    2003-07-01

    Large volumes of wastewater disposal capacity will be required for the production of bitumen at the Long Lake Project, located in northeastern Alberta. An unconsolidated sand aquifer is the target formation for disposal. An evaluation of two disposal well designs, perforated casing (standard oil and gas approach), and wire-wound telescopic screen (standard water well approach) was performed. Skin, transmissivity and storability were the hydraulic parameters quantified. Full superposition type curves were used to conduct the transient analysis, along with the use of pressure derivative data. The results from the injection tests revealed that the sand aquifer at the Long Lake Project had suitable aquifer disposal capacity. The test results also revealed that clogging takes place in the vicinity of the wellbore, probably because of suspended solids in the injection water and the degassing effects. The water well design, as opposed to the standard oilfields well, makes provision for less costly re-development during operations, something that might be required if clogging problems occur. 3 refs., 8 figs.

  8. Case report

    African Journals Online (AJOL)

    abp

    Primary omental torsion in children: case report ... Primary omental torsion is a rare cause of acute abdominal pain, we report a case of 10-year-old boy admitted with ... Pan African Medical Journal. ... nausea, vomiting, and diarrhea may occur.

  9. Assurance Cases

    Science.gov (United States)

    2015-01-26

    2015 Carnegie Mellon University Assurance Cases Software Engineering Institute Carnegie Mellon University Pittsburgh, PA 15213 Charles B...1. REPORT DATE 26 JAN 2015 2. REPORT TYPE N/A 3. DATES COVERED 4. TITLE AND SUBTITLE Assurance Cases 5a. CONTRACT NUMBER 5b. GRANT NUMBER... Assurance Cases Charles B. Weinstock, January 2015 © 2015 Carnegie Mellon University Copyright 2015 Carnegie Mellon University This material is based upon

  10. Case - Case-Law - Law

    DEFF Research Database (Denmark)

    Sadl, Urska

    2013-01-01

    Reasoning of the Court of Justice of the European Union – Constr uction of arguments in the case-law of the Court – Citation technique – The use of formulas to transform case-law into ‘law’ – ‘Formulaic style’ – European citizenship as a fundamental status – Ruiz Zambrano – Reasoning from...

  11. CASE REPORT

    African Journals Online (AJOL)

    DR ABDUL

    reported a case of Ogilvie's syndrome following a caesarean delivery ... perinatal mortality has been attributed to the difficulty in the early diagnosis ... The abdomen was full, moved with respiration and soft. There .... Acute intestinal obstruction.

  12. Case report

    African Journals Online (AJOL)

    abp

    Cerebral venous sinus thrombosis in HIV-infected patients: report of 2 cases. Julius Chacha ... affected adults are women, and direct causes or predisposing risk factors can be .... Some studies have reported a high prevalence of antibodies.

  13. Case report

    African Journals Online (AJOL)

    abp

    2017-05-05

    May 5, 2017 ... Chondroblastic osteosarcoma of the distal tibia: a rare case report ... 1Department of Orthopaedic Surgery, University Hospital, Monastir, Tunisia .... number of published reports describe pulmonary tumour metastasis.

  14. Case report

    African Journals Online (AJOL)

    abp

    2014-03-28

    Mar 28, 2014 ... Iatrogenic cushing's syndrome in children following nasal steroid. Isaac Oludare .... which a diagnosis of adenoidal hypertrophy was made and he was ... Oyenusi participated in patients' management and review of case.

  15. Case report

    African Journals Online (AJOL)

    ebutamanya

    2016-03-24

    Mar 24, 2016 ... Meknes, Morocco, 3Department of Radiology, Military Hospital Moulay Ismail, Meknes, ... Our case raises the awareness among health professionals about ... abdomen was sensitive and on the digital rectal examination the.

  16. Case series

    African Journals Online (AJOL)

    abp

    2015-11-23

    Nov 23, 2015 ... The prevalence and characteristics of right heart endocarditis in Africa are not well ... Anaemia was present in 9 patients whilst leukocytosis in 6 patients. The .... three cases of renal impairment, heart failure in two patients and.

  17. Case report

    African Journals Online (AJOL)

    abp

    2017-06-29

    Jun 29, 2017 ... Von Willebrand's disease: case report and review of literature. Hanae Echahdi1 ... glycoprotein crucial for platelet adhesion to the subendothelium after vascular injury. VWD include .... minor surgery including dental work.

  18. Case note

    African Journals Online (AJOL)

    with the Criminal Procedure Act has caused interpretational difficulties. Two cases have provided ... based on reports by monitors and social workers who had found ..... legislation, where possible, in conformity with the. Constitution.32 Courts ...

  19. Case report

    African Journals Online (AJOL)

    abp

    2017-06-13

    Jun 13, 2017 ... Enterobiasis (oxyuriasis) is a common infection in human caused by Enterobius vermicularis (E. ... We report a case of oxyuriasis that took place in the refugee camp ... slightly painful, especially in the lower right quadrant.

  20. Case report

    African Journals Online (AJOL)

    ebutamanya

    2016-04-06

    Apr 6, 2016 ... A case of Kartagener syndrome with rhinolalia clausa. Mohammed ... ciliary movement; it was described by manes kartagener in 1933 comprising a triad of ... The speech therapy examination report revealed the presence ...

  1. Case report

    African Journals Online (AJOL)

    abp

    2017-07-14

    Jul 14, 2017 ... In this report, we present a case of osteogenesis imperfecta (OI) type IV, seen in a female fetus with ... without fractures, short stature, dentinogenesis imperfecta and ... curvature of the femurs were detected (Figure 2A).

  2. Case series

    African Journals Online (AJOL)

    abp

    2013-06-20

    Jun 20, 2013 ... Upper cervical spine injuries: a management of a series of 70 cases. El Fatemi ... women, with traffic accidents being the major traumatic cause. .... osteosynthesis is preferred to respect the biomechanics of the cervical spine ...

  3. Case Report

    African Journals Online (AJOL)

    Arab Journal of Nephrology and Transplantation. 2013 Sep;6(3):177-9 ... Further systemic clinical examination ... Sternal marrow aspiration revealed slight myelodysplasia consistent ... case, renal biopsy findings and clinical follow-up made.

  4. Case Report

    DEFF Research Database (Denmark)

    Søborg, Marie-Louise Kulas; Rosenberg, Jacob; Burcharth, Jakob

    2016-01-01

    neuropathy (AMSAN). Reports of AMSAN with onset after epidural anesthesia and spinal surgery are extremely rare, and the linkage between development of GBS and neuroaxial anesthesia remains conclusively unconfirmed. We present a case in which the patient developed subacute motor and predominantly sensory...... neuropathy following epidural blockade. The case emphasizes the need of including AMSAN in differential diagnostic considerations to changes in motor and sensory function following epidural anesthesia, allowing accelerated rehabilitation and relevant alleviating therapy....

  5. Dermatology case

    Directory of Open Access Journals (Sweden)

    Sandrina Carvalho

    2016-03-01

    Full Text Available Pilomatrixoma is a benign tumor of skin appendages with follicular differentiation most frequently found in children and adolescents, predominantly female. Clinically it is characterized by an erythematous-violaceous mobile nodule of hard consistency located on the head or neck. Although rare, multiple pilomatrixomas can be associated with other pathologies, particularly myotonic dystrophy or Steinert’s disease. In these cases, a prolonged follow-up should be maintained to rule out relapses and/or development of other diseases. We describe the case of a 9-year-old girl with multiple pilomatrixomas.

  6. Case work

    DEFF Research Database (Denmark)

    Shaw, Ian Frank

    2016-01-01

    Answers to the question just what is the ?case? partly defined the fields of sociology and social work in early 20th century Chicago. Drawing on the archives of the University of Chicago, I describe and appraise the way the ?case? figured in social work at Chicago and elsewhere. I ask...... the corresponding question of sociology. Finally, I briefly consider why not much came of social work and sociology ploughing similar territory in ways that served for a time to hallmark their identities. This analysis opens up ways of rethinking how social work and sociological research are distinctive...

  7. Case report

    African Journals Online (AJOL)

    ebutamanya

    2015-02-27

    Feb 27, 2015 ... Key words: Headache, spinal analgesia, epidural anaesthesia, post-dural ... Clinical features the typical positional headache, a procession of ... The immediate postoperative analgesia was ... However, the day after surgery, the patient complained of ... In case of epidural analgesia, a prophylactic blood.

  8. Case report

    African Journals Online (AJOL)

    abp

    16 déc. 2015 ... C'est un cancer à évolution locorégionale, rarement extra pelvienne ... carcinomateux TTF1 négatif, p63 négatif et p16 fortement positif compatible .... cervix presenting as lymphangiticcarcinomatosis: a case report and reviex ...

  9. Cases Description

    DEFF Research Database (Denmark)

    Hansen, Jesper Rohr; Savini, Federico; Wallin, Sirkku

    2013-01-01

    The JPI Urban Europe research project ‘APRILab’ focuses on planning dilemmas for the transformation of city areas in the urban fringe. In this Working Document we describe the case studies selected by the involved partners: - Aalto University, Finland: T3 in Espoo City - Aalborg University, Denmark...

  10. Case study

    DEFF Research Database (Denmark)

    Milana, Marcella; Bernt Sørensen, Tore

    that time Roskilde University Centre and Learning Lab Denmark, DK)3. The case here presented is based on results from research activity carried out over a 1 year period (spring 2006 - spring 2007). Detailed information concerning participation in the project was collected in two DHSs only: the Sports Day...

  11. Case report

    African Journals Online (AJOL)

    abp

    15 juin 2017 ... Primary squamous cell carcinoma of the colon: about a case .... des cancers extradigestifs ; des cas de carcinomes ovarien, endométrial, prostatique et ... tumeur (peu différenciée et indifférenciée) et le stade IV de TNM. [1,10].

  12. Case report

    DEFF Research Database (Denmark)

    Füchtbauer, Laila; Brusgaard, Klaus; Ledaal, Pål;

    2015-01-01

    ey Clinical Message Vitamin D-dependent rickets type 1 VDDR-1 is a recessive inherited disorder with impaired activation of vitamin D, caused by mutations in CYP27B1. We present long-time follow-up of a case with a novel mutation including high-resolution peripheral quantitative computed tomography...

  13. Case report

    African Journals Online (AJOL)

    abp

    2015-11-24

    Nov 24, 2015 ... the first molecularly confirmed case of FOP in sub-Saharan Africa outside South ... She is the seventh child in her family of eight children and the only affected in ... mobility, weight loss due to ankylosis of the jaw and thoracic.

  14. Case competitions

    DEFF Research Database (Denmark)

    Schjoldager, Anne Gram

    2009-01-01

    The paper presents and discusses a teaching project with case competitions for MA students of specialised translation at the Aarhus School of Business, Aarhus University. Drawing on a series of online questionnaires, the paper ascertains how the project was evaluated by the participating students...

  15. Case competitions

    DEFF Research Database (Denmark)

    Schjoldager, Anne Gram

    2009-01-01

    The paper presents and discusses a teaching project with case competitions for MA students of specialised translation at the Aarhus School of Business, Aarhus University. Drawing on a series of online questionnaires, the paper ascertains how the project was evaluated by the participating students...

  16. A Case for Case Report

    Directory of Open Access Journals (Sweden)

    Vivek Gharpure

    2010-11-01

    Full Text Available Evidence based medicine (EBM is becoming popular among clinicians and medical publishers; as clinical research is tested against the touchstone of EBM. Theory of Quality of Evidence, considers randomized controlled trials to be the best quality evidence, while case reports and expert opinions are considered at the lowest ebb

  17. Corruption case.

    Science.gov (United States)

    1999-07-23

    A Federal jury in Puerto Rico found three defendants guilty of participating in the theft of $2.2 million in Federal funds from the San Juan AIDS Institute. The key figure in the case is [name removed], a consultant to the institute. He was convicted of 12 counts of money laundering and faces up to 25 years in prison. Two other administrative officials were also convicted in the case. Four others have pleaded guilty, and three more await trial. Rep. Jose Granados Navado was among those implicated; he received $100,000 for his campaign for mayor of San Juan in 1988 from the institute=s medical director. U.S. Rep. Tom Coburn (R-Okla.) has called for an audit of all Ryan White CARE Act funds since this scandal was uncovered.

  18. Radiological case

    Directory of Open Access Journals (Sweden)

    Filipe Macedo

    2016-03-01

    Full Text Available We present a case of a 15-year-old boy with sudden onset of left hip pain while playing football. The x-ray revealed an avulsion injury of the anterior inferior iliac spine. The anterior inferior iliac spine is one of the places in the pelvis where avulsion injuries can occur and is due to forceful contractions of the rectus femoris muscle.

  19. Dermatology case

    Directory of Open Access Journals (Sweden)

    Catarina Dias

    2017-01-01

    Full Text Available Glomuvenous malformations, also known as glomangiomas, are tumor-like malformations or hamartomas of the glomus body. They can be sporadic or inherited as an autosomal dominant disease. Glomuvenous malformations tend to resemble hemangiomas. Clinical distinction between these entities is important due to their different therapeutic approaches. Surgical excision is the treatment of choice for isolated, painful glomuvenous malformations. We describe a case of a 7-year-old girl with multiple glomuvenous malformations.

  20. Dermatology case

    Directory of Open Access Journals (Sweden)

    Sandrina Carvalho

    2015-12-01

    and self-limiting dermatosis with characteristic clinical and histopathological pattern that justify its designation. It is characterized by annular or arciform erythematous plaques, preferably affecting the extensor surface of upper and lower limbs of younger patients. There are four main variants of granuloma annulare: localized, generalized, subcutaneous and perforating. In childhood, localized and subcutaneous forms are most commonly observed. We describe the case of a seven-year-old girl with localized granuloma annulare.

  1. Dermatology Case

    Directory of Open Access Journals (Sweden)

    Catarina Matos

    2017-01-01

    Full Text Available The authors describe a clinical case of a 5-months-old boy with widespread rash since the first month of life. Diffuse papular rash with intensive itching. The shaved skin was inconclusive so we performed biopsy to conÞ rm the diagnosis of scabies. It’s a dermatosis very contagious caused by the mite Sarcoptes scabiei var. hominis. In infants skin eruption may have a polymorphic presentation with characteristic distribution.

  2. Case04

    DEFF Research Database (Denmark)

    Vestergaard, Flemming; Karlshøj, Jan; Hauch, Peter;

    Casestudiets formål er at beskrive og måle en større entreprenørvirksomheds omkostninger og gevin-ster ved at anvende metoder og værktøjer, der er modelbaserede. Case 04 tager udgangspunkt i et konkret byggeprojekt, hvor BIM teknologien er anvendt på et for den danske entreprenørbranche rela...

  3. Case Corabelle

    OpenAIRE

    Hansen, Casper; Henriksen, Jesper; Loznica, Javor; Ragnarsson, Stefan; Hensing, Marcus

    2015-01-01

    This project explores the relation between organizational identity and online brands as formed through interaction and communication on online, social media through a case study of the cancelled music festival event Corabelle that was supposed to have been held in August of 2014. The investigation draws on the theories of Carlos Scolari and David A. Whetten to establish the relation between organizational identity and online brands, and the theories of Henry Jenkins and Jan H. Kietzmann in an...

  4. Encouraging Cases

    DEFF Research Database (Denmark)

    Koss Rasmussen, Rasmus

    In CMS, debates on methodology have typically taken second stage to those on epistemology and ontology as the field embraced a plurality of methods. Recent work pushing for CMS to engage more strongly with mainstream theory, however, raises the need for a discussion on how to use methods recogniz......” (Schofield, 2002). In this way, employing case studies in a progressive fashion may serve as a valuable means for a critically perfomative CMS to achieve greater impact through influence on mainstream theory building, business school education and management practice.......In CMS, debates on methodology have typically taken second stage to those on epistemology and ontology as the field embraced a plurality of methods. Recent work pushing for CMS to engage more strongly with mainstream theory, however, raises the need for a discussion on how to use methods...... recognizable to the mainstream in progressive ways. This paper seeks to remedy this lacunae by linking the concept of Critical Performativity (Spicer, Alvesson & Kärreman, 2009) to case study research and shows how case studies informed by Critical Realism (Easton, 2010a) can be generalized to “what could be...

  5. The fluid-compensated cement bond log

    Energy Technology Data Exchange (ETDEWEB)

    Nayfeh, T.H.; Leslie, H.D.; Wheelis, W.B.

    1984-09-01

    An experimental and numerical wave mechanics study of cement bond logs demonstrated that wellsite computer processing can now segregate wellbore fluid effects from the sonic signal response to changing cement strength. Traditionally, cement logs have been interpreted as if water were in the wellbore, without consideration of wellbore fluid effects. These effects were assumed to be negligible. However, with the increasing number of logs being run in completion fluids such as CaCl/sub 2/, ZnBr/sub 2/, and CaBr/sub 2/, large variations in cement bond logs became apparent. A Schlumberger internal paper showing that bond log amplitude is related to the acoustic impedance of the fluid in which the tool is run led to a comprehensive study of wellbore fluid effects. Numerical and experimental models were developed simulating wellbore geometry. Measurements were conducted in 5-, 7-, and 95/8-in. casings by varying the wellbore fluid densities, viscosities, and fluid types (acoustic impedance). Parallel numerical modeling was undertaken using similar parameters. The results showed that the bond log amplitude varied dramatically with the wellbore fluid's acoustic impedance; for example, there was a 70 percent increase in the signal amplitude for 11.5-lb/ gal CaCl/sub 2/ over the signal amplitude in water. This led to the development of a Fluid-Compensated Bond log that corrects the amplitude for acoustic impedance of varying wellbore fluids, thereby making the measurements more directly related to the cement quality.

  6. System for fracturing an underground geologic formation

    Science.gov (United States)

    Mace, Jonathan L.; Tappan, Bryce C.; Seitz, Gerald J.; Bronisz, Lawrence E.

    2017-03-14

    An explosive system for fracturing an underground geologic formation adjacent to a wellbore can comprise a plurality of explosive units comprising an explosive material contained within the casing, and detonation control modules electrically coupled to the plurality of explosive units and configured to cause a power pulse to be transmitted to at least one detonator of at least one of the plurality of explosive units for detonation of the explosive material. The explosive units are configured to be positioned within a wellbore in spaced apart positions relative to one another along a string with the detonation control modules positioned adjacent to the plurality of explosive units in the wellbore, such that the axial positions of the explosive units relative to the wellbore are at least partially based on geologic properties of the geologic formation adjacent the wellbore.

  7. System for fracturing an underground geologic formation

    Energy Technology Data Exchange (ETDEWEB)

    Mace, Jonathan L.; Tappan, Bryce C.; Seitz, Gerald J.; Bronisz, Lawrence E.

    2017-03-14

    An explosive system for fracturing an underground geologic formation adjacent to a wellbore can comprise a plurality of explosive units comprising an explosive material contained within the casing, and detonation control modules electrically coupled to the plurality of explosive units and configured to cause a power pulse to be transmitted to at least one detonator of at least one of the plurality of explosive units for detonation of the explosive material. The explosive units are configured to be positioned within a wellbore in spaced apart positions relative to one another along a string with the detonation control modules positioned adjacent to the plurality of explosive units in the wellbore, such that the axial positions of the explosive units relative to the wellbore are at least partially based on geologic properties of the geologic formation adjacent the wellbore.

  8. Dermatology Case

    Directory of Open Access Journals (Sweden)

    Sandrina Carvalho

    2016-09-01

    Full Text Available Connective tissue nevus (CTN is a hamartomatous growth which can be associated to multiple syndromes, such as tuberous sclerosis, Buschke-Ollendorf syndrome, or Proteus syndrome. Familial cases of CTN have also been related to cardiac disease. Classically, CTN are characterized by asymptomatic, firm, multiple, skin-colored or yellowish plaques on the trunk or limbs, arising during childhood with no gender preference. A skin biopsy is usually necessary to confirm the diagnosis. Additional studies are oriented by signs or symptoms suggesting an underlying disease.

  9. Tesco Rotary Steerable Casing Drilling Technology%Tesco旋转导向套管钻井技术

    Institute of Scientific and Technical Information of China (English)

    张兰江; 张明杰; 梁玉斌; 谢新华; 夏竹君; 张国超

    2016-01-01

    为了使旋转导向套管钻井技术在我国的石油钻井行业中得到应用,介绍了Tesco公司旋转导向套管钻井技术特点,从井下和地面配套设备2方面介绍了旋转导向套管钻井系统的构成,并与常规定向钻具可回收式套管钻井系统进行了对比,同时分析了不适用旋转导向套管钻井技术的情况,借助马来西亚国家石油公司3口批钻井对旋转导向套管钻井技术进行了现场应用.应用结果表明,旋转导向套管钻井技术缩短了总的钻井周期,套管钻井省去了起钻、 通井、 循环和下套管的时间;具备常规旋转导向钻井的优势,降低了滑动钻进的事故发生率,所钻井眼轨迹平滑,并且提高了钻井机械钻速.建议我国加快技术研发,使旋转导向套管钻井技术在我国的海洋钻井中发挥出巨大优势.%The features of Tesco' s rotary steerable casing drilling technology have been introduced, and de-tails have been focused on the technology' s downhole and surface equipment. Comparison with conventional retriev-able directional casing drilling system has been conducted. Conditions that do not suitable for rotary steerable casing drilling technology have been analyzed. Field applications have been conducted in Petronas three wells. Application results show that the rotary steerable casing drilling technology has shortened the overall drilling time by eliminating the time for tripping out, wiper trip, circulation and casing running. The technology has the advantage of conven-tional rotary steerable drilling with reduced accident rate of sliding drilling, smooth wellbore trajectory, and im-proved ROP. Recommendation has been proposed to accelerate the technology development for providing the advan-tage of rotary steerable casing drilling technology in offshore drilling in China.

  10. Case management.

    Science.gov (United States)

    Rosenstein, A H; Propotnik, T

    1997-03-01

    Providing cost-effective high quality healthcare services ranks as the number one concern for anyone involved with the healthcare delivery system. While quality of care should always be the number one priority, controlling healthcare costs receives most of the attention. With limited healthcare dollars and providers assuming more of the financial risk for services rendered, a whole assortment of cost-containment strategies are being introduced in an effort to maintain some semblance of financial viability. Healthcare providers can approach cost control from two different angles. On the fixed-cost operational overhead side, traditional cost-containment techniques have focused on downsizing, maximizing productivity, staffing redesign, improved purchasing contracts, standardization, inventory control, and other more individualized restructured service models. On the variable-cost clinical side, cost control has been approached by introducing a variety of cost-containment strategies designed to improve efficiency and effectiveness of provider performance. While many of these strategies, previously discussed in the Journal of Healthcare Resource Management have stressed the importance of education, guidelines, pathways, and other clinical "tools for improvement," the success of many of these tools resides in the ability to provide real-time intervention. Real-time intervention rather than the more passive retrospective variance analysis has the greatest potential for producing cost savings by actually making a recommendation that prevents the unwanted event from occurring. In many institutions, the case manager bears the responsibility for monitoring and managing these programs. This article describes various case management models currently used by different institutions.

  11. Endoscopic case

    Directory of Open Access Journals (Sweden)

    Fernando Pereira

    2017-01-01

    Full Text Available We present the case of a ten-year-old female patient referred to Gastroenterolgy consultation for abdominal pain and cramping, usually worse after eating, recurring diarrhoea, hypochromic and microcytic anaemia with low serum iron and ferritin levels. Moderate to severe Crohn’s disease of the terminal ileum e right colon (L3 was diagnosed, based on endoscopic image and biopsy. The patient was treated with prednisone and azathioprine, but after one year of treatment she was steroids dependent and treatment was switched to infliximab. One year after beginning this treatment, the patient achieved remission (clinical and laboratorial parameters. A control colonoscopy showed mucosal healing with scars and deformation with stenosis of ileocecal valve (Figures 1-2. Surgical intervention will be probably necessary in near future.

  12. Dermatology case

    Directory of Open Access Journals (Sweden)

    Susana Vilaça

    2016-02-01

    Full Text Available Tinea corporis is a dermatophyte infection of the body. It usually begins as a pruritic circular or oval erythematous scaling patch or plaque that spreads centrifugally. Multiple lesions may run together to produce “flower petal” configurations. Tinea corporis contracted from infected animals is often intensely inflammatory. The history and clinical picture combination is characteristic, but the diagnosis could be confirmed by KOH (potassium hydroxide examination of scrapings from the lesions. Tinea corporis usually responds to the daily application of topical antifungals, but systemic therapy is needed in patients who have failed topical therapy. We report a case of a two -year old girl with tinea corporis of the vulvar region, initially misdiagnosed as irritant diaper dermatitis.

  13. Case Study: Testing with Case Studies

    Science.gov (United States)

    Herreid, Clyde Freeman

    2015-01-01

    This column provides original articles on innovations in case study teaching, assessment of the method, as well as case studies with teaching notes. This month's issue discusses using case studies to test for knowledge or lessons learned.

  14. Case Study: Testing with Case Studies

    Science.gov (United States)

    Herreid, Clyde Freeman

    2015-01-01

    This column provides original articles on innovations in case study teaching, assessment of the method, as well as case studies with teaching notes. This month's issue discusses using case studies to test for knowledge or lessons learned.

  15. 砂岩储层出砂段套管强度分析%Analyze of Production Casing Failure for Sand Production

    Institute of Scientific and Technical Information of China (English)

    吴怀志; 翟晓鹏; 姬辉; 管虹翔

    2013-01-01

    砂岩储层开采过程中储层砂岩会与储层流体一起流向井筒,易在井筒附近油层形成出砂空洞,使储层出砂段套管失去地层的保护作用,引起套管失效.分析出砂段套管强度校核采用的圆柱壳屈曲模型理论的局限性,提出依据普氏理论,建立疏松砂岩出砂后套管的受力模型;并采用数值方法确定出砂段套管强度值.研究表明:出砂段空洞高度与套管轴向力呈一定线性比例,出砂段空洞与出砂量是一定指数关系.该理论可用来进行出砂段套管的校核和设计.%Loose sandstone reservoir improve oil recovery with reasonable sand control, but cavities around the wellbore are formed when sand is produced, which makes the casing lost the protection of the formation and casing failure comes about. Comparing with the limitation of thin cylindrical shell theory , a mechanical model of stable sand arch acting on casing when sand production is established by M. M- ΠpoTOΠb(R)KOHOB. It is found that strength failure is the main casing failure under sand arching action and casing ultimate strength calibration formula is given. The research shows the cavity height and sand production volume are in a power relationship; the cavity height and axial force are in a linear relationship. With the increase of the overburden pressure, the used he used higher steel grade to keep the reliability of the casing. The research provides theoretical foundation for production casing design and casing strength verify.

  16. Utilizing observations of borehole failure in deviated wellbores to constrain the full stress tensor in deep wells and mines:Application to two complex case studies%利用斜井钻孔破裂观测值约束深井和深矿中的全应力张量——在两个复杂实例中的应用

    Institute of Scientific and Technical Information of China (English)

    Zoback Mark D; Paul Pijush; Lucier Amie; 骆佳骥

    2011-01-01

    经过15年时间我们发展出一套技术,即利用钻孔井壁的非致命性破裂,包括压性破裂、钻探诱发的张性破裂以及与切穿井孔断层的滑动有关的应力扰动观测值,来确定任意向井和钻孔中的全应力张量.这些技术已延伸应用到石油工业中,也应用到矿山开采的钻孔岩芯取样中,以取得开采区周围应力集中影响的区域内外的应力状态.条件允许时,可用水压致裂法估计最小主应力值.但不能估计最大水平主应力值.作者在文中先回顾了这套方法的概念,然后对两个复杂实例进行了研究.第1个实例涉及到圣安德烈斯断层深部观测站(San Andreas Fault Observatory at Depth,SAFOD)计划第1阶段钻探应力状态的确定,SAFOD计划是一个钻穿加州中部圣安德烈斯断层的科学钻井计划.第2个实例涉及到确定南非一个极深矿周围的地壳应力状态.这些研究表明,在相当大的深度范围内.斜井钻孔破裂观测值与应力大小和方向是一致的.

  17. Case Study: Writing a Journal Case Study

    Science.gov (United States)

    Prud'homme-Genereux, Annie

    2016-01-01

    This column provides original articles on innovations in case study teaching, assessment of the method, as well as case studies with teaching notes. This month's issue describes incorporating a journal article into the classroom by first converting it into a case study.

  18. Case Study: Writing a Journal Case Study

    Science.gov (United States)

    Prud'homme-Genereux, Annie

    2016-01-01

    This column provides original articles on innovations in case study teaching, assessment of the method, as well as case studies with teaching notes. This month's issue describes incorporating a journal article into the classroom by first converting it into a case study.

  19. The fluid-compensated cement bond log

    Energy Technology Data Exchange (ETDEWEB)

    Nayfeh, T.H.; Wheelis, W.B. Jr.; Leslie, H.D.

    1986-08-01

    Simulations of cement bond logging (CBL) have shown that wellbore fluid effects can be segregated from sonic-signal response to changing cement strengths. Traditionally, the effects have been considered negligible and the CBL's have been interpreted as if water were in the wellbore. However, large variations in CBL's have become apparent with the increasing number of logs run in completion fluids, such as CaCl/sub 2/, ZnBr/sub 2/, and CaBr/sub 2/. To study wellbore fluid effects, physical and numerical models were developed that simulated the wellbore geometry. Measurements were conducted in 5-, 7-, and 9 5/8-in. casings for a range of wellbore fluid types and for both densities and viscosities. Parallel numerical modeling used similar parameters. Results show that bond-log amplitudes varied dramatically with the wellbore fluid acoustic impedance-i.e., there was a 70% increase in signal amplitudes for 11.5 lbm/gal (1370-kg/m/sup 3/) CaCl/sub 2/ over the signal amplitude in water. This led to the development of a fluid-compensated bond log that corrects the amplitude for acoustic impedance of various wellbore fluids, thereby making the measurements more directly related to the cement quality.

  20. Clinical Case Registries (CCR)

    Data.gov (United States)

    Department of Veterans Affairs — The Clinical Case Registries (CCR) replaced the former Immunology Case Registry and the Hepatitis C Case Registry with local and national databases. The CCR:HIV and...

  1. Case Study Teaching

    Science.gov (United States)

    Herreid, Clyde Freeman

    2011-01-01

    This chapter describes the history of case study teaching, types of cases, and experimental data supporting their effectiveness. It also describes a model for comparing the efficacy of the various case study methods. (Contains 1 figure.)

  2. Case Study Teaching

    Science.gov (United States)

    Herreid, Clyde Freeman

    2011-01-01

    This chapter describes the history of case study teaching, types of cases, and experimental data supporting their effectiveness. It also describes a model for comparing the efficacy of the various case study methods. (Contains 1 figure.)

  3. CASING DRILLING TECHNOLOGY

    OpenAIRE

    Nediljka Gaurina-Međimurec

    2005-01-01

    Casing drilling is an alternative option to conventional drilling and uses standard oilfield casing instead of drillstring. This technology is one of the greatest developments in drilling operations. Casing drilling involves drilling and casing a well simultaneously. In casing driling process, downhole tools can be retrieved, through the casing on wire-line, meaning tool recovery or replacement of tools can take minutes versus hours under conventional methods. This process employs wireline-re...

  4. Project management case studies

    CERN Document Server

    Kerzner, Harold R

    2013-01-01

    A new edition of the most popular book of project management case studies, expanded to include more than 100 cases plus a ""super case"" on the Iridium Project Case studies are an important part of project management education and training. This Fourth Edition of Harold Kerzner''s Project Management Case Studies features a number of new cases covering value measurement in project management. Also included is the well-received ""super case,"" which covers all aspects of project management and may be used as a capstone for a course. This new edition:Contains 100-plus case studies drawn from re

  5. CASING DRILLING TECHNOLOGY

    Directory of Open Access Journals (Sweden)

    Nediljka Gaurina-Međimurec

    2005-12-01

    Full Text Available Casing drilling is an alternative option to conventional drilling and uses standard oilfield casing instead of drillstring. This technology is one of the greatest developments in drilling operations. Casing drilling involves drilling and casing a well simultaneously. In casing driling process, downhole tools can be retrieved, through the casing on wire-line, meaning tool recovery or replacement of tools can take minutes versus hours under conventional methods. This process employs wireline-retrievable tools and a drill-lock assembly, permitting bit and BHA changes, coring, electrical logging and even directional or horizontal drilling. Once the casing point is reached, the casing is cemented in place without tripping pipe.

  6. PSS Case Book

    DEFF Research Database (Denmark)

    Neugebauer, Line Maria; Mougaard, Krestine; Andersen, Jakob Bejbro;

    The transformation process towards a PSS-oriented company is describes, through the presentation of the best practice cases. Each case describes motivations, challenges, business models and PSS offerings.......The transformation process towards a PSS-oriented company is describes, through the presentation of the best practice cases. Each case describes motivations, challenges, business models and PSS offerings....

  7. Fracture Characterization in Enhanced Geothermal Systems by Wellbore and Reservoir Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Horne, Roland N.; Li, Kewen; Alaskar, Mohammed; Ames, Morgan; Co, Carla; Juliusson, Egill; Magnusdottir, Lilja

    2012-06-30

    This report highlights the work that was done to characterize fractured geothermal reservoirs using production data. That includes methods that were developed to infer characteristic functions from production data and models that were designed to optimize reinjection scheduling into geothermal reservoirs, based on these characteristic functions. The characterization method provides a robust way of interpreting tracer and flow rate data from fractured reservoirs. The flow-rate data are used to infer the interwell connectivity, which describes how injected fluids are divided between producers in the reservoir. The tracer data are used to find the tracer kernel for each injector-producer connection. The tracer kernel describes the volume and dispersive properties of the interwell flow path. A combination of parametric and nonparametric regression methods were developed to estimate the tracer kernels for situations where data is collected at variable flow-rate or variable injected concentration conditions. The characteristic functions can be used to calibrate thermal transport models, which can in turn be used to predict the productivity of geothermal systems. This predictive model can be used to optimize injection scheduling in a geothermal reservoir, as is illustrated in this report.

  8. High definition geomagnetic models: A new perspective for improved wellbore positioning

    DEFF Research Database (Denmark)

    Maus, Stefan; Nair, Manoj C.; Poedjono, Benny;

    2012-01-01

    Earth's gravity and magnetic fields are used as natural reference frames in directional drilling. The azimuth of the bottomhole assembly is inferred by comparing the magnetic field measured-while-drilling (MWD) with a geomagnetic reference model. To provide a reference of sufficient quality...... for accurate well placement, the US National Geophysical Data Center (NGDC), in partnership with industry, has developed high-definition geomagnetic models (HDGM), updated regularly using the latest satellite, airborne and marine measurements of the Earth's magnetic field. Standard geomagnetic reference models....... These are compiled into a global magnetic anomaly grid and expanded into ellipsoidal harmonics. The harmonic expansion coefficients are then included in the high-definition models to accurately represent the direction and strength of the local geomagnetic field. The latest global model to degree and order 720...

  9. On the analysis of well test data influenced by wellbore storage skin and bottom water drive

    Energy Technology Data Exchange (ETDEWEB)

    Chu, W.C.; Reynolds, A.C.; Raghavan, R.

    1981-01-01

    This paper discusses procedures to analyze pressure data in partially penetrating wells influenced by storage and skin effects. The effect of a gas cap or a bottom-water aquifer is also documented. Type curves are presented to analyze data influenced by storage, skin, partial penetration, and the influence of a constant pressure boundary. The main advantage of this work is that anisotropy (ratio of horizontal to vertical permeability) and penetration ratio are incorporated in a simple way. Procedures to minimize the problems of obtaining a unique type curve matching are also discussed. 16 refs.

  10. High definition geomagnetic models: A new perspective for improved wellbore positioning

    DEFF Research Database (Denmark)

    Maus, Stefan; Nair, Manoj C.; Poedjono, Benny

    2012-01-01

    Earth's gravity and magnetic fields are used as natural reference frames in directional drilling. The azimuth of the bottomhole assembly is inferred by comparing the magnetic field measured-while-drilling (MWD) with a geomagnetic reference model. To provide a reference of sufficient quality for a...

  11. Impact of chemical and mechanical processes on wellbore integrity in CO2 storage systems

    NARCIS (Netherlands)

    Wolterbeek, T.K.T.

    2016-01-01

    Carbon Capture and Storage (CCS), involving the capture of CO2 at large point sources, such as power plants, followed by long-term storage in depleted hydrocarbon reservoirs or saline aquifers remains a key option for reducing CO2 emissions while fossil fuel use continues. For CCS to be effective, t

  12. Enhanced Wellbore Stabilization and Reservoir Productivity with Aphron Drilling Fluid Technology

    Energy Technology Data Exchange (ETDEWEB)

    Fred Growcock

    2004-03-31

    During this second Quarter of the Project, the first four tasks of Phase I--all focusing on the behavior of aphrons--were continued: (a) Aphron Visualization--evaluate and utilize various methods of monitoring and measuring aphron size distribution at elevated pressure; (b) Fluid Density--investigate the effects of pressure, temperature and chemical composition on the survivability of aphrons; (c) Aphron Air Diffusivity--determine the rate of loss of air from aphrons during pressurization; and (d) Pressure Transmissibility--determine whether aphron bridges created in fractures and pore throats reduce fracture propagation. The project team expanded the laboratory facilities and purchased a high-pressure system to measure bubble size distribution, a dissolved oxygen (DO) probe and computers for data acquisition. Although MASI Technologies LLC is not explicitly ISO-certified, all procedures are being documented in a manner commensurate with ISO 9001 certification, including equipment inventory and calibration, data gathering and reporting, chemical inventory and supplier data base, waste management procedures and emergency response plan. Several opportunities presented themselves to share the latest aphron drilling fluid technology with potential clients, including presentation of papers and working exhibit booths at the IADC/SPE Drilling Conference and the SPE Coiled Tubing Conference & Exhibition. In addition, a brief trip to the Formation Damage Symposium resulted in contacts for possible collaboration with ActiSystems, the University of Alberta and TUDRP/ACTS at the University of Tulsa. Preliminary results indicate that the Aphron Visualization and Pressure Transmissibility tasks should be completed on time. Although the Aphron Air Diffusivity task has been impeded by the lack of a suitable DO probe, it is hoped to be completed on time, too. The Fluid Density task, on the other hand, has had significant delays caused by faulty equipment and will likely require an additional month of work. Meanwhile, an assessment of potential methodologies for the Aphron Hydrophobicity project has been initiated and is now focused on measuring wettability of the aphron surface rather than interfacial tension.

  13. A new type of cementation flushing fluid for efficiently removing wellbore filter cake

    Directory of Open Access Journals (Sweden)

    Erding Chen

    2015-11-01

    Full Text Available For effectively removing the water-based drilling fluid filter cake and improving interfacial cementing strength and cementing quality, a new type of cementation flushing fluid (WD-C was developed based on the strong flushing principle of water soluble fiber and the oxygenolysis principle of filter cake. It is composed of 0.5% WF-H fiber, 2.2% WF-O oxidant, 0.35% FeSO4, 1.8% KCl, 3.0% swollen powder perlite and water with its density of 1.03 g/cm3. This cementation flushing fluid was systematically tested and evaluated in terms of its washing efficiency on the filter cake of water-based drilling fluid and its capacity to improve the bonding strength of cementation interface. In addition, an analysis was performed of its effect on the physical-chemical characteristics and the micro-structures of interfacial cements by means of infrared spectrum (IR, scanning electron microscope (SEM and energy dispersive X-ray detector (EDS. It is shown that the new cementation flushing fluid presents excellent washing effect on water-based drilling fluid filter cake (with washing time within 10 min. The cement particles at the cemented interface can be hydrated normally, and hydrated calcium silicate gel, Ca(OH2 and rod-shaped ettringite (AFt crystal are generated and interwoven with each other. In this way, dense network structures are formed, so the bonding strength of the second cementing interface rises significantly, and then cementing quality is improved. Based on the research results, one more technology is set up for removing the water-based drilling fluid filter cake efficiently and improving the bonding strength of the second cementing interface.

  14. Enhanced Wellbore Stabilization and Reservoir Productivity with Aphron Drilling Fluid Technology

    Energy Technology Data Exchange (ETDEWEB)

    Miranda Fosdick; Fred Growcock

    2004-10-30

    Various methods were investigated to measure the oil-wetting character of transient bubbles under static and dynamic conditions, in order to determine the roles played by bubble and micellar agglomeration, coalescence and adhesion to mineral surfaces.

  15. In situ conversion process systems utilizing wellbores in at least two regions of a formation

    Energy Technology Data Exchange (ETDEWEB)

    Vinegar, Harold J. (Bellaire, TX); Hsu, Chia-Fu (Granada Hills, CA)

    2011-09-27

    A system for heating a subsurface formation is described. The system includes a plurality of elongated heaters located in a plurality of openings in the formation. At least two of the heaters are substantially parallel to each other for at least a portion of the lengths of the heaters. At least two of the heaters have first end portions in a first region of the formation and second end portions in a second region of the formation. A source of time-varying current is configured to apply time-varying current to at least two of the heaters. The first end portions of at least two heaters are configured to have substantially the same voltage applied to them. The second portions of at least two heaters are configured to have substantially the same voltage applied to them.

  16. Well-control methods and practices in small-diameter wellbores

    Energy Technology Data Exchange (ETDEWEB)

    Bode, D.J.; Noffke, R.B.; Nickens, H.V. (Amoco Production Co. (US))

    1991-11-01

    This paper reports on slim-hole drilling and continuous coring for oil and gas exploration which has been impeded by lack of documentation of well-control methods for small-annulus drilling. Research in annular pressure losses, kick identification, wireline swab effects, and dynamic-kill well-control effectiveness helped develop a slim-hole well-control methodology.

  17. Case Based Reasoning: Case Representation Methodologies

    Directory of Open Access Journals (Sweden)

    Shaker H. El-Sappagh

    2015-11-01

    Full Text Available Case Based Reasoning (CBR is an important technique in artificial intelligence, which has been applied to various kinds of problems in a wide range of domains. Selecting case representation formalism is critical for the proper operation of the overall CBR system. In this paper, we survey and evaluate all of the existing case representation methodologies. Moreover, the case retrieval and future challenges for effective CBR are explained. Case representation methods are grouped in to knowledge-intensive approaches and traditional approaches. The first group overweight the second one. The first methods depend on ontology and enhance all CBR processes including case representation, retrieval, storage, and adaptation. By using a proposed set of qualitative metrics, the existing methods based on ontology for case representation are studied and evaluated in details. All these systems have limitations. No approach exceeds 53% of the specified metrics. The results of the survey explain the current limitations of CBR systems. It shows that ontology usage in case representation needs improvements to achieve semantic representation and semantic retrieval in CBR system.

  18. Comparative Test Case Specification

    DEFF Research Database (Denmark)

    Kalyanova, Olena; Heiselberg, Per

     This document includes a definition of the comparative test cases DSF200_3 and DSF200_4, which previously described in the comparative test case specification for the test cases DSF100_3 and DSF200_3 [Ref.1]....... This document includes a definition of the comparative test cases DSF200_3 and DSF200_4, which previously described in the comparative test case specification for the test cases DSF100_3 and DSF200_3 [Ref.1]....

  19. Feasibibility study - cases

    DEFF Research Database (Denmark)

    2004-01-01

    The chapter presents two case studies to show the tools of feasibiliy studies within the context of technological innovation.......The chapter presents two case studies to show the tools of feasibiliy studies within the context of technological innovation....

  20. Disaster Case Management

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Disaster Case Management Program (DCM) is a time-limited process that involves a partnership between a case manager and a disaster survivor (also known as a...

  1. Interpretation of horizontal well performance in complicated systems by the boundary element method

    Energy Technology Data Exchange (ETDEWEB)

    Jongkittinarukorn, K.; Tiab, D. [Oklahoma Univ., School of Petroleum and Geological Engineering (United States); Escobar, F. H. [Surcolombiana Univ., Dept. of Petroleum Engineering (Colombia)

    1998-12-31

    A solution obtained by using the boundary element method to simulate pressure behaviour of horizontal wells in complicated reservoir-wellbore configurations is presented. Three different types of well bore and reservoir models were studied, i.e. a snake-shaped horizontal wellbore intersecting a two-layer reservoir with cross flow, a horizontal well in a three-layer reservoir with cross flow, and a vertical well intersecting a two-layer reservoir without cross flow. In each case, special attention was paid to the influence of wellbore inclination angle, the distance from the wellbore to the different boundaries and the permeability ratio. Performance of each of these types of wells are discussed. 9 refs., 18 figs.

  2. Geological structures from televiewer logs of GT-2, Fenton Hill, New Mexico: Part 2, Rectification

    Energy Technology Data Exchange (ETDEWEB)

    Burns, K.L.

    1987-08-01

    Televiewer logs from drill hole GT-2 at the Fenton Hill, New Mexico, Hot Dry Rock Site, have been rectified by conversion of structural traces on the scanner imagery to geographic location and orientation. The rectification method was direct inversion that consisted of mapping from the image to the wellbore, inverting the trace on the wellbore for principal points, and rotating from wellbore to geographic coordinates. From the test imagery of GT-2, 733 structures (fractures and foliations) were measured, compared with 42 structures from recovered core. The 733 new measurements listed in this report are a unique and unrepeatable collection of structural information from the Precambrian basement of northern New Mexico. This direct inversion method is accurate where the magnetic field vector is constant and the tool is centered and aligned in a circular wellbore. In other cases this method yields only approximate results.

  3. Case Teaching and Evaluation

    Science.gov (United States)

    Patton, Michael Quinn; Patrizi, Patricia

    2005-01-01

    Experience and reflection on experience are the best teachers, yet rich cases that capture experience for reflection have largely eluded professional training in evaluation. The absence of high-quality, readily available teaching cases has been an important gap in the field. This article reviews the benefits of case teaching, examines evaluation…

  4. FHEO Filed Cases

    Data.gov (United States)

    Department of Housing and Urban Development — The dataset is a list of all the Title VIII fair housing cases filed by FHEO from 1/1/2007 - 12/31/2012 including the case number, case name, filing date, state and...

  5. Portal cholangiopathy: case report

    Directory of Open Access Journals (Sweden)

    Maria Cecilia Almeida Maia

    2014-01-01

    Full Text Available The present report describes the case of a child that after blunt abdominal trauma presented with portal thrombosis followed by progressive splenomegaly and jaundice. Ultrasonography and percutaneous cholangiography revealed biliary dilatation secondary to choledochal stenosis caused by dilated peribiliary veins, characterizing a case of portal biliopathy. The present case report is aimed at presenting an uncommon cause of this condition.

  6. Case study research.

    Science.gov (United States)

    Taylor, Ruth; Thomas-Gregory, Annette

    2015-06-10

    This article describes case study research for nursing and healthcare practice. Case study research offers the researcher an approach by which a phenomenon can be investigated from multiple perspectives within a bounded context, allowing the researcher to provide a 'thick' description of the phenomenon. Although case study research is a flexible approach for the investigation of complex nursing and healthcare issues, it has methodological challenges, often associated with the multiple methods used in individual studies. These are explored through examples of case study research carried out in practice and education settings. An overview of what constitutes 'good' case study research is proposed.

  7. Defining a periodontitis case

    DEFF Research Database (Denmark)

    Baelum, Vibeke; Lopez, Rodrigo

    2012-01-01

    Aim The purpose of the present study was to assess the extent to which the three periodontitis case definition systems proposed by van der Velden, Tonetti & Claffey and Page & Eke identify the same cases in a population of never-treated adults with limited tradition for oral hygiene procedures...... of the concomitant presence of CAL and BOP at the site level. Results The case definitions by Tonetti & Claffey and by Page & Eke yielded similar results, which were also quite similar to the results of simply identifying a case of periodontitis as a person having at least one site showing both CAL ≥ 4 mm and BOP....... Conclusions The results indicate that it should be feasible for the periodontal community to reach an agreement over the distinction between a case and a non-case. The classification system proposed by van der Velden is better suited for providing clinicians with a clear image of the case....

  8. Haemospermia and 25 cases

    Directory of Open Access Journals (Sweden)

    Nikoubakht M

    1997-04-01

    Full Text Available During 3 years (1991-1994 25 cases were evaluated for hemospermia. 64% with primary management had improved. 36% that required more evaluation have at least one urologic problem in TRUS. Of these, adenocarcinoma of prostate, prostatic stone, seminal vesicle dilatation, each two cases, and verumontanum stone, urethral polyp, prostatic cyst each one case are diagnosed. According to this study the best method for evaluation of hemospermia is transrectal ultrasonography.

  9. From Use Cases to Activity Cases

    DEFF Research Database (Denmark)

    Bækgaard, Lars

    2005-01-01

    Use cases can be used to capture requirements and to subdivide IT-systems into functionally coherent units. Information systems are activity systems that carry out important business activities. Many systems development methods recognize activity modeling as an important development activity. Use...

  10. Teaching Case: Enterprise Architecture Specification Case Study

    Science.gov (United States)

    Steenkamp, Annette Lerine; Alawdah, Amal; Almasri, Osama; Gai, Keke; Khattab, Nidal; Swaby, Carval; Abaas, Ramy

    2013-01-01

    A graduate course in enterprise architecture had a team project component in which a real-world business case, provided by an industry sponsor, formed the basis of the project charter and the architecture statement of work. The paper aims to share the team project experience on developing the architecture specifications based on the business case…

  11. Right paraduodenal hernia CASE REPORT CASE

    African Journals Online (AJOL)

    6-day history of abdominal pain and vomiting. He had been ... Department of Diagnostic Radiology, University of Limpopo, Medunsa Campus. Fig. 1. Control film ... hernia, but as in this case, it can also be diagnosed on plain film and ... way back into the abdomen, and a final 90o within the abdomen to rotate a full 270o ...

  12. Teaching Case: Enterprise Architecture Specification Case Study

    Science.gov (United States)

    Steenkamp, Annette Lerine; Alawdah, Amal; Almasri, Osama; Gai, Keke; Khattab, Nidal; Swaby, Carval; Abaas, Ramy

    2013-01-01

    A graduate course in enterprise architecture had a team project component in which a real-world business case, provided by an industry sponsor, formed the basis of the project charter and the architecture statement of work. The paper aims to share the team project experience on developing the architecture specifications based on the business case…

  13. Case-based reasoning

    CERN Document Server

    Kolodner, Janet

    1993-01-01

    Case-based reasoning is one of the fastest growing areas in the field of knowledge-based systems and this book, authored by a leader in the field, is the first comprehensive text on the subject. Case-based reasoning systems are systems that store information about situations in their memory. As new problems arise, similar situations are searched out to help solve these problems. Problems are understood and inferences are made by finding the closest cases in memory, comparing and contrasting the problem with those cases, making inferences based on those comparisons, and asking questions whe

  14. AIDS-case surveillance.

    Science.gov (United States)

    Lal, S; Khodakevich, L; Sengupta, D

    1994-01-01

    In 1991 in India, the Ministry of Health realized that the diagnostic and reporting network for AIDS cases was inadequate as AIDS cases grew and that the establishment of specialized AIDS units in hospitals was not the best strategy. It decided to integrate AIDS diagnostic and management facilities into primary health services. It would arrange training for 1 physician from each district and peripheral hospital, private hospital, and inpatient service of other medical institutions in AIDS diagnosis and management. These physicians would then train others in the clinical diagnosis and management of AIDS cases. The physicians would use the World Health Organization [WHO] case definition of AIDS supported by HIV serological test results. All AIDS cases would be transferred to the Medical College Hospitals of the States and Union Territories (UTs), regional hospitals, and perhaps some private hospitals. Between May 1986 and October 1993, India had 459 AIDS cases reported from 19 States and UTs, especially the States of Tamil Nadul and Maharashtra. This AIDS case surveillance system should motivate political will, describe the underlying and preceding HIV epidemic, and contribute to the understanding of current and future course of the epidemic. Thus, it will guide decision makers to develop sound preventive strategies, to plan health care, and to evaluate interventions. The surveillance system's target population is all outpatients and inpatients at medical institutions. During 1993-1994, 1000 hospitals should make up the network of referral institutions. AIDS case surveillance coordinators (ASCs) at each institution form the basis of the network. The individual case record of each suspected AIDS case will have details on his/her life and medical history. Records of confirmed cases will be sent to State ASCs who will compile them for the National AIDS Control Organisation. After 3-4 year of training and practice in AIDS diagnosis and reporting, AIDS reporting will be

  15. Commissioners' Monthly Case Activity Report

    Data.gov (United States)

    Occupational Safety and Health Review Commission — Total cases pending at the beginning of the month, total cases added to the docket during the month, total cases disposed of during the month, and total cases...

  16. Essential trichomegaly: case report

    Directory of Open Access Journals (Sweden)

    Julia Dutra Rossetto

    2013-02-01

    Full Text Available The present study reports two cases of symptomatic essential trichomegaly. Trichomegaly may develop in various diseases, including anorexia nervosa, hypothyroidism, pregnancy, pretibial myxedema, systemic lupus erythematosus, vernal keratoconjunctivitis, and uveitis. The exact incidence trichomegaly is unknown, and the condition remains sporadically reported. Two cases of symptomatic trichomegaly without any associated systemic disorder are presented in this paper.

  17. Examples and Case Studies

    NARCIS (Netherlands)

    Asbach, C.; Aguerre, O.; Bressot, C.; Brouwer, D.H.; Gommel, U.; Gorbunov, B.; Bihan, O. le; Jensen, K.A.; Kaminski, H.; Keller, M.; Koponen, I.K.; Kuhlbusch, T.A.J.; Lecloux, A.; Morgeneyer, M.; Muir, R.; Shandilya, N.; Stahlmecke, B.; Todea, A.M.

    2014-01-01

    Release of nanomaterials may occur during any stage of the life-cycle and can eventually lead to exposure to humans, the environment or products. Due to the large number of combinations of release processes and nanomaterials, release scenarios can currently only be tested on a case-by-case basis. Th

  18. Objectivist case study research

    DEFF Research Database (Denmark)

    Ridder, Hanne Mette Ochsner; Fachner, Jörg

    2016-01-01

    be achieved through the use of objectivist case study research. The strength of the case study design is that it allows for uncovering or suggesting causal relationships in real-life settings through an intensive and rich collection of data. According to Hilliard (1993), the opposite applies for extensive...... designs, in which a small amount of data is gathered on a large number of subjects. With the richness of data, the intensive design is ―the primary pragmatic reason for engaging in single-case or small N research‖ (p. 374) and for working from an idiographic rather than a nomothetic perspective....

  19. Some of the cases

    DEFF Research Database (Denmark)

    Eller, Nanna Hurwitz; Mogensen, Jørn Thykjær; Gyntelberg, Finn

    2014-01-01

    matched on age and gender. The cases had experienced significantly fewer incidents of violence and had less anxiety and flashback symptoms than the controls. The results suggest that the negative press coverage was the reason for the psychiatric symptoms rather than exposures at the workplace.......Some of the cases of acknowledged occupational psychiatric disorder in Denmark have been exposed to negative press coverage. Such individuals might have been exposed to violence to a lower extent than other with an acknowledged psychological work injury. We compared 25 cases with 35 controls...

  20. Recent Case Law

    DEFF Research Database (Denmark)

    Petz, Thomas; Sagaert, Vincent; Østergaard, Kim

    2004-01-01

    In this section authors from various European countries report the recent case law in their country on the field of private patrimonial law, that is decisions on the law of property, juridical acts, the law of obligations, contract law and prescription. The European Review of Private Law (ERPL......) started this section in 2003. The section aims to give our readers an overview of what is happening in the most recent European case law. We have asked the national reporters to report the juridical essence of the decisions given by the highest courts in their country. These national reports...... not relate the facts of the decision, nor the personal opinion of the reporter. One can find discussions on the most important decisions of European courts in ERPL’s case note section. The recent case law section gives overviews of decisions published in periods of four months. The period of January...

  1. Parathyroid carcinoma: case report

    Science.gov (United States)

    STURNIOLO, G.; GAGLIANO, E.; TONANTE, A.; TARANTO, F.; PAPALIA, E.; CASCIO, R.; DAMIANO, C.; VERMIGLIO, F.; STURNIOLO, G.

    2013-01-01

    Summary: The authors present a case of parathyroid carcinoma in a patient with primary hyperparathyroidism. Following a literature review, the clinical and diagnostic profile, treatment and prognosis of this rare disease are discussed. PMID:23837957

  2. Case report: Perinephric lymphangiomatosis

    Directory of Open Access Journals (Sweden)

    Gorantla Rajani

    2010-01-01

    Full Text Available Perirenal lymphangiomatosis is a rare benign malformation of the lymphatic system. We report here a case of bilateral perirenal and parapelvic involvement with a normal excretory collecting system.

  3. PARAPHILLIA : A CASE REPORT

    Science.gov (United States)

    Pawar, A.A.; Valdiya, P.S.; Chaudhury, S.

    2001-01-01

    A case of paraphilia presenting with multiple sexual deviations is reported. The disorder occurred against a background of disordered childhood and was later associated with alcohol abuse. PMID:21407845

  4. Recent Case Law

    DEFF Research Database (Denmark)

    Petz, Thomas; Sagaert, Vincent; Østergaard, Kim

    2004-01-01

    In this section authors from various European countries report the recent case law in their country on the field of private patrimonial law, that is decisions on the law of property, juridical acts, the law of obligations, contract law and prescription. The European Review of Private Law (ERPL......) started this section in 2003. The section aims to give our readers an overview of what is happening in the most recent European case law. We have asked the national reporters to report the juridical essence of the decisions given by the highest courts in their country. These national reports...... not relate the facts of the decision, nor the personal opinion of the reporter. One can find discussions on the most important decisions of European courts in ERPL’s case note section. The recent case law section gives overviews of decisions published in periods of four months. The period of January...

  5. The Space for Case

    Science.gov (United States)

    Shafto, Michael

    1973-01-01

    Research supported by grants from the National Institute of Mental Health, the National Science Foundation, and the Educational Testing Service; examines the psychological validity of Fillmore's theory of case grammar. (DD)

  6. USCIS My Case Status

    Data.gov (United States)

    Department of Homeland Security — USCIS provide a way for the public who applied for U.S. citizenship to check the status of their application online. To view the status of a case, the application...

  7. Autoerotic deaths: four cases.

    Science.gov (United States)

    Cooke, C T; Cadden, G A; Margolius, K A

    1994-07-01

    We describe the circumstances and post mortem medical findings of 4 unusual fatalities where death occurred during autoerotic practice. Three cases occurred in young to middle-aged men--hanging, electrocution and inhalation of a zucchini. The manner of death in each was accidental. The fourth case was an elderly man who died of ischemic heart disease, apparently whilst masturbating with a vacuum cleaner and a hair dryer.

  8. ACROMEGALY: A CASE REPORT

    OpenAIRE

    -()

    2015-01-01

    Acromegaly is a rare disease caused due to hyper secretion of growth hormone. Most of the cases of acromegaly are caused by pitutary adenoma which can be microadenoma or macroadenomas. These adenomas are never malignant, but can have significant morbidity and mortality. We report a 35 year old female patient presented herewith classical presentation of acromegaly with chief complain of weight gain, excessive sweating , widening of both hands and feet and was diagnosed as a case of acromega...

  9. Paraendodontic surgery: case report

    OpenAIRE

    Letícia Marchetti LODI; Sheila POLETO; Renata Grazziotin SOARES; Luis Eduardo Duarte IRALA; Salles, Alexandre Azevedo; Limongi,Orlando

    2008-01-01

    Introduction: Paraendodontic surgery is a procedure that aims problemsresolution that couldn’t be solved by the conventional endodontictreatment, or when the accomplishment conventional treatment is notpossible. Case report and conclusion: The aim of this study was to report a clinical case where was made apicectomy on the teeth 11, 21 and 22.The tooth 22 was sealing of root-end cavity MTA retrofilling.

  10. [Qualitative case study].

    Science.gov (United States)

    Debout, Christophe

    2016-06-01

    The qualitative case study is a research method which enables a complex phenomenon to be explored through the identification of different factors interacting with each other. The case observed is a real situation. In the field of nursing science, it may be a clinical decision-making process. The study thereby enables the patient or health professional experience to be conceptualised. Copyright © 2016. Published by Elsevier Masson SAS.

  11. Case for diagnosis

    OpenAIRE

    Calistru,Ana Maria; Lisboa, Carmen; Bettencourt, Herberto; Azevedo, Filomena

    2012-01-01

    Riga-Fede disease is a rare, benign disorder characterized by reactive ulceration of the oral mucosa associated with repetitive dental traumatism. It was first described in children with neurologic disorders and is very rare in adults. This case report describes the occurrence of a large ulcer of the tongue, resembling squamous cell carcinoma, in an adult with hemiparesis. The lesion cleared after neurologic recovery. This case highlights the importance of considering this disorder in the dif...

  12. Comparative Test Case Specification

    DEFF Research Database (Denmark)

    Kalyanova, Olena; Heiselberg, Per

    This document includes the specification on the IEA task of evaluation building energy simulation computer programs for the Double Skin Facades (DSF) constructions. There are two approaches involved into this procedure, one is the comparative approach and another is the empirical one. In the comp....... In the comparative approach the outcomes of different software tools are compared, while in the empirical approach the modelling results are compared with the results of experimental test cases. The comparative test cases include: ventilation, shading and geometry....

  13. Effects of Fluid Saturation on Gas Recovery from Class-3 Hydrate Accumulations Using Depressurization: Case Study of Yuan-An Ridge Site in Southwestern Offshore Taiwan

    Science.gov (United States)

    Huang, Yi-Jyun; Wu, Cheng-Yueh; Hsieh, Bieng-Zih

    2016-04-01

    Gas hydrates are crystalline compounds in which guest gas molecules are trapped in host lattices of ice crystals. In Taiwan, the significant efforts have recently begun to evaluate the reserves of hydrate because the vast accumulations of gas hydrates had been recognized in southwestern offshore Taiwan. Class-3 type hydrate accumulations are referred to an isolated hydrate layer without an underlying zone of mobile fluids, and the entire hydrate layer may be well within the hydrate stability zone. The depressurization method is a useful dissociation method for gas production from Class-3 hydrate accumulations. The dissociation efficiency is controlled by the responses of hydrate to the propagating pressure disturbance, and the pressure propagation is relating to the amount (or saturation) of the mobile fluid in pore space of the hydrate layer. The purpose of this study is to study the effects of fluid saturation on the gas recovery from a class-3 hydrate accumulation using depressurization method. The case of a class-3 hydrate deposit of Yuan-An Ridge in southwestern offshore Taiwan is studied. The numerical method was used in this study. The reservoir simulator we used to study the dissociation of hydrate and the production of gas was the STARS simulator developed by CMG, which coupled heat transfer, geo-chemical, geo-mechanical, and multiphase fluid flow mechanisms. The study case of Yuan-An Ridge is located in southwestern offshore Taiwan. The hydrate deposit was found by the bottom simulating reflectors (BSRs). The geological structure of the studied hydrate deposit was digitized to build the geological model (grids) of the case. The formation parameters, phase behavior data, rock and fluid properties, and formation's initial conditions were assigned sequentially to grid blocks, and the completion and operation conditions were designed to wellbore blocks to finish the numerical model. The changes of reservoir pressure, temperature, saturation due to the hydrate

  14. Unusual Cases of Epidermoid cyst: Case Series

    Directory of Open Access Journals (Sweden)

    Lalita Yadav

    2013-09-01

    Full Text Available In the oro-facial region cystic lesions of different etiologies are encountered owing to the presence of the teeth in the jaw bones. A bewildering variety of developmental, odontogenic and non-odontogenic cysts are seen. Epidermoid cyst is a rare developmental cyst of the oro-facial region which results from entrapped epidermal elements without adnexal appendages. Dermoid and epidermoid cysts occur in oro-facial region with an incidence of 6.9-7% and represents less than 0.01% of all oral cavity cysts. Here we report two cases of epidermoid cysts occurring at unusual locations involving upper left maxillary region lateral to the nose and pinna of the ear.

  15. Writing of Patient Case History

    Institute of Scientific and Technical Information of China (English)

    Tian Junying

    2016-01-01

    This paper introduces the language features, structure and contents of case history. Good patient case history contributes to correct diagnosis and formulation of a treatment plan, therefore, it is important for physicians to learn how to write case history.

  16. Melioidosis: A case report

    Directory of Open Access Journals (Sweden)

    Purabi Barman

    2011-01-01

    Full Text Available Burkhloderia pseudomallei has recently gained importance as an emerging pathogen in India. It causes various clinical manifestations like pneumoniae, septicaemia, arthritis, abscess etc. Cases have been reported from Southeast Asia mainly Thailand, Malaysia, Vietnam, etc. In India, few cases have been reported mainly from the southern part of the country. Patient was a 65-year-old male and presented with fever 1 month back, cough and breathlessness for same period, swelling on both ankles from 7 days. B. pseudomallei was isolated from endotracheal secretions, blood cultures, leg wound. He was successfully treated with Imipenem and Doxycycline and put on maintenance therapy now, and is currently doing well.

  17. Melioidosis: a case report.

    Science.gov (United States)

    Barman, Purabi; Sidhwa, Harish; Shirkhande, Pinak A

    2011-04-01

    Burkhloderia pseudomallei has recently gained importance as an emerging pathogen in India. It causes various clinical manifestations like pneumoniae, septicaemia, arthritis, abscess etc. Cases have been reported from Southeast Asia mainly Thailand, Malaysia, Vietnam, etc. In India, few cases have been reported mainly from the southern part of the country. Patient was a 65-year-old male and presented with fever 1 month back, cough and breathlessness for same period, swelling on both ankles from 7 days. B. pseudomallei was isolated from endotracheal secretions, blood cultures, leg wound. He was successfully treated with Imipenem and Doxycycline and put on maintenance therapy now, and is currently doing well.

  18. [Eight cases of diphyllobothriasis].

    Science.gov (United States)

    Ebe, T; Matsumura, M; Mori, T; Takahashi, M; Kohara, T; Inagaki, M; Isonuma, H; Hibiya, I; Hamamoto, T; Funayama, H

    1990-03-01

    Eight cases of diphyllobothriasis have been experienced in the Juntendo University Hospital. Seven of the 8 patients excreted tapeworm fragments. Eggs of Diphyllobothrium latum were found in the feces in 5 cases. One patient had a history of ingestion of raw trout (Sushi), and 2 raw salmon. One might have been infected in foreign countries, and 3 could not tell the source of infection. Bithoinol was administered orally to 7 patients. Four of the 7 excreted the worm and the scolex was recognized in three of the four. Neither recurrence nor abnormal findings have been recognized so far.

  19. Tinea incognito: Case series

    Directory of Open Access Journals (Sweden)

    Mikail Yılmaz

    2015-09-01

    Full Text Available Tinea incognito is a dermatophytic infection which has lost its typical clinical appearance because of inappropriate use of topical or systemic corticosteroids. The clinical manifestations of tinea incognito can mimic many dermatoses such as eczema, psoriasis, allergic contact dermatitis, rosacea, seborrheic dermatitis and atopic dermatitis. The diagnosis of tinea incognito is confirmed by direct KOH (potassium hydroxide examination ( native preparation, making the fungal cultures from the lesion and histopathological examination in some cases. Systemic antifungal therapy is recommended in the treatment of tinea incognito. Herein, 10 cases of tinea incognito which mimicking various dermatoses were diagnosed and treated in our clinic in 2014 is presented.

  20. 液压式套管扶正器在侧钻水平井中的应用%Application of hydraulic casing centralizer in sidetracked horizontal well drilling

    Institute of Scientific and Technical Information of China (English)

    尹方雷; 白冬青; 龚建凯; 徐肇国; 于子涵; 夏进军

    2013-01-01

      常规侧钻水平井造斜段及水平段完井管柱居中困难,导致固井水泥环厚度不均,质量较差,易发生出水、出砂等问题,进而致使侧钻水平井生产寿命较短,严重影响了单井产量。现场多使用扶正器来提高套管居中度,但是常规扶正器存在扶正效果差、破坏井壁等问题,为此研制了液压式套管扶正器。该工具原始外径小、下入安全,膨胀后外径大、扶正能力强,能够极大地提高侧钻水平井完井管柱的居中程度,改善固井质量,延长侧钻水平井的生产寿命。该类扶正器现场应用简便,不影响正常的施工程序,在辽河和冀东油田进行了多口井的现场应用,效果显著。%When drilling the buildup section and horizontal section of conventional sidetracked horizontal wells, the drilling tools are difficult to be centralized, leading to uneven cement thickness, and poor cementing quality, resulting in water and sand production. The problem would lead to low production rate and short service time of sidetracked wells. In field application, centralizer is commonly used to improve the casing centralizing degree, but conventional centralizer has poor centralizing effect and would break wellbore. Therefore, a type of Hydraulic casing centralizer was developed. The tool has small original outer diameter, safe tripping process, large expended outer diameter, and great uprighting capacity, so it can greatly improve the centralizing degress of the completion string of sidetracked horizontal wells. Furthermore, the technique can improve cementing quality, enlarge service time of sidetracked horizontal wells, and increase production rate and economical effect. The tools are simple being applied in field, with no passive effect on normal drilling process

  1. 08 Case report 356

    African Journals Online (AJOL)

    Marinda

    Mediastinitis after oesophagoscopy: A case report. ABSTRACT. A 50-year-old male presented with signs and symptoms of oesophageal perforation after a biopsy. Suggestive symptoms and signs were pain in the neck radiating to the back, a rise in temperature ... On the second postoperative day his blood pressure was still.

  2. [Renal leiomyoma. Case report].

    Science.gov (United States)

    Joual, A; Guessous, H; Rabii, R; Benjelloun, M; Benlemlih, A; Skali, K; el Mrini, M; Benjelloun, S

    1999-01-01

    The authors report a case of renal leiomyoma observed in a 56-year-old man. This cyst presented in the from of loin pain. Computed tomography revealed a homogeneous renal tumor. Treatment consisted of radical nephrectomy. Histological examination of the specimen showed benign renal leiomyoma.

  3. Destroy The Bank! (case)

    NARCIS (Netherlands)

    Star, G.J. Van der; Maas, A.

    2016-01-01

    DZ Bank faces some significant challenges for the near future. One of them is the way payments are being made. This case is about Stefan, the Strategic Management Consultant of DZ Bank. He struggles with innovations and new technologies, such as Bitcoins. What does this mean for the future of the ba

  4. [Thoracic actinomycosis: three cases].

    Science.gov (United States)

    Herrak, L; Msougar, Y; Ouadnouni, Y; Bouchikh, M; Benosmane, A

    2007-09-01

    Actinomycosis is a rare condition which, in the thoracic localisation, can mimic cancer or tuberculosis. We report a series of three case of thoracic actinomycosis treated in the Ibn Sina University Thoracic Surgery Unit in Rabat, Morocco. CASE N degrees 1: This 45-year-old patient presented a tumefaction on the left anterior aspect of the chest. Physical examination identified a parietal mass with fistulisation to the skin. Radiography demonstrated a left pulmonary mass. Transparietal puncture led to the pathological diagnosis of actinomycosis. The patient was given medical treatment and improved clinically and radiographically. CASE N degrees 2: This 68-year-old patient presented repeated episodes of hemoptysis. The chest x-ray revealed atelectasia of the middle lobe and bronchial fibroscopy demonstrated the presence of a bud in the middle lobar bronchus. Biopsies were negative. The patient underwent surgery and the histology examination of the operative specimen revealed pulmonary actinomycosis. The patient recovered well clinically and radiographically with antibiotic therapy. CASE N degrees 3: This 56-year-old patient presented cough and hemoptysis. Physical examination revealed a left condensation and destruction of the left lung was noted on the chest x-ray. Left pleuropulmonectomy was performed. Histological analysis of the surgical specimen identified associated Aspergillus and Actinomyces. The outcome was favorable with medical treatment. The purpose of this work was to recall the radiological, clinical, histological, therapeutic, outcome aspects of this condition and to relate the problems of differential diagnosis when can suggest other diseases.

  5. [Ledderhose disease (case considerations)].

    Science.gov (United States)

    Bottinelli, N F

    1982-12-01

    After a preliminary note, the Author gives the casuistic survey of 30 patients, surgically treated during 12 years about. Moreover, a per cent analysis is done about the different possibilities of incidence of Ledderhose's disease in the cases considered. As a conclusion, the Author remembers the operative technique which gave the best results. Wide partial aponeurectomy.

  6. Nasal tooth: case report

    Energy Technology Data Exchange (ETDEWEB)

    Park, Si Hyun; Kim, Ji Hye; Hwang, Hee Young; Yang, Dal Mo; Kim, Hyung Sik; Park, Chol Heui [Gachon Medical School, Inchon (Korea, Republic of)

    2002-12-01

    Ectopic tooth is not uncommon and usually occurs in the palate and maxillary sinus. We report a case of ectopic tooth located in the nasal cavity, a rare site. The mass depicted by CT was highly attenuated, and central lucency was observed.

  7. a case report

    African Journals Online (AJOL)

    2015-03-26

    Mar 26, 2015 ... The speculated mechanism of SDH involves tear of the Falx ... The cause of this haemor- rhage was not known. Case Description. A female term Neonate with a birth weight of 3.2kg ... abnormalities6 such as fetal or maternal thrombocyto- penia7 or exposure to low molecular weight heparin as reported by ...

  8. Destroy The Bank! (case)

    NARCIS (Netherlands)

    dr. A. Maas; G.J. Van der Star

    2016-01-01

    DZ Bank faces some significant challenges for the near future. One of them is the way payments are being made. This case is about Stefan, the Strategic Management Consultant of DZ Bank. He struggles with innovations and new technologies, such as Bitcoins. What does this mean for the future of the

  9. 2 cases of thorotrastosis

    Energy Technology Data Exchange (ETDEWEB)

    Ippoliti, G.; Casirola, G.; Marini, G.; Barosi, G.

    1977-12-01

    Two cases of thorotrastosis unsuspected by the patients themselves are reported. Attention is drawn to the relevance of this disease at the present time. Reference is made to the relevant literature in asserting that the pathology of thorotrastosis must be understood if early diagnosis is to be obtained, and so initiate suitable treatment and satisfy medicolegal requirements.

  10. Intercultural Communicative Case Study

    Institute of Scientific and Technical Information of China (English)

    吴冬梅

    2009-01-01

    The essay is mainly about the author's comprehension of cultural differences and intercultural communication after reading the book Communication Between Cultures.In addition,the author also analyses three cases with the theories and approaches mentioned in Communication Between Cultures.

  11. national Case study

    African Journals Online (AJOL)

    from this, the national case study begins to conceptualise a new approach to ... teacher education environments and a piloting of a 'Train the Trainers' or .... Study) and TIMMS (Trends in International Mathematics and Science Study) ..... Objective 7: Publish the materials in an open learning system format and integrate the.

  12. Case Studies in Biology.

    Science.gov (United States)

    Zeakes, Samuel J.

    1989-01-01

    A case study writing exercise used in a course on parasitology was found to be a powerful learning experience for students because it involved discipline-based technical writing and terminology, brought the students in as evaluators, applied current learning, caused interaction among all students, and simulated real professional activities. (MSE)

  13. Case report 537: Chondroblastoma

    Energy Technology Data Exchange (ETDEWEB)

    Pignatti, G.; Nigrisoli, M.

    1989-05-01

    A case is reported of a 10-year-old girl who presented with pain in the left hip. Radiologically, a well-defined lytic lesion with a sclerotic border was present in the neck of the femur, with no epiphyseal involvement. The rarity of a metaphyseal site of origin of a chondroblastoma was stressed and the literature reviewed. (orig./GDG).

  14. The Directed Case Method.

    Science.gov (United States)

    Cliff, William H.; Curtin, Leslie Nesbitt

    2000-01-01

    Provides an example of a directed case on human anatomy and physiology. Uses brief real life newspaper articles and clinical descriptions of medical reference texts to describe an actual, fictitious, or composite event. Includes interrelated human anatomy and physiology topics in the scenario. (YDS)

  15. Case Consultation: Cathy.

    Science.gov (United States)

    Berman, Alan L., Ed.

    1990-01-01

    Presents case summary of Cathy, a client who interacted with emergency services over two-year period. Marshall Knudson comments on crisis centers' overall capabilities of offering appropriate services to this type of client. Ronald Dyck concludes that center provided crisis-appropriate services to the client but suggests that centers may need to…

  16. A Psychobiographical Case Study

    African Journals Online (AJOL)

    adopt a child and, in due course, assumed parenthood of. Jobs shortly after his .... The Psychobiographical Case Subject and Sampling ..... The school recommended that he skip .... look at pathways that could lead to personal fulfilment ...... Personology: Method and content in personality assessment and psychobiography.

  17. The Case of CUL

    DEFF Research Database (Denmark)

    Lauridsen, Ole; Jensen, Torben K.; Jørgensen, Bente Mosgaard

    The Case of CUL (Centre for Teaching and Learning), School of Business and Social Sciences, Aarhus University, Denmark: Dilemmas in Large Scale Educational Development Ole Lauridsen, Torben Jensen, Maja Hjerrild, Bente Jørgensen, Aarhus University. Abstract When developmental work within the area....... management support. Keywords: pedagogical courses, faculty, organisation, managemental support......The Case of CUL (Centre for Teaching and Learning), School of Business and Social Sciences, Aarhus University, Denmark: Dilemmas in Large Scale Educational Development Ole Lauridsen, Torben Jensen, Maja Hjerrild, Bente Jørgensen, Aarhus University. Abstract When developmental work within the area...... of HE pedagogy goes from small scale to large scale, it changes character and new challenges arise. The session invites directors of developmental units and all interested educational developers to discuss dilemmas of such a transition and exchange experiences with the aim of ameliorating the work...

  18. Odontoameloblastoma: A case report.

    Science.gov (United States)

    Negi, Amita; Puri, Abhiney; Nangia, Rajat; Sachdeva, Alisha

    2015-01-01

    Odontoameloblastoma (OA) is an extremely rare odontogenic tumor that contains an ameloblastomatous component together with odontoma-like elements. Till date, very few cases have fulfilled the criteria of the current World Health Organization classification of odontogenic tumors. It is characterized by slow, progressively growing lesion with growth pattern similar to solid multi-cystic ameloblastoma. The majority of the tumors are associated with unerupted teeth and commonly seen in males. It is usually asymptomatic and may occur in either maxilla or mandible, but shows a slight predilection for mandible. As this tumor is extremely rare, there exists controversy regarding its treatment. Here, we present a case of OA in 17-year-old female patient resembling a fibro-osseous lesion and a brief review of the related literature.

  19. ACROMEGALY: A CASE REPORT

    Directory of Open Access Journals (Sweden)

    10.5958/2319-5886.2015.00183.6

    2015-10-01

    Full Text Available Acromegaly is a rare disease caused due to hyper secretion of growth hormone. Most of the cases of acromegaly are caused by pitutary adenoma which can be microadenoma or macroadenomas. These adenomas are never malignant, but can have significant morbidity and mortality. We report a 35 year old female patient presented herewith classical presentation of acromegaly with chief complain of weight gain, excessive sweating , widening of both hands and feet and was diagnosed as a case of acromegaly due to macroadenoma of pirtutary gland, on the basis of typical clinical features and hormonal parameters also radiological findings. Patient underwent transsphenoidal surgical resection of macroadenoma and recovered completely from the disease. Early recognition and diagnosis will help to avoid the complications of disease.

  20. Eagle syndrome: case report.

    Science.gov (United States)

    Uludağ, İrem Fatma; Öcek, Levent; Zorlu, Yaşar; Uludağ, Burhanettin

    2013-01-01

    Eagle syndrome is an aggregate of symptoms caused by an elongated styloid process, most frequently resulting in headache, facial pain, dysphagia and sensation of foreign body in throat. The proper diagnosis is not difficult with clinical history, physical examination and radiographic assessment if there is a sufficient degree of suspicion. The treatment is very effective. We report here a typical case of Eagle syndrome which was misdiagnosed as trigeminal neuralgia for many years and was treated with carbamazepine. We aim to point the place of Eagle syndrome in the differential diagnosis of facial pain. We also re-emphasize the usefulness of the three-dimensional computed tomography in the diagnosis of Eagle syndrome. Even though Eagle syndrome is a rare condition, in cases of facial pain refractory to treatment or unexplained complaints of the head and neck region, it should be considered in the differential diagnosis as it has therapeutic consequences.

  1. Odontoameloblastoma: A case report

    Directory of Open Access Journals (Sweden)

    Amita Negi

    2015-01-01

    Full Text Available Odontoameloblastoma (OA is an extremely rare odontogenic tumor that contains an ameloblastomatous component together with odontoma-like elements. Till date, very few cases have fulfilled the criteria of the current World Health Organization classification of odontogenic tumors. It is characterized by slow, progressively growing lesion with growth pattern similar to solid multi-cystic ameloblastoma. The majority of the tumors are associated with unerupted teeth and commonly seen in males. It is usually asymptomatic and may occur in either maxilla or mandible, but shows a slight predilection for mandible. As this tumor is extremely rare, there exists controversy regarding its treatment. Here, we present a case of OA in 17-year-old female patient resembling a fibro-osseous lesion and a brief review of the related literature.

  2. Odontoameloblastoma: A case report

    Science.gov (United States)

    Negi, Amita; Puri, Abhiney; Nangia, Rajat; Sachdeva, Alisha

    2015-01-01

    Odontoameloblastoma (OA) is an extremely rare odontogenic tumor that contains an ameloblastomatous component together with odontoma-like elements. Till date, very few cases have fulfilled the criteria of the current World Health Organization classification of odontogenic tumors. It is characterized by slow, progressively growing lesion with growth pattern similar to solid multi-cystic ameloblastoma. The majority of the tumors are associated with unerupted teeth and commonly seen in males. It is usually asymptomatic and may occur in either maxilla or mandible, but shows a slight predilection for mandible. As this tumor is extremely rare, there exists controversy regarding its treatment. Here, we present a case of OA in 17-year-old female patient resembling a fibro-osseous lesion and a brief review of the related literature. PMID:26604505

  3. Multiple pregnancy. Case report.

    Directory of Open Access Journals (Sweden)

    Práxedes Regla Rojas Quintana

    2009-11-01

    Full Text Available We present a case of a 34-year-old white female patient, of rural origins, with a history of 3rd degree bronchial asthma and respiratory arrests for that cause, who has required several admissions in the ICU. Gestation history 1, no deliveries, 1 abortion and secondary infertility, for which she was treated, along with her spouse, in the infertility consultation, in which ovulation disorders were diagnosed, consisting of bilateral tubaric obstruction on her and severe oligospermia on her spouse, for which they underwent combined surgical treatment. Tubaric permeability with hydrotubation was first accomplished, then ovulation and spermatogenesis with clomiphene citrate and then low-technology fertilization was performed, resulting in a quadruple pregnancy, which satisfactorily arrived to full term at 34 weeks of gestation. Due to the mother’s medical history, the risks involved in this type of pregnancy and its happy outcome, we decided to publish the case.

  4. SCLERODERMA: A CASE REPORT*

    Directory of Open Access Journals (Sweden)

    Gülay Altan

    2015-04-01

    Full Text Available Scleroderma is an autoimmune connective tissue disorder which is characterized by fibrosis of visceral organs, skin and blood vessels. This condition can be localized or systemic. Its estimated prevalence is 250 cases in a million and it is more common in women than in men. Resorption of the mandibular angle and coronoid process can be observed in patients with scleroderma. Pressure of fibrous mucocutaneous tissues is thought to be the cause of the resorption. Decreased number of wrinkles due to sclerosis and distinct facial features because of the atrophy of ala nasi are among common clinical characteristics of this condition. The aim of this case report is to present a 40-year-old female patient with scleroderma who presented with signs of resorption at the angle of mandible, coronoid process, as well as widening of the periodontal space.

  5. Kleptomania: a case series.

    Science.gov (United States)

    Saluja, Bharat; Chan, Lai Gwen; Dhaval, Dani

    2014-12-01

    Kleptomania is an enigmatic condition and is among the very few psychiatric disorders in which crime is medicalised and used as a legal defence. The scientific literature on kleptomania is scarce. Early literature and recent studies have shown a female preponderance, with an early age of onset of stealing in people with comorbid personality disorder(s). In a retrospective review of the case notes of theft offenders who had forensic psychiatric evaluations performed in a one-year period in 2010 at the Institute of Mental Health, Singapore, we found three patients who were diagnosed with kleptomania. In this report, we describe the pertinent clinical and sociodemographic characteristics, as well as the diagnostic issues of kleptomania in relation to the three cases.

  6. Case report: Morgagni hernia.

    Science.gov (United States)

    Rogers, Frederick B; Rebuck, Jill A

    2006-03-01

    The case reported here is a 32-year-old man with a sudden onset of chest pain and an acute deterioration of lung function. An incarcerated Morgagni hernia was diagnosed with a computer tomographic CT scan, and repaired electively via a midline laparotomy. Morgagni hernia is a rare type of congenital diaphragmatic hernia, which may not be symptomatic until adulthood when the patient presents with acute symptoms or incarceration.

  7. Cystosarcoma phyllodess. Case presentation

    Directory of Open Access Journals (Sweden)

    Lidia Torres Ajá

    2006-08-01

    Full Text Available A 12 year-old patient is presented, with tumor of the left breast of 11,7 cms, of quick growth, without another accompanying sintomatology, which was diagnosed as cystosarcoma phyllodess benign. In the twenty-five years of existence of our hospital, it is the first tumor phyllodes detected in girl, for that is considered a curious and interesting case that can enrich the experience of other professionals of the health.

  8. OMC Compressor Case

    Science.gov (United States)

    Humphrey, W. Donald

    1997-01-01

    This report summarizes efforts expended in the development of an all-composite compressor case. Two pre-production units have been built, one utilizing V-CAP and one utilizing AFR-700B resin systems. Both units have been rig tested at elevated temperatures well above design limit loads. This report discusses the manufacturing processes, test results, and Finite Element Analysis performed. The V-CAP unit was funded by NASA-Lewis Research Center in 1994 under contract number NAS3- 27442 for Development of an All-Composite OMC Compressor Case. This contract was followed by an Air Force study in 1996 to build and identical unit using the AFR-700B resin system in place of the V-CAP system. The second compressor case was funded under U.S. Air Force contract F33615-93-D-5326, Advanced Materials for Aerospace Structures Special Studies (AMAS3), Delivery Order 0021 entitled "Advanced Polymeric Composite Materials and Structures Technology for Advanced High Temperature Gas Turbine Engines.' Initial studies using the V-CAP resin system were undertaken in 1993 under a NASA Lewis contract (NAS3-26829). A first prototype unit was developed in a joint program between Textron-Lycoming (now Allied Signal) and Brunswick (now Lincoln Composites). This unit included composite end closures using low density, high temperature molded end closures. The units was similar in size and shape to a titanium case currently used on the PT-21 0 engine and was funded as part of the integrated High Performance Turbine Engine Technology (EHPTET) initiative of DOD and NASA.

  9. [Central neurocytoma: case report].

    Science.gov (United States)

    Bouaziz, M; Mansour, A; Feknous, S; Yassi, F; Smati, S; Belhouchet, S; Lankar, A

    2009-12-01

    In this study, we report one case of central neurocytoma treated in our department. It is a benign tumor of the lateral ventricles of the brain with neuronal differentiation. The clinical symptoms mainly consisted in intracranial hypertension syndrome. Immunohistochemical studies are necessary for the histopathological diagnosis. The treatment of choice is surgical. To guarantee good progression, complete ablation is necessary. The clinical progression, radiological aspects, treatment, histopathology, and postoperative progression will be discussed.

  10. Malignant histiocytosis. Case report

    OpenAIRE

    RUIZ, OSCAR; Instituto de Investigaciones Clínicas, UNMSM; Servicio Hematologia Clínica, Hospital Dos de Mayo; QUIÑONES, WILLY; Servicio Hematologia Clínica, Hospital Dos de Mayo; MISAD, OSCAR; Laboratorio de Anatomia Patológica “Oscar Misad; Delgado, Carlos; Instituto de Investigaciones Clínicas, Facultad de Medicina, Universidad Nacional Mayor de San Marcos. Lima, Perú.; Ronceros, Sergio; Instituto de Investigaciones Clínicas, Facultad de Medicina Humana, Universidad Nacional Mayor de San Marcos, Lima, Perú. médico patólogo.; MARANGONI, MANUELA; Departamento de Enfermería, Hospital Dos de Mayo; BARDALES, LUZ; Servicio Hematologia Clínica, Hospital Dos de Mayo; REYES, RAFAEL; Servicio Hematologia Clínica, Hospital Dos de Mayo; CASTILLO, ALFREDO; Servicio Hematologia Clínica, Hospital Dos de Mayo; URRUTIA, KATIA; Servicio Hematologia Clínica, Hospital Dos de Mayo

    2013-01-01

    Fourteen year-old male patient referred from Huancayo who presented one month gastric intolerance, jaundice, fever and a lymph proliferative syndrome. Laboratory tests revealed severe pancytopenia due to phagocytosis. Haematologic and anatomy-pathology diagnosis was human malignant histiocytosis. We present this case due to its low frequency and the emergency character of the disease. Paciente varón de 14 años, procedente de Huancayo, que presenta un mes antes de su hospitalización intoler...

  11. Qualitative Case Study Guidelines

    Science.gov (United States)

    2013-11-01

    to develop a descriptive framework (e.g. a draft table of contents) for organising the case study, whilst not pre-empting outcomes before the data...has been fully analysed. Such a framework can help the analyst with organising the data as well as with developing a story line [48]. As...Publications Repository http://dspace.dsto.defence.gov.au/dspace/ 14. RELEASE AUTHORITY Chief, Joint and Operations Analysis Division 15

  12. Esthesioneuroblastoma A Case Report

    OpenAIRE

    Chadha, Snya; Pannu, Kulwant Kaur

    2011-01-01

    Esthesioneuroblastoma (ENB) also known as olfactory neuroblastoma is an uncommon malignant neoplasm arising in the roof of nasal cavity. It is now understood to originate from the olfactory epithelium. Case reports published worldwide have been very few. Common presenting symptoms of Esthesioneuroblastoma include nasal obstruction, epistaxis, facial pain, diplopia, proptosis, and anosmia. Apart from being locally aggressive, it metastasizes widely by both hematogenous and lymphatic routes.

  13. [Obstructive anuria. Thirty cases].

    Science.gov (United States)

    Bennani, S; Debbagh, A; Joual, A; el Mrini, M; Benjelloun, S

    1995-01-01

    The authors report 30 cases of obstructive anuria during the last fifteen years. The anuria was secondary to lithiasis in 60 per cent, in 26.6 per cent to pelvic cancer and in 13.4 per cent to retroperitoneal fibrosis. The diagnosis was facilitated by ultrasonography. Emergency treatment of obstructive anuria is based on urinary diversion by ureteral stent or by percutaneous nephrostomy under ultrasound control. Later the treatment depend of etiology.

  14. Case Studies - Cervical Cancer

    Centers for Disease Control (CDC) Podcasts

    2010-10-15

    Dr. Alan Waxman, a professor of obstetrics and gynecology at the University of New Mexico and chair of the American College of Obstetricians and Gynecologists (ACOG) committee for the underserved, talks about several case studies for cervical cancer screening and management.  Created: 10/15/2010 by National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP), Division of Cancer Prevention and Control (DCPC).   Date Released: 6/9/2010.

  15. Gastric syphilis - Case report*

    Science.gov (United States)

    Guimarães, Tais Ferreira; Novis, Camila Freitas Lobo; Bottino, Caroline Bertolini; D'Acri, Antonio Macedo; Lima, Ricardo Barbosa; Martins, Carlos José

    2016-01-01

    Gastric syphilis is an uncommon extracutaneous manifestation of syphilis, occurring in less than 1% of patients, presenting nonspecific clinical manifestations. In general, it occurs on secondary stage. The critical point is the recognition of the syphilitic gastric involvement, without which there may be incorrect diagnosis of malignancy of the digestive tract. In this report, a case of secondary syphilis with gastric involvement that had complete remission with benzathine penicillin will be described. PMID:27828649

  16. Scleromyxedema: An atypical case

    Directory of Open Access Journals (Sweden)

    Emy Thomas

    2015-01-01

    Full Text Available Scleromyxedema is a rare, chronic and persistent idiopathic disorder characterized by a generalized papular eruption due to dermal mucin deposition with an increase in dermal collagen. Patients usually have associated paraproteinemia. We describe the case of a 59-year-old gentleman with features of scleromyxedema, who had severe pruritus, scalp involvement, unrestricted mobility and associated peripheral eosinophilia, but no monoclonal gammopathy.

  17. Scleroderma. A case presentation.

    Directory of Open Access Journals (Sweden)

    Rubén Bembibre Taboada

    2005-08-01

    Full Text Available This article presents a brief review about generalized sclerosis (sclerodermia and reports a case with such disease talking into consideration that the patient received clinical intensive care assistaance and had a clinical diagnosis supoported by lab test for a clinical and differential diagnosis. Medical treatment was applied for the disease and for the possible complications, but the patients follow up was wrong due to multi organ failure as a consequence of derlying disease.

  18. IPEX syndrome: Case report

    OpenAIRE

    Radlović Nedeljko; Janić Dragana; Sajić Silvija; Janković Srđa; Ješić Maja; Leković Zoran; Petrović Rada

    2008-01-01

    INTRODUCTION IPEX syndrome, namely, a hereditary (X-linked) immunodysregulation with autoimmune polyendocrinopathy and enteropathy, as the basic manifestations, presents a rare and exceptionally severe disease. It develops due to gene mutation responsible for the synthesis of a specific protein (FOXP3), which, by differentiation and activation of regular T-lymphocytic CD4+CD25+, has the key role in the induction and maintenance of the peripheral tolerance of one's own tissue. CASE OUTLINE We ...

  19. [Chilaidity syndrome. Case report].

    Science.gov (United States)

    Candela, Stefano; Candela, Giancarlo; Di Libero, Lorenzo; Argano, Francesco; Romano, Ornella; Iannella, Iolanda

    2012-01-01

    Chilaidity syndrome is a mal position by bowel mal rotation o malfissation. It is more common in right side expecially in obese people. If asyimptomatic, the syndrome is an occasional comparison by radiology, surgical exploration by laparoscopy or autopsy, otherwise, if symptomatic, there are obstructive symptoms,abdominal pain, nausea, vomiting, abdominal distension, flatulence, breath, constipation and anorexia. Diagnosis is radiological. We present a rare case of this syndrome in a man with serious obstructive symptoms.

  20. Reconfigurable logic design case

    Science.gov (United States)

    Ma, Shing-Fat F.; Knight, John; Plett, Calvin

    2002-07-01

    This design case identifies generalizable features of a course-grained reconfigurable FPGA, Chameleon's reconfigurable platform. An FFT is used to identify typical design practices, problems, and solutions in targeting such a platform. This paper focuses on datapath mapping, separating it into functional design and placement of reconfigurable resources. In addition to exploring the design methodology, it analyzes numerical artifacts, demonstrates efficient packing of the data path, and highlights differences from ASIC design.

  1. Alkaptonuria: A case report

    Directory of Open Access Journals (Sweden)

    Nirupama Damarla

    2017-01-01

    Full Text Available Alkaptonuria is a rare inborn error of metabolism with autosomal recessive inheritance with a mutation in homogentisate 1,2-dioxygenase. It results in accumulation of homogentisic acid in connective tissues (ochronosis. Most common ocular manifestations are bluish-black discoloration of the conjunctiva, cornea, and sclera. In this case report, a 39-year-old Indian male patient with additional ocular features in the retina is described.

  2. LARYNGOCELE: A CASE REPORT

    Directory of Open Access Journals (Sweden)

    Umakanth Goud

    2015-04-01

    Full Text Available Laryngoceles are rare, cystic dilatation of saccule of ventricle of larynx. Three types are recognized – internal, external and mixed types. Many of the laryngoceles are asymptomatic; few require surgical excision via internal/endoscopic or external approach. Contrast CT is the investigation of choice. A 40year old male presented to our OPD with a neck Scar, later diagnosed as laryngocele. Here is the case report about presentation, di agnosis and management of a large mixed layngocele.

  3. Combustible Cartridge Case Characterization

    Science.gov (United States)

    1984-02-01

    University (NYU) has resulted in the selection of two cross-linked melamine / formaldehyde acrylic styrene resin systems that can be used in the beater additive... melamine resin Akaradit II stabilizer 20. ABSTRACT (con) Test coupons of combustible cartridge case material were fabricated using these recommended...and agitated for 30 min before the pH was slowly lowered to 3 with p-toluene sulfonic acid. In order to maintain this pH in the felting tank, it was

  4. Cystic fibrosis: case report

    Energy Technology Data Exchange (ETDEWEB)

    Park, Si Hyun; Lee, Hyun Ju; Kim, Ji Hye; Park, Chol Heui [Gachon Medical School, Inchon (Korea, Republic of)

    2002-12-01

    Cystic fibrosis is an autosomal recessive genetic disease. Among Caucasians, it is the most common cause of pulmonary insufficiency during the first three decades of life. The prevalence of cystic fibrosis varies according to ethnic origin: it is common among Caucasians but rare among Asians. We report a case in which cystic fibrosis with bronchiectasis and hyperaeration was revealed by high-resolution CT, and mutation of the cystic fibrosis conductance transmembrane regulator gene (CFTR) by DNA analysis.

  5. Case report: pelvic actinomycosis.

    Science.gov (United States)

    Maxová, K; Menzlová, E; Kolařík, D; Dundr, P; Halaška, M

    2012-01-01

    A case of pelvic actinomycosis is presented. The patient is 42-year-old female with a 5 weeks history of pelvic pain. An intrauterine device (IUD) was taken out 3 weeks ago. There is a lump length 9 cm between rectus muscles. Ultrasound, magnetic resonance imaging (MRI) and histology are used to make the diagnosis. Actinomycosis can mimic the tumour disease. The definitive diagnosis requires positive anaerobic culture or histological identification of actinomyces granulas. A long lasting antibiotic therapy is performed.

  6. Kleptomania: a case series

    OpenAIRE

    Saluja, Bharat; Chan, Lai Gwen; Dhaval, Dani

    2014-01-01

    Kleptomania is an enigmatic condition and is among the very few psychiatric disorders in which crime is medicalised and used as a legal defence. The scientific literature on kleptomania is scarce. Early literature and recent studies have shown a female preponderance, with an early age of onset of stealing in people with comorbid personality disorder(s). In a retrospective review of the case notes of theft offenders who had forensic psychiatric evaluations performed in a one-year period in 201...

  7. Empirical Test Case Specification

    DEFF Research Database (Denmark)

    Kalyanova, Olena; Heiselberg, Per

    This document includes the empirical specification on the IEA task of evaluation building energy simulation computer programs for the Double Skin Facades (DSF) constructions. There are two approaches involved into this procedure, one is the comparative approach and another is the empirical one. I....... In the comparative approach the outcomes of different software tools are compared, while in the empirical approach the modelling results are compared with the results of experimental test cases....

  8. Boerhaave syndrome - case report

    Directory of Open Access Journals (Sweden)

    Biljana Radovanovic Dinic

    Full Text Available ABSTRACT CONTEXT: Boerhaave syndrome consists of spontaneous longitudinal transmural rupture of the esophagus, usually in its distal part. It generally develops during or after persistent vomiting as a consequence of a sudden increase in intraluminal pressure in the esophagus. It is extremely rare in clinical practice. In 50% of the cases, it is manifested by Mackler's triad: vomiting, lower thoracic pain and subcutaneous emphysema. Hematemesis is an uncommon yet challenging presentation of Boerhaave's syndrome. Compared with ruptures of other parts of the digestive tract, spontaneous rupture is characterized by a higher mortality rate. CASE REPORT: This paper presents a 64-year-old female patient whose vomit was black four days before examination and became bloody on the day of the examination. Her symptoms included epigastric pain and suffocation. Physical examination showed hypotension, tachycardia, dyspnea and a swollen and painful abdomen. Auscultation showed lateral crackling sounds on inspiration. Ultrasound examination showed a distended stomach filled with fluid. Over 1000 ml of fresh blood was extracted by means of nasogastric suction. Esophagogastroduodenoscopy was discontinued immediately upon entering the proximal esophagus, where a large amount of fresh blood was observed. The patient was sent for emergency abdominal surgery, during which she died. An autopsy established a diagnosis of Boerhaave syndrome and ulceration in the duodenal bulb. CONCLUSION: Boerhaave syndrome should be considered in all cases with a combination of gastrointestinal symptoms (especially epigastric pain and vomiting and pulmonary signs and symptoms (especially suffocation.

  9. Case Study - Alpha

    Directory of Open Access Journals (Sweden)

    Stephen Leybourne

    2016-11-01

    Full Text Available This case study was developed from an actual scenario by Dr. Steve Leybourne of Boston University.  The case documents the historical evolution of an organization, and has been used successfully in courses dealing with organizational and cultural change, and the utilization of ‘soft skills’ in project-based management. This is a short case, ideal for classroom use and discussion.  The issues are easily accessible to students, and there is a single wide ranging question that allows for the inclusion of many issues surrounding strategic decision-making, and behavioural and cultural change. Alpha was one of the earlier companies in the USA to invest in large, edge-of-town superstores, with plentiful free vehicle parking, selling food and related household products. Alpha was created in the 1950s as a subsidiary of a major publicly quoted retail group.  It started business by opening a string of very large discount stores in converted industrial and warehouse premises in the south of the United States. In the early days shoppers were offered a limited range of very competitively priced products. When Alpha went public in 1981 it was the fourth largest food retailer in the US, selling an ever-widening range of food and non-food products.  Its success continued to be based on high volume, low margins and good value for money, under the slogan of ‘Alpha Price.’

  10. Automated Test Case Generation

    CERN Document Server

    CERN. Geneva

    2015-01-01

    I would like to present the concept of automated test case generation. I work on it as part of my PhD and I think it would be interesting also for other people. It is also the topic of a workshop paper that I am introducing in Paris. (abstract below) Please note that the talk itself would be more general and not about the specifics of my PhD, but about the broad field of Automated Test Case Generation. I would introduce the main approaches (combinatorial testing, symbolic execution, adaptive random testing) and their advantages and problems. (oracle problem, combinatorial explosion, ...) Abstract of the paper: Over the last decade code-based test case generation techniques such as combinatorial testing or dynamic symbolic execution have seen growing research popularity. Most algorithms and tool implementations are based on finding assignments for input parameter values in order to maximise the execution branch coverage. Only few of them consider dependencies from outside the Code Under Test’s scope such...

  11. RSG Deployment Case Testing Results

    Energy Technology Data Exchange (ETDEWEB)

    Owsley, Stanley L.; Dodson, Michael G.; Hatchell, Brian K.; Seim, Thomas A.; Alexander, David L.; Hawthorne, Woodrow T.

    2005-09-01

    The RSG deployment case design is centered on taking the RSG system and producing a transport case that houses the RSG in a safe and controlled manner for transport. The transport case was driven by two conflicting constraints, first that the case be as light as possible, and second that it meet a stringent list of Military Specified requirements. The design team worked to extract every bit of weight from the design while striving to meet the rigorous Mil-Spec constraints. In the end compromises were made primarily on the specification side to control the overall weight of the transport case. This report outlines the case testing results.

  12. Case Study: Guidelines for Producing Videos to Accompany Flipped Cases

    Science.gov (United States)

    Prud'homme-Généreux, Annie; Schiller, Nancy A.; Wild, John H.; Herreid, Clyde Freeman

    2017-01-01

    Three years ago, the "National Center for Case Study Teaching in Science" (NCCSTS) was inspired to merge the case study and flipped classroom approaches. The resulting project aimed to create the materials required to teach a flipped course in introductory biology by assigning videos as homework and case studies in the classroom. Three…

  13. Development and Achievements of Drilling Techniques in Sichuan Oil Province

    Institute of Scientific and Technical Information of China (English)

    Xia Shuming; Cheng Changxiu

    1995-01-01

    @@ Drilling Techniques Design methods for special wellbore structure The wellbore structure which suits all of the complicated conditions can be designed by special methods.The shut-in pressure is high when gas well is under well control and ell testing, in order to raise the pressure resistant capacity of the casing,and to control oil/gas pressure effectively,not only the inside compression strcngth and scaling property of the casing should be enhanced,but also the cement slurry should be retumed to the surface during each cementing job.

  14. Xeroderma pigmentosum. Case presentation.

    Directory of Open Access Journals (Sweden)

    Damaris Díaz Leonard

    2008-08-01

    Full Text Available Twelve years old patient (YGS, female, white, of rural origin; with history of facial and truncal bullae since the age of eight months when exposed to the sun light. It was first diagnosed as solar dermatitis. At the age of 6 it was assessed as xeroderma pigmentosum. This diagnosis was confirmed at the age of 10 by the histopathology department and reassessed by the National Reference Centre. For the infrequency of this disease, a bibliographic revision was carried out to make a report for this case presentation.

  15. Hypertrophic pachymeningitis: case report

    Directory of Open Access Journals (Sweden)

    Deus-Silva Leonardo de

    2003-01-01

    Full Text Available Hypertrophic pachymeningits is an unusual cause of neurological symptoms and is often secondary to infections, carcinomatosis or inflammatory diseases. It may also be idiopathic. We report a case of pachymeningitis which was manifested primarily by psychosis and visual loss with optic atrophy and destruction of nasal septum. The patient, a 45 year old woman was submitted to extensive investigation without evidence of any underlying disease. A meningeal biopsy was performed and showed a mostly unspecific inflammatory process with extensive fibrosis of the dura and few early stage granulomas. These findings suggest either neurosarcoidosis or idiopathic hypertrophic pachymeningitis.

  16. A case of peeling

    DEFF Research Database (Denmark)

    Nielsen, Anders

    2016-01-01

    Peeling of paint and plaster from building facades is a well-known phenomenon. This contribution analyses a case of peeling on a villa and its gardens walls, Figure 1. The walls were levelled with cement plaster, before painted with a formally very dense acrylic paint. - The analysis shows...... that the present layer of acryl paint is not very dense because it is applied on a rough plaster surface. - However, the main reason of the peeling seems to be the difference in thermal expansion between the masonry and the cement plaster. It is shown that the peeling takes place both winter and summer....

  17. Neurocysticercosis. Case report.

    Directory of Open Access Journals (Sweden)

    Gilberto Serrano Ocaña

    2009-05-01

    Full Text Available A female patient (15 years, from Eastern Cape, South Africa, was admitted in the hospital on July 13th, 2007 with general tonic-clonic convulsions. There was not history of epilepsy or fever convulsions and the patient denied alcohol, cigar or drugs consumption. The physical examination showed postictal confusion, without neurological deficit, neck rigidity or peripheral edema. Computer axial tomography was definitive for neurocysticercosis disgnosis. Since it is a serious health problem for the area the patient lives in, we decided to publish the case.

  18. Tracheobronchopathia osteochondroplastica: four cases

    Institute of Scientific and Technical Information of China (English)

    Dursun Tatar; Gunes Senol; Atike Demir; Gulru Polat

    2012-01-01

    Tracheobronchopathia osteochondroplastica (TO) is a rare and benign disorder of unknown cause affecting the large airways.It is characterized by the presence of multiple osseous and cartilaginous nodules in the submucosa of the trachea and main bronchi that is characterized by the progression of submucosal bone and/or cartilage including nodules through the lumen of trachea and bronchus.We present four cases that were diagnosed TO while investigating for the causes of hemoptysis and chronic cough.We plan to emphasize TO in differential diagnosis in proper patients.

  19. Government Contract Law Cases.

    Science.gov (United States)

    1983-10-01

    exoner company s on the d total orari ly ined. A e spirit are not (a)(9 tly e Howe rd co f the ated, which theo parti suspe ny ot...e n d case the d i s i o n ontra and, on t parties, ethod of ake theo F. 2d 9 i s h i n g A ites sym eprocure 1 j u d g m e the prim...provisions to create an ambiguity. Jansen v. United States, supra, at 356, 344 F. 2d at 370. Plaintiff’s interpretation of the specifications is not

  20. OBSESSIONS: CASE REPORT STUDY

    Directory of Open Access Journals (Sweden)

    Miloš Židanik

    2004-01-01

    Full Text Available Background. Obsessions are one of the most refractory psychiatric disorders. The therapeutic guidelines include a psychopharmacotherapy and the use of behavioural and supportive psychotherapy.Methods. This case report study presents a patient with a homicide obsessions at the forefront and narcissistic personality disorder in background. The use of analytical oriented psychotherapy, which helped to resolve axis-1 symptoms, is described.Conclusions. In the therapy of patients it is important to have the knowledge about the national therapeutic guidelines and critical distance toward them as well. Which therapy to use should be decided by the individual patient’s needs.

  1. Neuromyelitis Optica. Case Report

    Directory of Open Access Journals (Sweden)

    Patricia Quintero Cusguen

    2009-04-01

    Full Text Available Neuromyelitis Optica, also known as Devic’sSyndrome, is a disease which combines opticneuritis and transverse myelitis. Some years ago it was considered as a form of multiple sclerosis.Actually, it is consider as a different disease, onthe basis of the clinical, imaging, serology andimmunopatholoy profile.A case of 29 years old female patient is reported,based on her clinical findings which beganin the fifth postpartum month, with progressivelower limb paresis, associated with bilateralvision loss.This paper attempts giving a synoptic overviewof this uncommon immune mediateddemyelinating condition; it summarises themost important epidemiological parameters andpresents the diagnostic and therapeutic possibilitiesavailable today.

  2. Lumbar stenosis: clinical case

    Directory of Open Access Journals (Sweden)

    Pedro Sá

    2014-08-01

    Full Text Available Lumbar stenosis is an increasingly common pathological condition that is becoming more frequent with increasing mean life expectancy, with high costs for society. It has many causes, among which degenerative, neoplastic and traumatic causes stand out. Most of the patients respond well to conservative therapy. Surgical treatment is reserved for patients who present symptoms after implementation of conservative measures. Here, a case of severe stenosis of the lumbar spine at several levels, in a female patient with pathological and surgical antecedents in the lumbar spine, is presented. The patient underwent two different decompression techniques within the same operation.

  3. Company cases Denmark

    DEFF Research Database (Denmark)

    Tølle, Martin; Pedersen, Jørgen Lindgaard

    2005-01-01

    for government sector in Denmark. DC employed 1,000 persons and had a market share on 75 % in the market of large government institutions when it was taken over. Danish government wanted to sell DC in order to get more intensity in competion in IT - markets in general and especially in the market for public...... to technology but also from more focus on human beings and business.It has been important that CSC has respected Nordic values in worklife and that the CSC philosophy has been important and not so different from DC. The other case is from pharmaceutical industry in which Norwegian Nycomed buys DAK...

  4. Final report on case studies

    DEFF Research Database (Denmark)

    Ljungberg, Daniel; McKelvey, Maureen; Lassen, Astrid Heidemann

    2012-01-01

    Case study as a research design means investigating a single or multiple instance(s) or setting(s) (i.e. a case) and its entire context to explain a phenomenon and its processes. This is achieved through detailed understanding, usually comprised of multiple sources of information. In this way, case...... studies attempt to provide as a complete an understanding of a (complex) phenomenon as possible. Within the AEGIS project, survey and case study research are complementary. They are complementary in the sense that the former can provide more generalizable evidence on a phenomenon in terms of cross......-sectional data, while the latter can provide more in-depth (qualitative) understanding on specific issues. In systematically examining the case studies, however, this report goes beyond a typical single case study. Here we provide a synthesis of 86 case studies. Multiple case studies, following similar focus...

  5. Measles (Rubeola) Cases and Outbreaks

    Science.gov (United States)

    ... outbreak of 383 cases, occurring primarily among unvaccinated Amish communities in Ohio. Many of the cases in ... of spread in communities with groups of unvaccinated people. The U.S. experienced several outbreaks in 2008 including ...

  6. Final report on case studies

    DEFF Research Database (Denmark)

    Ljungberg, Daniel; McKelvey, Maureen; Lassen, Astrid Heidemann

    2012-01-01

    Case study as a research design means investigating a single or multiple instance(s) or setting(s) (i.e. a case) and its entire context to explain a phenomenon and its processes. This is achieved through detailed understanding, usually comprised of multiple sources of information. In this way, case...... studies attempt to provide as a complete an understanding of a (complex) phenomenon as possible. Within the AEGIS project, survey and case study research are complementary. They are complementary in the sense that the former can provide more generalizable evidence on a phenomenon in terms of cross......-sectional data, while the latter can provide more in-depth (qualitative) understanding on specific issues. In systematically examining the case studies, however, this report goes beyond a typical single case study. Here we provide a synthesis of 86 case studies. Multiple case studies, following similar focus...

  7. Autopsy profiles of malpractice cases.

    Science.gov (United States)

    Pakis, Isil; Yayci, Nesime; Karapirli, Mustafa; Gunce, Elif; Polat, Oguz

    2009-01-01

    Claims for medical malpractice and the number of lawsuits filed thereafter are increasing in Turkey as is the case throughout the world. In the present study all files issued by the associated boards of the Council of Forensic Medicine between 2001 and 2005 were studied and of those, 525 death cases in which there was a medical malpractice claim were included. 303 of the cases (57.7%) were male, 215 (41%) were female, while no gender was mentioned in seven cases (1.3%). The age of the subjects ranged between 0 and 90, with an average of 26.8. 147 cases (28%) were related to Emergency Units. 92% of the cases (482 cases) were resolved in the Council of Forensic Medicine, Ministry of Justice. 167 of the resolved cases were concluded as medical malpractice.

  8. Case of spontaneous ventriculocisternostomy

    Energy Technology Data Exchange (ETDEWEB)

    Yamane, Kanji; Yoshimoto, Hisanori; Harada, Kiyoshi; Uozumi, Tohru (Hiroshima Univ. (Japan). School of Medicine); Kuwabara, Satoshi

    1983-05-01

    The authors experienced a case of spontaneous ventriculocisternostomy diagnosed by CT scan with metrizamide and Conray. Patient was 23-year-old male who had been in good health until one month before admission, when he began to have headache and tinnitus. He noticed bilateral visual acuity was decreased about one week before admission and vomiting appeared two days before admission. He was admitted to our hospital because of bilateral papilledema and remarkable hydrocephalus diagnosed by CT scan. On admission, no abnormal neurological signs except for bilateral papilledema were noted. Immediately, right ventricular drainage was performed. Pressure of the ventricle was over 300mmH/sub 2/O and CSF was clear. PVG and PEG disclosed an another cavity behind the third ventricle, which was communicated with the third ventricle, and occlusion of aqueduct of Sylvius. Metrizamide CT scan and Conray CT scan showed a communication between this cavity and quadrigeminal and supracerebellar cisterns. On these neuroradiological findings, the diagnosis of obstructive hydrocephalus due to benign aqueduct stenosis accompanied with spontaneous ventriculocisternostomy was obtained. Spontaneous ventriculocisternostomy was noticed to produce arrest of hydrocephalus, but with our case, spontaneous regression of such symptoms did not appeared. By surgical ventriculocisternostomy (method by Torkildsen, Dandy, or Scarff), arrest of hydrocephalus was seen in about 50 to 70 per cent, which was the same results as those of spontaneous ventriculocisternostomy. It is concluded that VP shunt or VA shunt is thought to be better treatment of obstructive hydrocephalus than the various kinds of surgical ventriculocisternostomy.

  9. Ureterocele. A Case Report

    Directory of Open Access Journals (Sweden)

    Andrés Gualpa Jácome

    2013-12-01

    Full Text Available Ureterocele is a dilation of the distal end of the ureter that occurs during fetal stage. Its incidence varies according to the series between 1/500 to 1/4000 patients, predominantly in girls. A case of a 50-year-old white female patient with a history of recurrent urinary tract infections is presented. She attended the family doctor’s office due to the exacerbation of her condition by some episodes of dysuria, urinary frequency and urgency for several months. Abdominal ultrasound was recommended. A complex structure in the middle part of the right kidney was disclosed by a multislice ultrasonography of the abdominal region performed in the Dr. Gustavo Aldereguía Lima University General Hospital in Cienfuegos. Ureteropyelocaliectasis with good corticomedullary differentiation was observed in the left kidney, as well as dilation of the ureter until its entry into the bladder as a cystic intravesical mass. It was decided to report this case given its rare occurrence.

  10. Regional odontodysplasia: case report

    Directory of Open Access Journals (Sweden)

    Ana Carolina Magalhães

    2007-12-01

    Full Text Available Regional odontodysplasia (RO is a rare developmental anomaly involving both mesodermal and ectodermal dental components in a group of contiguous teeth. It affects the primary and permanent dentitions in the maxilla and mandible or both jaws. Generally it is localized in only one arch. The etiology of this dental anomaly is uncertain. Clinically, affected teeth have an abnormal morphology, are soft on probing and typically discolored, yellow or yellowish-brown. Radiographically, the affected teeth show a "ghostlike" appearance. This paper reports the case of a 5-year-old girl presenting this rare anomaly on the left side of the maxillary arch, which crossed the midline. The primary maxillary left teeth (except for the canine and the primary maxillary right central incisor were missing due to previous extractions. The permanent teeth had a "ghostlike" appearance radiographically. The treatment performed was rehabilitation with temporary partial acrylic denture and periodic controls. In the future, the extraction of affected permanent teeth and rehabilitation with dental implants will be evaluated. The presentation of this case adds valuable information to pediatric dentists to review special clinical and radiographic features of RO, which will facilitate the diagnosis and treatment of patients with this condition.

  11. Otocephaly: a case report

    Directory of Open Access Journals (Sweden)

    Anshu Sharma

    2016-04-01

    Full Text Available A case of otocephaly was reported in 26+/-4 week's female fetus during routine fetal autopsy at GMCH, Chandigarh, India. Mother was 25 years old, second gravid. The first child is one year old normal male baby. Present pregnancy resulted in spontaneous abortion. Antenatal history, past history, family history and medical history of mother was not suggestive of any ethiological factor responsible for the defect. The external examination showed 2 vessels in umbilical cord. There was anteroposterior lengthening of skull, mouth was in the form of a proboscis with a small opening in the centre, the right ear was absent. The left pinna was low placed and had small tags. On internal examination oral cavity was found small with hypoplastic mandible, tongue was absent (aglossia, thoracic cavity was small, left lung was absent, right lung had only single lobe, heart dilated with normal position of major vessels, In abdominal cavity gut was opening in a dilated cloaca like chamber. X-ray examination revealed small hypoplastic mandible and maxilla. Otocephaly is a rare lethal syndrome of microstomia, agnatia and ear anomalies. Other anomalies associated are holoprosenxcephaly, skeletal, genitourinary, cardiovascular system, endocrine gland hypoplasia etc. The differential diagnosis includes Treacher Collins syndrome, Goldenhar syndrome and Mobius syndrome. The etiology, incidence, causative factors of this case will be discussed in light of available literature. [Int J Res Med Sci 2016; 4(4.000: 1286-1289

  12. Fantom pain: Case report

    Directory of Open Access Journals (Sweden)

    Marić Sanja S.

    2017-01-01

    Full Text Available Background Phantom limb pain is a common problem after limb amputation (41-85%. It is described as an extremely painful sensation in the missing part of the body that can last for hours, days or even years. It is considered to arise from cortical reorganization, although many factors can increase the risk of phantom limb pain: pain before surgery, age and sex of the patients, the time elapsed since surgery, stump pain, inadequate prosthesis. Phantom limb pain therapy is very complicated. Case report We reported a case of 80-year-old patient suffering from phantom limb pain and phantom sensation 25 years after the amputation of his left leg due to the injury. The patient has pain at the site of amputation, sensation that he has the leg and that it occupies an unusual position and almost daily exhausting phantom limb pain (6-9 visual analogue scale - VAS with disturbed sleep and mood. We managed to reduce the pain under 4 VAS and decrease the patient suffering by combining drugs from the group of coanalgetics (antidepressants, antiepileptics, non-pharmacological methods (transcutaneous electroneurostimulation - TENS, mirror therapy and femoral nerve block in the place of disarticulation of the left thigh. Conclusion Phantom limb pain therapy is multimodal, exhausting for both the patient and the physician and it is often unsuccessful. The combination of different pharmacological and non-pharmacological modalities can give satisfactory therapeutic response.

  13. Coinfection: A Case Report

    Directory of Open Access Journals (Sweden)

    Huldah I. Nwokeukwu

    2013-01-01

    Full Text Available Background. Tuberculosis is a major public health problem, and its control has been facing a lot of challenges with emergence of HIV. The occurrence of multidrug-resistant strain has also propounded the problem especially in children where diagnosis is difficult to make. Multidrug-resistant tuberculosis (MDR-TB is in vitro resistant to isoniazid (H and rifampicin (R. Paediatric multi-drug resistant tuberculosis with HIV coinfection is rare, and there is no documented report from Nigeria. Objective. To report a case of paediatric MDR-TB in Nigeria about it. Methods. The case note of the patient was retrieved, and relevant data were extracted and summarized. Results. A 9-year-old female HIV-positive pupil with a year history of recurrent cough, 3 months history of recurrent fever, and generalized weight loss was diagnosed and treated for tuberculosis but failed after retreatment. She was later diagnosed with MDR-TB and is presently on DOT-Plus regimen. Conclusion. Paediatric MDR-TB with HIV co-infection is rare. Early diagnosis and treatment is important to prevent spread of the disease. The use of Isoniazid preventive therapy is recommended for children who come in contact with patients with active tuberculosis and also for HIV patients without active tuberculosis.

  14. Humeral lengthening: Case report

    Directory of Open Access Journals (Sweden)

    Gajdobranski Đorđe

    2013-01-01

    Full Text Available Introduction. Difference in length of upper extremities has mainly esthetic significance and is therefore not so often a subject of operative treatment, compared to lower extremities. Case Outline. We are presenting a case of a 16­year­old patient in whom a shortening of 9 cm of the right humerus was determined at the end of growth. This shortening was the result of surgical treatment of solitary bone cyst at the proximal end of the humerus done at the age of 10 years. In order to correct the length of the humerus we applied distraction osteogenesis with a compressive­distracting device according to Mitkovic (Traffix, and we achieved the lengthening of 7.5 cm. During the period of distraction we encountered the following complications: minimal suppuration at the site of the wedges that was successfully resolved with intensive local treatment, while pain and paresthesias along the N. radialis were resolved with a temporarily slowing of the distraction process. Fixation with a plate, i.e. bone grafting was not necessary, and final functional and esthetic result was excellent. Conclusion. Successful lengthening of the shortened humerus can be achieved with a unilateral compressive­distracting device according to Mitkovic as its application up to a complete bone reconstruction does not require additional plate fixation or bone grafting. The patient was capable of performing usual daily activities during application of the device.

  15. Scleroderma: a case report

    Directory of Open Access Journals (Sweden)

    Prachi Sankhe

    2015-06-01

    Full Text Available Scleroderma is systemic multi organ autoimmune disorder characterized by hardening of skin. Also known as systemic sclerosis. Estimated annual incidences of approximately 19 cases per million persons. The limited skin disease has a 10-year survival rate of 71%, whereas those with diffuse skin disease have a 10-year survival rate of just 21%. Risk is higher in women than men and peak in individuals aged 30-50 years. It has no definitive treatment. It may be limited or diffuse depending upon manifestations of symptoms or signs affecting internal organs especially lungs, heart, or kidney. We report a case of scleroderma with pulmonary hypertension and interstitial lung disease in our hospital who presented with tightening of skin, joint pain, dysphagia, and breathlessness. On examination skin appeared dark, shiny, and tight, with loss of hair, paraesthesia and digital ulceration. Patient also has history of Raynauds phenomenon. On investigation, Scl-70 and ANA (antinuclear antibodies by enzyme immunoassay came positive. HRCT thorax was suggestive of interstitial fibrosis and PFT revealed moderate restriction. On 2D echocardiography, mild pulmonary hypertension was present while barium swallow showed motility disorder involving oesophagus. On view of extensive systemic involvement like skin, respiratory system, gastrointestinal system and heart, we would like to present this rare disorder. [Int J Res Med Sci 2015; 3(3.000: 802-804

  16. Pseudohypoaldosteronism: Case Report

    Directory of Open Access Journals (Sweden)

    Kazım Küçüktaşçı

    2009-12-01

    Full Text Available Introduction: Pseudohypoaldosteronism is a disease which occurs as a result of peripheral resistance to aldosterone and is characterised by salt wasting. Case Report: Hyponatremia, hyperkalemia, metabolic acidosis, high renin and aldosterone levels were determined in the patient admitted with decrease in sucking and getting sleepy during breast-feeding. The case was diagnosed as systemic form of pseudohypoaldosteronism. His treatment was continued with oral salt. Conclusion: Pseudohypoaldosteronism has three types as primary, secondary and Gordon syndrome. Primary form is due to epithelial sodium channel and mineralocorticoid receptor gene mutation, whilst secondary form is frequently caused by urinary malformation and urinary tract infections. In Gordon syndrome, plasma aldosterone level is usuallly normal, and plasma renin activity is depressed, there is an adequate response to mineralocorticoids. Probability of secondary pseudohypoaldosteronism was investigated at the same time because of the urinary infection present in our subject. The patient was accepted as systemic form of primary pseudohypoaldosteronism because of positive sweat test result and prolonged salt necessity. (Journal of Current Pediatrics 2009; 7: 151-3

  17. [Neuroretinitis. Clinical cases].

    Science.gov (United States)

    Valverde-Gubianas, M; Ramos-López, J F; López-Torres, J A; Toribio-García, M; Milla-Peñalver, C; Gálvez Torres-Puchol, J; Medialdea-Marcos, S

    2009-08-01

    Evaluate the etiology and the most frequent funduscopic alterations of the neuroretinitis. We present the case of a woman 24 years old with a bilateral decrease of visual sharpness (AV), painless and progressive, the funduscopic examination of which reveals a bilateral optical disc edema, with no hemorrhages or exudates, retina edema of the posterior pole and phlebitic areas. The systematic study was normal except for the hemogram (18,000/mm(3) leucocytes with 79% neutrophils) and the positive serology next to a Chlamydia. We also present the case of a 64 years old woman with a decrease of AV at the right eye of one week duration. At the back of the eye a macular star can be seen, and papilla edema. A systematic study gave normal results and positive serology at Bartonella henselae. The illness produced by a cat scratch is the most common cause of neuroretinitis. The customary findings are a loss of AV, discromatopsia, afferent papillary defects and abnormality on the visual field. Other frequent findings at the back of the eye are hemorrhagic nerve fibers, cotton-like exudates, papilla edema, macular star and glassy inflammation. The roll of antibiotic therapy is questionable. Oral ciprofloxacine seems to give good results.

  18. Program evaluation and case study

    OpenAIRE

    Kushner, S

    2009-01-01

    This entry looks at the convergence of case study methodology and program evaluation. An early insight of some educational evaluation theorists was of the convergence of case study and program evaluation – the fusion of method with purpose. Program evaluation and case study came to be mutually-bracketed. In the educational evaluation field 'Responsive', 'Democratic', 'Illuminative' methodologies were developed in parallel with case study methods - the same authors contributing freely to both ...

  19. Perioral gustatory sweating: case report.

    NARCIS (Netherlands)

    Kayser, S.C.; Ingels, K.J.A.O.; Hoogen, F.J.A. van den

    2012-01-01

    OBJECTIVE: Presentation of a case of perioral Frey syndrome. DESIGN: Case report. SUBJECT: A 72-year-old woman with hyperhidrosis around the mouth and chin. RESULTS: This patient suffered from bilateral perioral gustatory sweating following a mandibular osteotomy; such a case has not previously been

  20. Natural Learning Case Study Archives

    Science.gov (United States)

    Lawler, Robert W.

    2015-01-01

    Natural Learning Case Study Archives (NLCSA) is a research facility for those interested in using case study analysis to deepen their understanding of common sense knowledge and natural learning (how the mind interacts with everyday experiences to develop common sense knowledge). The database comprises three case study corpora based on experiences…

  1. Natural Learning Case Study Archives

    Science.gov (United States)

    Lawler, Robert W.

    2015-01-01

    Natural Learning Case Study Archives (NLCSA) is a research facility for those interested in using case study analysis to deepen their understanding of common sense knowledge and natural learning (how the mind interacts with everyday experiences to develop common sense knowledge). The database comprises three case study corpora based on experiences…

  2. Emotion, Engagement, and Case Studies

    Science.gov (United States)

    Herreid, Clyde Freeman; Terry, David R.; Lemons, Paula; Armstrong, Norris; Brickman, Peggy; Ribbens, Eric

    2014-01-01

    Three college faculty taught large general biology classes using case studies and personal response systems (clickers). Each instructor taught the same eight cases in two different sections, except the questions within the cases differed. In one section the questions were lower order (LO) factual inquiries, and in the other they were largely…

  3. A case of unilateral dysmenorrhea

    Directory of Open Access Journals (Sweden)

    Tulon Borah

    2010-01-01

    Full Text Available Unilateral dysmenorrhea in an adolescent may be associated with uterine malformation. Relevant investigations in suspected cases and timely intervention can prevent future complications in such cases. Here, we present a case of unicornuate uterus with rudimentary horn in an adolescent complaining of unilateral dysmenorrhea.

  4. Emotion, Engagement, and Case Studies

    Science.gov (United States)

    Herreid, Clyde Freeman; Terry, David R.; Lemons, Paula; Armstrong, Norris; Brickman, Peggy; Ribbens, Eric

    2014-01-01

    Three college faculty taught large general biology classes using case studies and personal response systems (clickers). Each instructor taught the same eight cases in two different sections, except the questions within the cases differed. In one section the questions were lower order (LO) factual inquiries, and in the other they were largely…

  5. Well integrity assessment by a 1:1 scale wellbore experiment: Exposition to dissolved CO2 and overcoring

    NARCIS (Netherlands)

    Manceau, J.C.; Tremosa, J.; Lerouge, C.; Gherardi, F.; Nussbaum, C.; Wasch, L.J.; Alberic, P.; Audigane, P.; Claret, F.

    2016-01-01

    In this work, we present the results of a new in situ experiment to complete the existing scientific dataset on well integrity in the context of CO2 storage. This experimentation has been designed to evaluate the sealing behaviour of a monitored well after mechanical and chemical stresses due to

  6. Wellbore and groundwater temperature distribution eastern Snake River Plain, Idaho: Implications for groundwater flow and geothermal potential

    Science.gov (United States)

    McLing, Travis L.; Smith, Richard P.; Smith, Robert W.; Blackwell, David D.; Roback, Robert C.; Sondrup, Andrus J.

    2016-06-01

    A map of groundwater temperatures from the Eastern Snake River Plain (ESRP) regional aquifer can be used to identify and interpret important features of the aquifer, including aquifer flow direction, aquifer thickness, and potential geothermal anomalies. The ESRP is an area of high heat flow, yet most of this thermal energy fails to reach the surface, due to the heat being swept downgradient by the aquifer to the major spring complexes near Thousand Springs, ID, a distance of 300 km. Nine deep boreholes that fully penetrate the regional aquifer display three common features: (1) high thermal gradients beneath the aquifer, corresponding to high conductive heat flow in low-permeability hydrothermally-altered rocks; (2) isothermal temperature profiles within the aquifer, characteristic of an actively flowing groundwater; and (3) moderate thermal gradients in the vadose zone with values that indicate that over half of the geothermal heat flow is removed by advective transport in the regional aquifer system. This study utilized temperature data from 250 ESRP aquifer wells to evaluate regional aquifer flow direction, aquifer thickness, and potential geothermal anomalies. Because the thermal gradients are typically low in the aquifer, any measurement of groundwater temperature is a reasonable estimate of temperature throughout the aquifer thickness, allowing the construction of a regional aquifer temperature map for the ESRP. Mapped temperatures are used to identify cold thermal plumes associated with recharge from tributary valleys and adjacent uplands, and warm zones associated with geothermal input to the aquifer. Warm zones in the aquifer can have various causes, including local circulation of groundwater through the deep conductively dominated region, slow groundwater movement in low-permeability regions, or localized heat flow from deeper thermal features.

  7. A case against closure

    Directory of Open Access Journals (Sweden)

    Olin, Doris

    2005-01-01

    Full Text Available Este artigo examina a objeção ao fechamento [dedutivo] que surge no contexto de certos paradoxos epistêmicos, paradoxos cuja conclusão é que a crença justificada pode ser inconsistente. É universalmente aceito que, se essa conclusão é correta, o fechamento deve ser rejeitado, para que se evite a crença justificada em enunciados contraditórios (P, ~P. Mas, mesmo que os argumentos desses paradoxos - o paradoxo da falibilidade (do prefácio e o paradoxo da loteria - seja mal sucedidos, eles, ainda assim, sugerem a existência de evidência independente para uma objeção mais direta contra o fechamento. O exame do argumento da falibilidade revela uma exigência de modéstia epistêmica que viola o fechamento a partir de múltiplas premissas. A reflexão sobre o paradoxo da loteria nos confronta com um dilema em que cada alternativa fornece um contra-exemplo ao fechamento a partir de uma única premissa. Seja ou não possível a inconsistência racional, há uma objeção contra o fechamento. This paper examines the case against closure that arises in the context of certain epistemic paradoxes, paradoxes whose conclusion is that it is possible for justified belief to be inconsistent. It is generally agreed that if this conclusion is correct, closure must be rejected in order to avoid justified belief in contradictory statements (P, ~P. But even if the arguments of these paradoxes – the fallibility (preface paradox and the lottery paradox – are unsuccessful, they nonetheless suggest independent grounds for a more direct case against closure. Examination of the fallibility argument reveals a requirement of epistemic modesty that violates multiple premise closure. Reflection on the lottery paradox presents us with a dilemma in which each alternative provides a counterexample to single premise closure. Whether or not rational inconsistency is possible, there is a case against closure.

  8. Pore pressure prediction and well bore stability analysis in Lower Paleozoic shale formation, N Poland

    Science.gov (United States)

    Słota-Valim, Małgorzata

    2017-04-01

    Pore pressure and wellbore stability sometimes pose a serious challenge while drilling, especially through rock formations of reduced strength or through intervals where abnormally high pore pressure was formed. Lack of prediction of pore pressure and lack of wellbore stability analysis introduce an element of uncertainty in selection of drilling fluid density. Too low density of drilling fluid can lead to uncontrolled flow of the reservoir fluid to the wellbore (kicks), washouts and occurrence of cavern like structures called breakouts. On the other hand too high density can lead to formation fracturing and further fluid loss. Therefore wellbore stability loss frequently prolongs the operating time, rising the costs of the drilling and in severe cases may end up well abandons loss. The above mentioned complications can be avoided or greatly reduced by reliable analysis of drilling conditions with the aspects to geomechanical characteristics of drilled rock formations. This study presents the results of analysis of pore pressure performed with the use of commonly used in oil industry methods. The analysis of pore pressure was carried out in almost entire profile of four boreholes drilled through lower Paleozoic shales, deposited in the southern part of the Baltic Basin. In addition wellbore stability analysis was performed in the well with most complete geomechanical input data base. Obtained results helped identifying intervals with elevated pore pressure could pose a risk during drilling operation. Elaborated 1D geomechanical model provides safe mud weight window helping to reduce the instabilities risk and constitute a great tool for geomechanical model validation.

  9. Migraine Infarction. Case Report

    Directory of Open Access Journals (Sweden)

    Yoany Mesa Barrera

    2015-03-01

    Full Text Available Migraine is considered like a risk factor for ischemic ictus in adult young people. In spite of the criteria established for the treatment of the migraine infarct, they are not always fulfilled strictly, permitting certain flexibility in the aforementioned treatment. The case of a patient with a background of migraine with auras, who suffers an ischemic cerebral migraine infarct at the course of a migraine crisis, is presented. The ictus was manifested like an especial right hemiparesis of the female sex in fertile age. The prognosis is good with low risk of recurrence, with unstable disorders and dysarthria. The laboratories studies were normal and the cerebral infarct was detected in the magnetic resonance, at the half left cerebral artery's territory. The patient had favorable evolution without sequel.

  10. Unusual case of tuberculosis

    Directory of Open Access Journals (Sweden)

    Vatsal Bachkaniwala

    2015-12-01

    Full Text Available Though commonly encountered, extrapulmonary tuberculosis (TB can sometimes present with variable clinical picture intricating the diagnosis. The nonspecific symptoms include pyrexia of unknown origin, hepatosplenomegaly, lymphadenopathy, meningitis, and, rarely, variety of hematological abnormalities, namely, anemia, pancytopenia, and leukemoid reaction. When it presents with bone marrow (BM involvement, prognosis is usually poor. We, hereby, report a case of unusual TB presentation with a 4 month history of fever associated with fatigability, and diarrhea. During the hospital stay and follow up, the patient showed a spectrum of interesting hematological findings, including pancytopenia on peripheral smear, caseating granulomas consistent with TB on bone marrow examination. The patient showed a good clinical as well as hematological response to anti-tuberculosis treatment. This paper highlights the significance of a hematological picture in the final confirmation of TB, which may otherwise be passed off as nutritional or other unrelated causes. [Int J Res Med Sci 2015; 3(12.000: 3921-3923

  11. Company cases Denmark

    DEFF Research Database (Denmark)

    Tølle, Martin; Pedersen, Jørgen Lindgaard

    2005-01-01

    IT - solitions. CSC wanted to buy DC to penetrate the Nordic market. Some effects can be mentioned: Employment in CSC - DK is in 2003 1,700 persons or 2,600 including other companies bought up recently. In innovation positive effects can be registered from contacts with CSC - International. Not only from access...... for government sector in Denmark. DC employed 1,000 persons and had a market share on 75 % in the market of large government institutions when it was taken over. Danish government wanted to sell DC in order to get more intensity in competion in IT - markets in general and especially in the market for public...... to technology but also from more focus on human beings and business.It has been important that CSC has respected Nordic values in worklife and that the CSC philosophy has been important and not so different from DC. The other case is from pharmaceutical industry in which Norwegian Nycomed buys DAK...

  12. A case of acromegaly.

    Science.gov (United States)

    Siddiqui, N I; Chowdhury, K S; Rahman, S; Sarker, C B; Rahman, K M

    2003-01-01

    A fifty years old woman hailing from Purbadhala of Netrokona district complaining of gradual enlargement of hands, feet, nose and other acral parts of the body for about last eight years. She noticed coarsening of the skin and gradual protrusion of her lower jaw. She complained of headache, vertigo, frequent passage of urine, increased thirst, weight loss and fatiguability. She was found hypertensive having blood pressure 200/110 mm of Hg. Her appearance was coarse with rough skin. There were enlargement of hands, feet, nose, lower jaw with prognathism and enlargement of other acral parts. Investigations revealed high plasma glucose level, both fasting and 2 hrs. after glucose, high level of growth hormone, failure of suppression of growth hormone during OGTT. Thyroid function tests of the patient were found normal with increased heel pad size and enlarged sella turcica in all diameters. She was diagnosed as a case of acromegaly due to growth hormone hypersecretion.

  13. Executable Use Cases

    DEFF Research Database (Denmark)

    Jørgensen, Jens Bæk; Bossen, Claus

    2004-01-01

    Many software experts argue that when we design a new system, we should create an explicit description of the environment in which the proposed system is to be used. The argument becomes crucial for pervasive computing, which aims to tightly integrate systems into their environments and into the ......Many software experts argue that when we design a new system, we should create an explicit description of the environment in which the proposed system is to be used. The argument becomes crucial for pervasive computing, which aims to tightly integrate systems into their environments...... and into the work processes they're to support. However, prototypes typically provide an explicit representation only of the system itself. Executable use cases, on the other hand, can also describe the environment. EUCs are designed to: narrow the gap between informal ideas about requirements and the formalization...

  14. [Omental torsion. Case Report].

    Science.gov (United States)

    Zaleta-Cruz, Janny Lizbeth; Rojas-Méndez, Javier; Garza-Serna, Ulises; González-Ruvalcaba, Román; Ortiz de Elguea-Lizarraga, José; Flores-Villalba, Eduardo

    Omental torsion is an infrequent cause of acute abdomen and its symptoms are non-specific, often presenting with pain at the right iliac fossa as the only symptom. Its aetiology remains unknown, but different risk factors have been associated with the disease, including obesity, congenital malformations, and tumours. These risk factors have been classified as predisposing or triggering, primary or secondary, and external or internal. The is a case of a 24-year-old male who complained about pain in the right iliac fossa without any other symptoms. The diagnosis was acute appendicitis, but during the laparoscopic approach, omental torsion was found. The diagnosis of omental torsion is is complex. However, computed tomography and ultrasound have been used successfully. The treatment for omental torsion is the resection of necrotised tissue by a laparoscopic approach. Copyright © 2015 Academia Mexicana de Cirugía A.C. Publicado por Masson Doyma México S.A. All rights reserved.

  15. CADASIL: case report

    Directory of Open Access Journals (Sweden)

    Julio Cesar Vasconcelos da Silva

    Full Text Available ABSTRACT Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL is a hereditary cerebral arteriopathy caused by mutations in the Notch-3 gene. The diagnosis is reached by skin biopsy revealing presence of granular osmiophílic material (GOM, and/or by genetic testing for Notch-3. We report a case of a 52-year-old man with recurrent transient ischemic attacks (TIA, migraine, in addition to progressive sensory, motor and cognitive impairment. He was submitted to a neuropsychological assessment with the CERAD (Consortium to Establish a Registry for Alzheimer's Disease battery along with other tests, as well as neuroimaging and genetic analysis for Notch-3, confirming the diagnosis. Executive function, memory, language and important apraxic changes were found. Imaging studies suggested greater involvement in the frontal lobes and deep areas of the brain.

  16. Iniencephaly: Case Report

    Directory of Open Access Journals (Sweden)

    Hernando R Alvis-Miranda

    2015-01-01

    Full Text Available The iniencephaly involves a variable defect in the occipital bone, resulting in a large foramen magnum, partial or total absence of the cervical and thoracic vertebrae, accompanied by incomplete closure of arcs and/or vertebral bodies, significant shortening of the spinal column and hyperextension of the malformed cervicothoracic spine; the individual′s face is deviated upward, the mandibular skin is directly continuous with anterior thorax due to the absence of neck. Its incidence is about 1:1000-1:2000 births, so this is a pretty rare neural tube defect. We present a case of iniencephaly in association with cardiovascular, spinal cord, and intracranial malformations that ended demonstrating the low survival of patients affected with this condition.

  17. Parathyroid adenoma. Case presentation

    Directory of Open Access Journals (Sweden)

    Daniel Olivera Fajardo

    2016-10-01

    Full Text Available Parathyroid Adenoma is a non-malignant tumor of the thyroid glands, which increases the levels of parathormone. This hormone regulates blood and bone levels of calcium, phosphorus and Vitamin D. Its classic triad is characterized by the increase of the levels of parathormone, hyperkalimia and Hipophosphatemia. This entity affects between 500-1000 inhabitants and is the main cause of primary Hyperparathyroidism in about 80-85% of the patients. It is presented a case of a 69 year old female patient, admitted due to pathologic fractures of hip, clavicle, and fingers, caused by primary hyperparathyroidism originated by parathyroid adenoma. For the low incidence of this entity, its publication is considered of interest for the scientific staff.

  18. Alcoholic hallucinosis: case report

    Directory of Open Access Journals (Sweden)

    Bárbara Werner Griciunas

    2017-03-01

    Full Text Available Case report of patient who has been an alcoholic for 40 years and, after reducing alcohol intake, developed auditory and visual hallucinations, which caused behavior change. Neurological issues, electrolyte disturbances and other organ dysfunctions were excluded as cause of said change. After intake of haloperidol and risperidone, the patient had regression of symptoms and denied having presented hallucinatory symptoms. The Manual Diagnóstico e Estatístico de Transtornos Mentais – 5ª edição (DSM-V includes alcoholic hallucinosis in the Substance-Induced Psychotic Disorder (alcohol, beginning during abstinence; however, the document is not yet very well accepted among the medical community. The difficulty of the team to confirm the diagnosis of alcoholic hallucinosis lies in the differential diagnosis, as Delirium tremens and severe withdrawal syndrome with psychotic symptoms. Thus, psychopathological differentiation is important, as well as continuity of research and collaboration of other clinical teams in the evaluation.

  19. Chinese court case fiction

    DEFF Research Database (Denmark)

    Hansen, Kim Toft

    2011-01-01

    Western history of crime fiction usually designates Edgar Allan Poe as the undisputed father of the detective story. Crime fiction is, hence, generally associated with incipient modernity and modern societies and cityscapes. Sir Arthur Conan Doyle even asks: Where was the detective story until Poe...... breathed the breath of life into it? The usual answer is that crime fiction, in fact, was invented by Poe, but another counter-view is that China – at that point – had had a long narrative tradition for stories about crime and detection. The socalled gongan genre – court case fiction – was probably...... sinological sources introducing a revised introduction of crime fiction on the world’s literary scene. So to answer Doyle’s question about crime fiction before Poe: Crime fiction may have been in China....

  20. Tuberous sclerosis. Case presentation.

    Directory of Open Access Journals (Sweden)

    Graciela Caridad Cabrera Acea

    2009-03-01

    Full Text Available A mixed race female, 34 years of age was attended due to papule lesions in the facial area between one and ten mm of diameter. These lesions were flat, with skin colour, symmetrically distributed in the central part of the face (cheeks, chin and nose, of soft texture with telangiectasia. She referred to present these lesions since she was seven years of age, and three months before attending to consultation she noticed an increase in the number and size of these lesions. The patient has a normal intelligence coefficient and declared family history of these lesions. The diagnosis was sebaceous adenoma. Since this is not a frequent disease and due to the patient’s age we decided to publish this case.

  1. Agressive angiomyxoma: Case report

    Directory of Open Access Journals (Sweden)

    Fatma Eskicioğlu

    2012-09-01

    Full Text Available Aggressive angiomyxoma is a rare benign mesenchymal neoplasm. It is often diagnosed in genital, pelvic and perineal region of women in reproductive ages. Aggressive angiomyxoma is associated with a high risk of local recurrence. Aggressive angiomyxoma is mixed with Bartholin’s gland cyst, lipoma and vaginal cysts in diagnosis. Generally, stromal invasion is detected in these benign neoplasms. Therefore, wide local excision should be performed to treat. GnRH agonists could be administered in patient with aggressive angiomyxoma, either primary or recurrent. We reported a case with vulvar aggressive angiomyxoma presented with vulvar mass and treated with wide local excision. J Clin Exp Invest 2012; 3 (3: 420-422Key words: Angiomyxoma, myxoma, vulvar mass

  2. Choroidal osteoma - case reports.

    Science.gov (United States)

    Khan, N; Rahman, N A; Uddin, M S

    2014-07-01

    Choroidal osteoma is a rare disease. In this article four case histories were described. All were female and young patient. One patient had bilateral and other three had unilateral involvement. They had no family history. One patient reported at eye department in Bangabandhu Sheikh Mujib Medical University (BSMMU) and the other three patients reported in Bangladesh Eye Hospital. Choroidal osteoma is a benign tumor. It is diagnosed by fundoscopy, ocular B-scan ultrasonography, x-ray orbit, FFA, OCT and CT-scan of orbit. Most patients do not require treatment. Hemorrhage on the lesion suggests the presence of sub-retinal neovascularization which are typically treated with laser or intra-vitreal anti-VEGF.

  3. Mucormycosis: 2 Case Report

    Directory of Open Access Journals (Sweden)

    M. Faruk Oktay

    2007-01-01

    Full Text Available Mucormycosis is a rare, saprophytic, invasive and fulminant fungal disease. It is infective to patients with underlying immunocompromised conditions. We presented two cases of mucormycosis, one of which occured in the nose and the other on the auricle. A two-year-old female patient with diabetic ketoacidosis revealed necrosis and surrounding hyperemia in the nasal vestibule, nasal septum and dorsum of nose. A 17-year-old female diabetic patient had been suffering from black-colored lesion on the auricle. Physical examination presented necrosis on the auricle. Facial paralysis occured in the patient with auricular mucormycosis. Systemic amphotericin B was empirically administered after the sample was obtained for microbiologic and histopathologic examination in both patients. Necrotic tissues was also debrided in the second patient. The first patient died on the second day of treatment, and the second patient on the seventh day. We discussed the bacteriologic characteristics, histological peculiarities, and alternative treatments.

  4. The case for cryonics.

    Science.gov (United States)

    Moen, Ole Martin

    2015-08-01

    Cryonics is the low temperature preservation of people who can no longer be sustained by contemporary medicine in the hope that future medicine will make it possible to revive them and restore their health. A speculative practice at the outer edge of science, cryonics is often viewed with suspicion. In this paper I defend two theses. I first argue that there is a small, yet non-negligible, chance that cryonics is technically feasible. I make the case for this by reference to what we know about death and cryobiology, and what we can expect of future nanorobotics. I further argue that insofar as the alternatives to cryonics are burial or cremation, and thus certain, irreversible death, even small chances for success can be sufficient to make opting for cryonics a rational choice. Finally, I reply to five objections.

  5. Hemihydranencephaly; a Case Report

    Directory of Open Access Journals (Sweden)

    Amit Agrawal

    2009-04-01

    Full Text Available Background:Hemihydranencephaly is a rare disorder of the brain characterized by complete or almost complete unilateral absence of cerebral cortex with preservation of meninges, basal ganglia, pons, medulla, cerebellum, and falx. Case Presentation:Thirteen year-old male child presented with left sided upper and lower limb weakness with facial asymmetry since the age of six months. His magnetic resonance imaging (MRI scans demonstrated a nearly complete absence of the right cerebral hemisphere including basal ganglion, which was replaced by cerebrospinal fluid with a small residual rim of the occipital cortex. The imaging features were suggestive of right-sided hemihydranencephaly. Conclusion:Patients with hemihydranencephaly provide an experiment of nature with potential implications for normal cognitive development and illustrate how much there is still to be learned about human development.

  6. TETANUS: A CASE REPORT

    Directory of Open Access Journals (Sweden)

    Sreelatha

    2014-09-01

    Full Text Available Clostridium tetani is the causative agent of Tetanus. The aim was to detect the presence of Clostridium tetani in a case of suspected Tetanus in a 40 year old male who had history of handling a a thorn injury in the agricultural field 15 days ago. The patient presented with spasm of all the limb muscles and Lockjaw of 2 days duration together with history of convulsions for the last 3 days. Bits of tissue were collected from the necrotic depth of the wound abscess and were analyzed. Clostridium tetani was isolated. A diagnosis of Tetanus was made and the concerned authority was immediately notified. The patient was successfully treated with complete recovery. An early diagnosis of TETANUS is significant because it can help the clinician in early management and prevention of development of terminal respiratory failure and death

  7. Lamellar Ichtyosis: Case Report

    Directory of Open Access Journals (Sweden)

    Kamer Gündüz

    2009-12-01

    Full Text Available Introduction: Ichtyosiform dermatoses are a group of hereditary disorders characterized by excessive scaling on the skin. Lamellar ichtyosis is an autosomal recessive disorder. The clinical findings are seen at birth and become widespread and prominent in time; gray-brown scales are seen all over the body. Emollients and keratolytics containing salicylic acid or glycolic acid are used topically. Symptoms are improved significantly by acitretin usage. Case Report: Here we present a 5-year-old girl with lamellar ichtyosis. She was born in a collodion membrane. Besides the skin scales, ectropion and deformities of the nails and ears were observed. Significant clinical improvement was seen with acitretin (10 mg/day therapy. Conclusion: Lamellar ichtyosis is a severe form of ichtyosiform dermatoses and topical agents may be insufficient. Systemic acitretin treatment improves the symptoms significantly but long term side effects limit its usage. (Journal of Current Pediatrics 2009; 7: 154-7

  8. Disulfiram neuropathy: two case reports

    OpenAIRE

    2016-01-01

    Background Neuropathy is a rare adverse side effect of disulfiram therapy and is under-recognized. There have been few case reports documenting this side effect. Case presentation Two cases of disulfiram peripheral neuropathy are discussed. The first case is that of a 25-year-old Caucasian woman who was exposed to disulfiram therapy for a total of 8 months and developed pain and stiffness that prevented her from walking. The second case is that of a 46-year-old Caucasian woman who developed s...

  9. TACE Case Presentations

    Directory of Open Access Journals (Sweden)

    Mahyar Mohammadifard

    2010-05-01

    Full Text Available Gold standard treatment of hepatocellular carci-noma is surgical resection but more than 80% of patients with HCC are unresectable at the time of diagnosis, and due to poor local circumstances or the patient's general condition, the prognosis is poor. "nBecause HCC tumors are fed exclusively by the he-patic artery, successful TACE leads to tumor necrosis. The liver parenchyma is rarely damaged because it is fed by the portal vein. Injection of an emulsion of iodized oil and cytostatic agents into the hepatic artery leads to selective deposition of the emulsion in the tumor. Compared with intravenous administration of cytostatic material, TACE reduces the maximum plasma concentration and increases the average concentration of cytostatic agents in the tumor, especially when the cytostatic material is combined with gelatin powder particles. "nFor example, concentration of an emulsion of cisplatin in iodized oil 4-9 weeks after intraarterial administration is 42 times greater in the tumor than in the parenchyma."nTwo cases of HCC are presented which were treated successfully with TACE 20 months ago."nIn the first patient after one session of TACE, tumor markers fell down into normal range and MDCT showed complete necrosis and cystic changes in the mass without residual or recurrent tumor until this time. "nIn the next case tumor markers showed no significant decrease after the first session of TACE and MDCT showed residual tumor which was fed by an accessory arterial branch from SMA. This branch was treated in another session. Two months later, tumor markers fell down and MDCT showed no tumor activity. "nThese patients have been symptom free after the mentioned interventions.

  10. [Pheochromocytoma. Report of 10 cases].

    Science.gov (United States)

    Rabii, R; Joual, A; Rais, H; Bennani, S; el Mrini, M; Benjelloun, S

    1999-01-01

    We report 10 cases of adrenal pheochromocytoma seen over a period 15-years. A female predominance was noted (8 women/2 men). Patients were aged between 16-46 years with a mean of 34 years. Clinical manifestations consisted of hypertension observed in all cases, with vasomotor symptoms (90%). Time to consultation was prolonged (mean: 23 months). CT scan performed in 7 cases showed pheochromocytoma in all cases, located on the right side in 6 cases, while one pheochromocytoma was located in Zukerkandal organ. All patients were operated via anterior approach and adrenalectomy was performed. A favourable course was observed in 90% of cases with normalisation blood pressure. One death was noted. Histological examination showed no malignancy in all cases.

  11. The case for the case report: refine to save.

    LENUS (Irish Health Repository)

    Lennon, P

    2012-01-31

    INTRODUCTION: The case report is the cornerstone of both medical teaching and writing. However, during recent years the value of the case report has been questioned, so much so that it has been abandoned by many journals. The aim of this study was to assess case reports published by the Irish Journal of Medical Science (IJMS) and to examine ways to preserve this type of article. METHODS: A review of all single-patient case reports published in the IJMS in 2008 and 2009. RESULTS: Forty-eight cases were published from nine countries. The range of authors was 2-11, length 525-1,787 words and number of references 4-24. All cases contained abstracts. CONCLUSION: Stricter guidelines with regards to a shorter more focused article should help to preserve this form of publication.

  12. Delusional Parasitosis : Series Of 25 Cases

    Directory of Open Access Journals (Sweden)

    Bhatia M S

    1996-01-01

    Full Text Available A series 25 cases of delusional parasitosis is being reported. There were three cases below 45 years, 12 cases between 46-45 years and 11 cases above 55 years of age, 64% cases were females. A majority of cases (92% had insidious onset. The duration of symptoms in all the cases (except one was 6 months or more. 13 cases presented with infestation with insects over body and 10 cases with insects crawling over scalp. There were three cases each with diabetes mellitus and leprosy. Three cased had dementia, 2 cases had depression and one case presented with trichotillomania. Pimozide was used in22 cases, amitriptyline in 2 cases and fluoxetine in one. 14 cases (52% showed complete remission while receiving drug, 8 cases showed partial improvement and 3 cases did not respond.

  13. Safety Cases for Advanced Control Software: Safety Case Patterns

    Science.gov (United States)

    2007-10-15

    Classification Argument (from [14]) The classification of software failure modes can be useful for adaptive systems. Kurd in [15] shows how HAZOPS ...Safety Cases for Advanced Control Software : Safety Case Patterns Robert Alexander, Tim Kelly, Zeshan Kurd, John...5a. CONTRACT NUMBER FA8655-07-1-3025 5b. GRANT NUMBER 4. TITLE AND SUBTITLE Safety Cases for Advanced Control Software 5c. PROGRAM ELEMENT

  14. Celiac disease - case report

    Directory of Open Access Journals (Sweden)

    Bojković Gradimir

    2002-01-01

    Full Text Available Introduction Celiac disease (nontropical sprue, gluten-sensitive enteropathy, chronic intestinal malabsorption disorder is caused by gluten intolerance. This hereditary disorder is caused by sensitivity to gliadin. Because the body's own immune system causes the damage, celiac disease is considered to be an autoimmune disorder. However, it is also classified as a disease of malabsorption because nutrients are not absorbed. When people with celiac disease eat foods containing gluten, their immune system responds by damaging the small intestine. Specifically, tiny finger-like protrusions, called villi, on the lining of the small intestine are lost. The diagnosis is suspected on the basis of symptoms and signs, enhanced by laboratory and x-ray studies, and confirmed by biopsy revealing flat mucosa and subsequent clinical and histologic improvement on a gluten-free diet. Gluten must be excluded from diet. Supplementary vitamins, minerals and hematinics may be given depending on deficiency. Case report This is a case report of a 23-year old female patient with a mineralization defect (osteomalacia and secondary osteoporosis caused by long-time unrecognized celiac disease. The patient had many symptoms: short stature, steatorrhea, anemia, weight loss and chronic bone pain. Laboratory and x-ray studies and jejunal biopsy revealed a chronic intestinal malabsorption disorder caused by gluten intolerance. Gluten-free diet and supplementary vitamins, minerals and hematinics were included with apparent clinical remission. Discussion and Conclusion Some people with celiac disease may not have symptoms. The undamaged part of their small intestine is able to absorb enough nutrients to prevent symptoms. However, people without symptoms are still at risk for complications of celiac disease. Biopsy of the small intestine is the best way to diagnose celiac disease. Decreased bone density (osteoporosis and osteomalacia is a serious problem for celiacs. If calcium

  15. IPEX syndrome: Case report

    Directory of Open Access Journals (Sweden)

    Radlović Nedeljko

    2008-01-01

    Full Text Available INTRODUCTION IPEX syndrome, namely, a hereditary (X-linked immunodysregulation with autoimmune polyendocrinopathy and enteropathy, as the basic manifestations, presents a rare and exceptionally severe disease. It develops due to gene mutation responsible for the synthesis of a specific protein (FOXP3, which, by differentiation and activation of regular T-lymphocytic CD4+CD25+, has the key role in the induction and maintenance of the peripheral tolerance of one's own tissue. CASE OUTLINE We present a male infant with classic clinical features of IPEX syndrome, which manifested by the end of the first month after birth, first with type 1 diabetes mellitus and chronic diarrhoea followed by dehydration and disordered development, and then with facial eczema and laboratory signs of thyroiditis without thyroid dysfunction (antithyreoglobulin antibodies 1:5500, antimicrosomal antibodies 1:40. In addition, plasma IgE level was high (517 IU/l, while antibodies to tissue transglutaminase were mildly increased (IgA 7.5 U/ml, and anti-smooth muscle and anti-DNA antibodies were absent. Based on the typical clinical features, as well as the laboratory findings, IPEX syndrome was diagnosed, which was further confirmed by proved IVS7+5G>A mutations in the FOXP3 gene. Therapy with insulin and Pronison, combined with parenteral and semielementary nutrition resulted in the patient's clinical improvement. At the age of 9 months, despite Pronison and hypoallergenic nutrition, the child had a relapse of severe and persistent diarrhoeal disorder followed by dehydration, weight loss and deterioration of general condition. Beside the complete parenteral nutrition, as well as other measures, azathioprine was introduced into the treatment, but without the desired effect. At the age of 12.5 months, due to bacteraemia and disseminated intravascular coagulation as complications, the patient ended lethally. CONCLUSION IPEX syndrome should be kept in mind in all the cases of

  16. Cryptococcosis in captive cheetah (Acinonyx jubatus : two cases : case report

    Directory of Open Access Journals (Sweden)

    L.A. Bolton

    1999-07-01

    Full Text Available Cryptococcus neoformans is a yeast-like organism associated with pulmonary, meningoencephalitic, or systemic disease. This case report documents 2 cases of cryptococcosis with central nervous system involvement in captive cheetah (Acinonyx jubatus. In both cases the predominant post mortal lesions were pulmonary cryptococcomas and extensive meningoencephalomyelitis. Both cheetahs tested negative for feline immunodeficiency virus and feline leukaemia virus. The organism isolated in Case 2 was classified as Cryptococcus neoformans var. gattii, which is mainly associated with disease in immunocompetent hosts.

  17. Multiple myeloma: 45 cases

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Hee Chul; Suh, Jin Suck; Park, Chang Yun [Yonsei University College of Medicine, Seoul (Korea, Republic of)

    1990-10-15

    We evaluated 45 cases of multiple myelomas retrospectively confirmed in Severance Hospital from the period of 1983-1989. In order to assess the radiologic features of the multiple myeloma and to assist in possible early diagnosis and treatment. The result were as follows: 1. IgG(41%) was the most common immunoglobulin type secreted followed by light chain(36%). IgA(19%) and IgD(2%). Two percent of the patients had non-secretory type. 89% of patients were in their stage III of the disease. 2. Among the 45 patients, 96% had abnormal plain radiographic findings with average number of 4.5 lesions. Common sites were the spine, rib, skull, pelvis, and humerus in descending orders. The findings were localized or diffuse osteolytic bone destruction(85%). osteoporosis(49%), pathologic fracture and endosteal scalloping(55%). Osteoporosis was more prominent in stage III than stage II. 3. Both plain X-ray and radioisotope study was available for comparison in 28 patients. Concordance between the two studies were 44%, lesions detected only on plain X-ray film were 51%, and lesions detected only on the radioisotope were 5%. The plain radiography was able to detect only 54% of bone lesions confirmed by bone marrow biopsy. With the above results, accurate evaluation of bone lesions in multiple myeloma may be difficult with radiologic studies only. But familiarity with these radiologic findings of the this disease entity is necessary for early suspicion of the disease, thus for early diagnosis and treatment.

  18. Dioxin: a case study.

    Science.gov (United States)

    Bond, G G

    1993-01-01

    The need to notify individuals of a possible health risk from their past exposure to potentially hazardous agents frequently extends beyond workers to include community groups. The issues to consider in community notification are frequently similar to those that are important for worker notification but may include some that are unique. This case study traces the evolution of one company's strategy for communicating with the public about possible dioxin contamination associated with its operations. Early communications tended to emphasize the technical aspects of the issues in the fashion of scientists talking to other scientists. This was interpreted by some to be symptomatic of an arrogant and uncaring attitude. Beginning in the early 1980s, the company's management recognized the need to reach out to a variety of audiences on multiple levels, and shifted to a more comprehensive communications strategy. A similar shift is now occurring throughout the chemical manufacturing industry as top managers realize that, if they expect to continue to operate, they must become more accountable and responsive to the public.

  19. NECROTIZING SIALOMETAPLASIA. CASE REPORT

    Directory of Open Access Journals (Sweden)

    A.I. Navazo Eguía

    2010-01-01

    Full Text Available Introduction: Necrotizing sialometaplasia (NSM is a benign lesion affecting the salivary glands mainly in the hard palate. It presents as an ulcer with irregular borders, slightly elevated and necrotic The differential diagnosis should include malignant neoplasms. Case Report: A 26-year-old woman sought medical advice for a painful 2 cm ulceration of the hard palate. She is carrying pierced tongue. The patient had a history of cigarette smoking, chronic anxiety disorder and bulimia,. Analytical normal (including HIV and syphilis serology. Histopathology: accessory gland with squamous metaplasia, pseudoepitheliomatous hyperplasia and conservation lobulararchitecture. She had an important improvement with total resolution of the lesion in 4 months Discussion: The NSM is a necrotizing inflammatory process. It presents as an ulcer located in the posterior hard palate or the junction between the hard and soft palate. This situation has been associated with local ischemia as surgical trauma, thromboangiitis obliterans, dentures, alcohol, snuff, cocaine, and certain malignancies such as lymphomas, rhabdomyosarcoma or Warthin tumor. Currently associated withbulimia, it being necessary suspected in young women. It is important to rule out neoplasms and infectious processes (tuberculosis or syphilis. Also consider subacute necrotizing sialadenitis, nonspecific acute inflammatory process of unknown cause, with focal necrosis without hyperplasia or ductal metaplasia pseudoepitheliomatous. Treatment is symptomatic and usually resolves in 2-3 months. Conclusion: The NSM is a benign lesion which may mimic neoplasia. The trend is toward resolution. It must be recognized to avoid unnecessary surgery.

  20. Arthrogryposis - case report

    Directory of Open Access Journals (Sweden)

    Mariana CEVEI

    2008-05-01

    Full Text Available Arthrogryposis is a congenital disorder characterized by multiple joint contractures found throughout the body at birth. We present the case of a 3.5 year-old girl with multiple congenital defects: arthrogryposis involving bilateral hip, knee and ankle joints, together with sacral agenesis and with lumbar dysmorphism, anorectal agenesis, hydronephrosis of the left kidney as the result from reflux, right kidney hypoplasia, renal fusion and heart anomalies: tetralogy of Fallot. Immediately after birth, in several steps, colostomy, left ureterocystoneostomy and suprapubic cystostomy were performed. Later in infancy corrective surgery for the heart defect was required. At the age of 2 years, surgery for the equinovarus deformities and for left genu flexum was performed. Medical rehabilitation tries to maximize independent function. The main goals were increasing the muscle tonus of upper-limbs, increase the rate of motion of the joints, establishment of stability for ambulation, learning different schemes of movement according to her needs, obtaining of a functional independency. The therapies were successful, after 10 weeks an improvement of the moving capacity and of the transfer in orthostatism with minimal external assistance, with the obvious increasing of the patient's satisfaction, were noticed.

  1. Perilunar Luxation. Case Report

    Directory of Open Access Journals (Sweden)

    Yaniel Truffín Rodríguez

    2015-06-01

    Full Text Available Within the specter of injuries found in dorsal perilunar luxation or injuries of the bigger arch, the one belonging to bigger frequency reciprocates with the fracture luxation trasescafo dorsal perilunar. Much less frequent are the luxations that associate the big bone's fractures and those with displaced fractures of the pyramidal. Throughout the above, the case of a 19 year old patient is presented, that came to the emergency room of Gustavo Aldereguía Lima, Cienfuegos Hospital, after suffering a fall on his left hand with background of previous health. Great increase of volume in the left-handed wrist, acute pain in spite of immobilization and absolute functional impotence were verified. Manual reduction under general anesthesia of the perilunar luxation of the carpus was accomplished. By means of X-ray pictures of control, anteroposterior and lateral of the wrist, escafoides's fracture and its characteristics were verified. For the marked angulation and conminution of the fracture surgical open-cast treatment was decided, using the technique of Ruse, that was postpone to the tenth day from the initial lesion, when the wrist was less inflamed and the risks of complications were less. The patient was discharged of the consultation of orthopedics to the six months of operated showing functional acceptable results.

  2. [Broncholithiasis: six cases].

    Science.gov (United States)

    Ghraïri, H; Ketata, W; Kartas, S; Ayadi, A; Ammar, J; Abid, H; Kilani, T; Hamzaoui, A

    2007-04-01

    Broncholithiasis is an exceptional condition characterized by the presence of stony formations in the bronchial lumen. We report six cases. Mean age was 41 years. Revealing signs were hemoptysis (n=5), cough (n=5), fever (n=1) and recurrent lower respiratory tract infections (n=1). Physical examination found sonorous rales in two patients and was normal in four. The chest x-ray showed a parenchymal opacity suggestive of calcification in one patient, atelectasia in two, and alveolar images in three. Bronchial endoscopy demonstrated broncholithiasis in one patient, an endobronchial blood clot in one patient with abundant hemoptysis, an endoluminal bud simulating a tumor in two, an inflammatory aspect in one, and was normal in one. Thoracic computed tomography demonstrated broncholithiasis in three patients. Treatment consisted in lobectomy in five patients. The pathology specimen confirmed broncholithiasis in all five and in one revealed caseofollicular lesions of the hillar nodes. Anti-tuberculosis treatment was prescribed for this patient. Therapeutic abstention with regular surveillance was chosen for one patient with an uncomplicated broncholithiasis. Broncholithiasis is an exceptional condition with potentially serious consequences. Certain diagnosis is based on high-resolution computed tomography and endoscopic findings but can nevertheless be a surgical discovery.

  3. Case consultation: ablatio penis.

    Science.gov (United States)

    Money, J

    1998-01-01

    In male infants, traumatic ablation of the penis, with or without loss of the testicles may occur as a sequel to mutilatory violence, accidental injury, or circumcision error. Post-traumatically, one program of case management is surgical sex reassignment to live as a girl, with female hormonal therapy at the age of puberty. The other program is genital reconstructive surgery to live as a boy, with male hormonal therapy at puberty if the testicles are missing. In both programs, the long term outcome is less than perfect and is contingent on intervening variables that include societal ideology; surgical technology; juvenile and adolescent timing and frequency of hospital admissions construed by the child as nosocomial abuse; development of body image; health and sex education; fertility versus sterility; coitus and orgasm; possible lesbian orientation if living as a girl; and long-term cost accounting, including the psychic cost of being a pawn in possible malpractice litigation on whose disability a very large fortune in compensation may devolve. There is, as yet, no unanimously endorsed set of guidelines for the treatment of genital trauma and mutilation in infancy, and no provision for a statistical depository for outcome data.

  4. Patellar osteochondroma: case report,

    Directory of Open Access Journals (Sweden)

    Frederico Barra de Moraes

    2014-04-01

    Full Text Available The aim was to report on a rare case of patellar osteochondroma. A 60-year-old man presented a tumor on his left patella that had developed over a 10-year period, which is a rare occurrence, considering the patient's age and the site at which the tumor appeared. The clinical condition comprised mild pain and the presence of a mass, without limitation of flexion-extension or any neurovascular deficit. The tumor dimensions were 8 cm longitudinally × 6 cm transversally × 3 cm anteroposteriorly. It was hardened and was adhering to the patellar bone plane. On radiographs and tomographic scans, we observed areas of greater density corresponding to bone and other less dense areas that could correspond to slow-growing cartilage, with irregularities on the patellofemoral joint surface. Simple resection of the tumor was performed, and the anatomopathological examination confirmed that it was a patellar osteochondroma. Osteochondroma, or osteocartilaginous exostosis, includes a large proportion of the benign bone tumors. It results from cell alterations that trigger unregulated production of spongy bone. It is basically treated by means of surgical removal of the tumor mass. This is not essential, but is recommended in order to avoid lesions caused by contiguity and the risk of malignant transformation.

  5. Pseudoachondroplasia: A case report

    Directory of Open Access Journals (Sweden)

    Radlović Vladimir

    2013-01-01

    Full Text Available Introduction. Pseudoachondroplasia (PSACH is an autosomal dominant osteochondrodysplasia due to mutations in the gene encoding cartilage oligomeric matrix protein. It is characterized by rhizomelic dwarfism, limb and vertebral deformity, joint laxity and early onset osteoarthrosis. We present the girl with the early expressed and severe PSACH born to clinically and radiographically unaffected parents. Case Outline. A 6.5-year-old girl presented with short-limbed dwarfism (body height 79.5 cm,

  6. Case of administrative dispute

    Directory of Open Access Journals (Sweden)

    Xhemazie Ibraimi

    2015-11-01

    Full Text Available The activity of administrative bodies includes big numbers of various acts and actions, through which the will of public administration is formed. The will of public administration bodies, expressed in administrative individual and normative acts, in administrative contracts and real acts, finds its reflection in the Constitution, laws and other provisions of legal character. All this activity is not inerrant and therefore, it is not uncontrollable. The supervision of executive activity is subject to political control of administrative acts through authorities designated for this purpose, as well as internal control and the judicial control. The institution of judicial control of administrative acts and actions appears as very important and widely treated in the legal doctrine. The protection of constitutional and legal rights of private persons is accomplished by subjecting administrative activity both to internal administrative control, as well as to the judicial control in accordance with legal provisions. The judicial control of administrative acts represents a constitutional guarantee for citizens to protect their rights through public and fair trial by an independent and impartial court. In this way, the Constitution empowers the common administrative court that invalidates an action or administrative act, but not all administrative acts may be subject to administrative dispute, with the exception of cases against which the administrative conflict cannot be carried out (negative enumeration.

  7. Numerical Simulation of Geostress and Pore Pressure Evolution around Oil or Water Well under Different Injection-Production Ratio

    Directory of Open Access Journals (Sweden)

    Liu Jian-jun

    2013-01-01

    Full Text Available Geostress evolution in the process of oil field development can directly influence wellbore stability. Therefore, it is significant to strengthen the research of the evolution rule for well drilling and casing protection. Considering the interaction between reservoir seepage and stress fields, a mathematical model to characterize the stress evolution around wellbore was built. Using the FEM Software ABAQUS, through numerical simulation, the authors studied the evolution features of pore pressure and stress changes with time under different injection-production ratio, which disclosed the dynamic change regulation of pore pressure and stress of surrounding rock nearby the injection and production wells. These results may have implications in the treatment of wellbore stability and optimizing the injection and production processes during oil and gas production.

  8. Pressurized waterproof case electronic device

    KAUST Repository

    Berumen, Michael L.

    2013-01-31

    A pressurized waterproof case for an electronic device is particularly adapted for fluid-tight containment and operation of a touch-screen electronic device or the like therein at some appreciable water depth. In one example, the case may be formed as an enclosure having an open top panel or face covered by a flexible, transparent membrane or the like for the operation of the touchscreen device within the case. A pressurizing system is provided for the case to pressurize the case and the electronic device therein to slightly greater than ambient in order to prevent the external water pressure from bearing against the transparent membrane and pressing it against the touch screen, thereby precluding operation of the touch screen device within the case. The pressurizing system may include a small gas cartridge or may be provided from an external source.

  9. A report on case reports

    Directory of Open Access Journals (Sweden)

    Gopikrishna Velayutham

    2010-01-01

    Full Text Available Case reports are defined as the scientific documentation of a single clinical observation and have a time-honored and rich tradition in medicine and scientific publication. This article discusses the role and relevance of case reports in the current evidence-based medical literature. It also seeks to help and guide authors to understand how to prepare a reasonable and well-written case report and how they may anticipate concerns that peer reviewers may express when scrutinizing their manuscript. An overview of the Journal of Conservative Dentistry′s review process of a manuscript submission is provided for the benefit of future authors. It is important to be able to read a case report critically and to use the information they contain appropriately. This article also discusses the factors to consider in evaluating individual case reports, and discusses a practical conceptual scheme for evaluating the potential value and educational content of a case report.

  10. Three cases of pulmonary varix

    Energy Technology Data Exchange (ETDEWEB)

    Takishima, Teruo; Sakuma, Hajime; Tajima, Tsunemi; Okimoto, Takao; Yamamoto, Keiichiro; Dohi, Yutaka (Saitama Medical School (Japan))

    1982-06-01

    Three cases of pulmonary varix associated with valvular heart disease were reported. Round shadows were clearer on first oblique or lateral films of chest x-ray in all 3 cases. On chest tomograms, the shadows were substantial and round-elliptical. RI angiography with sup(99m)Tc-RBC demonstrated these shadows in agreement with the site of influx of the pulmonary vein into the left atrium in Cases 1 and 3 and with the pulmonary vein slightly apart from the left atrium in Case 2. On CT scans in Cases 1 and 3, enhancement with a contrast medium visualized dilatation of the pulmonary vein close to, and in continuation with, the shadow of the left atrium. The diagnosis of pulmonary varix in agreement with the venous phase of pulmonary angiography was made for all 3 cases. Non-surgical examinations (especially CT scan) proved highly useful for the diagnosis of pulmonary varix.

  11. [Bursitis intermetacarpophalangea calcarea (case report)].

    Science.gov (United States)

    Piza-Katzer, H; Weinstabl, R

    1987-03-01

    A case of bursitis intermetacarpophalangea calcarea is presented which, after clinical and X-ray examination, raised problems regarding differential diagnosis. Because of the rarity of the findings, the anatomical localization as well as the surgical procedure is presented. Calcifications which may show in tendons and ligaments are discussed. In cases of acute calcareous infiltration in hands, surgery very rarely is indicated. By contrast, in cases of bursitis intermetacarpophalangea calcarea, surgery should be performed as soon as possible to preserve normal hand function.

  12. Dioctophymiasis: A Rare Case Report.

    Science.gov (United States)

    Chauhan, Sapna; Kaval, Sunil; Tewari, Swati

    2016-02-01

    Dioctophyma renale commonly known as "giant kidney worm' is found in the kidney of carnivorous mammals. Human infestation is rare, but results in destruction of the kidneys. Very few cases have been reported worldwide. We are here reporting a case of Dioctophymiasis in a 35-year-old male patient who presented with retention of urine and subsequent passage of worm and blood in urine. The worm was confirmed as Dioctophyma renale based on its morphology and clinical presentation. This is a very rare case report and to best of our knowledge only two cases have been reported from India.

  13. Theory Testing Using Case Studies

    DEFF Research Database (Denmark)

    Møller, Ann-Kristina Løkke; Dissing Sørensen, Pernille

    2014-01-01

    testing using case studies, including the associated research goal, analysis, and generalisability. We argue that research designs for theory testing using case studies differ from theorybuilding case study research designs because different research projects serve different purposes and follow different......The appropriateness of case studies as a tool for theory testing is still a controversial issue, and discussions about the weaknesses of such research designs have previously taken precedence over those about its strengths. The purpose of the paper is to examine and revive the approach of theory...... research paths....

  14. Hemimegalencephaly without epilepsy: case report.

    Science.gov (United States)

    James, Greg; Shanmuganathan, Mano; Harkness, William

    2014-09-01

    Hemimegalencephaly is a rare sporadic brain malformation characterized by enlargement of one cerebral hemisphere. The classical clinical triad consists of intractable epilepsy, severe psychomotor delay and hemiparesis. In this report, we describe a case of a 3-year-old girl, with all the radiological features of severe hemimegalencephaly but with a comparatively benign clinical course. She had no hemiparesis, mild delay and no seizures. An extensive literature review reveals only one previously reported case of hemimegalencephaly with the absence of seizures, as part of case series. This is the first dedicated case report, with clinical description and radiological images, of this entity.

  15. Urachal endometrioma: a case report.

    LENUS (Irish Health Repository)

    Browne, Katherine M

    2009-01-01

    INTRODUCTION: We discuss a rare presentation of an unusual case of endometrioma. CASE PRESENTATION: A 40-year-old Caucasian woman presented with subacute abdominal pain and a suprapubic mass. A final diagnosis was made after the mass was resected and histopathology confirmed an endometrioma originating from an urachal remnant. Select imaging studies and histopathology are presented in this case report. CONCLUSION: While endometriomata are well known to arise from abdominal scars, the condition described in this case report is a rare example of an endometrioma arising from the urachus. A review of the pathological complications of the urachus is also included.

  16. Theory Testing Using Case Studies

    DEFF Research Database (Denmark)

    Møller, Ann-Kristina Løkke; Dissing Sørensen, Pernille

    2014-01-01

    testing using case studies, including the associated research goal, analysis, and generalisability. We argue that research designs for theory testing using case studies differ from theorybuilding case study research designs because different research projects serve different purposes and follow different......The appropriateness of case studies as a tool for theory testing is still a controversial issue, and discussions about the weaknesses of such research designs have previously taken precedence over those about its strengths. The purpose of the paper is to examine and revive the approach of theory...... research paths....

  17. Esthesioneuroblastoma: a case report.

    Science.gov (United States)

    Shukla, R C; Singh, P K; Senthil, S; Pathak, R

    2010-06-01

    Esthesioneuroblastoma (olfactory neuroblastoma) is an uncommon neuroectodermal tumor. Its biological activity ranges from indolent growth to local recurrence and rapid widespread metastasis. Treatment options consist of surgical resection followed by radiation therapy for primary lesions and the addition of chemotherapy for advanced, recurrent, or metastatic lesions. Patients often present with nasal obstruction, rhinorrhea, recurrent epistaxis, hyposmia, or anosmia. We report a case of esthesioneuroblastoma involving bilateral nasal cavity leading to bilateral nasal obstruction, epistaxis and proptosis of the right eye associated with decreased visual acquity on that eye and loss of smell. A diffuse nontender, 6x6 cms swelling with illdefined margins was seen over the nasal bridge, extending superiorly to glabella and laterally to right maxillary region. X-ray PNS showed soft tissue mass in the nasal cavity with destruction of nasal septum, intense periosteal reaction with destruction of right maxillary wall and extension to right orbit. CT scan of paranasal sinuses showed 8.5 x 4.9 x 7.8 cms irregularly marginated heterogeneous iso- to hyper dense soft tissue mass lesion with extensive adjacent bony destruction and spiculated periosteal reaction involving bilateral nasal cavity and anterior cranial fossa. Biopsy from right nasal mass showed neuroblastoma. The patient received radiotherapy and chemotherapy. The modified Kadish staging system, lymph node status, treatment modality, and age are useful predictors of survival in patients who present with esthesioneuroblastoma. Excellent outcomes for esthesioneuroblastoma are achievable. Long-term follow-up is necessary because of the extended interval for recurrent disease; unlike most sinonasal malignancies, surgical salvage is possible.

  18. Case Study: Case Studies and the Flipped Classroom

    Science.gov (United States)

    Herreid, Clyde Freeman; Schiller, Nancy A.

    2013-01-01

    This column provides original articles on innovations in case study teaching, assessment of the method, as well as case studies with teaching notes. This month's issue discusses the positive and negative aspects of the "flipped classroom." In the flipped classroom model, what is normally done in class and what is normally done as…

  19. Building theories from case study research: the progressive case study

    NARCIS (Netherlands)

    Steenhuis, Harm-Jan; Bruijn, de Erik J.

    2006-01-01

    Meredith (1998) argues for more case and field research studies in the field of operations management. Based on a literature review, we discuss several existing approaches to case studies and their characteristics. These approaches include; the Grounded Theory approach which proposes no prior litera

  20. Making a case for case studies in psychotherapy training

    DEFF Research Database (Denmark)

    Mackrill, Thomas Edward; Iwakabe, Shigeru

    2013-01-01

    articulated explicitly or researched systematically in spite of its cardinal importance. An analysis of the role of case studies in psychotherapy training is presented. Reading, watching, or hearing about cases can offer novice psychotherapists access to a closed world; access to psychological theory...

  1. Demystifying Instructional Innovation: The Case of Teaching with Case Studies

    Science.gov (United States)

    Kantar, Lina D.

    2013-01-01

    Issues emerging from instructional innovation are inevitable, yet basing any curriculum shift on a theoretical framework is paramount. This paper grounds the case-based pedagogy in three learning theories: behaviorism, cognitivism, and constructivism. The three theories are described and situated in relation to the case study method. An…

  2. 一修正设计系数的套管层次与下入深度设计方法%An improved casing design method and its application in deepwater drilling

    Institute of Scientific and Technical Information of China (English)

    柯珂; 管志川; 王志远; 路保平

    2016-01-01

    传统井身结构设计过程中用以确定安全钻井液密度窗口所采用的各类设计系数均采用经验或统计估算的方法,且在全井段各设计系数取值相同。对原有安全钻井液密度窗口确定准则中的部分公式和系数进行改进和修正,并提出一种修正设计系数的井身结构设计方法,新方法中各类设计系数将根据实际井条件精细计算,避免过度浪费安全窗口空间,使井身结构设计结果更为合理高效。以西非深水区块B-1井为例进行实例计算。结果表明,不同井段、不同井眼尺寸对各类设计系数具有明显影响,尺寸差距越大,设计系数的差异性也越大,其对井身结构设计结果的影响也越大。%In conventional casing designs for oil and gas well drilling, all the design coefficients used for the determination of safe drilling fluid density window are defined by empirical evaluation or statistical methods, and a consistent value of each co-efficient is taken for all well sections. For drilling under complicated conditions, especially in deepwater drilling and at high temperature and high pressure ( HTHP) conditions or for ultra-deep wells, the safe drilling fluid density window required is much narrower, and the conventional casing design method is not appropriate. When the values of the design coefficients are taken too low, it may lead to less safe drilling conditions, but when they are too high, it can waste some safe drilling fluid window space, resulting unnecessary casing and drilling cost. In this paper, an improved casing design method was pro-posed, in which each design coefficient needed to be calculated and determined based on the well structure in order to opti-mize the safe drilling fluid density window. The new method has been applied for a case study of a deepwater well in west of Africa, and the results show that the wellbore size, depth and the drilling string size have significant influence on

  3. Intracortical chondrosarcoma: a case report.

    Directory of Open Access Journals (Sweden)

    Khodamorad Jamshidi

    2014-02-01

    Full Text Available Chondrosarcoma is the second most common primary mesenchymal malignant tumor of the bone. The most common form is central chondrosarcoma and the rarest is intracortical chondrosarcoma. Here, we describe the clinical, pathological, and imaging features of a case of intracortical chondrosarcoma as well as the outcome of surgical treatment. This is the third case reported in the literature.

  4. Dermatomyositis panniculitis: a case report.

    Science.gov (United States)

    Carroll, Melissa; Mellick, Nick; Wagner, Godfrey

    2015-08-01

    Dermatomyositis-related panniculitis is a rare cutaneous manifestation of dermatomyositis. There are few reported cases in the medical literature. We present the case of a 60-year-old woman with a 2-year history of dermatomyositis and recent biopsy-confirmed panniculitis treated with prednisone, cyclophosphamide and i.v. immunoglobulin.

  5. Proliferative periostitis: a case report.

    Science.gov (United States)

    Zand, Vahid; Lotfi, Mehrdad; Vosoughhosseini, Sepideh

    2008-04-01

    Proliferative periostitis of Garré represents a periosteal reaction to the presence of infection or other irritants. This can be odontogenic or nonodontogenic. This is a case report of an odontogenic periostitis resulting from endodontic origin. It was successfully treated by nonsurgical root canal therapy without using antibiotic therapy during the treatment of this case.

  6. Three Community College Case Studies

    Science.gov (United States)

    Wojtysiak, Joseph; Sutton, William J., II; Wright, Tommy; Brantley, Linda

    2011-01-01

    This article presents three case studies that focus on specific projects that are underway or have been completed. In the first case study, Joseph Wojtysiak and William J. Sutton, II discuss the Green Center of Central Pennsylvania, which is designed to serve as the state's preeminent source for education, training and public information about…

  7. Instructional Computing: Ten Case Studies.

    Science.gov (United States)

    Hargan, Carol; Hunter, Beverly

    These case studies are written for educational institutions that wish to plan, extend, or improve their use of computers for learning and teaching. Each case study includes a brief description of each of the following: profile of the institution, history of the development of instructional computing, organization and management, student access to…

  8. Fuzzy-Set Case Studies

    Science.gov (United States)

    Mikkelsen, Kim Sass

    2017-01-01

    Contemporary case studies rely on verbal arguments and set theory to build or evaluate theoretical claims. While existing procedures excel in the use of qualitative information (information about kind), they ignore quantitative information (information about degree) at central points of the analysis. Effectively, contemporary case studies rely on…

  9. Nevus comedonicus: a case series.

    Science.gov (United States)

    Ferrari, Bruno; Taliercio, Vanina; Restrepo, Paola; Luna, Paula; Abad, María Eugenia; Larralde, Margarita

    2015-01-01

    Twelve previously unreported cases of nevus comedonicus are presented. Characteristic closely grouped dilated follicular openings with horny plugs that mimic comedones led to the diagnosis. One patient had nevus comedonicus syndrome and there were cases with atypical locations and unusual complications of this condition. We also highlight clinical associations and therapeutic options. © 2014 Wiley Periodicals, Inc.

  10. The Economic Case for Education

    Science.gov (United States)

    Woessmann, Ludger

    2016-01-01

    The case for education can be made from many perspectives. This paper makes the case for education based on economic outcomes. Surveying the most recent empirical evidence, it shows the crucial role of education for individual and societal prosperity. Education is a leading determinant of economic growth, employment, and earnings in modern…

  11. CASE-BASED CONCEPTUAL DESIGN

    Institute of Scientific and Technical Information of China (English)

    Ling Weiqing; Yan Junwei; Wang Jian; Xie Youbai

    2004-01-01

    The current method of case-based design (CBD) can be well practiced for configuration design in which design experience knowledge is involved.However, since the design case is confined to a certain application domain, it is difficult for CBD to be applied to conceptual design process that develops concepts to meet design specifications.Firstly, a function factor description space is erected to provide an exhibition room for all functions of design cases.Next, the approach for identifying the space state of function factor in description space is proposed, including the determination of the similarities between function factors of design case.And then a general object-oriented representation for design case is presented by bringing the class of function and in-out flow into the current case representation.Finally, a living example for electro-pet design that illustrates the implementation of the method for case-based conceptual design based on distributed design case repositories is described.

  12. Joint Case Development with Wharton

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    @@ February 18,2005marked an agreement between Wharton School of the University of Pennsylvania and the China Europe International Business School (CEIBS).Together,Wharton's Snider Entrepreneurial Research Centre (SEC) and CEIBS' Centre of Entrepreneurship and Case Development Centre will work together creating a series of cases to be used in each institution's entrepreneurship courses.

  13. Joint Case Development with Wharton

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

      February 18,2005marked an agreement between Wharton School of the University of Pennsylvania and the China Europe International Business School (CEIBS).Together,Wharton's Snider Entrepreneurial Research Centre (SEC) and CEIBS' Centre of Entrepreneurship and Case Development Centre will work together creating a series of cases to be used in each institution's entrepreneurship courses.……

  14. A case of testicular rupture

    OpenAIRE

    野俣, 浩一郎; 林, 幹男

    1987-01-01

    A case of testicular rupture is reported. A 26-year-old man was referred to our hospital because of testicular trauma. Ultrasound of the testis was performed preoperatively. Ultrasonography revealed a disruption of the tunica albuginea and dense clusters of echoes in the tunica vaginalis. In the case of acute testicular trauma, this echo pattern suggests testicular rupture.

  15. Periodontal considerations in veneer cases.

    Science.gov (United States)

    Peto, David

    2015-04-01

    Porcelain veneers are a minimally invasive technique to enhance patients' smiles. A crucial component in these cases is the supporting periodontal apparatus and its interaction with the restorations. This article addresses basic concepts such as biologic width, altered eruption patterns, appropriate gingival contouring and smile design to give practitioners the tools to diagnose, evaluate and treat cases successfully and predictably.

  16. Iatrogenic psoas abscess. Case report

    DEFF Research Database (Denmark)

    Bernstein, Inge Thomsen; Hansen, B J

    1991-01-01

    A case of iatrogenic pneumococcus psoas abscess is reported. The etiology was probably repeated local anaesthetic blockades in the lumbogluteal structures because of lumbago.......A case of iatrogenic pneumococcus psoas abscess is reported. The etiology was probably repeated local anaesthetic blockades in the lumbogluteal structures because of lumbago....

  17. CaseWorld™: Interactive, media rich, multidisciplinary case based learning.

    Science.gov (United States)

    Gillham, David; Tucker, Katie; Parker, Steve; Wright, Victoria; Kargillis, Christina

    2015-11-01

    Nurse educators are challenged to keep up with highly specialised clinical practice, emerging research evidence, regulation requirements and rapidly changing information technology while teaching very large numbers of diverse students in a resource constrained environment. This complex setting provides the context for the CaseWorld project, which aims to simulate those aspects of clinical practice that can be represented by e-learning. This paper describes the development, implementation and evaluation of CaseWorld, a simulated learning environment that supports case based learning. CaseWorld provides nursing students with the opportunity to view unfolding authentic cases presented in a rich multimedia context. The first round of comprehensive summative evaluation of CaseWorld is discussed in the context of earlier formative evaluation, reference group input and strategies for integration of CaseWorld with subject content. This discussion highlights the unique approach taken in this project that involved simultaneous prototype development and large scale implementation, thereby necessitating strong emphasis on staff development, uptake and engagement. The lessons learned provide an interesting basis for further discussion of broad content sharing across disciplines and universities, and the contribution that local innovations can make to global education advancement. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

  18. Case Studies in Science Ethics

    Science.gov (United States)

    Williams, Karen

    2010-03-01

    Everyone in science should have ethics education training. I have seen graduate students taken advantage of by their mentors. Many of us have seen misconduct...but what should we do about it? Young scientists are often unaware of the rules in science and make mistakes because of their ignorance of the rules in that particular field of study. Then there are an increasing number of cases in the news of overt cases of misrepresentation in science. All are welcome to attend this discussion of case studies. A case study on topics such as: how to treat data properly, how our values in science affect our work, who gets authorship on scientific papers, who is first author on a paper, what you should do if you uncover misconduct or plagiarism in your university, and we will discuss the scientist's role in society. This will be a painless, non-confrontational small group, then large group discussion of each case

  19. Case and Administrative Support Tools

    Science.gov (United States)

    Case and Administrative Support Tools (CAST) is the secure portion of the Office of General Counsel (OGC) Dashboard business process automation tool used to help reduce office administrative labor costs while increasing employee effectiveness. CAST supports business functions which rely on and store Privacy Act sensitive data (PII). Specific business processes included in CAST (and respective PII) are: -Civil Rights Cast Tracking (name, partial medical history, summary of case, and case correspondance). -Employment Law Case Tracking (name, summary of case). -Federal Tort Claims Act Incident Tracking (name, summary of incidents). -Ethics Program Support Tools and Tracking (name, partial financial history). -Summer Honors Application Tracking (name, home address, telephone number, employment history). -Workforce Flexibility Initiative Support Tools (name, alternative workplace phone number). -Resource and Personnel Management Support Tools (name, partial employment and financial history).

  20. Theory testing using case studies

    DEFF Research Database (Denmark)

    Dissing Sørensen, Pernille; Løkke Nielsen, Ann-Kristina

    Case studies may have different research goals. One such goal is the testing of small-scale and middle-range theories. Theory testing refers to the critical examination, observation, and evaluation of the 'why' and 'how' of a specified phenomenon in a particular setting. In this paper, we focus...... on the strengths of theory-testing case studies. We specify research paths associated with theory testing in case studies and present a coherent argument for the logic of theoretical development and refinement using case studies. We emphasize different uses of rival explanations and their implications for research...... design. Finally, we discuss the epistemological logic, i.e., the value to larger research programmes, of such studies and, following Lakatos, conclude that the value of theory-testing case studies lies beyond naïve falsification and in their contribution to developing research programmes in a progressive...

  1. Case Study: A Picture Worth a Thousand Words? Making a Case for Video Case Studies

    Science.gov (United States)

    Pai, Aditi

    2014-01-01

    A picture, they say, is worth a thousand words. If a mere picture is worth a thousand words, how much more are "moving pictures" or videos worth? The author poses this not merely as a rhetorical question, but because she wishes to make a case for using videos in the traditional case study method. She recommends four main approaches of…

  2. Case Study: A Picture Worth a Thousand Words? Making a Case for Video Case Studies

    Science.gov (United States)

    Pai, Aditi

    2014-01-01

    A picture, they say, is worth a thousand words. If a mere picture is worth a thousand words, how much more are "moving pictures" or videos worth? The author poses this not merely as a rhetorical question, but because she wishes to make a case for using videos in the traditional case study method. She recommends four main approaches of…

  3. A case of cerebral paragonimiasis in Denmark. Case report.

    Science.gov (United States)

    Møller, A; Settnes, O P; Jensen, N O; Kruse-Larsen, C

    1995-01-01

    A case of cerebral paragonimiasis with severe neurological symptoms is presented. The patient, a 45-year-old woman, recovered completely after resection of a large cyst at the C3 level. The pathogenesis is discussed.

  4. CASE REPORT CASE Emphysematous pyelonephritis in a patient ...

    African Journals Online (AJOL)

    Abstract. A case report demonstrating the plain film and CT find- ... history of frank haematuria, severe lower back ache, diarrhoea and ... Plain radiographs of the chest and abdomen showed an elevated left ... Stellenbosch University. Fig 1.

  5. [Ectopic breast fibroadenoma. Case report].

    Science.gov (United States)

    Senatore, G; Zanotti, S; Cambrini, P; Montroni, I; Pellegrini, A; Montanari, E; Santini, D; Taffurelli, M

    2010-03-01

    Among the rare anomalies of the breast development, polythelia is the most common, between 1% and 5% of women and men present supernumerary nipples. Polymastia, usually presenting as ectopic breast tissue without areola-nipple complex, is seen mostly along the milk line, extending from the axilla to the pubic region. Ectopic breast tissue is functionally analogous to mammary gland and it is subjected to the same alterations and diseases, whether benign or malignant, that affect normal breast tissue. We report the case of a 21 years-old female evaluated by the medical staff after founding a solid nodular mass by suspect axillary lymphadenopathy. Differential diagnosis with lymphoma is the major problem in these cases. The mass was removed and the intraoperative histological examination showed fibroadenoma in axillary supernumerary breast. Presence of ectopic breast tissue is a rare condition; development of benign mass or malignant degeneration is possible, but it is very unusual. In case of polymastia diagnosis is simple; in case of isolated nodule, without local inflammation or infection, there are greater difficulties. Ultrasonography is diagnostic in case of breast fibroadenoma, but it might be inadequate in ectopic localizations owing to the shortage of mammary tissue around the mass. Preoperative diagnosis is important to plan an adequate surgical treatment; lumpectomy is indicated in case of benign tissue; in case of malignancy, therapy is based on the standard treatment used for breast cancer (surgery, chemotherapy and radiation therapy).

  6. Health policy and case management.

    Science.gov (United States)

    Mark, D D

    2000-01-01

    The purpose of this article is to analyze the performance of and support for case management using a policy framework in order to increase case managers' awareness of policy making and facilitate successful planning for future policy initiatives. Feldstein's (1996) theory of opposing legislative outcomes indicates that legislation can be viewed on a continuum, ranging from legislation that meets the needs of the public to legislation considered to be in the self-interest of the participants and legislators. The current health care system requires that case managers working for publicly funded health care organizations balance the need for stewardship of U.S. tax dollars and the health care needs of consumers. It is apparent from the literature that case managers are successfully achieving this balance. However, certain conditions should exist that allow for case manager decision-making that promotes effective and efficient utilization of health care resources. Case managers must work within the context of the health care policy environment. Realizing that it is more likely that the conflicts between stewardship and the provision of health care services will continue, case managers' knowledge and influence regarding policy making becomes imperative in order to ensure that these conflicting goals do not become mutually exclusive.

  7. Two cases of rheumatoid meningitis.

    Science.gov (United States)

    Magaki, Shino; Chang, Edward; Hammond, Robert R; Yang, Isaac; Mackenzie, Ian R A; Chou, Benedict T; Choi, Soo I; Jen, Joanna C; Pope, Whitney B; Bell, David A; Vinters, Harry V

    2016-02-01

    Central nervous system (CNS) involvement by rheumatoid arthritis (RA) in the form of rheumatoid meningitis (RM) is rare and most commonly occurs in the setting of longstanding severe RA. Due to a wide range of clinical presentations and nonspecific laboratory findings, it presents a diagnostic challenge often requiring brain biopsy. Only a few histopathologically confirmed cases have been described in the literature. Our aim is to describe two cases of RM and review the literature. The first case is of a previously healthy 37-year-old man who presented with severe headaches and focal neurologic deficits. Magnetic resonance imaging demonstrated abnormal leptomeningeal enhancement in the left frontal and parietal sulci. The second case is of a 62-year-old woman with a history of mild chronic joint pain who presented with confusion, personality changes and seizures. Both patients ultimately underwent brain biopsy which demonstrated RM on pathologic examination. Administration of corticosteroids resulted in significant clinical improvement in both cases. To our knowledge, our unusual case of RM in the young man is the fifth reported case of rheumatoid meningitis in a patient with no prior history of RA. Such an atypical presentation makes diagnosis even more difficult and highlights the need for awareness of this entity in the diagnostic consideration of a patient presenting with unexplained neurologic symptoms. Our literature review underscores the clinical and pathologic heterogeneity of CNS involvement in RA.

  8. Influence of Casing Shoe Depth on Sustained Casing Pressure

    OpenAIRE

    2012-01-01

    In 2006 the Petroleum Safety Authority Norway (PSA) performed a well integrity survey. The survey indicated that about 20 % of wells on the Norwegian Continental shelf (NCS) may suffer from well integrity issues. Most of the problems were related to deficiency in annulus safety valve, tubing, cement and casing. Pressure build-up in annulus, i.e. sustained casing pressure, is one of the main indicators of a significant well integrity problem. Increased understanding on the field may help engin...

  9. A case of inflammatory ascites

    Directory of Open Access Journals (Sweden)

    Marco Biolato

    2008-03-01

    Full Text Available Even ascites appears mainly as sign of portal hypertension in patiens with liver cirrhosis, in some case depends on a different lying condition such as right congestive heart failure, peritoneal carcinomatosis or tuberculosis. In these cases, paracentesis represents the key tool for diagnosis. We report a case of cardiac ascites in a 71-years-old woman who developed in four-month an abdominal distension. Preliminary exams showed exudative ascites related to portal hypertension, a pelvic mass with caseous apparence, and inflammatory status ad an elevation of CA-125. Successive evaluation exluded peritoneal carcinomatosis or tuberculosis, underlyng a tricuspidal regurgitation. The literature on ascites has also been reviewed.

  10. Task descriptions versus use cases

    DEFF Research Database (Denmark)

    Lauesen, Søren; Kuhail, Mohammad Amin

    2011-01-01

    Use cases are widely used as a substantial part of requirements, also when little programming is expected (COTS-based systems, Commercial-Off-The-Shelf). Are use cases effective as requirements? To answer this question, we invited professionals and researchers to specify requirements for the same...... project: Acquire a new system to support a hotline. Among the 15 replies, eight used traditional use cases that specified a dialog between user and system. Seven used a related technique, task description, which specified the customer’s needs without specifying a dialog. It also allowed the analyst...

  11. Use cases versus task descriptions

    DEFF Research Database (Denmark)

    Lauesen, Søren; Kuhail, Mohammad Amin

    2011-01-01

    Abstract. [Context and motivation] Use cases are widely used as a substantial part of requirements, also when little programming is expected (COTS-based systems). [Question/problem] Are use cases effective as requirements? To an-swer this question, we invited professionals and researchers...... to specify require-ments for the same project: Acquire a new system to support a hotline. [Princi-pal ideas/results] Among the 15 replies, eight used traditional use cases that specified a dialog between users and system. Seven used a related technique, task description, which specified the customer's needs...

  12. Renal myxoma: a case report

    Directory of Open Access Journals (Sweden)

    Carlos Henrique C Souza

    2015-04-01

    Full Text Available Myxomas are rare tumors that can appear in many anatomical locations. There are only 14 cases of renal involvement documented in the literature. This article reports a case of renal myxoma in an elderly woman with recurrent cystitis. After five years of follow-up, the computed tomography (CT revealed a large solid tumor mass in the left kidney. Tumor resection was performed preserving the affected kidney with histopathological diagnosis of renal myxoma. The objective of this study is to report a rare case of renal myxoma, emphasizing the importance of the differential diagnosis from other benign and malignant mesenchymal tumors.

  13. Case-yrityksen hinnoittelun kannattavuus

    OpenAIRE

    Huhtasalo, Jenna

    2015-01-01

    Opinnäytetyön aiheena oli selvittää siivousalalla toimivan Case-yrityksen hinnoittelun kannattavuutta. Opinnäytetyön tarkoituksena oli perehtyä Case-yrityksen hinnoittelemiin sopimuksiin, sekä niihin kohdistuviin kustannuksiin. Tarkoituksena oli myös kehittää Excel-pohjaan laskukaava kannattavien sopimushintojen laskemiseen. Opinnäytetyön tavoitteena oli selvittää Case-yrityksen palvelukohteiden hinnoittelun kannattavuus kustannuslaskennan, sekä hinnoittelu- ja kannattavuuslaskelmien avulla. ...

  14. Five cases of cystic osteoechinococcosis

    Institute of Scientific and Technical Information of China (English)

    JIANG Ci-peng

    2005-01-01

    @@ Osseous cystic echinococcosis (CE) is a rare disease caused by the larval stage of Echinococcus granulosus (E. granulosus) and CE is different from alveolar echinococcosis (AE) caused by the larva of E. multilocularis. During a period of 20 years (1983-2003), a total of 364 cases of echinococcosis, including 263 CE and 101 AE cases were diagnosed at Hydatidos Research Laboratory (HRL), Basic Medical College, Lanzhou University, China. Of them, 5 cases of osseous CE (1.37%) were encountered and now reported as follows.

  15. Dirofilariasis: A rare case report

    Directory of Open Access Journals (Sweden)

    Singh R

    2010-01-01

    Full Text Available Human dirofilariasis is a zoonotic infection most commonly caused by Dirofilaria repens. It has not been widely recognized in India. There is probably a focus of human infection with D. repens in Kerala. We report the first case of dirofilariasis, from the Eastern-part of India, to the best of our knowledge. Among the documented cases of human dirofilariasis caused by D. repens, recorded in India, most of them had ocular infections and few had subcutaneous involvement of the face. This is the first case report of human dirofilariasis from India involving the lower part of human body.

  16. Emphysematous cystitis: 3 cases report

    Energy Technology Data Exchange (ETDEWEB)

    Chun, Ho Jong; Byun, Jae Young; Lee, Jae Moon; Ro, Hee Jung; Shinn, Kyung Sub [Catholic University Medical College, Seoul (Korea, Republic of)

    1995-09-15

    Emphysematous cystitis is a rare condition characterized by gas collection in the wall and lumen of the bladder. We experienced three cases of emphysematous cystitis. All patients were female; one was associated with a long term history of diabetes mellitus and another with urinary indwelling catheter. All of the cases were easily diagnosed on plain radiograph and CT scan, and were successfully treated with antibiotic therapy. In one of the cases, however, associated abscess due to perivesical extension of inflammation was treated by combined external drainage.

  17. A Comprehensive Statistically-Based Method to Interpret Real-Time Flowing Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Keita Yoshioka; Pinan Dawkrajai; Analis A. Romero; Ding Zhu; A. D. Hill; Larry W. Lake

    2007-01-15

    With the recent development of temperature measurement systems, continuous temperature profiles can be obtained with high precision. Small temperature changes can be detected by modern temperature measuring instruments such as fiber optic distributed temperature sensor (DTS) in intelligent completions and will potentially aid the diagnosis of downhole flow conditions. In vertical wells, since elevational geothermal changes make the wellbore temperature sensitive to the amount and the type of fluids produced, temperature logs can be used successfully to diagnose the downhole flow conditions. However, geothermal temperature changes along the wellbore being small for horizontal wells, interpretations of a temperature log become difficult. The primary temperature differences for each phase (oil, water, and gas) are caused by frictional effects. Therefore, in developing a thermal model for horizontal wellbore, subtle temperature changes must be accounted for. In this project, we have rigorously derived governing equations for a producing horizontal wellbore and developed a prediction model of the temperature and pressure by coupling the wellbore and reservoir equations. Also, we applied Ramey's model (1962) to the build section and used an energy balance to infer the temperature profile at the junction. The multilateral wellbore temperature model was applied to a wide range of cases at varying fluid thermal properties, absolute values of temperature and pressure, geothermal gradients, flow rates from each lateral, and the trajectories of each build section. With the prediction models developed, we present inversion studies of synthetic and field examples. These results are essential to identify water or gas entry, to guide flow control devices in intelligent completions, and to decide if reservoir stimulation is needed in particular horizontal sections. This study will complete and validate these inversion studies.

  18. [Congenital retinal folds in different clinical cases].

    Science.gov (United States)

    Munteanu, M

    2005-01-01

    We present 12 clinical cases of congenital retinal folds with different etiologies: posterior primitive vitreous persistency and hyperplasia (7 cases),retinocytoma (1 case). retinopathy of prematurity (1 case), astrocytoma of the retina (1 case), retinal vasculitis (1 case), Goldmann-Favre syndrome (1 case). Etiopathogenic and nosological aspects are discussed; the congenital retinal folds are interpreted as a symptom in a context of a congenital or acquired vitreo-retinal pathology.

  19. Case Study: del Amo Bioventing

    Science.gov (United States)

    The attached presentation discusses the fundamentals of bioventing in the vadose zone. The basics of bioventing are presented. The experience to date with the del Amo Superfund Site is presented as a case study.

  20. Typhoid spine - A case report

    Directory of Open Access Journals (Sweden)

    Rajesh P

    2004-01-01

    Full Text Available A case of Salmonella typhi isolated from L4-L5 spine is reported here. The causative organism was not suspected preoperatively. The patient responded favourably to surgical drainage and appropriate antibiotic therapy.

  1. Updated Cases for Medical Microbiology

    Directory of Open Access Journals (Sweden)

    Brinda Govindan

    2015-08-01

    Full Text Available Review of: Cases in Medical Microbiology and Infectious Diseases, 4th ed.; Peter H. Gilligan, Daniel S. Shapiro, and Melissa B. Miller; (2014. ASM Press, Washington, DC. 589 pages.

  2. Hydrogeologic Case Studies (Seattle, WA)

    Science.gov (United States)

    Hydrogeology is the foundation of subsurface site characterization for evaluations of monitored natural attenuation (MNA). Three case studies are presented. Examples of the potentially detrimental effects of drilling additives on ground-water samples from monitoring wells are d...

  3. The Japanese "Internment" Cases Revisited.

    Science.gov (United States)

    Robinson, Edward T.

    2003-01-01

    Reviews topics discussed in the OAH article, "Incarcerating Japanese Americans" (Roger Daniels). States that the three internment cases were correct. Asks whether internment could re-occur given the climate in U.S. society since September 11, 2001. (CMK)

  4. Nasopharyngeal Case-Control Study

    Science.gov (United States)

    A case-control study conducted in Taiwan between 1991-1994 among approximately 1,000 individuals to examine the role of viral, environmental, and genetic factors associated with the development of nasopharyngeal carcinoma

  5. On Kindling Flames with Cases

    Science.gov (United States)

    Fuchs, H. O.

    1974-01-01

    Describes how case studies, involving written accounts of engineering jobs as they were actually done or problems as they were actually encountered, can be effectively used to motivate engineering students. (JR)

  6. Case Studies in Strategic Planning

    Science.gov (United States)

    1990-03-06

    Contains developed case studies in strategic planning on The Navy General Board, Joint Service War Planning 1919 to 1941, Navy Strategic Planning , NASA...in Strategic Planning NPS-56-88-031-PR of September 1988. Strategic planning , Strategic Management.

  7. Worst Case Efficient Data Structures

    DEFF Research Database (Denmark)

    Brodal, Gerth Stølting

    . The first problem we consider is how to make bounded in-degree and out-degree data structures partially persistent, i.e., how to remember old versions of a data structure for later access. A node copying technique of Driscoll et al. supports update steps in amortized constant time and access steps in worst...... case constant time. The worst case time for an update step can be linear in the size of the structure. We show how to extend the technique of Driscoll et al. such that update steps can be performed in worst case constant time on the pointer machine model. We present two new comparison based priority......We study the design of efficient data structures. In particular we focus on the design of data structures where each operation has a worst case efficient implementations. The concrete problems we consider are partial persistence, implementation of priority queues, and implementation of dictionaries...

  8. Teaching Ethics by Case Analysis.

    Science.gov (United States)

    Fromer, Margot Joan

    1980-01-01

    Starting with basic philosophic positions and principles, nursing students can be helped to analyze ethical dilemmas of increasing complexity. A hypothetical situation is presented and discussed as an example of a case study used to teach these principles. (CT)

  9. Case and Administrative Support Tools

    Data.gov (United States)

    U.S. Environmental Protection Agency — Case and Administrative Support Tools (CAST) is the secure portion of the Office of General Counsel (OGC) Dashboard business process automation tool used to help...

  10. A case of complicated otomastoiditis

    Directory of Open Access Journals (Sweden)

    Mario Atzeni

    2015-12-01

    Full Text Available We describe the case of a child who, at her first episode of clinically evident acute otitis media, has developed a bilateral mastoiditis, though with unilateral simptomatology. The mastoiditis was complicated by the spontaneous drainage of the postauricular abscess in the subcutaneous tissue. According to the literature, we believe that the temporal bone computed tomography scan is the fundamental examination to properly define an anusual case of mastoiditis, plan adequate therapy (medical o surgical, and rule out other possible complications.

  11. Supernumerary Jawbone Tooth: Clinical Case

    OpenAIRE

    Rivas Gutiérrez, Jesús; Carlos Sánchez, María Dolores

    2016-01-01

    Introduction: supernumerary teeth are dental development anomalies, alsoknown as hyperdontia or extra teeth. Their prevalence ranges between 0.3% and 3.8%.Their morphology may be normal or dismorphic and are associated to the etiology ofocclusal alterations. It is important to make an early diagnostic through a radiographicalstudy. Case presentation:this article presents a clinical case of a supernumerary tooth thatcaused rotation and crowding of the anterior bottom teeth, which was addressed...

  12. Cutaneous actinomycosis: A rare case

    Directory of Open Access Journals (Sweden)

    Metgud S

    2007-01-01

    Full Text Available Cutaneous actinomycosis is a rare presentation. Here we present a case of cutaneous actinomycosis with no history of trauma or systemic dissemination. The isolate was identified as Actinomyces viscosus by standard methods. The isolate was found to be penicillin resistant by Kirby Bauer disc diffusion method. Therefore, the patient was treated with cotrimoxazole and improved. Thus, this case highlights the importance of isolation and susceptibility testing in actinomycotic infection. The sinuses have healed, and the patient has recovered.

  13. A case of etizolam dependence

    Directory of Open Access Journals (Sweden)

    Sumit Gupta

    2014-01-01

    Full Text Available Etizolam is a thienodiazepine anxiolytic which is said to have lower dependence potential than other benzodiazepines. We report a case of etizolam dependence in a young male with social anxiety disorder and moderate depression. This case report highlights the fact that the same caution be exercised while prescribing etizolam with respect to its potential to cause dependence as with any other benzodiazepine.

  14. Toxoplasmosis Neuroretinitis: A Case Report

    OpenAIRE

    2016-01-01

    Introduction Neuroretinitis (NR) is considered to be an inflammatory condition which is characterized by optic disc edema and, as a result, formation of a macular star figure. NR is an atypical presentation of toxoplasmosis infection, and such cases are quite rare. Case Presentation A 13-year-old girl presented with painless subacute visual loss in her right eye for a week at Khatam-Al-Anbia eye hospital in Mashhad, Iran. Following comprehensive evaluation, a diagnosis of toxoplasmic NR was m...

  15. [Heterolateral renal dystopia (2 cases)].

    Science.gov (United States)

    Anastasov, G; Peneva, S; Mushmov, D; Salambashev, L

    1982-01-01

    The authors observed two cases with crossed renal dystopia, to which venous urography, renal scintigraphy, echographic and gamma-chamber investigations were performed. The venous urography, in case of the appropriate symptomatics, is stressed to be able to establish the presence of heterolateral dystopia by as far as the distributional function of the anomaly is concerned--the gamma-chamber investigation is with the highest information value.

  16. Pulmonary artery sling: Case report

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Gil Hyun; Lee, Sun Wha; Cha, Sung Ho [Kyunghee University College of Medicine, Seoul (Korea, Republic of)

    1993-09-15

    Aberrant left-sided pulmonary artery(pulmonary artery sling) is an uncommon anomaly,which may cause significant respiratory abnormality. We report a case of pulmonary artery sling which is combined with persistent left superior vena cava and dextrocardia. This case were identified by esophagogram and CT and confirmed by MRI and angiography. We consider that MRI is a valuable new method for the diagnosis of aberrant left-sided pulmonary artery.

  17. Secondary middle turbinate: case report

    Energy Technology Data Exchange (ETDEWEB)

    Aburjeli, Bruna de Oliveira Melim; Avila, Ana Flavia Assis de; Diniz, Renata Lopes Furletti Caldeira; Motta, Emilia Guerra Pinto Coelho; Ribeiro, Marcelo Almeida; Moreira, Wanderval, E-mail: bruninha86@hotmail.com [Radiology and Imaging Diagnosis, Hospital Mater Dei, Belo Horizonte, MG (Brazil)

    2012-11-15

    Secondary middle turbinate is an anatomical variant rarely observed in the nasal cavity, firstly described by Khanobthamchai et al. as a bone structure originating from the lateral nasal wall and covered by soft tissue. In most cases reported in the literature, this variant is bilateral, occurring without associated complications. In the present report, the authors describe the case of patient of their institution with such anatomical variation. (author)

  18. Abdominal pregnancy- a case report.

    Science.gov (United States)

    Okafor, Ii; Ude, Ac; Aderibigbe, Aso; Amu, Oc; Udeh, Pe; Obianyo, Nen; Ani, Coc

    2011-01-01

    A case of abdominal pregnancy in a 39 year old female gravida 4, para 0(+3) is presented. Ultrasonography revealed a viable abdominal pregnancy at 15 weeks gestational age. She was initially managed conservatively. Surgical intervention became necessary at 20 weeks gestational age following Ultrasound detection of foetal demise. The maternal outcome was favourable. This case is presented to highlight the dilemma associated with diagnosis and management of abdominal pregnancy with a review of literature.

  19. Translation Procedures (a Case Study)

    OpenAIRE

    Silalahi, Roswita; Lestari, Disa Evawani

    2012-01-01

    Roswita Silalahi This research is entitled Translation Procedures (A Case Study) which analysis translation procedures used in translating economic terms from English language book Principles of Economics by N. Gregory Mankiw into Bahasa Indonesia book Pengantar Ekonomi by Haris Munandar. The improvement of economic science which creates new economic terms challenges translator especially in translating a word or phrase, which in some cases, does not exist in the target l...

  20. A Case of Hepatopulmonary Syndrome.

    Science.gov (United States)

    Sriram, P B; Sindhuja, R; Natarajan, M; Rajamurugan, P S Arul; Palanikumar, B

    2016-03-01

    We report the case of a 52-year-old female, a known case of Chronic Liver Disease with portal hypertension. She presented with dyspnoea, platypnoea, melena, cyanosis, clubbing and orthodeoxia. She had oesophageal varices and splenomegaly indicating portal hypertension. Her arterial blood gas revealed hypoxaemia and orthodeoxia. From this clinical background and investigation, a diagnosis of hepatopulmonary syndrome was made. Patient was managed conservatively as she was not willing for liver transplantation.