Sample records for yuhatsu kindenzu hakei

  1. Development of a downhole seismic source with controlled waveform; Hakei seigyogata kochu shingen no kaihatsu

    Kuroda, T.; Ikawa, T. [Japex Jeoscience Institute, Tokyo (Japan); Sato, T. [Meiho Engineering Co. Ltd., Tokyo (Japan); Kakuma, H. [Akashi Corp., Tokyo (Japan); Onuma, H. [Engineering Advancement Association of Japan, Tokyo (Japan)


    A downhole seismic source which can output continuous waves having arbitrary waveforms was developed. The development was targeted to make tomographic exploration purposed to evaluate geological properties of a ground bed before and after constructing a building in a ground several hundred meters deep from the ground surface. The source is considered to be used in an environment consisting of soft rocks or more robust rocks and having no casing. It can be used in a well hole having a diameter of 100 mm, is capable of measuring P and S waves in a distance between well holes of up to 100 m, can be used at a depth of up to 500 m, and can output waveforms having seismic source spectra of up to 1000 Hz. An oscillation actuator using laminated piezo-electric elements was used for the oscillation element. The seismic source consists of a hydraulic device to clamp the equipment onto hole walls, piezo-electric elements as the oscillation element, and an inertia weight for applying vibration from above and below. To make an oscillation, the main body is first clamped on the hole wall. For horizontal oscillation, the piezo-electric elements contained in a clamping device provide the horizontal oscillation. For vertical oscillation, the piezo-electric elements placed below the main body oscillates the inertia weight. The initially targeted specifications have been achieved. 3 refs., 4 figs., 1 tab.

  2. Active SWD using monochromatic source wavelet; Tan`itsu shuhasu no shingen hakei wo mochiita active SWD

    Tsuru, T.; Kozawa, T. [Japan National Oil Corp., Tokyo (Japan); Taniguchi, R. [Mitsubishi Electric Corp., Tokyo (Japan); Nishikawa, N. [Fuji Research Institute Corp., Tokyo (Japan); Matsuhashi, K.


    As part of developing efforts for physical exploration technologies for oil reservoirs, this paper describes development of an active seismic while drilling (SWD). The SWD is a seismic exploration method to acquire records equivalent to VSP using seismic waves generated from a bit executing excavation, and is capable of detection and control on a real time basis during the excavation. However, the drawback is that it is subjected to a limitation in the bit. To eliminate this limitation, an artificial seismic source method was devised. In other words, this is an SWD utilizing an artificial seismic source. The contrivance is such that a shot sub containing a magnetic distortion oscillator is attached directly above a bit to generate vibration artificially, and try to utilize larger seismic energy by combining this vibration with that generated from the excavating bit. Frequency band in the seismic source is as narrow as nearly a single frequency waveform. Preparing a time-depth curve from the data and identifying position of a bit making excavation requires reading the initial travel time. A waveform recognition technology was applied, which utilizes a matching evaluation function used in pattern recognition. This made waveform recognition possible at high accuracy. 2 figs., 1 tab.

  3. Analysis of seismogram envelopes. State of the art and future developments; Jishin hakei no envelope kaiseki. Genjo to kongo no kadai

    Sato, H. [Tohoku University, Sendai (Japan)


    Reviewed herein are researches on seismogram envelopes of small earthquakes and observations. The physical exploration tries to search for coherent portions in the waves by array observation, to detect strong contrasts in underground structures. Analysis of seismogram envelopes is much different from the above. The coda wave in the seismogram of local earthquake is characterized by a structure of random short-waves overlapping three-dimensionally the upper surface of a gradually changing structure. This paper describes characteristics of heterogeneous earth structures and coda waves, modeling based on the radiation propagation theories, and simulation and analysis examples of 3-component, total waveform envelopes, based on the Born approximation in the theory of elasticity. It also outlines the envelopes, in the seismograms of earthquakes which have occurred in the Kanto and Tokai districts, changing from a pulse-shape to spindle-shape, theoretical models developed by diffractiometry for strongly random heterogeneous structures, and future research prospects. 37 refs., 28 figs.

  4. Optimization of the ship type using waveform by means of Rankine source method; Rankine source ho ni yoru hakei wo mochiita funagata saitekika ni tsuite

    Hirayama, A.; Eguchi, T. [Mitsui Engineering and Shipbuilding Co. Ltd., Tokyo (Japan)


    Among the numerical calculation methods for steady-state wave-making problems, the panel shift Rankine source (PSRS) method has the advantages of rather precise determination of wave pattern of practical ship types, and short calculation period. The wave pattern around the hull was calculated by means of the PSRS method. The waveform analysis was carried out for the wave, to obtain an amplitude function of the original ship type. Based on the amplitude function, a ship type improvement method aiming at the optimization of ship type was provided using a conditional calculus of variation. A Series 60 (Cb=0.6) ship type was selected for the ship type improvement, to apply this technique. It was suggested that optimum design can be made for reducing the wave making resistance by means of this method. For the improvement of Series 60 ship type using this method, a great degree of reduction in the wave making resistance was recognized from the results of numerical waveform analysis. It was suggested that the ship type improvement aiming at the reduction of wave-making resistance can be made in shorter period and by smaller labor compared with the method using a waveform analysis of cistern tests. 5 refs., 9 figs.

  5. Sensing of subsurface faults based on an imaging technique for teleseismic waveform data. 2. Feasibility study for application to oblique incidence, multi-event and noise data; Enchi jishin hakei data wo mochiita chika kozo imaging ni yoru chichu danso kenshutsu no kokoromi. 2. Naname nyusha, multi event, noise wo fukumu hakei eno tekiyo

    Murakoshi, T.; Takenaka, H.; Saita, T. [Kyushu University, Fukuoka (Japan). Faculty of Science; Suetsugu, D. [Building Research Institute, Tokyo (Japan); Furumura, T. [Hokkaido University of Education, Sapporo (Japan)


    An examination was made on the method in which imaging of subsurface was carried out with teleseismic waveform data for sensing of faults. In the examination, an experiment was done on the sensing of faults with higher precision, by applying oblique incidence as well as perpendicular upward incidence of SH plane waves, and thereby stacking the imaging in plural events. In numerical experiments, 28 observation points were arranged at 500m spaces apart on the surface, and the incident waves were made the SH plane waves having a bell-shaped time function, with incidence made at an angle varied as 0{degree}, +15{degree} and -15{degree} from the lowest layer of a model. In the calculation of the wave motion field, a difference calculus with secondary accuracy was used for both time and space. In addition, data was prepared with a random noise added to a synthesized waveform to be used as observation data. The calculated waveform data were likened to the observation waveform, to which the method for imaging faults was applied. Consequently, it was noted that satisfactory results were obtained compared with the case where faults were sensed by one event alone. 5 refs., 4 figs.

  6. Detection of the oscillation mode of measured waveforms in power systems by Prony analysis; Puroni kaisekiho ni yoru denryoku keito ni okeru jissoku hakei no doyo mode kenshutsu ni tsuite

    Shibata, K. [Kansai Electaric Power Co. Inc., Osaka (Japan)


    This paper describes the detection method of the oscillation modes by Prony analysis from measured data on power systems. A Prony analysis method can obtain the oscillation frequency and logarithmic damping rate corresponding to eigenvalue directly, and is suitable for detecting the oscillation modes. The analysis result showed that longer sampling intervals of 0.2-0.4s allows detection of the long-period oscillation modes from less data, and the index corresponding to waveform areas allows evaluation of the significance of each mode. It was also confirmed that a low-pass filter with a time constant of nearly 0.2s is effective for poor data including various noises, and correction of amplitude and phase shifts is possible by filter. In addition, the study result on application of a Prony analysis method to instantaneous value waveforms showed that analysis of harmonic characteristics is possible by selecting proper analytical parameters, and a Prony analysis method is applicable to analysis of measured data enough. (NEDO)

  7. Trial to active SWD using artificial energy source. Use of monochromatic source wavelet; Jinko shingen wo mochiita SWD eno kokoromi. Tan`itsu shuhasu no shingen hakei no riyo

    Tsuru, T.; Kozawa, T. [Japan National Oil Corp., Tokyo (Japan); Taniguchi, R. [Mitsubishi Electric Corp., Tokyo (Japan); Matsuhashi, K. [Matsuhashi Techno Research, Hiroshima (Japan); Nishikawa, N. [Fuji Research Institute Corp., Tokyo (Japan)


    Seismic while drilling (SWD) is an accurate and safe method for drilling, by which real-time information regarding bit location and bedding boundary below the bit can be predicted by using elastic wave during drilling of rocks in a borehole. However, the signal level is rather low compared with the noise generated from the rig during drilling, resulting in the deteriorated data quality. Since the impact resiliency is small in soft beds, it is difficult to obtain good data due to the small energy of seismic wave propagating along drilling pipe. In order to overcome these problems, active SWD method using artificial seismic source has been developed. This method provides stable low-frequency seismic wave with large energy by the artificial seismic source adopting spring-mass system resonance method. Although the seismic source wave is monochromatic, the direct wave can be sufficiently analyzed and the bit location can be detected on the time profile of seismic prospecting. Protection of borehole damage during dropping of the equipment, energy propagation efficiency in the beds, and analysis of reflected wave are future problems. 11 refs., 6 figs., 4 tabs.

  8. Aliasing characteristics of tau-P transform and is application to signal and noise separation; Tau-P henkan no aliasing tokusei to hakei iji wo koryoshita S/N bunri

    Kawabuchi, H.; Rokugawa, S.; Matsushima, J.; Ichie, Y. [The University of Tokyo, Tokyo (Japan); Minegishi, M.; Tsuburaya, Y. [Japan National Oil Corp., Tokyo (Japan). Technology Research Center


    With respect to the tau-P transform method as a signal and noise (S/N) separation technology used in seismic exploration using the reflection method, a discussion has been given on conditions for the post S/N separation by the tau-P transform to function more effectively. Averaging the energy in performing the tau-P transform makes the wave energy scatter to a certain range. As a result, an aliasing phenomenon appears, in which noise is superimposed on the post-processing record. As a result of the discussion, it was verified that satisfying the two equations of G. Turner is effective in order to reduce the aliasing and maintain the relative amplitude. However, in actual calculation accuracy, waveform change was recognized to some extent, particularly amplification of events in low frequencies, and low restorability in higher frequencies. It was also observed that a method to give the tau-P region a two-dimensional Fourier transform and perform the same processing as an f-k filter can remove aliasing more simply and effectively than the HVF, and improve the S/N ratio maintaining the amplitude at the current level. 5 refs., 13 figs.