Effect of lithologic character, petroleum and effective overburden pressure on compressional wave and shear wave velocity (in Chinese)

1995 ◽  
Vol 32 (2) ◽  
pp. A68
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Compressional Wave ◽  
Overburden Pressure ◽  
Lithologic Character

scholarly journals Prediction of the Shear Wave Velocity from Compressional Wave Velocity for Gachsaran Formation

2015 ◽  
Vol 63 (5) ◽  
pp. 1231-1243 ◽  
Author(s):  
Saeed Parvizi ◽  
Riyaz Kharrat ◽  
Mohammad R. Asef ◽  
Bijan Jahangiry ◽  
Abdolnabi Hashemi
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Compressional Wave ◽  
Compressional Wave Velocity ◽  
Gachsaran Formation

Investigation of a coarse alluvial foundation for an embankment dam

1986 ◽  
Vol 23 (2) ◽  
pp. 203-215 ◽  
Author(s):  
A. W. Hanna ◽  
G. Ambrosii ◽  
A. D. McConnell
Keyword(s):  
Relative Density ◽  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Penetration Resistance ◽  
Embankment Dam ◽  
Overburden Pressure ◽  
Alluvial Deposits ◽  
Dynamic Penetration ◽  
Test Embankment

Investigation of the coarse alluvial foundation for the Pichi Picun Leufu embankment dam is described and evaluated. Direct and indirect investigation methods are compared and an assessment is made of their relative adequacy in order to gain a realistic understanding of foundation conditions. Indirect methods—dynamic cone penetration testing and shear wave velocity measurement—calibrated by comparative testing in a test embankment, have been found to provide a satisfactory means of evaluating the density of thick alluvial deposits below the water table. Relationships of relative density, penetration resistance, and shear wave velocity are discussed. Dynamic penetration resistance normalized for effective overburden pressure appears to be the more sensitive indicator of changes in material density. Key words: coarse alluvium, relative density, dynamic penetration, shear wave velocity, test embankment, overburden pressure.

Shear‐wave logging to enhance seismic modeling

Geophysics ◽  
1991 ◽  
Vol 56 (12) ◽  
pp. 2129-2138 ◽  
Author(s):  
M. A. Payne
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Field Data ◽  
Compressional Wave ◽  
Oil Sand ◽  
Wave Velocities ◽  
Shear Wave Velocities ◽  
Amplitude Versus Offset ◽  
Amplitude Versus

In an effort to understand better the amplitude variation with offset for reflections from an oil sand and the sensitivity of the AVO response to shear‐wave velocity variations, I studied synthetic and field gathers collected from an onshore field in the Gulf of Mexico basin. A wave‐equation‐based modeling program generated the synthetic seismic gathers using both measured and estimated shear‐wave velocities. The measured shear‐wave velocities came from a quadrupole sonic tool. The estimated shear‐wave velocities were obtained by applying published empirical and theoretical equations which relate shear‐wave velocities to measured compressional‐wave velocities. I carefully processed the recorded seismic data with a controlled‐amplitude processing stream. Comparison of the synthetic gathers with the processed field data leads to the conclusion that the model containing the measured shear‐wave velocities matches the field data much better than the model containing the estimated shear‐wave velocities. Therefore, existing equations which relate shear‐wave velocities to compressional‐wave velocities yield estimates which are not sufficiently accurate for making quantitative comparisons of synthetic and field gathers. Even small errors in the shear‐wave velocities can have a large impact on the output. Such errors can lead to an incomplete and perhaps inaccurate understanding of the amplitude‐versus‐offset response. This situation can be remedied by collecting shear‐wave data for use in amplitude‐versus‐offset modeling, and for building databases to generate better shear‐wave velocity estimator equations.

ULTRASONIC SHEAR‐WAVE VELOCITIES IN ROCKS SUBJECTED TO SIMULATED OVERBURDEN PRESSURE AND INTERNAL PORE PRESSURE

Geophysics ◽  
1965 ◽  
Vol 30 (1) ◽  
pp. 117-121 ◽  
Author(s):  
B. S. Banthia ◽  
M. S. King ◽  
I. Fatt
Keyword(s):  
Hydrostatic Pressure ◽  
Pore Pressure ◽  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Overburden Pressure ◽  
Wave Velocities ◽  
Shear Wave Velocities ◽  
The Matrix ◽  
Internal Pore

Change in shear‐wave velocity for four dry sedimentary rocks has been studied as a function of the variation of both external hydrostatic pressure and internal pore pressure in the range 0 to 2,500 psi. The experimental method employs a beam of ultrasonic energy passing through a liquid in which a copper‐jacketed parallel‐sided slab of rock is rotated. The shear‐wave velocity is calculated from the laws of refraction and reflection of waves at a liquid‐solid boundary applied to the angle at which minimum energy is transmitted. The variation of shear‐wave velocity with pressure has been found to be a function of net overburden pressure, [Formula: see text], where [Formula: see text] hydrostatic pressure on the jacketed sample, [Formula: see text] pore pressure and n = a pressure‐dependent factor less than unity. The values of n at several differential pressures were chosen to yield a smooth curve passing through the displaced data points when the shear‐wave velocities were plotted as a function of net overburden pressure. Using the n values so obtained, the matrix compressibility [Formula: see text] for two of the sandstones has been calculated from the relation [Formula: see text]. The bulk compressibility [Formula: see text] for these two rocks had previously been obtained experimentally as a function of differential pressure. The values obtained for the matrix compressibility are in the range expected from a knowledge of the grain and cementing materials for these sandstones.

scholarly journals Near surface shear wave velocity in Bucharest, Romania

2008 ◽  
Vol 8 (6) ◽  
pp. 1299-1307 ◽  
Author(s):  
M. von Steht ◽  
B. Jaskolla ◽  
J. R. R. Ritter
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Seismic Velocity ◽  
Seismic Refraction ◽  
Compressional Wave ◽  
Seismic Zone ◽  
Surface Shear ◽  
Near Surface ◽  
Surface Shear Wave

Abstract. Bucharest, the capital of Romania with nearly 2 1/2 million inhabitants, is endangered by the strong earthquakes in the Vrancea seismic zone. To obtain information on the near surface shear-wave velocity Vs structure and to improve the available microzonations we conducted seismic refraction measurements in two parks of the city. There the shallow Vs structure is determined along five profiles, and the compressional-wave velocity (Vp) structure is obtained along one profile. Although the amount of data collected is limited, they offer a reasonable idea about the seismic velocity distribution in these two locations. This knowledge is useful for a city like Bucharest where seismic velocity information so far is sparse and poorly documented. Using sledge-hammer blows on a steel plate and a 24-channel recording unit, we observe clear shear-wave arrivals in a very noisy environment up to a distance of 300 m from the source. The Vp model along profile 1 can be correlated with the known near surface sedimentary layers. Vp increases from 320 m/s near the surface to 1280 m/s above 55–65 m depth. The Vs models along all five profiles are characterized by low Vs (<350 m/s) in the upper 60 m depth and a maximum Vs of about 1000 m/s below this depth. In the upper 30 m the average Vs30 varies from 210 m/s to 290 m/s. The Vp-Vs relations lead to a high Poisson's ratio of 0.45–0.49 in the upper ~60 m depth, which is an indication for water-saturated clayey sediments. Such ground conditions may severely influence the ground motion during strong Vrancea earthquakes.

scholarly journals Studies on a Piezoelectric Cylindrical Transducer for Borehole Dipole Acoustic Measurements

2021 ◽  
Vol 11 (3) ◽  
pp. 1036
Author(s):  
Yinqiu Zhou ◽  
Xiuming Wang ◽  
Yuyu Dai
Keyword(s):  
Numerical Simulation ◽  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Low Frequency ◽  
Compressional Wave ◽  
Wave Measurements ◽  
New Development ◽  
Cylindrical Transducer ◽  
Simulation Results

In this article, a novel design of a piezoelectric dipole transducer is proposed for formation acoustic velocity measurement in the vicinity of a borehole with a frequency range of 0.4–6 kHz. The transducer which actuates a cylindrical shell to generate a pure dipole mode wave by using multiple piezoelectric bender bars is analyzed theoretically and simulated numerically by using the finite element method (FEM). Moreover, the transducer is fabricated and tested to compare with the numerical simulation results, which shows that the test and simulation results are in good agreement. Finally, compared with numerical simulation results of the traditional dipole transducer, it is shown that the proposed dipole transducer has higher transmitting sensitivities than commonly used ones, especially in low frequency responses. This work lays a foundation for the new development of the transducer in borehole dipole acoustic shear wave measurements. Especially, in a slow formation where the shear wave velocity is lower than that of compressional wave in the borehole fluid, the transducer could be used for highly efficient shear wave velocity measurements.

scholarly journals An An Accurate Estimation of Shear Wave Velocity Using Well Logging Data for Khasib Carbonate Reservoir - Amara Oil Field

2020 ◽  
Vol 26 (6) ◽  
pp. 107-120
Author(s):  
Rwaida K. AbdulMajeed ◽  
Ayad A. Alhaleem
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Reservoir Characterization ◽  
Compressional Wave ◽  
Carbonate Reservoir ◽  
Oil Field ◽  
Accurate Estimation ◽  
Hydrocarbon Reservoir ◽  
Neutron Porosity

    Shear and compressional wave velocities, coupled with other petrophysical data, are vital in determining the dynamic modules magnitude in geomechanical studies and hydrocarbon reservoir characterization. But, due to field practices and high running cost, shear wave velocity may not available in all wells. In this paper, a statistical multivariate regression method is presented to predict the shear wave velocity for Khasib formation - Amara oil fields located in South- East of Iraq using well log compressional wave velocity, neutron porosity and density. The accuracy of the proposed correlation have been compared to other correlations. The results show that, the presented model provides accurate estimates of shear wave velocity with correlation coefficient of about unity than other currently available methods.  

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