On: “Reflection and transmission of plane compressional waves by R. D. Tooley, T. W. Spencer, and H. F. Sagori, (GEOPHYSICS, 30, 552, April, 1965).

Geophysics ◽  
1984 ◽  
Vol 49 (12) ◽  
pp. 2195-2195 ◽  
Author(s):  
L. R. Denham ◽  
R. A. R. Palmeira
Keyword(s):  
Wave Velocity ◽  
Seismic Wave ◽  
Velocity Ratio ◽  
The Other ◽  
P Wave ◽  
Angle Of Incidence ◽  
Reflection And Transmission ◽  
Compressional Waves ◽  
P Wave Velocity ◽  
Simplified Formula

One of the most widely reproduced figures for the partition of energy of a seismic wave at an interface between two media is from Tooley et al.’s 1965 paper. Recently we referred to this paper and noticed some anomalies in the curves shown there in Figure 11. We looked at the values of the curves at zero angle of incidence and noted that while the values of a P-wave velocity ratio of 2, 3, and 4 agree with the values given by the simplified formula {(V2−V1)/(V2+V1)}**2, the values shown for the P-wave velocity ratios less than 1 do not agree. For a ratio of 0.25, the coefficient at zero angle should be 0.36; it is shown as about 0.72. A ratio of 0.5 should give a coefficient of 0.11; 0.52 is shown. There are similar discrepancies for all the other ratios less than 1.

High‐resolution crosswell imaging of a west Texas carbonate reservoir: Part 5—Core analysis

Geophysics ◽  
1995 ◽  
Vol 60 (3) ◽  
pp. 712-726 ◽  
Author(s):  
Richard C. Nolen‐Hoeksema ◽  
Zhijing Wang ◽  
Jerry M. Harris ◽  
Robert T. Langan
Keyword(s):  
Wave Velocity ◽  
Field Experiments ◽  
Velocity Ratio ◽  
Carbonate Reservoir ◽  
P Wave ◽  
Core Analysis ◽  
S Wave ◽  
Traveltime Tomography ◽  
West Texas ◽  
P Wave Velocity

We conducted a core analysis program to provide supporting data to a series of crosswell field experiments being carried out in McElroy Field by Stanford University’s Seismic Tomography Project. The objective of these experiments is to demonstrate the use of crosswell seismic profiling for reservoir characterization and for monitoring [Formula: see text] flooding. For these west Texas carbonates, we estimate that [Formula: see text] saturation causes P‐wave velocity to change by −1.9% (pooled average, range = −6.3 to +0.1%), S‐wave velocity by +0.6% (range = 0 to 2.7%), and the P‐to‐S velocity ratio by −2.4% (range = −6.4 to −0.3%). When we compare these results to the precisions we can expect from traveltime tomography (about ±1% for P‐ and S‐wave velocity and about ±2% for the P‐to‐S velocity ratio), we conclude that time‐lapse traveltime tomography is sensitive enough to resolve changes in the P‐wave velocity, S‐wave velocity, and P‐to‐S velocity ratio that result from [Formula: see text] saturation. We concentrated here on the potential for [Formula: see text] saturation to affect seismic velocities. The potential for [Formula: see text] saturation to affect other seismic properties, not discussed here, may prove to be more significant (e.g., P‐wave and S‐wave impedance).

scholarly journals ESTIMASI SEBARAN HIDROKARBON DENGAN MENGGUNAKAN INDIKATOR P-WAVE DIFFERENCE DISPERSION FACTOR PADA LAPANGAN BONAPARTE

2020 ◽  
Vol 5 (3) ◽  
pp. 45-54
Author(s):  
Mokhammad Puput Erlangga ◽  
Handoyo Handoyo ◽  
Egie Wijaksono
Keyword(s):  
Wave Velocity ◽  
Seismic Wave ◽  
Physical Property ◽  
Seismic Energy ◽  
Wave Dispersion ◽  
Hydrocarbon Exploration ◽  
P Wave ◽  
P Wave Velocity ◽  
Saturated Media ◽  
Standing Problem

In the hydrocarbon  exploration, we need the method that result the direct hydrocarbon indicator to estimate the reservoir location and dimension accurately. It is a difficult and long standing problem. The method that used before was inverting the linearized of Zoepprit’s equation. But this method would not result the physical property depend on frequency. We know that the seismic wave propagate in the porous and fluid saturated media will attenuate and wave dispersion. This phenomenon is caused by the dissipation of seismic energy that depend on frequency. So by this idea, we will use the frequency-dependent of physical property to improve the accuracy of direct hydrocarbon indicator. The physical property will be used here is the P-Wave velocity. The method is call the P-Wave Difference Dispersion Factor (PPDF).

scholarly journals Comparison of Sandstone Damage Measurements Based on Non-Destructive Testing

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5154
Author(s):  
Duohao Yin ◽  
Qianjun Xu
Keyword(s):  
Elastic Modulus ◽  
Wave Velocity ◽  
Damage Variable ◽  
The Other ◽  
P Wave ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
P Wave Velocity ◽  
Amplitude Attenuation ◽  
Non Destructive

Non-destructive testing (NDT) methods are an important means to detect and assess rock damage. To better understand the accuracy of NDT methods for measuring damage in sandstone, this study compared three NDT methods, including ultrasonic testing, electrical impedance spectroscopy (EIS) testing, computed tomography (CT) scan testing, and a destructive test method, elastic modulus testing. Sandstone specimens were subjected to different levels of damage through cyclic loading and different damage variables derived from five different measured parameters—longitudinal wave (P-wave) velocity, first wave amplitude attenuation, resistivity, effective bearing area and the elastic modulus—were compared. The results show that the NDT methods all reflect the damage levels for sandstone accurately. The damage variable derived from the P-wave velocity is more consistent with the other damage variables, and the amplitude attenuation is more sensitive to damage. The damage variable derived from the effective bearing area is smaller than that derived from the other NDT measurement parameters. Resistivity provides a more stable measure of damage, and damage derived from the acoustic parameters is less stable. By developing P-wave velocity-to-resistivity models based on theoretical and empirical relationships, it was found that differences between these two damage parameters can be explained by differences between the mechanisms through which they respond to porosity, since the resistivity reflect pore structure, while the P-wave velocity reflects the extent of the continuous medium within the sandstone.

Inversion of the seismic AVF/AVA signatures of highly attenuative targets

Geophysics ◽  
2011 ◽  
Vol 76 (1) ◽  
pp. R1-R14 ◽  
Author(s):  
Kristopher A. Innanen
Keyword(s):  
Reflection Coefficient ◽  
Wave Velocity ◽  
P Wave ◽  
Reflection Coefficients ◽  
Angle Of Incidence ◽  
Amplitude Variation ◽  
P Wave Velocity ◽  
Amplitude Variation With Angle ◽  
Source Of Information ◽  
Two Parameter

Frequency-dependent seismic field data anomalies, appearing in association with low-[Formula: see text] targets, have, on occasion, been attributed to the presence of a strong absorptive reflection coefficient. This “absorptive reflectivity” represents a potent, and largely untapped, source of information for determining subsurface target properties. It would most likely be encountered where a predominantly elastic/nonattenuating overburden suddenly is interrupted by a highly attenuative target. Series expansions of absorptive reflection coefficients about small parameter contrasts and incidence angles can expose these anomalies to analysis, either frequency-by-frequency (amplitude variation with frequency [AVF]) or angle-by-angle (amplitude variation with angle of incidence [AVA]). Within this framework, variations in P-wave velocity and [Formula: see text] can be estimated separately through a range of direct formulas, both linear and with nonlinear corrections. The latter come to the fore when a contrast from an incidence medium [Formula: see text] (i.e., acoustic/elastic) to a target medium [Formula: see text] is encountered, in which case the linearized estimate can be in error by as much as 50%. Algorithmically, it is a differencing of the reflection coefficient across frequencies that separates [Formula: see text] variations from variations in other parameters. This holds for both two-parameter (P-wave velocity and [Formula: see text]) problems and five-parameter anelastic problems, and would appear to be a general feature of direct absorptive inversion.

Nonlinear Multiple Earthquake Location and Velocity Estimation in the Canadian Rocky Mountain Trench

2020 ◽  
Vol 110 (6) ◽  
pp. 3103-3114
Author(s):  
Joshua Chris Shadday Purba ◽  
Jan Dettmer ◽  
Hersh Gilbert
Keyword(s):  
Prior Knowledge ◽  
Wave Velocity ◽  
Field Data ◽  
Velocity Ratio ◽  
Rocky Mountain ◽  
P Wave ◽  
Earthquake Location ◽  
S Wave ◽  
Data Noise ◽  
P Wave Velocity

ABSTRACT The calculation of earthquake hypocenters requires careful treatment, particularly when prior knowledge of the study area is limited. The prior knowledge, such as wave velocity and data noise, is often assumed to be known in earthquake location algorithms. Such assumptions can greatly simplify the inverse problem but are less general than nonlinear approaches. A nonlinear treatment is of particular importance when the uncertainty quantification of locations is of interest. We present a nonlinear multiple-earthquake location method that is applicable when little prior knowledge of the area exists. Efficient Markov chain Monte Carlo (MCMC) sampling is employed in conjunction with a hierarchical Bayesian model that treats earthquake hypocenter parameters, as well as P-wave velocity, ratio in P-/S-wave velocities, and P- and S-data noise standard deviations as unknown. Hypocenters for multiple earthquakes are located concurrently to provide sufficient constraints for the parameter’s P-wave velocity, ratio in P-/S-wave velocity, and P- and S-data noise standard deviations, which are shared among events. The algorithm is applied to simulated and field data. With field data, 47 event hypocenters are located in 1 yr of data from 10 sensors in the Canadian Rocky Mountain trench. To analyze the probabilistic solutions, we compare single-earthquake and multiple-earthquake locations for the 47 events and find that the multiple-earthquake location produces better-constrained solutions when compared with the single-event case. In particular, depth uncertainties are significantly reduced for the multiple-earthquake location. The algorithm is inexpensive, considering that it is based on an MCMC approach and highly objective, requiring little practitioner choice for tuning.

Empirical Equations of P-Wave Velocity in the Shallow and Semi-Deep Sea Sediments from the South China Sea

2021 ◽  
Vol 20 (3) ◽  
pp. 532-538
Author(s):  
Guanbao Li ◽  
Zhengyu Hou ◽  
Jingqiang Wang ◽  
Guangming Kan ◽  
Baohua Liu
Keyword(s):  
South China Sea ◽  
Wave Velocity ◽  
South China ◽  
Deep Sea ◽  
The South China Sea ◽  
P Wave ◽  
Empirical Equations ◽  
China Sea ◽  
P Wave Velocity ◽  
Deep Sea Sediments

scholarly journals Geophysical and analytical determination of overstressed zones in exploited coal seam: a case study

2021 ◽  
Author(s):  
Dariusz Chlebowski ◽  
Zbigniew Burtan
Keyword(s):  
Coal Seam ◽  
Wave Velocity ◽  
Seismic Tomography ◽  
Analytical Modeling ◽  
Coal Mines ◽  
Vertical Stress ◽  
P Wave ◽  
Rockburst Hazard ◽  
State Of Stress ◽  
P Wave Velocity

AbstractA variety of geophysical methods and analytical modeling are applied to determine the rockburst hazard in Polish coal mines. In particularly unfavorable local conditions, seismic profiling, active/passive seismic tomography, as well as analytical state of stress calculating methods are recommended. They are helpful in verifying the reliability of rockburst hazard forecasts. In the article, the combined analysis of the state of stress determined by active seismic tomography and analytical modeling was conducted taking into account the relationship between the location of stress concentration zones and the level of rockburst hazard. A longwall panel in the coal seam 501 at a depth of ca.700 m in one of the hard coal mines operating in the Upper Silesian Coal Basin was a subject of the analysis. The seismic tomography was applied for the reconstruction of P-wave velocity fields. The analytical modeling was used to calculate the vertical stress states basing on classical solutions offered by rock mechanics. The variability of the P-wave velocity field and location of seismic anomaly in the coal seam in relation to the calculated vertical stress field arising in the mined coal seam served to assess of rockburst hazard. The applied methods partially proved their adequacy in practical applications, providing valuable information on the design and performance of mining operations.

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