scholarly journals Results of studying the azimuthal anisotropy of the paleozoic basement with vsp technique at the Bystrovka vibroseismic test site

2021 ◽  
pp. 19-37
Author(s):  
S. B. Gorshkalev ◽  
V. V. Karsten ◽  
P. A. Dergach
Keyword(s):  
Significant Variation ◽  
Shear Waves ◽  
Test Site ◽  
Azimuthal Anisotropy ◽  
Compressional Waves ◽  
Paleozoic Basement ◽  
Novosibirsk Region ◽  
Head Waves ◽  
Refracted Waves

At the Bystrovka vibroseismic test site (Novosibirsk region) 3-component refracted waves profiling was performed at three intersecting lines. Shear waves analysis made possible to detect anisotropy of the Paleozoic basement occurring at depth of about 10 m and to suggest symmetry elements of this medium along with their orientation. Compressional waves data were used to construct depth sections estimating head waves velocities. These velocities demonstrate significant variation in lines of different orientation. The results obtained agree with previously performed VSP.

scholarly journals Results of studying the azimuthal anisotropy of the Paleozoic basement with VSP technique at the Bystrovka vibroseismic test site

2021 ◽  
pp. 42-49
Author(s):  
S. B. Gorshkalev ◽  
W. V. Karsten
Keyword(s):  
Western Siberia ◽  
Oil And Gas ◽  
Practical Interest ◽  
Test Site ◽  
Azimuthal Anisotropy ◽  
Paleozoic Basement ◽  
Oil And Gas Fields ◽  
Shallow Seismic ◽  
Novosibirsk Region ◽  
Gas Fields

At present due to depletion of reserves in the majority of Western Siberia oil and gas fields, with reservoirs mainly related to lower Cretaceous and Jurassic section interval, the basement intervals present primary scientific and practical interest for prospecting and exploration. At the Bystrovka vibroseismic test site (Novosibirsk region), the Paleozoic basement occurs at depth of about 10 m. This allowed investigating its elastic properties with shallow seismic technique using VSP. Results of these investigations are presented in the present paper. 

Delineating a cased borehole in unconsolidated formations using dipole acoustic data from a nearby well

Geophysics ◽  
2021 ◽  
pp. 1-39
Author(s):  
Gu Xihao ◽  
Xiao-Ming Tang ◽  
Yuan-Da Su
Keyword(s):  
Shear Waves ◽  
Low Frequency ◽  
Well Being ◽  
Compressional Wave ◽  
Acoustic Imaging ◽  
Wave Radiation ◽  
Dipole Source ◽  
Compressional Waves ◽  
Single Well ◽  
Cased Borehole

A potential application for single-well acoustic imaging is the detection of an existing cased borehole in the vicinity of the well being drilled, which is important for drilling toward (when drilling a relief well), or away from (collision prevention), the existing borehole. To fulfill this application in the unconsolidated formation of shallow sediments, we propose a detection method using the low-frequency compressional waves from dipole acoustic logging. For this application, we perform theoretical analyses on elastic wave scattering from the cased borehole and derive the analytical expressions for the scattered wavefield for the incidence of compressional and shear waves from a borehole dipole source. The analytical solution, in conjunction with the elastic reciprocity theorem, provides a fast algorithm for modeling the whole process of wave radiation, scattering, and reception for the borehole acoustic detection problem. The analytical results agree well with those from 3D finite-difference simulations. The results show that compressional waves, instead of shear waves as commonly used for dipole acoustic imaging, are particularly advantageous for the borehole detection in the unconsolidated formation. Field data examples are used to demonstrate the application in a shallow marine environment, where dipole-compressional wave data in the measurement well successfully delineate a nearby cased borehole, validating our analysis results and application.

SHEAR WAVES FROM EXPLOSIVE SOURCES

Geophysics ◽  
1963 ◽  
Vol 28 (6) ◽  
pp. 1001-1019 ◽  
Author(s):  
J. E. White ◽  
R. L. Sengbush
Keyword(s):  
Shear Waves ◽  
Shear Velocity ◽  
Compressional Waves ◽  
Pierre Shale ◽  
Strong Shear ◽  
Water Pulse ◽  
Pulse Waves ◽  
Tube Wave ◽  
A Charge ◽  
Shear Energy

This experimental study of the generation of shear waves by explosive sources stemmed from Heelan’s theoretical result that pressure acting on the wall of a cylindrical hole in a solid should radiate shear waves quite as effectively as compressional waves. The measurements confirm this expectation, but good overall agreement was not achieved until expressions were derived which take into account radiation from strong water‐pulse waves in the shothole. Our results show that the ratio of shear‐to‐compressional amplitudes generated by an explosive source increases as the charge size decreases. At an angle of 45 degrees, the ratio is approximately unity for a charge consisting of 10 ft of Primacord. We found that the shot‐generated water pulse (tube wave) is a strong shear source, continuously generating shear energy in the formation as it travels in the borehole. This drastically affects the directivity of SV waves and in Pierre shale gives a pattern whose maximum is near‐vertical. This suggests the possibility of prospecting with shear waves, using a distributed charge detonated at shear velocity to generate substantial downward‐direction shear energy in the earth. However, the substantially larger attenuation of shear waves compared to compressional waves has discouraged us from pursuing this further.

THE USE OF SEISMIC SHEAR WAVES AND COMPRESSIONAL WAVES FOR LITHOLOGICAL PROBLEMS OF SHALLOW SEDIMENTS*

1984 ◽  
Vol 32 (4) ◽  
pp. 662-675 ◽  
Author(s):  
H. STUMPEL ◽  
S. KAHLER ◽  
R. MEISSNER ◽  
B. MILKEREIT
Keyword(s):  
Shear Waves ◽  
Compressional Waves ◽  
Seismic Shear ◽  
Shallow Sediments

Sonic to ultrasonic Q of sandstones and limestones: Laboratory measurements at in situ pressures

Geophysics ◽  
2009 ◽  
Vol 74 (2) ◽  
pp. WA93-WA101 ◽  
Author(s):  
Clive McCann ◽  
Jeremy Sothcott
Keyword(s):  
Wave Attenuation ◽  
Shear Waves ◽  
Compressional Wave ◽  
Ultrasonic Frequency ◽  
Laboratory Measurements ◽  
Compressional Waves ◽  
Wave Velocities ◽  
Poisson's Ratios ◽  
Poisson’S Ratios

Laboratory measurements of the attenuation and velocity dispersion of compressional and shear waves at appropriate frequencies, pressures, and temperatures can aid interpretation of seismic and well-log surveys as well as indicate absorption mechanisms in rocks. Construction and calibration of resonant-bar equipment was used to measure velocities and attenuations of standing shear and extensional waves in copper-jacketed right cylinders of rocks ([Formula: see text] in length, [Formula: see text] in diameter) in the sonic frequency range and at differential pressures up to [Formula: see text]. We also measured ultrasonic velocities and attenuations of compressional and shear waves in [Formula: see text]-diameter samples of the rocks at identical pressures. Extensional-mode velocities determined from the resonant bar are systematically too low, yielding unreliable Poisson’s ratios. Poisson’s ratios determined from the ultrasonic data are frequency corrected and used to calculate thesonic-frequency compressional-wave velocities and attenuations from the shear- and extensional-mode data. We calculate the bulk-modulus loss. The accuracies of attenuation data (expressed as [Formula: see text], where [Formula: see text] is the quality factor) are [Formula: see text] for compressional and shear waves at ultrasonic frequency, [Formula: see text] for shear waves, and [Formula: see text] for compressional waves at sonic frequency. Example sonic-frequency data show that the energy absorption in a limestone is small ([Formula: see text] greater than 200 and stress independent) and is primarily due to poroelasticity, whereas that in the two sandstones is variable in magnitude ([Formula: see text] ranges from less than 50 to greater than 300, at reservoir pressures) and arises from a combination of poroelasticity and viscoelasticity. A graph of compressional-wave attenuation versus compressional-wave velocity at reservoir pressures differentiates high-permeability ([Formula: see text], [Formula: see text]) brine-saturated sandstones from low-permeability ([Formula: see text], [Formula: see text]) sandstones and shales.

Study of near–surface azimuthal anisotropy with refracted waves

2020 ◽  
Author(s):  
Sergey V. Yaskevich ◽  
◽  
Petr A. Dergach ◽  
Gleb S. Chernyshov ◽  
Viktor I. Karpukhin ◽  
...  
Keyword(s):  
Data Processing ◽  
Field Work ◽  
Azimuthal Anisotropy ◽  
Observation System ◽  
Strong Anisotropy ◽  
Near Surface ◽  
Axis Of Symmetry ◽  
Object Of Study ◽  
Refracted Waves ◽  
Hti Medium

The method of refracted waves is often used for shallow investigations. Moreover, a rather limited observation system in the form of unidirectional profiles is often used. In our work, we selected an object of study with a known strong anisotropy of the upper part of the section. Field work and data processing were carried out. The results show strong anisotropy of one of the layers of the medium, the azimuthal anisotropy of which led to the fact that the refraction on its top ceases to appear in the first arrivals, for the direction of the profile along the axis of symmetry of the corresponding HTI medium.

Seismo-Acoustic Benchmark Problems Involving Sloping Fluid–Solid Interfaces

2016 ◽  
Vol 24 (04) ◽  
pp. 1650022 ◽  
Author(s):  
Katherine Woolfe ◽  
Michael D. Collins ◽  
David C. Calvo ◽  
William L. Siegmann
Keyword(s):  
Finite Element ◽  
Wave Equation ◽  
Parabolic Equation ◽  
Finite Element Model ◽  
Shear Waves ◽  
Element Model ◽  
Single Scattering ◽  
Benchmark Problems ◽  
Sediment Layer ◽  
Compressional Waves

The accuracy of the seismo-acoustic parabolic equation is tested for problems involving sloping fluid–solid interfaces. The fluid may correspond to the ocean or a sediment layer that only supports compressional waves. The solid may correspond to ice cover or a sediment layer that supports compressional and shear waves. The approach involves approximating the medium in terms of a series of range-independent regions, using a parabolic wave equation to propagate the field through each region, and applying single-scattering approximations to obtain transmitted fields across the vertical interfaces between regions. The accuracy of the parabolic equation method for range-dependent problems in seismo-acoustics was previously tested in the small slope limit. It is tested here for problems involving larger slopes using a finite-element model to generate reference solutions.

scholarly journals STUDY OF NEAR-SURFACE ANISOTROPY FOR THE KLUCHI CITE BY REFRACTED WAVES SUTVEYING

2021 ◽  
Vol 2 (3) ◽  
pp. 90-97
Author(s):  
Sergey V. Yaskevich ◽  
Petr A. Dergach ◽  
Gleb S. Chernyshov ◽  
Viktor I. Karpukhin ◽  
Anton A. Duchkov
Keyword(s):  
Cross Section ◽  
Azimuthal Anisotropy ◽  
Observation System ◽  
Surface Anisotropy ◽  
Anisotropic Layer ◽  
Near Surface ◽  
Surface Exploration ◽  
Axis Of Symmetry ◽  
The Cross ◽  
Refracted Waves

Refracted waves are often used in neat-surface exploration. A limited observation system in the form of unidirectional profiles is often used. In our work, we selected an object with a known anisotropic upper part of the cross-section. The results of refracted waves processing show the anisotropy of one of the layers of the medium, the azimuthal anisotropy of which led to the observation that the refraction on its top ceases from the first arrivals, for the direction of the profile aligned with the axis of symmetry of the azimuthally anisotropic layer.

scholarly journals SEISMIC MODEL OF THE UPPER EARTH`s CRUST ON NORTH-EAST PART OF TRAVERSE 3-DV BASED ON RESULTS OF HEAD WAVES DIGITAL PROCESSING

2021 ◽  
Vol 2 (2) ◽  
pp. 225-233
Author(s):  
Pavel O. Polyansky ◽  
Alexander F. Emanov ◽  
Alexandr S. Salnikov
Keyword(s):  
Sedimentary Cover ◽  
Mineral Resources ◽  
Digital Processing ◽  
Velocity Model ◽  
Depth Interval ◽  
Tectonic Block ◽  
East Part ◽  
North East ◽  
Head Waves ◽  
Refracted Waves

Digital processing of refracted waves data, which are registered on North-East part of profile3-DV, is done. Time sections and velocity model are formed. It is proved, that refraction horizons on depth interval of 0-1.5 km are geologic boundaries in sedimentary cover on Ayan-Yuryakh tectonic block. Refraction boundary on depth of ~1.0 km is not lithologic border on Inyaly-Debin block. Layers, which are potentially productive for ore mineral resources, are substracted by low values of V/V (1.66-1.70) on depth below 1.0 km, on Inyaly-Debin block and Orotukan-Balygychan elevation.

Sign in / Sign up

Export Citation Format

Share Document