Azimuthal investigation of compressional seismic-wave attenuation in a fractured reservoir

Bouchaala, Fateh; Ali, Mohammed Y.; Matsushima, Jun; Bouzidi, Youcef; Takougang, Eric M. Takam; Mohamed, Aala A. I.; Sultan, Akmal

doi:10.1190/geo2019-0079.1

Cited by 36 publications

(12 citation statements)

References 29 publications

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“…This is obviously easier in zerooffset data, but this is not a strict requirement, especially when there is a small lateral velocity variation as the case of the oilfield of this study [Takougang et al, 2020]. Bouchaala et al [2019b] critically discussed the effect of the offset on the accuracy of the spectral ratio method, by using synthetic data similar to VSP data used in the present study. They noticed that the effect of offset on SR method is noticeable at offsets larger than 2000 m, where the trend and magnitudes of attenuation profiles start to considerably differ from the zero-offset profile.…”

Section: Estimation Of Vsp Attenuationmentioning

confidence: 99%

Compressional and shear wave attenuations from walkway VSP and sonic data in an offshore Abu Dhabi oilfield

Bouchaala¹,

Ali²,

Matsushima³

2021

Comptes Rendus. Géoscience

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Seismic attenuation was estimated from compressional (P) and shear (S) waves carefully extracted from three-component vertical seismic profiling (VSP) data. A high sensitivity of attenuation to fluid content was noticed, which shows the advantage of its use as a seismic attribute for reservoir studies. Contrary to most observations in fully saturated sandstones, the magnitude of P to S wave attenuation in the studied carbonate reservoir zones is higher than one. This disagreement is most probably because the fluid flow models developed to describe the attenuation mechanisms in sandstones are not valid for carbonate rocks due their complex texture. Moreover, the magnitude of seismic attenuation in the reservoir zones is controlled by the saturation of pore fluids and clay content. Furthermore, the attenuation magnitudes obtained at sonic and VSP frequencies are of the same order, and compressional and shear attenuations show similar variation at both frequencies. This indicates frequency-independent attenuations in the studied oilfield.

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Section: Estimation Of Vsp Attenuationmentioning

confidence: 99%

Compressional and shear wave attenuations from walkway VSP and sonic data in an offshore Abu Dhabi oilfield

Bouchaala¹,

Ali²,

Matsushima³

2021

Comptes Rendus. Géoscience

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“…Using sub-azimuth pre-stack inversion and shear wave splitting theory methods, multi-azimuth shear wave impedance can be obtained, and then the fracture trend and density of tight oil fractured reservoirs can be finely described. Theory and practice have proved that the fracture direction and density obtained by the two methods have high reliability, and can effectively predict the formation fracture system, and ultimately guide the exploration and development deployment of fractured oil and gas reservoirs (Bouchaala et al 2019).…”

Section: Exploration and Development Significancementioning

confidence: 99%

A study on the characteristics of seismic wave propagation in fractured marlstone reservoirs based on mechanical principles

Zhang

Liu

et al. 2021

Arab J Geosci

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Marlstone reservoirs are closely related to the degree of fracture development and their hydrocarbon accumulation are also controlled by the distribution of fractures. Hence, the prediction of fracture development zones is very important to the discovery of fractured oil and gas reservoirs. Tectonic movements and their intensities are one of the key factors affecting the formation of fracture systems and the distribution of tectonic stress field has great impact on the generation of fractures. Therefore, taking marginal subsags in the Jiyang Depression, Eastern China, as an example, this paper studied the characteristics of seismic wave propagation in fractured marlstone reservoirs based on mechanical principles. This study proposed the equivalent geological model and elastic characterization parameters for the fractured marlstone reservoirs in study area, analyzed the seismic response patterns, anisotropy characteristics, and seismic wave-field distribution of the marginal subsags in the Jiyang Depression, discussed the influences of fracture filling fluid, density, inclination, orientation, and layer thickness on the characteristics of seismic wave propagation in fractured marlstone reservoirs, and finally explored the shear wave splitting phenomenon and the exploration and development significance of the seismic wave propagation in fractured marlstone reservoirs. The study results show that the fracture filling fluid can lead to the dispersion and attenuation of seismic wave propagating in the medium, and rock saturated with fluid can exhibit frequency-dependent attenuation and dispersion due to wave-induced fluid flow between pores and fractures. The change of fracture density can make seismic wave appear anisotropic and biphasic and the difference between the high and low frequency of the longitudinal wave phase velocity becomes more and more obvious. The change of fracture inclination and orientation can cause the shear wave splitting phenomenon, in which the fast shear wave polarized parallel to the fracture with a fast velocity and a slow attenuation and the slow shear wave is polarized in the direction perpendicular to the crack with slow velocity and fast attenuation. The change of fracture layer thickness can make because the change of phase velocity and attenuation and the larger the thickness of the fracture layer is, the greater the difference between the reflection amplitude of the bottom interface and that of the non-fracture layer is. The study of characteristics of seismic wave propagation in fractured marlstone reservoirs can effectively obtain the multi-directional shear wave impedance and then fine characterize the fracture strike and density of tight oil fractured reservoir, which has important theoretical research and practical exploration significance. The study results provide a reference for further researches on the characteristics of seismic wave propagation in fractured marlstone reservoirs based on mechanical principles.

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“…The new method avoided errors caused by inertia and friction effects. The inertia frictional area was well studied and explained by Bouchaala et al [12,13].…”

Section: Introductionmentioning

confidence: 99%

Comparative Study on the Application of Different Slug Test Models for Determining the Permeability Coefficients of Rock Mass in Long-Distance Deep Buried Tunnel Projects

et al. 2022

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In large-scale water diversion projects, especially in the central and western regions of China, long-distance deep buried tunnels are generally involved. Therefore, it is essential to carry out field tests to obtain the permeability of the rock mass through which tunnels pass. However, the test holes of large-scale water diversion projects are basically located in mountain areas with complex hydrogeological conditions. Meanwhile, the test holes are far apart and large in depth. As a result, traditional pumping tests cannot meet the requirements. Therefore, the slug test was chosen as the main test method, and the calculation results of the water injection test, the water pressure test and the slug test are analyzed and compared. The calculation results of the three test methods are basically consistent. However, the water injection test and the water pressure test are difficult to implement at a large scale due to many environmental constraints, complex test equipment, long test periods and other factors. Furthermore, the Kipp model, the CBP model and the proposed HWS model, considering the effect of the finite thickness well-skin layer for the first time, were used to analyze and process the slug test data, respectively. The curve fitting effect of the Kipp model was the best, but the calculations were generally larger. The difference between the CBP model and the proposed HWS model is smaller in the calculation results; however, the curve fitting effect of the CBP model is the worst, and the CBP model needs to be further improved. The curve fitting effect of the proposed HWS model was between that of the Kipp model and the CBP model, and the proposed HWS model can be applied to the parameter calculations of the slug test with well-skin. In general, with reference to the criteria for the damping coefficient of the aquifer in the Kipp model, the Kipp model was applicable to the slug test for test holes without well-skin and an aquifer damping coefficient between 0.1 and 5.0. The CBP model was applicable to the slug test under the conditions of no well-skin and an aquifer damping coefficient greater than 2.0. The novel proposed HWS model was applicable to the slug test when the aquifer damping coefficient was greater than 1.0 under the conditions of no well-skin, positive well-skin and negative well-skin.

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Azimuthal investigation of compressional seismic-wave attenuation in a fractured reservoir

Cited by 36 publications

References 29 publications

Compressional and shear wave attenuations from walkway VSP and sonic data in an offshore Abu Dhabi oilfield

Compressional and shear wave attenuations from walkway VSP and sonic data in an offshore Abu Dhabi oilfield

A study on the characteristics of seismic wave propagation in fractured marlstone reservoirs based on mechanical principles

Comparative Study on the Application of Different Slug Test Models for Determining the Permeability Coefficients of Rock Mass in Long-Distance Deep Buried Tunnel Projects

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