Intelligent calculation method of relative sonic attenuation and its application to fracture evaluation in tight sandstone reservoir

Cai, Ming; Wu, Hongliang; Liu, Peng; Zhang, Chengguang; Tie, Jun; Chen, Yuanbo; Tan, Lihong

doi:10.1016/j.petrol.2022.110968

Cited by 10 publications

(6 citation statements)

References 22 publications

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“…On one hand, fractures play a role in connecting oil and gas and increasing reservoir permeability; On the other hand, fractures may cause casing deformation, inter-well frachit and other accidents. Therefore, identifying and evaluating the fractures near the well, especially the fractures intersected with the well bore, has guiding significance for formulating reasonable development and production planning for unconventional reservoirs (Cai et al, 2022a;Cai et al, 2022b;Qian et al, 2022). At present, the unconventional reservoir fracture logging evaluation method is difficult to meet the field demand, especially in highly deviated wells and horizontal wells.…”

Section: Introductionmentioning

confidence: 99%

“…Due to problems of the electrode plate opening and the instrument size, it is difficult to effectively collect the electrical imaging and nuclear magnetic resonance logging data. Therefore, the use of array acoustic logging data to identify and evaluate the fractures near the well bore has unique advantages (Spring and Dudley, 1992;Lynn et al, 1995;Yan et al, 2020;Cai et al, 2022a;Cai et al, 2022b).…”

Section: Introductionmentioning

confidence: 99%

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Forward modeling of P- and S-waves response of fractures intersected with horizontal wells in tight reservoirs

et al. 2023

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Horizontal wells play an important role in expanding the drilling volume of reservoirs and oil production area, and are widely used in unconventional reservoirs. Fractures have a positive effect on reservoir permeability, but fractures can also cause accidents such as casing deformation and inter-well frac-hit. It is of great significance to identify and evaluate fractures intersected with horizontal wells in tight reservoirs. In this paper, a three-dimensional numerical model of horizontal wells and fractures in tight reservoirs is designed. The responses of monopole P-wave and dipole S-wave to fractures with different width, dip angle and filling medium are systematically studied, by using three-dimensional finite difference algorithm. The results show that when the fracture is filled with calcite, the amplitude attenuation of monopole P-wave and dipole S-wave has a monotonic exponential increase with the increase of fracture width and the decrease of fracture dip angle. In the real data processing, the amplitude attenuation of P- and S-waves can be used to jointly evaluate the fracture filled with calcite. When the fracture is filled with water, both P- and S-waves have prominent amplitude attenuation. P wave amplitude attenuation does not have a monotonic variation with the increase of fracture width but it has a monotonic increase with the decrease of fracture dip angle. S wave amplitude attenuation has a monotonic increase with the increase of fracture width and the decrease of fracture dip angle. The amplitude attenuation of P- and S- waves rises significantly when the fracture is filled with natural gas. This study is crucial for better understanding the response of P- and S-waves to fractures intersected with borehole in tight reservoirs, and it provides useful information for the inversion of fracture parameters by using P- and S-waves.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Forward modeling of P- and S-waves response of fractures intersected with horizontal wells in tight reservoirs

et al. 2023

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“…36 The principle of using XMAC logs to determine the horizontal principal stress is shear wave splitting. 38,39 Shear waves mainly propagate in two directions; fast shear waves (FSWs) propagate along the fracture direction and spread faster, whereas slow shear waves (SSWs) propagate perpendicular to the fracture direction and spread slower. The existence of shear wave splitting in the local layer shows that shear wave anisotropy is related to changes in the fast and SSW velocities; thus, shear wave splitting can be expressed by shear wave anisotropy.…”

Section: Introductionmentioning

confidence: 99%

“…XMAC logging has been indicated to be a reliable method to determine the direction and magnitude of in situ stress 36 . The principle of using XMAC logs to determine the horizontal principal stress is shear wave splitting 38,39 . Shear waves mainly propagate in two directions; fast shear waves (FSWs) propagate along the fracture direction and spread faster, whereas slow shear waves (SSWs) propagate perpendicular to the fracture direction and spread slower.…”

Section: Introductionmentioning

confidence: 99%

Unreliable determination of in situ stress orientation by cross multipole array acoustic logging in fractured shale reservoirs

Yang

Liu

et al. 2023

Energy Science & Engineering

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With the development of shale gas exploration in China, the use of conventional logging tools has been introduced, and cross multipole array acoustic logging tools have gradually been used to determine the stress orientation in shale. The direction of fast shear waves (FSWs) is generally parallel to the horizontal maximum principal compression stress (SHmax). However, the azimuth of FSWs is found to be parallel to the main strike (but not to the SHmax) direction of structural fractures in shale reservoirs. Outcrop and image logging data indicate that the natural fractures in this area strike NE‒SW. If the shear wave anisotropy is caused by only the stress around the borehole and the FSWs are known to be NE‒SW, SHmax should be parallel to NE‒SW; however, according to statistics of land movement in adjacent areas, anelastic strain recovery, earthquake focal mechanism, borehole breakouts, hydraulic fracturing data, deviated well data, and drilling‐induced fracture data in local regions, SHmax is oriented in the NW‒SE direction, and the directions of FSWs are generally parallel to the structural fracture direction. This contradiction indicates that the development of structural fractures may affect the orientation of FSWs. Therefore, it is not reliable to use XMAC (Cross‐Multipole Array Acoustilog) logging only to determine the direction of in situ stress in fractured shale reservoirs. In addition, the direction of the FSWs in the middle of thick mudstones is NW‒SE, which may represent accurate information about the in situ stress direction.

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“…This logging method has the obvious advantage of describing the lateral inhomogeneity in carbonate reservoirs, the attitudes and distributions of fractures, and small geological structures near boreholes [ 1 , 2 ]. Therefore, it has been widely used in the identification and fine description of unconventional reservoirs and in the optimization of drilling trajectories [ 3 , 4 ].…”

Section: Introductionmentioning

confidence: 99%

A Plasma Transmitting Source for Borehole Acoustic Reflection Imaging

Hao

Zhou

Shang

et al. 2022

Sensors

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The detection depth of current borehole acoustic reflection imaging is only tens of meters without high resolution. This considerably limits its wide application in the identification and fine description of unconventional reservoirs and in the optimization of drilling trajectories. Increasing the directional energy from the transmitter to a geological structure is an excellent way to solve this issue. In this study, a plasma source with a parabolic reflector was introduced during borehole acoustic reflection imaging. First, an experimental system was built for testing the plasma source. Next, the acoustic-electrical characteristics and directional radiation of the source were studied using experiments and a numerical simulation. Finally, the advantages, disadvantages, and feasibility of the plasma-transmitting source were analyzed; some suggestions for further work on the source and its logging application were proposed. The experimental and simulation results show that the use of a plasma source with a parabolic reflector can increase the detection depth of borehole acoustic reflection imaging to hundreds of meters with high resolution. This is crucial in imaging the geological structures near boreholes and enhancing oil–gas exploration and development.

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Intelligent calculation method of relative sonic attenuation and its application to fracture evaluation in tight sandstone reservoir

Cited by 10 publications

References 22 publications

Forward modeling of P- and S-waves response of fractures intersected with horizontal wells in tight reservoirs

Forward modeling of P- and S-waves response of fractures intersected with horizontal wells in tight reservoirs

Unreliable determination of in situ stress orientation by cross multipole array acoustic logging in fractured shale reservoirs

A Plasma Transmitting Source for Borehole Acoustic Reflection Imaging

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