Frequency-dependent elastic properties of fracture-induced VTI rocks in a fluid-saturated porous and microcracked background

Wang，Wenhao1; Li，Shengqing1,2; Guo，Junxin3,4; Zhang，Chengsen5; Duan，Wenxing5; Su，Yuanda1,2; Tang，Xiao Ming1,2

2024-05-01

10.1190/geo2023-0229.1

Geophysics   影响因子和分区

0016-8033

1942-2156

Fractures are widely distributed underground. The stiffness matrix of fractured rocks has been extensively investigated in a fluid-saturated porous background medium. However, the existing stiffness models only incorporate the attenuation mechanism of wave-induced fluid flow (WIFF). For macroscopic fractures, the elastic scattering (ES) of fractures cannot be ignored. To alleviate this issue, a frequency-dependent stiffness matrix model is developed, including the mesoscopic WIFF between fractures and background (FB-WIFF), the microscopic squirt flow, and the macroscopic ES from the fractures. By combining the far-field scattered wavefields of normal incident P and SV waves with the linear slip theory, the dynamic full-stiffness matrices for fracture-induced effective vertically transversely isotropic rocks in a fluid-saturated porous and microcracked background are derived. Then, the P, SV, and SH-wave velocities and attenuation can be obtained through the Kelvin-Christoffel equation. The results indicate that the FB-WIFF mechanism significantly affects the velocities and attenuation of the P and SV waves but has almost no effect on the SH wave, whereas the squirt flow and ES mechanisms affect the velocities and attenuation of all the P, SV, and SH waves. For validation, the model is compared with existing models and previous experimental ultrasonic data.

anisotropy attenuation fractures velocity analysis

EI

英语

其他

GEOSCIENCES

2-s2.0-85190407793

Scopus

1.China University of Petroleum (East China),School of Geosciences,Qingdao,China
2.Laoshan National Laboratory,Qingdao,China
3.Guangdong Provincial Key Laboratory of Geophysical High-resolution Imaging Technology,Shenzhen,China
4.Southern University of Science and Technology,Department of Earth and Space Sciences,Shenzhen,China
5.PetroChina Tarim Oilfield Company,Research Institute of Exploration and Development,Korla,China

Wang，Wenhao,Li，Shengqing,Guo，Junxin,et al. Frequency-dependent elastic properties of fracture-induced VTI rocks in a fluid-saturated porous and microcracked background[J]. Geophysics,2024,89(3):MR137-MR153.

Wang，Wenhao.,Li，Shengqing.,Guo，Junxin.,Zhang，Chengsen.,Duan，Wenxing.,...&Tang，Xiao Ming.(2024).Frequency-dependent elastic properties of fracture-induced VTI rocks in a fluid-saturated porous and microcracked background.Geophysics,89(3),MR137-MR153.

Wang，Wenhao,et al."Frequency-dependent elastic properties of fracture-induced VTI rocks in a fluid-saturated porous and microcracked background".Geophysics 89.3(2024):MR137-MR153.