WANG Jiawei, ZHANG Bohu, HU Yao, et al. Inversion of multiphase tectonic stress field and fracture evolution in shale gas reservoirs[J]. Petroleum Reservoir Evaluation and Development, 2024, 14(4): 560-568. DOI: 10.13809/j.cnki.cn32-1825/te.2024.04.005.
The shale gas reserves in the Wufeng Formation-Longmaxi Formation of the Luzhou Block in southern Sichuan are substantial. Tectonic movements alter the ground stress
significantly impacting the exploration and development of shale gas. To optimize exploration areas for deep shale
methods such as seismic comprehensive data
ancient structural maps
and rock mechanics parameter testing have been employed. Additionally
neural network algorithms and geological mechanics modeling analysis have been used to invert the stress field of ancient geological structures across multiple stages within the study area and to predict the development of reservoir fractures influenced by stress. The research indicates that numerical simulation methods and neural network algorithms effectively invert the crustal stress field across multiple stages. Tectonic movements have altered the crustal stress
concentrating it in the stratigraphic anticline. Here
the core of the anticline
affected by strong tectonic activity
is fractured
gradually releasing stress. The ongoing multi-stage tectonic movements have facilitated changes in the stress of the reservoir rock
making the fracture zone conducive to fault formation with decreasing stress over time. Around the original faults
crack development is pronounced
leading to stress attenuation zones prone to numerous
short
small cracks. The current stress field
shaped by multiple tectonic periods
presents a complex distribution and irregular crack development
significantly influencing shale gas drilling and development. These findings offer valuable insights for the exploration and development of deep shale gas.