Academy of Mathematics and Systems Science, CAS
Colloquia & Seminars

Speaker:	吴天昊副研究员，东方理工高等研究院
Inviter:	张晨松
Title:	页岩基质中渗流与破裂过程的微观机理及其数值模拟方法
Language:	Chinese
Time & Venue:	2022.11.30 19:30-21:00 腾讯会议：124-107-886 会议密码：2022
Abstract:	点击链接入会，或添加至会议列表： https://meeting.tencent.com/dm/F4aV9eSHTVrm The production of oil and gas from organic-rich shale formations has changed the worldwide economy and energy outlook. Although extensive research on macroscopic behaviors in shale has been carried out, the mechanisms of fluid flow and mechanical processes at the microscale are not fully understood, which is a key factor for production rate prediction and hydraulic fracturing efficiency improvement. We provide a systematic investigation of multiscale pore structure in organic-rich shale by means of a combination of various advanced imaging techniques, which achieves insight into the major features at each scale and suggests affordable techniques for specific objectives. A comprehensive workflow is proposed based on the characteristics acquired from the multiscale pore structure analysis to simulate the gas transport process. The results of apparent permeability from simulations agree well with the values acquired from experiments. Considering the difficulties in the experiments, molecular dynamics (MD) simulations have been given much attention to gain insights into the mechanisms. Generally, kerogen is the predominant component of organic matter in most shale gas/oil formations. We provide a systematic study on the failure mechanisms of typical minerals from organic-rich shale by molecular dynamics simulations. The results indicate that the Mohr–Coulomb failure criterion and tensile strength criterion can describe the failure envelope of the kerogen matrices very well. The kerogen matrices have lower Young’s modulus, compressive strength, tensile strength, and fracture toughness than typical minerals. It reveals that kerogen is a potentially weak component in shale, and the fractures may initiate and propagate around kerogen aggregates. The effects of different fracturing fluids, including H2O and CO2, are also examined. This work provides a practical method to link the nanoscale and macroscale mechanical properties in organic-rich shales and kerogen, which sets the stage for investigating the complex mechanisms of hydraulic fracturing in the organic-rich shale formation.