How Induced Earthquakes Response to Pre-Existing Fractures and Hydraulic Fracturing Operations? a Case Study in South China
Description:
Hydraulic fracturing in shale gas production can induce damaging earthquakes, making it crucial to understand and mitigate the induced seismicity. The Cen'gong shale gas block in South China offers extensive data – 3D seismic, geological structure, microseismic data, and detailed stimulation operations – allowing a comprehensive investigation into induced earthquakes by hydraulic fracturing. Using a dense temporary seismic array and deep-learning workflows, we build a high-precision earthquake catalog and determine their focal mechanisms. Pre-existing fractures are identified through the Ant Tracking attribute derived from the 3D seismic data. We analyze the distribution, frequency, magnitude, and focal mechanisms of induced earthquakes, compare them spatially with the distribution of the pre-existing fractures, and track their temporal changes during and after hydraulic fracturing. Most induced earthquakes occurred along pre-existing fractures, exhibiting larger magnitudes and persisting post-stimulation. Focal mechanisms remain consistent throughout and after the stimulations. Abrupt drops in injection pressure often coincide with significant earthquakes. Our observations reveal that induced earthquakes initiated from the far side of the fractures, and then linearly migrated along the pre-existing fractures. This directional migration pattern is explained by differential stresses along the fractures. Our analysis suggests that both pre-existing fractures and stimulation operations significantly influence induced earthquake occurrences. Therefore, enhancing our comprehension of pre-existing fractures and optimizing stimulation operations can migrate earthquake hazards in shale gas production.
Session: Induced Earthquakes: Source Characteristics, Mechanisms, Stress Field Modeling and Hazards [Poster Session]
Type: Poster
Date: 5/1/2024
Presentation Time: 08:00 AM (local time)
Presenting Author: Miao
Student Presenter: No
Invited Presentation:
Authors
Dewei Li dewei.li@student.cumtb.edu.cn China University of Mining and Technology |
Miao Zhang Presenting Author Corresponding Author miao.zhang@dal.ca Dalhousie University |
Jing Zheng zhengjing8628@163.com China University of Mining and Technology |
Suping Peng psp@cumtb.edu.cn China University of Mining and Technology |
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How Induced Earthquakes Response to Pre-Existing Fractures and Hydraulic Fracturing Operations? a Case Study in South China
Session
Induced Earthquakes: Source Characteristics, Mechanisms, Stress Field Modeling and Hazards