Hydraulic fracturing-induced microseismicity controlled by rock brittleness and natural fractures in Tongren, Guizhou, China

Abstract

Hydraulic fracturing-induced microseismicity has drawn public attention in recent years. However, understanding the behavior of hydraulic fracture is limited due to the complex relationship between microseismicity and various geologic conditions. To further understand this question, we conduct a study to detect and locate hydraulic fracturing-induced microseismicity at a shale gas production site in Tongren, Guizhou, China. We investigate the relationship between their distribution and two important geologic factors: the brittleness index (BI) of rocks and the distribution of natural fractures. With the aid of a 3D active seismic survey, we first calculate the BI of rocks in the hydraulic fracturing region using Young’s modulus and Poisson’s ratio, compared with the locating result of fracturing-induced microseismicity, which indicates that most of the events are distributed in the area with higher BI. We then delineate natural fractures using the ant-tracking method of the 3D seismic attribute. The microseismic location is consistent with the region of natural fractures. Based on our findings, we suggest that the spatial distribution of induced microseismicity is highly controlled by the brittleness of rocks and the distribution of natural fractures in this region. This research provides insights into the factors controlling hydraulic fracturing-induced microseismicity and enhances our understanding of the complex interplay between geologic conditions and the behavior of hydraulic fractures.