Measurements of Hydraulic-Fracture-Induced Seismicity in Gas Shales

Hydraulic fracturing is an essential technology for hydrocarbon extraction from both conventional and unconventional reservoirs. Recently, concern has developed regarding induced seismicity generated in association with multistage fracturing of horizontal wells in shale reservoirs. Microseismic monitoring of hydraulic fractures, which has been a routine service for over a decade, can provide information about the levels of seismic activity commonly found during fracturing. A review of thousands of fracture treatments that have been microseismically monitored shows that the induced seismicity associated with hydraulic fracturing is very small and not a problem under any normal circumstances. Results are presented for six major shale basins in North America in which hundreds to thousands of fracture treatments have been conducted in predominatly gas reservoirs. This paper reviews the methodology, the data, and the interpretation of the microseismicity.