Microseismicity has been used to monitor hydraulic fracturing for many years, and usage has increased in recent times due to the successful development of unconventional plays. However, there remain fundamental questions regarding the physical causes of the microseismicity, and the relationship between microseismicity and hydraulic / natural fractures. We show that stress inversion with event focal mechanisms could help us better interpret microseismicity by identifying slip direction, and the true fault plane on which it occurs. We present a field case study in the Vaca Muerta formation in Argentina. Comparison of the orientation of fault planes calculated from microseismic focal mechanisms with the natural fracture systems in the area shows that the microseismicity observed in the field correspond to slippage on natural fractures. Specifically, the majority of the apparent dip-slip events, which strike in the maximum horizontal stress direction, are resolved predominantly to slip along sub-vertical direction, while only a few events are truly slipping in the near horizontal direction.
Presentation Date: Wednesday, September 18, 2019
Session Start Time: 8:30 AM
Presentation Start Time: 9:20 AM
Presentation Type: Oral