Marrying seismic attributes and geomechanical analysis for de-risking induced seismicity in unconventional reservoirs

Abstract

Summary Induced seismicity resulted from hydraulic fracturing is an unintended issue, and unpredicted by-product of tight reservoir development. We introduce a new workflow to identify the location and extent of the subtle faults (I.e. below or close to seismic resolution), which may also contribute to the risk of potential induced seismicity. A sequence of post stack seismic processing workflow is introduced. The location of the new identified subtle faults correlates well with the focus of the induced micro-seismicity events. Most Positive Curvature attribute identified a constant NW-SE fault orientation parallel to the Rocky Mountains. The stresses and pore pressures resulted from Mechanical earth models (ID MEM) were then applied on the interpreted faults, and fault susceptibility analysis was conducted. The authors suggest that N-NNE trending faults oriented to current day in-situ stress are critically stressed. This workflow offers a solution to avoid such critically stressed faults that may be prone to slip. It should be noted, that smaller scaled seismicity events, known as micro-seismicity should not be confused with larger events. This is primarily because micro-seismicity, and any seismicity under a Richter scale value of three are not believed to be associated with damage to buildings, or man-made structures.