Integration of Structural Analysis with Microseismic Fracture Mapping

Sherilyn C. Williams-Stroud
Microseismic, Inc., Houston, TX

Mapping of microseismic events generated during a hydraulic fracture treatment allows identification of fracture trends as they develop in response to reservoir stress changes during treatment. In an isotropic rock where the stress state is known, the ideal orientation of tensile fracture formation can be predicted. When the microseismic signals are strong, or when the event locations appear to mark the expected fracture orientation, the uncertainty in the location of events is less problematic leading to a high confidence of the results by geoscientists and engineers . When the results diverge from the expected and /or do not identify clear trends, additional constraints can be applied to the processing to illuminate trends. The natural fractures that are present in every rock will have varying impacts on the character of the induced fracturing and seismic events, but prediction of the locations and orientations of those natural fractures also can have a high uncertainty. This using an example from the Uinta Basin in Utah, this study shows how that uncertainty can be reduced by integrating structural analysis and rock mechanics information with the microseismic event mapping to identify orientations and locations of fractures generated and reactivated in the reservoir during the hydraulic fracturing treatment, as well as how the near-wellbore induced fractures may be connecting to the natural fracture network.

Presented AAPG Eastern Section Meeting, Pittsburgh, Pennsylvania 2008 © AAPG Eastern Section