Utilizing Ant-tracking to Identify Slowly Slipping Faults in the Barnett Shale

Abstract

In this study, we present the results of using Ant-tracking to identify faults in the vicinity of five horizontal wells drilled in the Barnett shale. In these five wells, Long Period Long Duration (LPLD) events were observed during multi-stage hydraulic fracturing. LPLD events are believed to be caused by relatively large faults slipping slowly and stably. By utilizing Ant-tracking, we were able to identify a steep fault dipping to the north which intersects the middle of the five wells exactly where the largest density of fractures was found in FMI images. Moreover, the local orientation of the fault has the same strike as the observed fractures. This fault appears to be located in the source of the LPLD events produced during hydraulic fracturing. It is also coincident with a distinct gap in microseismicity. Thus, it appears that slip on this relatively large scale fault is responsible for the LPLD events observed.