The Distribution Pattern of SRV Fractures in Horizontal Shale Gas Well, Lacustrine Yanchang Formation, Ordos Basin, China

Wang, Xiangzeng; Gao, Ruimin; Zhang, Lixia; Shen, Feng; Wu, Jinqiao; Zhang, Juntao; Guo, Qing; Liang, Quansheng

Ordos Basin, one of the typical craton basins in China, is abundant of Triassic-aged lacustrine organic-rich shales. The lacustrine Yanchang Formation shales vary significantly in lateral and vertical lithological facies and contain low content of brittle minerals, high content of clay minerals and poor petrophysical properties. Our preliminary success in shale gas production from the lacustrine shale system has provided clear evidence that, the key technology for the success of the lacustrine shale gas formation is the combination of horizontal well drilling and the stimulated reservoir volume (SRV) by hydraulic fracturing.

Microseismic hydraulic fracture monitoring applies to several horizontal wells in our studied area and records microseismic activity in real time during the fracturing process. Based on the real-time monitoring data and fracturing treatment data, the distribution pattern of SRV fracturing network, the maximum principal stress of a reservoir, hole azimuth of horizontal well, fracturing partition, perforating parameter, fracturing treatment parameter etc, can be obtained and optimized.

Our test results show that SRV fractures in the horizontal wells of the Yanchang lacustrine shale have the following unique features: an asymmetric distribution in fracture extensions, extensively varied fracture azimuths in different fracturing partitions, and rapidly diverted fracture orientations. China's shale gas exploration is in the early stage of its development, the pioneer study on the distribution pattern of SRV fractures provide a reference/or a case study of optimizing hydraulic fracturing design for the lacustrine shale gas reservoir in China.

AAPG Search and Discovery Article #90163©2013AAPG 2013 Annual Convention and Exhibition, Pittsburgh, Pennsylvania, May 19-22, 2013