Hot dry rock geothermal potential of the Xujiaweizi area in Songliao Basin, northeastern China

Abstract

A series of studies was conducted to determine a suitable site for enhanced geothermal systems (EGSs) in mainland China. First, the Xujiaweizi (XJWZ) area in the Songliao Basin in northeastern China was identified to possess several features indicating a huge potential for hot dry rock (HDR) resource development from the aspects of tectonics, geology, geophysics, and geothermics. Then, a hydraulic fracturing model based on the real geological and logging data of well YS-2 and field fracturing experience in this region was established, and the geometric dimension and flow conductivity of the induced fracture were imported into a 3D hydrothermal coupled model established using TOUGH2-EOS1. The electricity generation potential of the fractured reservoir using three horizontal well production patterns is evaluated. Finally, three enhanced methods are proposed and discussed based on the simulation results. Results indicate that HDR resources in the XJWZ area demonstrate a significant potential for development from the aspect of geology. The Yingcheng Formation is selected as the potential target formation. The gel-proppant fracturing method is adopted in consideration of the undeveloped natural fractures in the target formation. The generalized EGS reservoir region possessed a considerable length of 600 m. The maximum production flow rate is determined to be 1 kg/s. The water flow impedance is relatively high during the heat production process for economic exploitation. Such an EGS reservoir has poor electricity generation capacity. A naturally fractured reservoir with a higher temperature should be targeted for electricity generation.