Abstract: With a self-developed numerical model, we simulate seepage flows in reservoir of an imaginary doublet EGS and perform a systemic investigation on flow pattern correlating with the reservoir hydraulic permeability. It reveals that the flow pattern in reservoir is mainly decided by relative magnitude of "basic pressure difference" caused by gravity and hydrodynamic-hydrostatic pressure transformation to fluid flow resistance through fractured rock mass. Circulation flow rate exhibits a limited effect on the flow pattern. Based on this we bring forward two strategies, horizontal well and multiple well layouts, to restrain the down-hole flow circuit in EGS reservoir, which acts as theoretical guidelines for practical construction of EGSs.

Key words: EGS, HDR, seepage flow in fractured rock, porous medium