Effects of Artificial Fracture Geometry on Geothermal Well Production

Abstract

This paper examines the effects of various artificial and natural fracture systems on geothermal well productivity. Two dimensional finite element porous flow computer models are constructed and exercised under a variety of conditions. The model is verified for a planar fracture system created with hydraulic stimulation by comparing the results with an analytical solution. It is confirmed that fractures that penetrate deeply into the formation are needed to significantly improve well productivity in low permeability matrix formations. In high permeability matrix or fractured formations, multiple artificial fractures of even limited length are more effective. This is particularly true for reservoirs that contain large, highly conductive natural fractures that the wellbore passes near but fails to penetrate. These results demonstrate that a stimulation technique capable of producing multiple fractures may be beneficial to geothermal well production.