Well Test Analysis in Naturally Fissured, Geothermal Reservoirs with Fracture Skin

Abstract

Minerai deposition or alteration is commonly found at fracture-block lnterfaces in fissured, geothermal reservolrs. In response to pressure red-uctlon in the fissures such mineralization, i f less permeable than the matrix rock, will retard the flow of fiaid from the blocks to the fissure s and is termed fracture skin in this paper. ??le problem of fluid flow to a prodilction well in a double-porosity reservoir wlth fracture skin was analyzed theoretically. One of the findings of the analysis was that filily transient block-to-fissure flow can be approximazed by pseudo-steady state flow i f fractures k in Permeability is sufficiently low. Type cilrves generated by numerical inversion of Laplace transform soiutions are used to illilstrate this effecz. They are also used to corroborate the results of a finite - difference model of steam transport to a well in a naturally fissured, geothermal reservoir with fracture skin.