Using Chemicals to Optimize Conformance Control in Fractured Reservoirs

Abstract

This technical progress report describes work performed from October 1, 1998 through December 31, 1998, for the project, ''Using Chemicals to Optimize Conformance in Fractured Reservoirs.'' In our first task area, disproportionate permeability reduction, a literature survey and analysis are underway to identify options for reducing permeability to water much more than that to oil. In our second task area, we are encouraging the use of our recently developed software for sizing gelant treatments in hydraulically fractured production wells. In several field applications, we noted the importance of obtaining accurate values of the static reservoir pressure before using our program. In our third task area, we examined gel properties as they extruded through fractures. We found stable pressure gradients during injection of a large volume of a one-day-old Cr(III)-acetate-HPAM gel into a 0.04-in.-wide, four-ft-long fracture. This finding confirms that gel injection (under our specific circumstances) did not lead to continuously increasing pressure gradients and severely limited gel propagation. Our experiments also provided insights into the mechanism for gel propagation during extrusion through fractures.