Microbial Methods for Improved Conformance Control in Porous Media

Abstract

Abstract Water handling is a major expense involved in producing mature oil fields. Reservoir heterogeneities and variations in permeability can aggravate the problem of water production and significantly reduce the efficiency of oil production. Several methods for improving reservoir sweep through conformance control have been used. Methods such as crosslinked polymer technology have alleviated problems associated with reservoir heterogeneity. Other alternatives such as microbial- and surfactant-based methods have been proposed. This paper presents the results of research conducted on polymer-producing bacteria that were isolated and tested at various temperatures and salinities. Coreflooding experiments were conducted to show the effectiveness of microbial treatments. Reduction in effective permeabilities by as much as 90% were achieved due to in situ polymer production. Noninvasive imaging techniques such as magnetic resonance imaging (MRI) and computer-aided tomography (CT) were employed to visualize changes in fluid distribution in porous media. High permeability areas were blocked by biopolymer production, resulting in brine diversion into lower permeability areas.