Deep reservoir thief-zone conformance has been one of the most challenging tasks to achieve in the oil industry, particularly with regard to identifying a stable, cost-effective, and easy-to-apply conformance agent. One recent technology, borrowed from treatment of drilling-circulation losses, involves calcium carbonate (CaCO3) particles. This study presents applications involving the use of CaCO3 particles for conformance improvement for CO2 water-alternating-gas (WAG) injection in the Permian Basin.
CaCO3 Conformance-Operation Overview
Being an abundant, naturally occurring material, granular CaCO3 is a cost-effective bridging material commonly used by drilling rigs.In the Permian Basin, local drilling-fluid providers offer granular CaCO3 from a median particle diameter of approximately 5 μm up to 1,200 μm (Fig. 1). Crushers are used to break the rock into sizes suitable for milling before vertical roller mills generate finer particles.
