Second-Contact Water Displacement Oil Recovery Process

Abstract

Abstract The Double Displacement oil recovery process (DDP) consists of injecting gas into waterflooded oil zones. Upon contact with the injected gas, residual oil globules spread out and form a thin film. Subsequent drainage of the oil film creates a bank which migrates downdip and can be produced. The technical feasibility of DDP has been tested in three fields and is currently being investigated by a joint DOE/Amoco project.1 During laboratory investigation of the DDP at LSU, we observed that a significant amount of oil was displaced when gas-flooded zones were subjected anew to water displacement2. This process was termed Second-Contact Water Displacement (SCWD). Consolidated cores and unconsolidated sandpacks were flooded at high-pressure and high temperature to simulate different aspects of the process. In addition, experiments using low-pressure transparent cells were performed to gain conceptual insight into the process. Core and sandpack experiments proved that second-contact waterflooding following gas injection could recover up to 20% of oil remaining after the initial water contact. This process can be used in conjunction with the Double Displacement Process to shorten its duration hence improving its economic potential. The process can also be applied in single-well strong water-drive reservoirs in conjunction with attic-oil recovery.