High-Temperature Blowdown Experiments in a Vuggy Carbonate Core

Abstract

Summary We conducted a series of tests on a vuggy carbonate core sample to quantify recovery mechanisms during a high-temperature blow-down process. We heated the core to 300°F, keeping the pressure above the bubblepoint, and then reduced the pore pressure at a constant rate from one end of the sample. Tests were conducted with the core at initial oil saturation, Soi, and at residual oil saturation, Sor, to water, with pressure reduction from top or bottom of the sample. The blowdown experiments show that 50 to 68% of the oil is recovered, with 8 to 20% owing to thermal expansion, 20 to 24% owing to thermally enhanced solution gas drive, 12 to 16% owing to distillation, and 8 to 10% owing to in-situ steamdrive.