Patent ID: 8356665
Filing Date: 2013-01-22
Classification: E21B

Abstract:
1. A method of recovering oil and other formation fluids from a reservoir comprising an oil-bearing reservoir rock and having at least one production well and at least one injection well and conducting secondary production operations using a displacement fluid, and wherein the produced oil has a gravity in the range of ≦30° API, the method comprising the steps of: (a) overinjecting the displacement fluid into the reservoir rock at a voidage replacement ratio (VRR) of from 0.95 to 1.11 until the produced fluids reach a water to oil ratio (WOR) of at least 0.25; (b) underinjecting the displacement fluid into the reservoir rock at a VRR of <0.95 until the produced fluids have a gas to oil ratio (GOR) of at least 2 times the solution GOR of the initial oil produced from the well; and (c) repeating steps (a) and (b) one or more times, wherein during water injection a cumulative VRR is maintained within a range of 0.6 to 1.25.