Enhanced oil recovery process including the simultaneous injection of a miscible gas and water
First Claim
1. A process for the enhanced recovery of oil from an oil-bearing reservoir formation comprising at least periodically sequentially injecting effective oil producing amounts of (i) a non-condensible gas and (ii) an aqueous drive fluid into the formation characterized in that the gas and aqueous drive fluid are injected at a preselected water to gas ratio and the amount of gas injected prior to switching to injection of aqueous drive fluid as measured in hydrocarbon pore volume, is less than 0.25% wherein the amount of said gas injected is effective to reduce the viscosity of the oil or to increase its mobility through the reservoir formation.
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Abstract
An enhanced oil recovery process comprises of the at least periodic introduction of (i) a non-condensible gas preferably selected from among carbon dioxide, nitrogen, methane or mixtures thereof, and (ii) an aqueous drive solution, preferably brine, into a reservoir formation. In this process, the half cycle of non-condensible gas injection, prior to aqueous drive fluid injection, measured in hydrocarbon pore volume is less than 0.25%. In this preferred embodiment, the non-condensible gas, e.g., carbon dioxide, and water, are simultaneously injected into the formation.
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13 Claims
- 1. A process for the enhanced recovery of oil from an oil-bearing reservoir formation comprising at least periodically sequentially injecting effective oil producing amounts of (i) a non-condensible gas and (ii) an aqueous drive fluid into the formation characterized in that the gas and aqueous drive fluid are injected at a preselected water to gas ratio and the amount of gas injected prior to switching to injection of aqueous drive fluid as measured in hydrocarbon pore volume, is less than 0.25% wherein the amount of said gas injected is effective to reduce the viscosity of the oil or to increase its mobility through the reservoir formation.
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7. In an enhanced oil recovery process including at least periodic injection of (i) a non-condensible gas and (ii) an aqueous drive fluid into a reservoir formation, wherein the improvement comprises injecting (i) and (ii) simultaneously into the reservoir formation
wherein the amount of non-condensible gas injected as, measured in hydrocarbon pore volume, is less than 0.25% and wherein the amount of said non-condensible gas injected is effective to reduce the viscosity of the oil or to increase its mobility through the reservoir formation.
Specification