Miscible stimulation and flooding of petroliferous formations utilizing viscosified oil-based fluids

Abstract

A viscosified miscible enhanced oil recovery fluid includes (a) a hydrocarbon fluid and viscosifying agent, wherein the viscosified fluid is a Newtonian fluid, (b) a hydrocarbon fluid and gelling agent, wherein the viscosified fluid is a power law fluid, (c) a hydrocarbon fluid, a gelling agent, and a rheological additive, wherein the viscosified fluid is a yield power law fluid, or (d) a hydrocarbon fluid, a gelling agent, a rheological additive, and solvent for the rheological additive, wherein the viscosified fluid is a yield power law fluid. The hydrocarbon fluid is preferably weighted with nano-scale weighting agents. The viscosified fluids are prepared and pumped into a subterranean petroliferous formation to recover a majority of the oil, heavy oil, condensate, or gas originally in place. A method for subsequently recovering a substantial fraction of the miscible injectant conventionally or by applying a viscosity breaker and recovering the viscosity-broken miscible injectant conventionally.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims the benefit of the filing date of and priority to U.S. Provisional Application Ser. No. 61 / 210,615 entitled “Miscible stimulation and flooding of petroliferous formations utilizing viscosified oil-based fluids” and filed Mar. 20, 2009, Confirmation No. 2199. Said provisional application is incorporated by reference herein.STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT[0002]Not Applicable.BACKGROUND OF THE INVENTION[0003]1. Field of the Invention[0004]The invention relates generally to viscosified, oil-based or hydrocarbon-based fluids and the use of said viscosified, oil-based or hydrocarbon-based fluids in miscible stimulation or miscible flooding. The invention relates further to the use of readily available oil-based or hydrocarbon-based fluids which may be converted into viscosified—Newtonian, Bingham-plastic, power-law, or yield-power-law—fluids for use in miscible stimulation or miscible floo...

AI Technical Summary

Problems solved by technology

Economically, of course, the idea was ludicrous because not even the relatively less costly Arabian Heavy crude will ever be readily available economically as a miscible injectant for the Prudhoe Bay field.

Just transportation costs for getting the injectant to the field would raise the cost of oil production well beyond its market value during most of the life of the Prudhoe Bay field.

However, such fluids have not been used as miscible injectants into a petroliferous formation.

Additionally, as recognized by the present inventor in Leggett et al., another short-coming of the above-referenced hydraulic fracturing fluids has been their limited stability—after all, they need only last a matter of hours, since even a massive hydraulic fracturing job involving 2,000,000 pounds of proppant is typically concluded in less than 8 hours.

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