Methods and compositions for improving hydrocarbon recovery by water flood intervention

Abstract

Methods useful in improving hydrocarbon recovery from subterranean formations using relative permeability modifier (RPM) macromolecules are described. The RPMs are typically crosslinked RPMs having K-values from 250-300 which, when injected into an injector well associated with a producer well, redirect the production water so as to improve the injection profile of the well and simultaneously improve hydrocarbon recovery from the producer well.

Description

FIELD OF THE INVENTION [0001] The present invention provides methods of enhanced recovery of hydrocarbons from subterranean formations. In particular, the present invention provides methods for improving the recovery of hydrocarbons from subterranean formations using relative permeability modifier macromolecules. DESCRIPTION OF RELATED ART [0002] Water production is always a harbinger of problems in a subterranean well, with water cuts in oil producing wells increasing as time passes and oil fields become more mature. The source of the water is often either formation water or injected water used for the purpose of reservoir maintenance. In other instances, heterogeneities encountered in reservoir rocks can cause water channeling through higher permeability streaks / hairline fractures, or near wellbore water coning at early periods in the well's productivity life span, often due to limited reservoir thickness or excessive pressure drawdowns. [0003] Such water production can cause a va...

AI Technical Summary

Benefits of technology

[0011] In a further aspect of the present invention, a method for increasing hydrocarbon production from a production well in a hydrocarbon-bearing formation having at least one injector well associated with the production well is provided, wherein the method comprises the steps of introducing an aqueous composition comprising a relative permeability modifier (RPM) macromolecule into an injector well in a permeable formation in an amount effective to enhance oil production from the production well, and continuing the injection of the RPM macromolecule into the at least one injector well for a time sufficient to increase oil flow from the formation to the production well where it is subsequently produced to the surface. In accordance with this aspect of the invention, the RPM macromolecule is capable of redirecting water flow through the hydrocarbon-bearing formation to provide an improved injection profile, and / or the method can further comprise the step of forming a treating solution comprising at least one RPM macromolecule prior to the introducing step.

[0013] In a further aspect of the present invention, a method for increasing hydrocarbon production from a production well in a subterranean formation is provided, the method comprising introducing an aqueous treating solution comprising a crosslinked relative permeability modifier (RPM) macromolecule into the subterranean formation through an injector well that is associated with the production well. In accordance with this aspect of the invention, the crosslinked RPM macromolecule comprises a terpolymer, copolymer, or homopolymer comprising an anchoring monomer and a hydrophilic monomer, and is capable of redirecting water flow through the hydrocarbon-bearing formation to provide an improved injection profile.

[0015] In yet another aspect of the present invention, a method for enhancing hydrocarbon recovery from a reservoir or formation containing substantially immobile hydrocarbons is provided, wherein the method comprises drilling and completing at least one injector well in a subterranean formation in proximity to a producer well, or converting a producer well into an injector well in proximity to other producer wells; directing an aqueous mixture comprising a crosslinked relative permeability modifier (RPM) macromolecule into the injector well, wherein the RPM macromolecule is present in an amount effective to redirect water flow in the subterranean formation and thereby increase hydrocarbon flow therefrom; and continuing the injection of the aqueous treating composition into the injector well for a time sufficient to increase flow of hydrocarbons from the formation towards the producer well, where it is subsequently produced to the surface via the producer well.

Problems solved by technology

Water production is always a harbinger of problems in a subterranean well, with water cuts in oil producing wells increasing as time passes and oil fields become more mature.

In other instances, heterogeneities encountered in reservoir rocks can cause water channeling through higher permeability streaks / hairline fractures, or near wellbore water coning at early periods in the well's productivity life span, often due to limited reservoir thickness or excessive pressure drawdowns.

Such water production can cause a variety of problems.

It can cause scaling problems in susceptible wells, induce fines migration or sandface failure, increase corrosion of tubulars, and sometimes even kill wells by hydrostatic loading, among other things.

In particular, hydrocarbon recovery using this method is reportedly not optimum in formations that are deeply buried and / or have not been extensively exposed to the atmosphere or oxygen bearing formation water, resulting in an interfacial tension and oil / rock wettability issues in these formations.

However, while the use of polymeric compositions are exhibiting increased utility and promise for downhole applications, many water control compositions, and even some relative permeability modifiers, do not always impart extended effectiveness, or exhibit utility in formations having permeability's greater than 1 Darcy.

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