Marathon Oil Company

Marathan Oil Company

Robert D Sydansk

Perry A Argabright

Karl D Dreher

Paul R Gucwa

George P Southwell

Richard W McAtee

David N Burdge

Noel D Wygant

Sharon A Stonecipher

Lyndon C Ibele

M Marc Sengul

Frank S Cordiner

A process is provided for reducing the permeability of or fluid mobility within a carbonate-containing treatment region in or proximate to a hydrocarbon-bearing formation below an earthen surface penetrated by a well bore. The process is initiated by preparing a gelation solution at the earthen surface which includes an acrylamide polymer, a crosslinking agent, a stabilizing agent and an aqueous solvent. The stabilizing agent is an acid additive, acidic pH buffer system, or delayed acid generator. The crosslinking agent is a chromium(III) complex having one or more chromium(III) cations and one or more carboxylate anions. The gelation solution is injected into the well bore and displaced into the treatment region where it is gelled in situ to form a gel which substantially reduces the permeability of or fluid mobility within the treatment region. The stabilizing agent maintains the stability of the gelation solution and resulting gel in situ by diminishing the detrimental effect of the alkaline carbonate minerals on the crosslinking agent.

Application of a stabilized polymer gel to an alkaline treatment region for improved hydrocarbon recovery

A foamed gel composition useful in a subterranean hydrocarbon-bearing formation to reduce the permeability of a treatment region therein or control the mobility of a drive fluid in the formation. The foamed gel is formed from a crosslinkable carboxylate-containing polymer, a crosslinking agent containing a reactive transition metal cation, a polyvinyl alcohol, an aqueous solvent, and an added gas.

Foamed gel for permeability reduction or mobility control in a

A process is provided for reducing the permeability of or fluid mobility within a high-temperature treatment region in or proximate to a hydrocarbon-bearing formation below an earthen surface penetrated by a well bore. The process is initiated by preparing a gelation solution at the earthen surface which includes a base loading of a high molecular weight acrylamide polymer, an additive loading of a low molecular weight acrylamide polymer, a crosslinking agent, and an aqueous solvent. The crosslinking agent is preferably a chromium(III) complex having one or more chromium(III) cations and one or more carboxylate anions. The resulting gelation solution is injected into the well bore and displaced into the treatment region where it is gelled in situ to form a gel which substantially reduces the permeability of or fluid mobility within the treatment region.

Permeability or fluid mobility reduction treatment for a

A process is provided for reducing fluid leakage from or into a subterranean storage cavern through the earthen wall of the storage cavern by sealing a relatively high permeability region of the earthen wall, through which the leakage occurs, with a sealing composition in the form of a gel. The process is initiated by preparing a gelation solution from a crosslinkable polymer, a crosslinking agent, and an aqueous solvent. The gelation solution is dispensed into the storage cavern and substantially gelled at the relatively high permeability region, forming a gel that reduces the permeability of the relatively high permeability region and effectively seals the region to fluid flow therethrough. Alternatively, the gelation solution is placed at the relatively high permeability region of the subterranean storage cavern by injecting the gelation solution into an injection well in fluid communication with the relatively high permeability region. The gelation solution is substantially gelled at the relatively high permeability region, forming the permeability-reducing gel. Either of the above-recited alternatives can also be practiced by substantially gelling the gelation solution prior to placement at the relatively high permeability region and placing the resulting flowing gel at the relatively high permeability region.

Process for reducing hydrocarbon leakage from a subterranean storage

A process employing a foamed gel in a subterranean hydrocarbon-bearing formation to reduce the permeability of a treatment region therein or control the mobility of a drive fluid in the formation. The foamed gel is formed from a crosslinkable carboxylate-containing polymer, a crosslinking agent containing a reactive transition metal cation, a polyvinyl alcohol, an aqueous solvent, and an added gas.

A process and composition are provided for permeability reduction in a hydrocarbon-bearing formation to improve hydrocarbon recovery therefrom. The process includes placement of a crosslinked polymer gel in the treatment region preceded by surface preparation of a gelation solution which is the gel precursor. The gelation solution contains a crosslinkable polymer, a chromium(III)/carboxylate complex crosslinking agent, an inorganic fluoride salt stabilizing agent and an aqueous solvent containing hard salts. The gel is placed in the treatment region by injecting the gelation solution into a well bore in fluid communication with the formation, displacing the gelation solution into the desired treatment region and gelling the solution to completion forming the permeability-reducing gel in situ. The inorganic fluoride salt stabilizing agent promotes the long-term stability of the gel in the treatment region, particularly at high temperatures.

Permeability reduction in a hydrocarbon-bearing formation using a

A foam is provided having utility for improving sweep efficiency in subterranean oil-bearing formations and having specific utility for conformance improvement treatments and mobility control in such formations. The foam is a gel medium having a gas dispersed therein. The gel medium is made up of a crosslinkable polymer, a crosslinking agent, a surfactant and a liquid solvent.

Foam for improving sweep efficiency in subterranean oil-bearing

A process for fracturing a subterranean formation below an earthen surface in fluid communication with a wellbore. A foamed fracturing fluid comprising an aqueous solvent, a water-soluble synthetic polymer, a surfactant, and a gas is premixed at the surface. The aqueous solvent may be a fresh water or a brine. The fracturing fluid may additionally comprise a proppant, fluid loss additive, and/or a foam breaker. After the fluid is mixed and foamed, it is injected into the formation via the wellbore at a pressure sufficient to induce at least one hydraulic fracture in the formation.

Hydraulic fracturing process

Polymer enhanced foam fluid is utilized for completion, workover, and kill operations in wells penetrating subterranean formations. The foam is formed by appropriately adding a gas to an aqueous solution of a substantially noncrosslinked water soluble polymer and a surfactant. The solution and the foam are substantially free of crosslinking agents. The foam may be generated at the surface or in a wellbore.

Polymer enhanced foam workover, completion, and kill fluids

A process employing a foamed gel in a wellbore as a completion, workover, or kill fluid. The foamed gel is formed from an aqueous solvent, a water-soluble carboxylate-containing polymer crosslinked by a crosslinking agent containing a reactive transition metal cation, a surfactant, and an added gas. The foamed gel is placed in the wellbore, where it substantially prevents the flow of formation fluid into or out of the wellbore. The completion, workover, or kill operation is then performed. Alternatively, the foamed gel may be combined with another completion, workover, or kill fluid after commencing a wellbore operation.

Foamed gel completion, workover, and kill fluid

A process and composition are provided for permeability reduction in a hydrocarbon-bearing formation to improve hydrocarbon recovery therefrom. The process includes placement of a crosslinked polymer gel in the treatment region preceded by surface preparation of a gelation solution which is the gel precursor. The gelation solution contains a crosslinkable polymer, a chromium(III)/carboxylate complex crosslinking agent, a carboxylate salt delaying agent and an aqueous solvent. The gel is placed in the treatment region by injecting the gelation solution into a well bore in fluid communication with the formation, displacing it into the desired treatment region and gelling the solution to completion forming the permeability-reducing gel in situ. The gelation rate is retarded in a controlled manner by adjusting the composition or concentration of the delaying agent in the gelation solution.

Process for reducing permeability in a subterranean hydrocarbon-bearing

A process and composition are provided for permeability reduction in a treatment region to improve hydrocarbon recovery from a hydrocarbon-bearing formation. The process includes placement of a crosslinked polymer gel in the treatment region preceded by surface preparation of a gelation solution which is the gel precursor. The gelation solution contains a crosslinkable polymer, a chromium(III)/carboxylate complex crosslinking agent, a carboxylate salt delaying agent and an aqueous solvent. The gel is placed in the treatment region by injecting the gelation solution into a well bore in fluid communication with the treatment region, displacing it into the desired treatment region and gelling the solution to completion forming the permeability-reducing gel in situ. The gelation rate is retarded in a controlled manner by adjusting the composition or concentration, and correspondingly the pH, of the delaying agent in the gelation solution.

pH dependent process for retarding the gelation rate of a polymer gel

A process employing a polymer enhanced foam in a wellbore as a drilling fluid during a wellbore drilling operation. The polymer enhanced foam is formed from an uncrosslinked acrylamide polymer, a surfactant, an aqueous solvent, and an added gas.

Polymer enhanced foam drilling fluid

A process employing a foamed gel in a wellbore as a drilling fluid, lost circulation fluid, or combined drilling/lost circulation fluid during the wellbore drilling operation. The foamed gel is formed from a crosslinkable carboxylate-containing polymer, a crosslinking agent containing a reactive transition metal cation, a surfactant, an aqueous solvent, and an added gas.

Foamed gel employed as a drilling fluid, a lost circulation fluid, or a

A process is provided for selectively placing a permeability-reducing material in an interval of a subterranean hydrocarbon-bearing formation penetrated by a well bore to inhibit the vertical flow of fluid between the well bore and an aquifer underlying the interval. The process is performed by simultaneously injecting a pair of fluids into the well bore, wherein one fluid has a density substantially less than the density of the other, and displacing the fluids out into the interval. The two fluids directly contact one another as they are displaced, however, the density difference between the fluids causes the first fluid to preferentially enter an upper portion of the interval and the second fluid to preferentially enter a lower portion of the interval under the force of gravity stratification or gravity segregation. The second fluid is aged in the lower portion of the interval, transforming it into a permeability-reducing material that substantially inhibits vertical flow between the aquifer and the well bore.

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Littleton, CO, United States of America

Robert D Sydansk