Mobil Oil Corporation

Craig H Phelps

Paul Shu

E Thomas Strom

Ricky C Ng

Krishnaswamy Sampath

William C Hunt, Iii

Thomas O Mitchell

Dennis H Hoskin

Mark L Hoefner

Leonard V Grego

A method and composition for controlling the profile of a formation where temperatures higher than 200.degree. F. are encountered. An aqueous solution of an organoammonium silicate, alkali metal or ammonium silicate is injected into a zone of higher permeability in a formation. Subsequently, a spacer volume of a water-immiscible organic solvent is directed into said zone. Afterwards, a water-miscible organic solvent containing an alkylpolysilicate is injected into the higher permeability zone. A silica cement is formed in-situ thereby substantially closing the higher permeability zone to fluid flow. Thereafter, a steam-flooding, water-flooding, carbon dioxide-flooding, or fire-flooding EOR operation is commenced in a lower permeability zone.

In-situ cementation for profile control

A method for controlling the profile of a formation where temperatures higher than 200.degree. F. are encountered. Initially, an aqueous solution of an alkali metal hydroxide, ammonium hydroxide or organoammonium hydroxide is injected into a zone of greater permeability in a formation. Thereafter, a spacer volume of a water-miscible organic solvent is injected into said zone. Afterwards, a water-miscible organic solvent containing an alkylpolysilicate is injected into the greater permeability zone. A silica cement is formed in-situ thereby substantially closing off the higher permeability zone to fluid flow. Thereafter, a steam-flooding, water-flooding, carbon dioxide stimulation or fire-flooding EOR operation is commenced in a lower permeability zone.

In-situ silica cementation for profile control during steam injection

A method for selectively closing an intermediate zone of a near wellbore area in a formation. Initially, a drillable mechanical packer is placed into the wellbore below the intermediate zone. The wellbore area adjacent to the intermediate zone is cooled to a critical temperature between about 130.degree. to about 180.degree. F. Subsequently, a novolac or resole-type phenolformaldehyde resin containing an acid catalyst is placed into the wellbore where it forms a solid platform over the packer and intermediate zone in about 2 hours. The critical temperature is maintained in the wellbore and intermediate zone while placing a second resinous material containing an alkaline catalyst into the wellbore and intermediate zone. Thereafter, the second material forms a steam resistant solid gel in the intermediate zone, thereby closing it.

Method for selectively closing an intermediate zone of a near wellbore

A method for controlling the profile of a formation where temperatures higher than 200.degree. F. are encountered. Initially, an aqueous solution of an alkali metal hydroxide, ammonium hydroxide or organoammonium hydroxide is injected into a zone of greater permeability in a formation. Thereafter, a spacer volume of a water miscible organic solvent is injected into said zone. Afterwards, a water-miscible organic solvent containing an alkylpolysilicate is injected into the greater permeability zone. A silica cement is formed in-situ thereby substantially closing off the higher permeability zone to fluid flow. Thereafter, a steam-flooding, water-flooding, carbon dioxide stimulation or fire-flooding EOR operation is commenced in a lower permeability zone.

A method to prevent damage to a water-sensitive hydrocarbonaceous fluid-producing zone of a formation which is penetrated by a well which has a water-influx problem. A gellable petroleum mixture is injected into the well where it forms a solid hydrophobic gel in situ sufficient to temporarily close pores in the water-sensitive zone. The mixture is allowed to remain in the water-sensitive zone for a time sufficient to form a solid gel so as to preclude fluid entry into the water-sensitive zone. Afterwards, an aqueous based gel mixture is injected into the water-influx zone where it forms a solid hydrophilic gel which is substantially stable thereby precluding fluid entry into the well. Subsequently, the solid petroleum gel degrades at formation conditions and opens the water-sensitive zone to production of hydrocarbonaceous fluids. Thereafter, substantially water-free hydrocarbonaceous fluids are produced from the water-sensitive zone.

Aqueous and petroleum gel method for preventing water-influx

A profile control method for closing off a more permeable zone of a formation where water, high fluid flow, or high perssures are encountered. A water-external emulsion containing a monomer, a cross-linker, free radical initiators and reaction inhibitors is injected into the formation. There they react to form plastic-like solid spheres in the more permeable formation zone. Because the spheres are not water soluble and have high compressive strength, they can be used in severe flow applications. Ethylene, propylene and styrene monomers can be utilized to form solid spheres of polyethylene, polypropylene or polystyrene.

In-situ emulsion polymerization of ethylene derivatives

A method for selectively closing pores in a zone of greater permeability in a formation for profile control. A rehealable Xanthan biopolymer is combined with a crosslinked non-selective polyacrylamide polymer gel. The combined gel system is injected into a formation where the Xanthan biopolymer gel selectively enters a zone of greater permeability carrying therewith said non-selective gel. Once in the formation's zone of greater permeability, the gel reheals and forms a rigid gel with substantially better temperature stability.

Method for imparting selectivity to otherwise nonselective polymer

A method for minimizing damage to downhole equipment utilized in controlled pulse fracturing (CPF) where a drag reducing fluid tamp is used. Said tamp has a viscosity sufficient to reduce the flowing pressure drop thereby diminishing frictional forces along fluid/solid interfaces. The CPF device is submersed in said tamp. Upon ignition of a CPF device, the upwardly traveling pressure forces the tamp of drag-reducing characteristics to pass the downhole equipment thereby minimizing tool and equipment damage. Afterwards, the pressure is allowed to leak off slowly into the formation.

Method to reduce movement of a CPF device via a drag-reducing fluid tamp

A method for minimizing damage to downhole equipment utilized during controlled pulse fracturing ('CPF') where an oil based thickened fluid is used as a tamp. A gelled oil based fluid overlies a CPF propellant device thereby creating a tamp. When the propellant contained in the device is ignited, this high viscosity gelled fluid prevents the remnant of said device and wireline from moving upwardly which minimizes damage thereto.

Method to reduce movement of a CPF device via a gelled petroleum based

A method for minimizing damage to downhole equipment utilized during controlled pulse fracturing ('CPF') where a shear thickening fluid is used as a tamp. A shear thickening aqueous fluid having particles therein overlies a CPF device thereby creating a tamp. Movement of the fluid by pressure forces resultant from the ignited propellant causes the fluid to thicken. This thickened fluid prevents and device and wireline from moving upwardly which minimizes damage thereto.

Method to reduce movement of a CPF device via a shear-thickening fluid

A method for reducing the gelation time of a biopolysaccharide which utilizes a hydroxide of an alkaline earth metal in an aqueous solution containing said biopolysaccharide wherein the mixture is afterwards complexed with a polyvalent metal ion. The resultant stable gel can be injected into a hydrocarbonaceous fluid formation for the recovery of hydrocarbonaceous fluids.

Sodium hydroxide treatment of field water in a biopolymer complex

A method for selectively closing pores in a formation's zone of greater permeability. A rehealable Xanthan or Alcaligenes biopolymer in an aqueous medium is combined with an organic or transition metal cross-linker which forms a first stage selective ex-situ gel. Second stage non-selective gel precursors are also included. The second stage gel comprises a polymer cross-linked with organic cross-linkers so as to form an in-situ gel more able to withstand formation conditions. The combination is injected into a formation after the first stage gel forms where it selectively enters a zone of greater permeability carrying therewith said non-selective gel. Once in the formation's zone of greater permeability, the gel reheals and forms a rigid gel having the desirable characteristics of the non-selective gel.

A method for selectively closing pores in a zone of greater permeability in a formation for profile control. A rehealable Xanthan biopolymer is combined with a crosslinked non-selective polyacrylamide polymer gel. The combined gel system is injected into a formation where the Xanthan biopolymer gel selectively enters a zone of greater permeability carrying therewith said non-slective gel. Once in the formation's zone of greater permeability, the gel reheals and forms a rigid gel with substantially better temperature stability.

A process for minimizing gravity override via carbon dioxide combined with a sized gel. A polysaccharide gel of a size sufficiently greater than the pores contained in a more permeable formation area is prepared ex situ in the presence of sodium hydroxide. Said gel is then pumped into said formation causing pores in the more permeable formation area to be blocked off. Thereafter, carbon dioxide flooding is commenced and said flood is directed into the less permeable formation area causing hydrocarbonaceous fluids to be produced therefrom.

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Carrollton, TX, United States of America

Craig H Phelps