Mobil Oil Corporation

E Thomas Strom

Paul Shu

Charles S Yeh

Lloyd G Jones

Craig H Phelps

William P Donlon

J Michael Sanchez

Larry L Cox

Alfred R Jennings, Jr

Thomas O Mitchell

Dennis H Hoskin

Wilton F Espenscheid

Randy D Hazlett

Bassem R Alameddine

Mark L Hoefner

Formation stability surrounding a deviated wellbore penetrating a hydrocarbon reservoir is improved by alternately injecting higher and lower density consolidating materials, the higher density material improving stability in the formation primarily on the low side of the wellbore and the lower density material improving stability in the formation primarily on the high side of the wellbore.

Method for improving formation stability surrounding a deviated wellbore

A method for consolidating a subterranean formation to control the production of particulates therefrom. A specific consolidating solution comprised of an allyl monomer and an initiator is injected into the formation where it is allowed to set at an elevated temperature to harden and form a permeable, consolidated mass. The allyl monomer is an allyl ester selected from the group of diallyl orthophthalate, diallyl isophthalate, diallyl terephthalate, diallyl benzenephosphonate, diethylene glycol bis (allyl carbonate) and other known allyl monomers and the initiator is preferably a peroxy compound (e.g. benzoyl peroxide, diisopropyl peroxydicarbonate, etc.) or an azo compound (e.g. 4,4'-azobis(4-cyanovaleric acid). A diluent such as an alcohol (e.g. isopropyl alcohol or isobutyl alcohol) or a mutual solvent (e.g. ethylene glycol monobutyl ether, diacetin, triacetin, acetone, etc.) and a coupling agent (e.g. an organofunctional silane) may be added if needed.

Method for consolidating a subterranean formation

A method for plugging a zone of a subterranean formation to block flow therethrough. A specific plugging solution comprised of an allyl monomer and an initiator is injected into the zone where it is allowed to set at an elevated temperature to harden and form a flow-blocking solid. The allyl monomer is an allyl ester selected from the group of diallyl orthophthalate, diallyl isophthalate, diallyl terephthalate, diallyl benzenephosphonate, diethylene glycol bis(allyl carbonate) and other known allyl monomers and the initiator is preferably a peroxy compound (e.g. benzoyl peroxide, diisopropyl peroxydicarbonate, etc.) or an azo compound (e.g. 4,4'-azobis(4-cyanovaleric acid). A diluent such as an alcohol (e.g. isopropyl alcohol or isobutyl alcohol) or a mutual solvent (e.g. ethylene glycol monobutyl ether, diacetin, triacetin, acetone, etc.) and a coupling agent (e.g. an organofunctional silane) may be added if needed.

Method for treating formations to plug flow

A cement for forming a gravel pack in a washed-out interval is provided where a borehole penetrates an unconsolidated or loosely consolidated oil or gas reservoir which is likely to introduce substantial amounts of sand into the borehole. After perforating the borehole's casing at a washed-out interval of the formation, sand is introduced into the interval. Afterwards, an aqueous silicate solution is injected into said interval. Next, a spacer volume of a water-immiscible hydrocarbonaceous liquid is introduced into the interval. Thereafter, a water-miscible organic solvent containing an alkylpolysilicate is injected into the interval. A permeability retaining silica cement is formed in the interval thereby making a gravel pack. Injection of the aqueous silicate and organic solvent containing an alkylpolysilicate is continued until the interval has been consolidated by the silica cement to an extent sufficient to exclude sand and formation fines.

Sand control agent and process

A method for gravel packing perforations in a wellbore where an acid is directed into the perforations so as to dissolve formation fines in channels contained in said perforations. The acid is of a strength sufficient to dissolve said fines. After the fines are dissolved, a sand consolidation agent is introduced into the perforations before the channels can be filled with formation fines. The consolidation agent remains in the perforations for a time sufficient to form a cement in situ which cement has permeability retentive characteristics. The cement forms pores of a size sufficient to exclude formation fines from the wellbore. Thereafter, a substantially fines free hydrocarbonaceous fluid is produced from the wellbore.

Acidizing method for gravel packing wells

A method for forming a gravel pack in a washed-out interval is provided where a borehole penetrates an unconsolidated or loosely consolidated oil or gas reservoir which is likely to introduce substantial amounts of sand into the borehole. After perforating the boreholes's casing at a washed-out interval of the formation, sand is introduced into the interval. Afterwards, an aqueous silicate slug is injected into said interval. Next, a spacer volume of a water-immiscible hydrocarbonaceous liquid is introduced into the interval. Thereafter, a water-miscible organic solvent slug, containing an alkylpolysilicate and an inorganic or organic salt or a chelated calcium mixture, is injected into the interval. A permeability retaining silicate cement is formed in the interval thereby making a gravel pack. Injection of the aqueous silicate slug spacer volume and organic solvent EPS mixture are continued until the porosity of the interval has been reduced by the silicate cement to an extent sufficient to exclude formation fines and sand.

A method for gravel packing perforations in a wellbore where an acid is directed into the perforations so as to dissolve formation fines in channels contained in said perforations. The acid is of a strength sufficient to dissolve said fines. After the fines are dissolved, a three slug sand consolidating agent is introduced into the perforations before the channels can be filled with formation fines. The consolidating agent remains in the perforations for a time sufficient to form a silicate cement in situ which cement has permeability retentive characteristics. The cement forms pores of a size sufficient to exclude formation fines from the wellbore. Thereafter, the wellbore is packed with gravel to remove any escaping fines from hydrocarbonaceous fluids produced to the surface.

A method for forming a gravel pack in a washed-out interval is provided where a borehole penetrates an unconsolidated or loosely consolidated oil or gas reservoir which is likely to introduce substantial amounts of sand into the borehole. After perforating the borehole's casing at a washed-out interval of the formation, sand is introduced into the interval. Afterwards, an aqueous silicate solution is injected into said interval. Next, a spacer volume of a water-immiscible hydrocarbonaceous liquid is introduced into the interval. Thereafter, a water-miscible organic solvent containing an alkylpolysilicate is injected into the interval. A permeability retaining silica cement is formed in the interval thereby making a gravel pack. Injection of the aqueous silicate and organic solvent containing an alkylpolysilicate is continued until the interval has been consolidated by the silica cement to an extent sufficient to exclude sand and formation fines.

A method for producing substantially sand or fines free hydrocarbonaceous fluids from a wellbore which is initially gravel packed. Thereafter, an acid is directed into the wellbore so as to dissolve formation fines in channels contained in perforations communicating with a productive interval of the formation. The acid is of a strength sufficient to dissolve said fines. After the fines are dissolved, a sand consolidation agent is introduced into the perforations before the channels can be filled with formation fines. The consolidation agent remains in the perforations for a time sufficient to form a cement in situ which cement has permeability retentive characteristics. The cement forms pores of a size sufficient to exclude formation fines from the wellbore.

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 method for forming a gravel pack in a washed-out interval is provided where a borehole penetrates an unconsolidated or loosely consolidated oil or gas reservoir which is likely to introduce substantial amounts of sand into the borehole. After perforating the borehole's casing at a washed-out interval of the formation, sand is introduced into the interval. Afterwards, an aqueous solution of potassium silicate is injected into said interval. Thereafter, an alcoholic solution of hydrated calcium chloride is injected into the interval. A permeability retaining calcium silicate cement is formed in the interval thereby making a gravel pack. Injection of the potassium silicate and hydrated calcium chloride solutions is continued until the porosity of the interval has been reduced by the calcium silicate cement to an extent sufficient to exclude formation fines and sand.

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 recovering viscous oil from a formation having a bottom water zone below an oil containing zone. Steam is directed into the bottom water zone thereby heating this zone and an oil containing zone thereabove. Afterwards, steam injection is ceased and a gellable composition is directed into the bottom water zone where it forms a solid gel. Once the solid gel has formed, steam is injected into the bottom water zone where the solid gel causes it to flow upwardly into the oil containing zone. Oil, water, and steam are removed via a recompleted producer well.

Method of preheating a heavy oil zone through existing bottom water and

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 process for closing pores in a bottom water zone where steam is directed so as to by-pass a zone of the formation containing hydrocarbonaceous fluids. Once a portion of the bottom water zone has reached a temperature in excess of about 300.degree. F., steam entry is ceased. Afterwards, a temperature activated gellable composition is placed into the bottom water zone. When the composition reaches that portion of the bottom water zone where a temperature in excess of about 300.degree. F. has been reached, the composition activates and forms a rigid gel. Thereafter, a steam flooding method is commenced. Steam is diverted from the bottom water zone and into an upper zone containing hydrocarbonaceous fluids.

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Dallas, TX, United States of America

E Thomas Strom