Mobil Oil Corporation

William P Donlon

E Thomas Strom

Lloyd G Jones

Paul Shu

Charles S Yeh

Malcolm K Strubhar

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.

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 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 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 for producing multiple fractures by a single operation from a single wellbore which penetrates a fracture interval which, in turn, includes a plurality of zones which break-down under different fracturing pressures. Fracturing fluid is delivered from a workstring directly to different levels within a section of the wellbore which lies adjacent the fracture interval through a plurality of alternate paths which, in turn, lie substantially adjacent to the zones to be fractured.

Multiple fractures from a single workstring

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.

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Dallas, TX, United States of America

William P Donlon