Methods for fracturing well formations

Claim 1

A method of fracturing a subterranean formation penetrated by a well bore which comprises introducing a crosslinked aqueous fracturing gel into said formation through said well bore at a rate sufficient to fracture said formation wherein said fracturing gel consists essentially of the reaction product of a hydratable polysaccharide, which has been hydrated with an aqueous liquid, and a crosslinking agent; wherein said hydratable polysaccharide is present in the range of about 0.3% to about 3% by weight of said aqueous liquid, said crosslinking agent is present in the range of about 0.001% to about 0.5% by weight of said aqueous liquid and said reaction product is produced at a pH in the range of about 1.5 to about 5.5; further wherein said hydratable polysaccharide has a molecular weight of at least about 100,000 and is selected from the group consisting of galactomannan gums, glucomannan gums and cellulose derivatives having hydrophillic constituents; and still further wherein said crosslinking agent is selected from compounds which will provide antimony (V) ions.

Claim 2

A method of fracturing a subterranean formation penetrated by a well bore which comprises introducing a crosslinked aqueous fracturing gel into said formation through said well bore at a rate sufficient to fracture said formation wherein said fracturing gel consists essentially of the reaction product of a hydratable polysaccharide, which has been hydrated with an aqueous liquid, and a crosslinking agent; wherein said hydratable polysaccharide is present in the range of about 0.3% to about 3% by weight of said aqueous liquid, said crosslinking agent is present in the range of about 0.001% to about 0.5% by weight of said aqueous liquid and said reaction product is produced at a pH in the range of about 1.5 to about 5.5; further wherein said hydratable polysaccharide has a molecular weight of at least about 100,000 and is selected from the group consisting of galactomannan gums, glucomannan gums and cellulose derivatives having hydrophillic constituents; and still further wherein said crosslinking agent is selected from compounds which will provide antimony (V) ions.

Claim 9

A method of fracturing a subterranean formation penetrated by a well bore which comprises introducing a crosslinked aqueous fracturing gel into said formation through said well bore at a rate sufficient to fracture said formation wherein said fracturing gel consists essentially of the reaction product of a hydratable polysaccharide, which has been hydrated with an aqueous liquid, and a crosslinking agent selected from potassium permanganate and sodium permanganate; wherein said hydratable polysaccharide is present in the range of about 0.3% to about 3% by weight of said aqueous liquid, said crosslinking agent is present in the range of about 0.001% to about 0.5% by weight of said aqueous liquid and said reaction product is produced at a pH in the range of greater than about 5 to about 7; further wherein said hydratable polysaccharide has a molecular weight of at least about 100,000 and is selected from the group consisting of galactomannan gums and glucomannan gums.

Claim 10

A method of fracturing a subterranean formation penetrated by a well bore which comprises introducing a crosslinked aqueous fracturing gel into said formation through said well bore at a rate sufficient to fracture said formation wherein said fracturing gel consists essentially of the reaction product of a hydratable polysaccharide, which has been hydrated with an aqueous liquid, and a crosslinking agent selected from potassium permanganate and sodium permanganate; wherein said hydratable polysaccharide is present in the range of about 0.3% to about 3% by weight of said aqueous liquid, said crosslinking agent is present in the range of about 0.001% to about 0.5% by weight of said aqueous liquid and said reaction product is produced at a pH in the range of greater than about 5 to about 7; further wherein said hydratable polysaccharide has a molecular weight of at least about 100,000 and is selected from the group consisting of galactomannan gums and glucomannan gums.

Claim 16

A method of fracturing a subterranean formation penetrated by a well bore which comprises introducing a crosslinked aqueous fracturing gel into said formation through said well bore at a rate sufficient to fracture said formation wherein said fracturing gel consists essentially of the reaction product of guar gum which has been hydrated with an aqueous liquid, and a crosslinking agent; wherein said guar gum is present in the range of about 0.3% to about 1% by weight of said aqueous liquid, said crosslinking agent is present in the range of about 0.01% to about 0.25% by weight of said aqueous liquid and said reaction product is produced at a pH in the range of greater than about 5 to about 7; further wherein said guar gum has a molecular weight in the range of about 100,000 to about 300,000; and still further wherein said crosslinking agent is selected from the group consisting of sodium permanganate and potassium permanganate.

Claim 17

A method of fracturing a subterranean formation penetrated by a well bore which comprises introducing a crosslinked aqueous fracturing gel into said formation through said well bore at a rate sufficient to fracture said formation wherein said fracturing gel consists essentially of the reaction product of guar gum which has been hydrated with an aqueous liquid, and a crosslinking agent; wherein said guar gum is present in the range of about 0.3% to about 1% by weight of said aqueous liquid, said crosslinking agent is present in the range of about 0.01% to about 0.25% by weight of said aqueous liquid and said reaction product is produced at a pH in the range of greater than about 5 to about 7; further wherein said guar gum has a molecular weight in the range of about 100,000 to about 300,000; and still further wherein said crosslinking agent is selected from the group consisting of sodium permanganate and potassium permanganate.

Claim 18

A method of fracturing a subterranean formation penetrated by a well bore which comprises introducing a crosslinked aqueous fracturing gel into said formation through said well bore at a rate sufficient to fracture said formation wherein said fracturing gel consists essentially of the reaction product of guar gum, which has been hydrated with an aqueous liquid, and a crosslinking agent; wherein said guar gum is present in the range of about 0.3% to about 3% by weight of said aqueous liquid, said crosslinking agent is present in the range of about 0.001% to about 0.5% by weight of said aqueous liquid and said reaction product is produced at a pH in the range of about 2.5 to about 7; further wherein said guar gum has a molecular weight of at least about 100,000; and still further wherein said crosslinking agent is selected from combinations of oxidizing agents and reducing agents; said oxidizing agents being selected from the group consisting of sodium chromate, potassium chromate sodium dichromate and potassium dichromate; and said reducing agents being selected from the group consisting of sodium sulfite, potassium sulfite, ammonium sulfite, ammonium bisulfite, alkali metal dithionates, ammonium dithionate, and ammonium thiosulfate.

Claim 19

A method of fracturing a subterranean formation penetrated by a well bore which comprises introducing a crosslinked aqueous fracturing gel into said formation through said well bore at a rate sufficient to fracture said formation wherein said fracturing gel consists essentially of the reaction product of guar gum, which has been hydrated with an aqueous liquid, and a crosslinking agent; wherein said guar gum is present in the range of about 0.3% to about 3% by weight of said aqueous liquid, said crosslinking agent is present in the range of about 0.001% to about 0.5% by weight of said aqueous liquid and said reaction product is produced at a pH in the range of about 2.5 to about 7; further wherein said guar gum has a molecular weight of at least about 100,000; and still further wherein said crosslinking agent is selected from combinations of oxidizing agents and reducing agents; said oxidizing agents being selected from the group consisting of sodium chromate, potassium chromate sodium dichromate and potassium dichromate; and said reducing agents being selected from the group consisting of sodium sulfite, potassium sulfite, ammonium sulfite, ammonium bisulfite, alkali metal dithionates, ammonium dithionate, and ammonium thiosulfate.

Claim 28

A method of fracturing a subterranean formation penetrated by a well bore which comprises introducing a crosslinked aqueous fracturing gel into said formation through said well bore at a rate sufficient to fracture said formation wherein said fracturing gel consists essentially of the reaction product of guar gum, which has been hydrated with an aqueous liquid, and a crosslinking agent; wherein said guar gum is present in the range of from about 0.3% to about 1% by weight of said aqueous liquid, said crosslinking agent is present in the range of about 0.01% to about 0.25% by weight of said aqueous liquid and said reaction product is produced at a pH in the range of about 2.5 to about 7; further wherein said guar gum has a molecular weight in the range of about 100,000 to about 300,000, and still further wherein said crosslinking agent is selected from combinations of oxidizing agents and reducing agents; said oxidizing agents being selected from sodium chromate and potassium chromate and said reducing agents being selected from the group consisting of sodium sulfite, potassium sulfite, ammonium sulfite, ammonium bisulfite, alkali metal dithionates, ammonium dithionate, and ammonium thiosulfate.

Claim 29

A method of fracturing a subterranean formation penetrated by a well bore which comprises introducing a crosslinked aqueous fracturing gel into said formation through said well bore at a rate sufficient to fracture said formation wherein said fracturing gel consists essentially of the reaction product of guar gum, which has been hydrated with an aqueous liquid, and a crosslinking agent; wherein said guar gum is present in the range of from about 0.3% to about 1% by weight of said aqueous liquid, said crosslinking agent is present in the range of about 0.01% to about 0.25% by weight of said aqueous liquid and said reaction product is produced at a pH in the range of about 2.5 to about 7; further wherein said guar gum has a molecular weight in the range of about 100,000 to about 300,000, and still further wherein said crosslinking agent is selected from combinations of oxidizing agents and reducing agents; said oxidizing agents being selected from sodium chromate and potassium chromate and said reducing agents being selected from the group consisting of sodium sulfite, potassium sulfite, ammonium sulfite, ammonium bisulfite, alkali metal dithionates, ammonium dithionate, and ammonium thiosulfate.

Claim 30

A method of fracturing a subterranean formation penetrated by a well bore which comprises introducing a crosslinked aqueous fracturing gel into said formation through said well bore at a rate sufficient to fracture said formation wherein said fracturing gel consists essentially of the reaction product of guar gum, which has been hydrated with an aqueous liquid, and a crosslinking agent; wherein said guar gum is present in the range of about 0.3% to about 1% by weight of said aqueous liquid, said crosslinking agent is present in the range of about 0.01% to about 0.25% by weight of said aqueous liquid and said reaction product is produced at a pH in the range of about 2.5 to about 7; further wherein said guar gum has a molecular weight in the range of about 100,000 to about 300,000 and still further wherein said crosslinking agent is a combination of an oxidizing agent and a reducing agent; said oxidizing agent being potassium dichromate, and said reducing agent being sodium sulfite.

Claim 31

A method of fracturing a subterranean formation penetrated by a well bore which comprises introducing a crosslinked aqueous fracturing gel into said formation through said well bore at a rate sufficient to fracture said formation wherein said fracturing gel consists essentially of the reaction product of guar gum, which has been hydrated with an aqueous liquid, and a crosslinking agent; wherein said guar gum is present in the range of about 0.3% to about 1% by weight of said aqueous liquid, said crosslinking agent is present in the range of about 0.01% to about 0.25% by weight of said aqueous liquid and said reaction product is produced at a pH in the range of about 2.5 to about 7; further wherein said guar gum has a molecular weight in the range of about 100,000 to about 300,000 and still further wherein said crosslinking agent is a combination of an oxidizing agent and a reducing agent; said oxidizing agent being potassium dichromate, and said reducing agent being sodium sulfite.

Claim 32

A method of fracturing a subterranean formation penetrated by a well bore which comprises introducing a crosslinked aqueous fracturing gel into said formation through said well bore at a rate sufficient to fracture said formation wherein said fracturing gel consists essentially of the reaction product of guar gum, which has been hydrated with an aqueous liquid and a crosslinking agent; wherein said guar gum is present in the range of about 0.3% to about 3% by weight of said aqueous liquid, said crosslinking agent is present in the range of about 0.001% to about 0.5% by weight of said aqueous liquid and said reaction product is produced at a pH in the range of about 2.5 to about 7; further wherein said guar gum has a molecular weight of at least about 100,000; and still further wherein said crosslinking agent is selected from combinations of oxidizing agents and reducing agents; said oxidizing agents being selected from the group consisting of sodium chromate, potassium chromate, sodium dichromate and potassium dichromate; and said reducing agents being selected from the group consisting of arsenous oxide, arsenous chloride, arsenous oxychloride, potassium antimony tartrate, fused potassium antimony tartrate, antimony oxalate, antimony tartrate, antimony ammonium fluoride, tin chloride and tin sulfate.

Claim 33

A method of fracturing a subterranean formation penetrated by a well bore which comprises introducing a crosslinked aqueous fracturing gel into said formation through said well bore at a rate sufficient to fracture said formation wherein said fracturing gel consists essentially of the reaction product of guar gum, which has been hydrated with an aqueous liquid and a crosslinking agent; wherein said guar gum is present in the range of about 0.3% to about 3% by weight of said aqueous liquid, said crosslinking agent is present in the range of about 0.001% to about 0.5% by weight of said aqueous liquid and said reaction product is produced at a pH in the range of about 2.5 to about 7; further wherein said guar gum has a molecular weight of at least about 100,000; and still further wherein said crosslinking agent is selected from combinations of oxidizing agents and reducing agents; said oxidizing agents being selected from the group consisting of sodium chromate, potassium chromate, sodium dichromate and potassium dichromate; and said reducing agents being selected from the group consisting of arsenous oxide, arsenous chloride, arsenous oxychloride, potassium antimony tartrate, fused potassium antimony tartrate, antimony oxalate, antimony tartrate, antimony ammonium fluoride, tin chloride and tin sulfate.