Basf Corporation

Dowell Schlumberger Incorporated

The Dow Chemical Company

Clare H Kucera

Stefano C Crema

Gerd Konrad

Heinrich Hartmann

Richard M Hodge

Michael D Roznowski

Sandra E Baranet

Heinrich Hartman

Donald N DeMott

Richard B Connell

A cementing composition useful in cementing oil, gas and water wells, comprising water, hydraulic cement and an effective amount of water soluble fluid loss additive comprised of a blend of a copolymer (i) of acrylamide/vinyl imidazole in a weight percent ratio of from about 95:5 to 5:95, said copolymer (i) having a molecular weight range of from about 100,000 to 3,000,000, and a copolymer (ii) of vinyl pyrrolidone and the sodium salt of vinyl sulfonate in a weight percent ratio of 80:20 to 20:80, said copolymer (ii) having a molecular weight range of from about 100,000 to 3,000,000. The blend is comprised of a weight percent ratio of copolymer (i) to copolymer (ii) in the range of 20:80 to 80:20. The composition can also optionally include a dispersant such as sodium or potassium salts or a sulfonated naphthalene formaldehyde condensate.

Fluid loss control additives for oil well cementing compositions

A cementing composition useful in cementing oil, gas and water wells, comprising water, hydraulic cement and an effective amount of water soluble fluid loss additive comprised of a copolymer of acrylamide/vinyl formamide and derivatives thereof in a weight percent ratio of from about 95:5 to 5:95, said copolymer having a molecular weight range of from about 100,000 to 3,000,000. The composition can also optionally include a dispersant such as sodium or potassium salts or a sulfonated naphthalene formaldehyde condensate.

A cementing composition useful in cementing oil, gas and water wells, comprising water, hydraulic cement and an effective amount of water soluble fluid loss additive comprised of a blend of a copolymer of acrylamide/vinyl imidazole in a weight percent ratio of from about 95:5 to 5:95, said copolymer having a molecular weight range of from about 100,000 to 3,000,000, and a terpolymer of acrylamide/acrylamidomethylpropane sulfonic acid sodium salt/vinyl imidazole in a weight percent ratio of 60:20:20, said terpolymer having a molecular weight range of from about 100,000 to 3,000.000. The blend is comprised of a weight percent ratio of copolymer to terpolymer in the range of 20:80 to 80:20. The composition can also optionally include a dispersant such as sodium or potassium salts or a sulfonated naphthalene formaldehyde condensate.

A cementing composition useful in cementing oil, gas and water wells, comprising water, hydraulic cement and an effective amount of water soluble fluid loss additive comprised of a blend of a copolymer of acrylamide/vinyl imidazole in a weight percent ratio of from about 95:5 to 5:95, said copolymer having a molecular weight range of from about 100,000 to 3,000,000, and a terpolymer of acrylamide/acrylamidomethylpropane sulfonic acid sodium salt/vinyl imidazole in a weight percent ratio of 60:20:20, said terpolymer having a molecular weight range of from about 100,000 to 3,000,000. The blend is comprised of a weight percent ratio of copolymer to terpolymer in the range of 20:80 to 80:20. The composition can also optionally include a dispersant such as sodium or potassium salts or a sulfonated naphthalene formaldehyde condensate.

A cementing composition useful in cementing oil, gas and water wells, comprising water, hydraulic cement and an effective amount of water soluble fluid loss additive comprised of a copolymer of acrylamide/vinyl imidazole and derivatives thereof in a weight percent ratio of from about 95:5 to 5:95, said copolymer having a molecular weight range of from about 100,000 to 3,000,000. The composition can also optionally include a dispersant such as sodium or potassium salts or a sulfonated naphthalene formaldehyde condensate.

Various organometallic crosslinkers containing titanium or zirconium atoms in the +4 oxidation (valence) state have been used to crosslink solvatable polysaccharides (e.g., hydroxypropyl guar) in aqueous media. The crosslinked gels are useful as fracturing fluids. Aqueous solutions of the organometallic crosslinkers are stabilized against deterioration upon storage by adding an alkanolamine (e.g., triethanolamine). Additionally, the alkanolamines also stabilize the crosslinked gels against shear degradation at elevated temperatures.

Stabilized fracture fluid and crosslinker therefor

Novel aqueous crosslinked gels are described herein which are useful for fracturing subterranean formations. The novel gels are comprised of a solvatable polysaccharide and a soluble zirconium crosslinking agent. The zirconium crosslinking agents are novel and are prepared by reacting a zirconium alkoxide with certain alkanolamines under anhydrous conditions. The zirconium compounds are activated by contact with water. As an example, a zirconium crosslinker was prepared by reacting zirconium tetra(n-propoxide) with triethanolamine in an n-propanol solvent under anhydrous conditions. The zirconium compound thus prepared was activated with water and used to form a stable aqueous crosslinked gel by blending the aqueous crosslinker into an aqueous hydroxypropylguar solution.

Fracturing of subterranean formations

Aqueous compositions having properties making them suitable for use as a hydraulic fracturing fluids are disclosed. These compositions comprise (a) an uncrosslinked aqueous polysaccharide solution, and (b) a 4,4'-thiodiphenol. Ingredient (b) acts as a 'breaker' and causes the composition to lose viscosity at a controlled rate.

Breaker system for hydraulic fracturing fluids

A drilling fluid having extremely desirable physical properties which comprises an aqueous solution of a hydroxyalkyl polysaccharide derivative and a water soluble ionic aluminum crosslinking agent, preferably sodium aluminate.

Growing community of inventors

Tulsa, OK, United States of America

Clare H Kucera