# US 5,350,528 A · Method of supporting fractures in geological formations and hydraulic fluid composition for same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,350,528 A - Document ID: US5350528A - Status: Granted - Kind: A - Application number: 07/861,801 - Filed: 1992-06-12 - Granted: 1994-09-27 - Earliest claimed: 1989-12-13 - Assignees: Weyerhaeuser Company - Inventors: John A. Westland; Glenn S. Penny; R. Scott Stephens; Alan R. Winslow - Web page: https://patentgrep.com/patent/US5350528A ## CPC - C09K 8/90: of natural origin, e.g. polysaccharides, cellulose - C09K 8/62: Compositions for forming crevices or fractures - E21B 43/267: reinforcing fractures by propping - Y10S 435/823: Acetobacter - Y10S 507/922: Fracture fluid - C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE - E21B: EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS - Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS ## Abstract The addition of relatively small quantities of a bacterial cellulose to hydraulic fracturing fluids improves their rheological properties for hydraulic fracturing of geological formations. Proppant suspension is markedly improved and friction loss through well casings is significantly reduced, resulting in lower pumping energy requirements. Computer models also indicate that formation fractures will be propagated for greater distances as will the propped portion of the fracture. Normally only about 0.60-1.8 g of bacterial cellulose per liter of fracturing fluid is needed. A preferred bacterial cellulose is one made in agitated fermentors using mutation resistant strains of a bacterium from the genus Acetobacter. ## Claims ### Claim 1 A method of preparing a hydraulic fracturing fluid composition which comprises: providing an aqueous transport medium; increasing the viscosity of the medium by dispersing sufficient amounts of gellant and a bacterial cellulose in said medium; crosslinking the fracturing fluid by adding a sufficient amount of a crosslinking agent; and suspending proppant particles in said medium whereby said bacterial cellulose decreases the settling rate of the proppant particles prior to and during transport into a drill hole and fractured geologic formation. ### Claim 2 (depends on 1) The method of claim 1 in which the bacterial cellulose is produced by a cellulose generating strain of the genus Acetobacter grown in an agitated culture. ### Claim 3 (depends on 2) The method of claim 2 in which said Acetobacter strain is selected from one resistant to mutation to non-cellulose producing types under agitated culturing conditions. ### Claim 4 (depends on 1) The method of claim 1 in which the bacterial cellulose is present in an amount of 0.12-4.8 g/L of fracturing fluid. ### Claim 5 (depends on 4) The method of claim 4 in which the bacterial cellulose is present in an amount of about 0.60-1.8 g/L of fracturing fluid. ### Claim 6 (depends on 1) The method of claim 1 in which the gellant is selected from the group consisting of guar, hydroxypropyl guar, carboxymethylhydroxypropyl guar, xanthan, hydroxyethyl cellulose, carboxymethylhydroxyethyl cellulose, and hydroxypropylmethyl cellulose and mixtures thereof. ### Claim 7 (depends on 6) The method of claim 6 in which the gellant is present in an amount of 2.4-6.0 g/L of fracturing fluid. ### Claim 8 (depends on 1) The method of claim 1 in which the crosslinking agent is selected from a group consisting of borates, zirconates, titanates, aluminates, chromates and mixtures thereof. ### Claim 9 (depends on 1) The method of claim 1 in which the crosslinking agent is selected from a group consisting of disodium octaborate tetrahydrate and aqueous titanate chelates. ### Claim 10 A hydraulic fracturing fluid composition comprising: an aqueous transport medium; a gellant and a bacterial cellulose dispersed in said medium to raise the viscosity thereof; a crosslinking agent dispersed in said medium to crosslink the fracturing fluid; and proppant particles suspended in said medium whereby said bacterial cellulose decreases the settling rate of the proppant particles prior to and during transport into a drill hole and fractured geologic formation. ### Claim 11 (depends on 10) The composition of claim 10 in which the proppant is present in an amount of about 120-960 g/L. ### Claim 12 (depends on 10) The composition of claim 10 in which the bacterial cellulose is produced by a cellulose generating strain of the genus Acetobacter grown in an agitated culture. ### Claim 13 (depends on 12) The composition of claim 12 in which said Acetobacter strain is selected from one resistant to mutation to non-cellulose producing types under agitated culturing conditions. ### Claim 14 (depends on 11) The composition of claim 11 in which the bacterial cellulose is present in an amount of about 0.12-4.8 g/L of fracturing fluid. ### Claim 15 (depends on 14) The composition of claim 14 in which the bacterial cellulose is present in an amount of about 0.60-1.8 g/L of fracturing fluid. ### Claim 16 (depends on 11) The composition of claim 11 in which the gellant is selected from the group consisting of guar, hydroxypropyl guar, carboxymethylhydroxypropyl guar, xanthan, hydroxyethyl cellulose, carboxymethylhydroxyethyl cellulose, and hydroxypropylmethyl cellulose and mixtures thereof. ### Claim 17 (depends on 16) The composition of claim 16 in which the gellant is present in an amount of 2.4-6.0 g/L of fracturing fluid. ### Claim 18 (depends on 10) The composition of claim 10 in which the crosslinking agent is selected from a group consisting of borates, zirconates, titanates, aluminates, chromates and mixtures thereof. ### Claim 19 (depends on 10) The composition of claim 10 in which the crosslinking agent is selected from the group consisting of disodium octaborate tetrahydrate and aqueous titanate chelates. ### Claim 20 (depends on 11) A method of fracturing a geological formation using the fracturing fluid composition of claim 11, comprising: drilling a drill hole which passes into said formation; and delivering the hydraulic fracturing fluid into the drill hole and to the formation at a sufficient volumetric rate and pressure to cause fracturing and initiate and maintain cracks in said formation.