United States Patent (19) 11 Patent Number: 5,253,711 Mondshine (45) Date of Patent: Oct
USOO525371 1A United States Patent (19) 11 Patent Number: 5,253,711 Mondshine (45) Date of Patent: Oct. 19, 1993 54) PROCESS FOR DECOMPOSING 2,268,215 12/1941 Kerr ...................................... 127/33 POLYSACCHARDES IN ALKALINE 3,167,510 /1965 Alter ..... sa as A8 a X8 a P. 252/8.551 3,655,644 4/1972 Durand ........................... 106/21 X AQUEOUS SYSTEMS 3,935,187 1/1976 Speakman ........................... 536/102 75 Inventor: Thomas C. Mondshine, Houston, 4,202,795 5/1980 Burnham et al. ............... 166/308 X Tex. 4,552,668 11/1985 Brown et al. ................... 166/300X Lachenal et al. ..................... 162/25 Assignee: Texas United Chemical Corp., 4,787,959 11/1988 (73) Primary Examiner-George A. Suchfield Houston, Tex. Attorney, Agent, or Firm-Roy F. House 21 Appl. No.: 844,167 57 ABSTRACT 22 Filed: Mar. 2, 1992 Alkaline earth metal or transition metal peroxides are (51) int. Cli.............................................. E21B 43/26 used as a delayed breaker in alkaline aqueous fluids 52) U.S. C. .................................... 166/300; 166/308; containing a water soluble hydrophilic polysaccharide 252/8.551; 252/326 polymer hydrated therein. The peroxide is activated by (58) Field of Search ............................... 166/300, 308; increasing the temperature of the fluid. The invention is 252/8.551, 326,358; 536/41, 80, 88 particularly useful for the delayed break of hydraulic 56) References Cited fracturing fluids containing hydroxypropyl guar poly c. U.S. PATENT DOCUMENTS i,953,398 4/1934 Eskew ................................... 536/41 10 Claims, No Drawings 5,253,711 1. 2 G. W. Hawkins, and H. D. Brannon, Feb.
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