Successful Strawn Sand Water Flood

Abstract

Abstract The field performance of waterflood operations in the Cherrykirk field, located in North Texas, is proving highly responsive to water flooding. High injection rates, in the order of 0.95 to 1.00 B/D/acre-ft, are being utilized to make the project successful and economically feasible. Prior to any attempts at water flooding, a detailed reservoir study aided materially towards successful operations. Pilot injection was initiated Oct. 18, 1955, using a 20-acre double five-spot. The pilot flood indicated efficient water flooding could be conducted so the injection pattern was expanded on a five-spot plan to encompass full field operations. Oil recovery by primary methods to Sept. 1, 1955, was 804,545 bbl. Reservoir pressure was depleted rapidly within 21/2 years from an initial pressure of 558 psig. A total of 2,901,575 bbl of water had been injected to Dec. 1, 1957, resulting in the recovery of 612,147 bbl of oil or 4.7 bbl of water injected per barrel of oil produced. The revenue to Oct. 1, 1957, from the T. H. Cherryhomes and the Newmont Oil Co. leases amounted to $953,336 from an investment of $164,722 development and equipment costs and $206,277 operating costs. This is $582,387 profit to the full working interest. Since the pilot development cost was $43,131 this is a risk to gain ratio of 13.5 to 1 or an expenditure to return ratio of 1 to 3.88. A high rate of income is still being realized. Introduction The Cherrykirk (Strawn) field is located approximately 10 miles east of Jacksboro in Jack County, Tex. (Fig. 1).The discovery well, T.H. Cherryhomes No.1, drilled in Dec., 1951, potentialed 90 BOPD pumping. All wells in the field were drilled by mid-year 1952. The highest initial potential, 112 BOPD pumping, was obtained from the Cherryhomes No. 12. Forty-eight other wells were completed in the field by 1952 (see Fig. 2). Some wells required frac jobs for completion as producers. Rotary drilling tools were used to drill the wells to the top of the pay. Casing was then run, cemented, and the wells "tailed in" with the cable tools. The program on the wells consisted of 90 to 100 ft of 10.75-in. OD surface casing and either 5.5- or 7-in. OD casing as a production string cemented with 100 to 125 sacks of cement.