In the 1970’s, wells were stimulated with 65,000 lbs of sand in 105,000 gallons of gelled water. Initial production benefits were frequently not sustained. Between 1979 and 1983, 100 wells were treated with 200,000 to 300,000 lbs of sand with concentrations as high as 14 ppg, which resulted in sustained production increases achieving a 100-day payout and $15 million incremental value.
This paper documents a very successful fracture stimulation program in a mature West Texas waterflood. Amoco's Anton Irish Clearfork Unit (AICF) has undergone a 100 well fracture stimulation program since 1979 which has resulted in significant increases in oil production.
Hydraulic fracturing has gradually evolved over the years at the Anton Irish field due to experience gained in new stimulation techniques. Fracture stimulations in the 1970s involved pumping 105,000 gallons of gelled water with 65,000 pounds of 20-40 mesh sand at rates as high as 200 barrels per minute. Although nearly all were initially successful, production increases were sometimes not sustained, due possibly to the insufficient amount of sand/proppant utilized in hydraulic fracturing large 400' dolomite pay sections. Fracture stimulations since 1979 have involved pumping 200,000-300,000 pounds of 20-40 mesh sand in 90,000-150,000 gallons of cross-linked gelled water at 50 barrels per minute (concentrations as high as 14 pounds of sand per gallon of fluid) to create propped fractures which have resulted in sustained production increases from the affected wells. One hundred eighty days after the workover, average per-well production increases of 38 BOPD yielded payouts of 3-1/2 months. This paper will specifically address fracture stimulation results, quality control measures, and mechanical considerations in beam or electrical submersible pumping equipment, as well as post-appraise the economics associated with the $8 million program.
Author(s): J.R. Ilseng, Amoco Production Co.; M.J. Cortez, Amoco Production Co. (USA)
Paper Number: SPE 11930