Paper: Hydraulic Fracture Treatment Evaluation Shafter Lake San Andres Unit

The Shafter Lake San Andres Unit was formed on July 1, 1967, and water injection was initiated in August, 1968. Prior to the start of water injection, an extensive stimulation program was undertaken to increase current production from the unit wells and to prepare them for flood response. Since the initiation of the stimulation program in September, 1967, a total of 40 hydraulic fracturing treatments have been performed on 38 wells using lease oil, refined oil, and salt water as fracturing fluids. Of the 40 fracturing treatments that were conducted, lease oil was used on five treatments, refined oil was used on 13 treatments, and salt water was used on 22 treatments. The investigation described in this paper was undertaken to determine the relative effectiveness of oil-base and water-base fracturing fluids used in the 40 fracturing treatments and to evaluate the overall results of the entire fracturing program. To accomplish the above objectives, it was necessary to evaluate the design criteria and treatment procedures employed in the fracturing treatments and to describe the prefractured quality of the wells that were fractured. A detailed investigation of each fracturing treatment and two computer programs, one for designing hydraulic fracture treatments and one for determining well reconditioning economics, were used in attaining the objectives.