Case History of Hydraulic Fracture Optimization in Tight Gas Wells with Water Production in the Wind River Basin, Wyoming

摘要

The Cooper Reservoir is located in the north-eastern end ofrnthe Wind River Basin. Wells are completed in the lower FortrnUnion and Lance formations at true vertical depths from 3300rnto 8200 ft. Fracture treatments are complicated by waterrnproducing sands interspersed among up to a dozen or more gasrnproducing sands as well as mobile water within the gasrnproducing zones. An extensive data set of core analysis, rockrnmechanics testing, pre- and post-fracture well logs, pressurernbuild up analysis, detailed fracture modeling, and detailedrnproduction analysis was compiled on 56 completions in orderrnto better understand and evaluate well performance andrnstimulation effectiveness in this field. The evaluation is basedrnprimarily on the use of the reciprocal productivity index (RPI)rngraphical production analysis method. RPI uses dailyrnproduction and wellhead pressure data to determine therneffectiveness of the treatments by several parameters includingrnflow capacity (kh), reservoir flow geometry, drained volumern(area), and effectiveness of produced liquids management.rnSignificant variations in reservoir quality and completionrneffectiveness were observed.