Evolving Completion Designs to Optimize Well Productivity from a Low Permeability Oil Sandstone Turner Reservoir in the Powder River Basin—One Operator's Experience

Abstract

As the Powder River Basin (PRB) development continues and more wells are drilled, identifying best completion practices is critical to economic success. This operator has completed several Turner horizontal wells drilled at 10,300-11,000 ft TVD using crosslinked gel with encouraging results. Although reservoir quality varies in the basin, the Turner interval is more than 30 ft thick in the area of interest (AOI) in Campbell County, Wyoming. In this area, production history matched permeability ranges from 0.005 to 0.1 mD, with pore pressure gradient from 0.55 to 0.64 psi/ft. Fracture modeling and production history matching/sensitivities were performed on a few horizontal wells. This paper discusses the results of this modeling and history matching, and it summarizes the evolution of Turner Formation fracture treatment designs, that were done by one operator to maximize the return on investment. The operator collected core data, open hole logs, and Diagnostic Fracture Injection Test (DFIT) data. The objectives of this study were to: a) determine reservoir parameters from DFIT, b) estimate fracture height growth, fracture half-length, and conductivity for Turner crosslinked gel fracs, c) determine the most appropriate perforation cluster or fracture spacing, as well as treatment rate, fluid/proppant loading, and proppant types/sizes based on the expected long-term production performance, d) compare the estimated production of cemented sleeve vs. plug-and-perf completions, and e) perform multivariate analysis of public production and completion data to compare with the detailed physical modeling. The results presented in this paper show well-performance predictions as a function of sleeve/perforation cluster spacing, treatment size, proppant type, mesh size, and pump rate. Implications for implementation of a certain treatment and completion design are discussed in detail.