The Upper Devonian-age black shale of the Central Appalachian basin has been a major natural gas production reservoir since the initial discovery in 1921. In the ensuing 80 years, an assortment of drilling and completion techniques have been applied to the black shale with varying degrees of success. Recent efforts at improving well productivity have focused on improving the hydraulic fracturing operations, especially the minimization of fluid damage to the targeted shale reservoirs. The development of fluid systems with lower polymer loadings has been an important achievement in this effort. Recently, polymer-free viscoelastic surfactant-based (VES) fluid systems have been used in the hydraulic fracturing industry as a final step in the elimination of polymer-based damage. A statistical study of the application of a VES foam fracturing fluid in the Central Appalachian basin was performed. The study compared recent results of polymer-free treatments to traditional completions throughout the field. Results from the polymer-free completions were compared to immediate offsets drilled in the same time frame and completed in correlated intervals. In general, the use of polymer-free fluids improved well productivity, when compared to wells that were completed with a conventional polymer-based fluid. The study also compared the economic impact of the use of VES completion fluids from both an operations and production perspective.

You can access this article if you purchase or spend a download.