An Analytical Solution of Fracture-Induced Stress and Its Application in Shale Gas Exploitation

Abstract

Natural gas and oil exploration and production from shale formations have gained a great momentum in many regions in the past five years. Producing hydrocarbons from shale is challenging because of low productivity of wells. Optimal design of transverse fractures is a key to achieving successful well completion and field economics. This paper presents a simple analytical method to determine the minimum fracture spacing required for preventing fracture-merging. Result of the analytical method has been verified by a Finite Element Method for a typical fracturing condition in a shale gas formation. Field performances of shale gas wells are found consistent with what suggested by this work. The analytical method presented in this paper can replace the sophisticated solutions and time-consuming numerical simulators in calculating stresses around hydraulic fractures and identifying the minimum required fracture spacing. The method can be applied to designing of multifrac completions in shale plays to optimize placement of transverse fractures for maximizing well productivity and hydrocarbon recovery. This work provides engineers a simple tool for optimizing their well completion design in shale gas reservoirs.