Optimization of major parameters in multiple hydraulically fractured shale gas reservoirs

초록

Shale gas, one of unconventional gas, constitutes about the half of the total unconventional gas resources. Thus, shale gas reservoirs represent a potential long-term, global resource of natural gas. Shale gas cannot be produced at economic flow rates nor in economic volumes of natural gas unless the well is stimulated by a large hydraulic fracture treatment together with horizontal wellbore. The optimal design of fracture parameters is important not only to increase the efficiency of the multi-stage hydraulic fracturing but also to maximize the total stimulated reservoir volume. In this study, reservoir simulation was conducted to investigate the effects of the major controlling parameters in multi-stage hydraulic fracturing, namely fracture half-length and fracture spacing, on gas production from shale gas reservoirs. Net present value and profitability index of Haynesville, Marcellus, and Eagle Ford shale gas reservoirs in the U.S were used to optimize the design of the multi-stage hydraulic fracturing. The highest economic feasibility was obtained at the fracture half-length of 550ft and a fracture spacing of 80ft for all reservoirs. Haynesville shale was the only exception, with the highest economic feasibility at the fracture half-length of 550ft and fracture spacing of 100ft. It was observed that fracture half-length was more influential than fracture spacing in multiple hydraulically fractured shale gas reservoirs.