Evaluation of shale gas reservoirs considering the effect of fracture half-length and fracture spacing in multiple hydraulically fractured horizontal wells

Abstract

Shale gas reservoirs have very low matrix permeability. Thus, it is necessary to increase the contact area between the producing well and reservoir through multistage hydraulic fracturing. The optimal design of fracture parameters is important not only to increase the efficiency of the multistage hydraulic fracturing but also to maximize the total stimulated reservoir volume. In this study, the effects of fracture half-length and fracture spacing, which are the central controlling parameters in multistage hydraulic fracturing, are investigated to evaluate the economic viability of shale gas reservoirs. Net present value, profitability index, and the recovery factor (RF) are used to optimize the design of the multistage hydraulic fracturing. The highest RF was obtained at the fracture half-length of 550 ft and fracture spacing of 40 ft, in all reservoirs. The highest economic feasibility was obtained at the fracture half-length of 550 ft and a fracture spacing of 80 ft for all reservoirs. Haynesville shale was the only exception, with the highest economic feasibility at the fracture half-length of 550 ft and fracture spacing of 100 ft. The fracture half-length was more influential than fracture spacing; however, both were found to be the most important controlling parameters for both productivity and economic feasibility.

Keywords::

• shale gas
• stimulated reservoir volume
• multistage hydraulic fracturing
• fracture half-length
• fracture spacing

Additional information

Funding

The authors would like to acknowledge the financial support of the Ministry of Trade, Industry, and Energy (MOTIE) for the Korea Energy and Mineral Resources Engineering Program, the Special Education Program for Offshore Plant, and INHA University.