Comprehensive Optimization Methodology for Stimulation Design of Unconventional Gas Reservoirs

Development of low-permeability natural gas resources require knowledge of the horizontal wells to be drilled, the number of transverse fractures to be placed on each well, the dimensions of each fracture, and the amount of proppant to be used. Such information is obtained by making decisions using trial and error approach, but this process is time consuming and may not result in an optimal solution. In this work we present a methodology that can help make decisions on the issues raised above in a systematic and efficient way. In this work, we develop such a methodology that optimizes net present value (NPV). The methodology poses the design problem as nested optimization, where the outer optimization shell involves decisions on the number of wells, number of fractures per well, and amount of proppant, while the inner optimization maximizes the productivity index by selecting optimal fracture dimensions. The proposed methodology integrates in a systematic way a Fracture Design Module, a Production Estimation Module, and an Economics Module. Because the methodology is automated and numerically efficient, it can be used effectively for field development.