A MINLP model for combination pressurization optimization of shale gas gathering system

Abstract

AbstractThe combination pressurization of the shale gas gathering system is one of the most common pressurization methods in the current engineering site, but it is mostly set by manual experience or simulation analysis, and thus the optimal pressurization scheme cannot be obtained. In order to optimize the pressurization mode of the shale gas gathering and transportation system, a mixed integer nonlinear programming model (MINLP) is established based on the existing pressurization mode of the shale gas field. The model takes the minimum total cost of the compressor unit as the objective function. Various constraints are also taken into account, such as pipe pressure, flowrate, compressor related, well and platform throttling, uniqueness for well and platform pressurization. Solving this optimization model can figure out the appropriate pressurization position, operating power, and compressor unit cost. An actual case for a shale gas block is applied to determine the combined pressurization scheme suitable for this production condition. The results show that the combination of more pressurization methods can meet the pressurization requirements under different production conditions. When both well and platform pressurization are considered, the optimized pressurization position is more concentrated, the number of compressors is reduced by two sets, and the total compressor cost is reduced by 99.28 × 104 Yuan, which reflects the advantages of combined pressurization in the pressurization of shale gas gathering and transportation systems.