Optimal Design of Natural Gas Gathering Systems with Production Capacity Expansion

In the mid to late stages of gas field development, new blocks would be added to the existing gas gathering system (GGS) for stable production. Consequently, new compressor stations (CSs) and pipelines should be constructed to adjust the original gas pipeline networks (GPNs) for minimizing energy consumption. In this paper, an optimal design framework for GPNs is developed considering the future production capacity expansion and possible extensions of the pipeline network structures. The objective function of the present study includes investment and operating costs. A two-stage hybrid algorithm which is composed of a modified genetic algorithm (MGA) and a modified particle swarm optimization (MPSO) algorithm is proposed to solve this problem. The MGA is first used for layout optimization of new pipelines and then MPSO is employed to determine the design variables, including the diameter of each pipeline, the locations of new CSs, and the optimal operation conditions of compressor facilities. This method can also give the reconstruction scheme of the built CSs. Finally, a real pipeline network of a gas field in China is studied, size and operation conditions are optimized. The results illustrate that the model can tackle complex gas network reconstruction problems, and there is a 3.68% decrease in the total costs compared to the design scheme without modification of the original CSs.