An integrated MILP model for optimal planning of multi-period onshore gas field gathering pipeline system

Onshore gas field gathering pipeline system (GPS) plays a key role in the onshore gas field production and is often constructed in stages due to the phased development of the gas field. However, the influence of phased development on the optimal design of GPS has been neglected in previous studies. Although some research on the optimization of gas field development strategy involves the multi-period construction of GPS, they simplify the characteristics of the gathering network and ignore some very important parameters. This study develops an integrated mixed-integer linear programming (MILP) model for optimizing multi-period GPS to determine the central processing facility (CPF) location, pipeline (routes and diameters) installation and expansions, well site-CPF connections, the flowrate of each pipeline, and the operating pressure of each node in each time period simultaneously. Taking minimum total construction cost as the objective function, the proposed model considers various operational and technical constraints related to multi-period construction and hydraulic characteristics, such as obstacles, three-dimensional terrain, pipeline topological structures, pipeline diameters, and wellhead pressure. Ant colony optimization is used for route optimization to provide parameters for the proposed model. A piecewise approximation method is employed to deal with the nonlinear terms of hydraulic equations. Therefore, the MILP model can be solved by the branch-and-bound algorithm to obtain the global optimal solution integrally. Finally, the model is successfully applied to three real-world gas fields. Compared with the actual construction scheme and other literature methods, the results prove the superiority of multi-period planning considering time.