Optimization design of coalbed methane pipeline network–coupled wellbore/reservoir simulation

The extraction of coalbed methane, unlike that of conventional gas resources, is characterized by low gas production and low pressure. The traditional optimization methods only focus on the surface system, ignoring the relationship between the surface system and coalbed methane production. Furthermore, the pipeline network suggested by these methods is based on the given productivity of a single well. This article proposes a surface system layout optimization architecture coupled with a production system simulation that considers the profit made in the production cycle as the objective function. Using case studies, we show that the proposed optimization method improves the gas production rate by about 10.9% and increases the profit by 2 million dollars. When the results are analyzed under different network topologies, the tree network emerges as the cheapest and the star network emerges as the most expensive in terms of ground investment. However, when considering productivity and profit, the star network is the best and the tree network is the worst, while the concatenated network is intermediate. The results show that the structure of the surface network has a considerable influence on the coalbed methane reservoirs. Therefore, this article recommends the star structure arrangement for the coalbed methane surface system.