Analysis on Underground-Surface Integrated Pressure Distribution and Loss Law in Coalbed Methane Fields

In order to explore the law of pressure loss in the current CBM fields, seek the key factors of energy efficiency optimization bottlenecks, and guide the unified management of the whole life cycle production-gathering and transportation system of CBM field. The production-gathering systems are divided into 4 parts: wellbore, wellsite, branch-trunk line and pipeline network. An integrated model of the wellbore, wellsite and branch-trunk line is established based on the mid-shallow layer CBM fields branch-trunk line, and quantitatively described the pressure distribution of the CBM fields production-gathering and transportation system from underground to the surface with the pressure loss pattern of each unit. It is found that the wellbore lift (52–72%) and surface flow (25–50%) are the key to the pressure loss in the process of CBM flow, and the overall production-gathering and transportation capacity increased by less than 1% due to the pressurized high-pressure ratio at the outlet of the branch-trunk line, consistent with actual process transformation characteristics. As a key position restricting the release of CBM fields production capacity, the wellbore will be the focus of future process optimization.