关键词: 深部煤层气, 煤层气井, 排采影响因素, 阶段划分, 排采制度, 排采工艺

Abstract: Coalbed methane (CBM) resources in China are abundant, but the geological and engineering conditions are complex. The applicability of natural gas well drainage technology in coalbed methane wells is limited, especially for deep coalbed methane (coalbed methane resources buried deeper than 1000 m). Its drainage characteristics There are significant differences from shallow coalbed methane. Through theoretical analysis and on-site summary, this article systematically analyzes the characteristics of deep coalbed methane reservoirs, drainage stages and main control factors, and the development direction of drainage technology. The results show: ① Characteristics of deep coalbed methane: It generally has reservoir characteristics such as high reservoir pressure and temperature, sufficient formation energy, thick coal seams, high gas content, and abundant free gas. It also has characteristics such as low matrix permeability, poor pore connectivity, high effective stress, and low fracturing fluid return rate. ② Main control factors of drainage and production: In the early stage of drainage and pressure reduction, the influence of pulverized coal Drainage effect; in the stage from gas breakthrough to stable production, stress sensitivity is significant, and the number of shut-ins should be reduced to avoid formation pollution caused by discontinuous drainage; ③In terms of production stage division and drainage and production system: It is recommended that deep coalbed methane wells adopt a refined and quantitative five-stage or six-stage stage division, which is conducive to controlling the steady decline of bottom hole pressure. The purpose of the drainage and production system is to extend the stable production period. The duration of the stable production stage determines the final production capacity; ④ Development direction of drainage and production technology: integrated drainage and extraction throughout the life cycle of the gas well , geological engineering integrated drainage and mining machine learning and smart drainage and other technology applications. This research can provide certain guidance for the optimization of related process technologies for deep coalbed methane well drainage.

Key words: deep coalbed methane, coalbed methane wells, drainage and gas production influencing factors, stage division, drainage and gas production system, drainage and gas production process