1.School of Geosciences, China University of Petroleum (Beijing), Beijing China;2.State Key Lab of Petroleum and Gas Resources and Exploration,Beijing , China;3.Beijing Institute of Petroleum Technology, Beijing , China; 4.China Petroleum Exploration and Development Research Institute, Beijing , China;5.Beijing Petropark Company Limited, Beijing , China

为了分析滇东老厂和恩洪区块前期煤层气井排采效果不佳的原因,对滇东老厂和恩洪区块煤层气地质参数进行了系统整理,并对其煤层气可动性-渗透率和解吸时间进行对比分析,分析2个区块内前期煤层气井的产气曲线,揭示了可动性对产气动态的影响机理,并提出了初始排水速度控制的建议。结果表明:(1)老厂区块和恩洪区块皆属低渗透煤层气区块,老厂区块煤储层渗透率总体上低于恩洪区块,这一差异主要是由2个区块的地应力强度差异引起的;(2)老厂区块煤岩解吸时间总体高于恩洪区块,这一差异主要是由2个区块间煤岩的煤阶差异造成的;(3)由于前期煤层气井初始排水速度过快,2个区块煤层气井峰值产量不高,初始排水速度过快问题在恩洪区块更突出,且恩洪区块煤岩解吸时间较短,在有效应力、快速扩散效应的双重作用下,不利于降压漏斗扩展;(4)老厂区块和恩洪区块煤层气井初始排水速度控制是今后煤层气井排采工作制度优化的重要内容之一,对煤岩解吸时间相对较短的恩洪区块,坚持缓慢排水策略更加重要。

In order to analyze the reasons for the poor drainage performance of the CBM wells in the early stage in Laochang and Enhong Blocks of Eastern Yunnan,a systematic preparation was conducted on the coalbed methane geological parameters of Laochang Block and Enhong Block in Eastern Yunnan. A comparison and analysis were conducted on the coalbed methane mobility-permeability and desorption time of Laochang Block and Enhong Block. In combination with the analysis on gas production curves of the initial coalbed methane wells in the two blocks, the paper revealed the influence mechanism of the mobility the gas production dynamic and provided the proposals to control the initial water drainage speed. The result showed as the followings: ①Laochang and Enhong Blocks both were the low permeability coalbed methane blocks. The permeability of the coal reservoir in Laochang Block was generally lower than Enhong Block. The difference mainly was caused by the geostress intensity differences of the two blocks.②The desorption time of the coal and rock in Laochang Block was generally higher than Enhong Block and the difference was mainly caused by the coal grade differences of the coal and rock in the two blocks. ③Due to the initial water drainage speed of the previous coalbed methane wells was too fast, the peak gas production of the coalbed methane wells in Laochang Block and Enhong Block was not high. The initial water drainage speed too fast was more evident in Enhong Block and the desorption time of the coal and rock in Enhong Block was relatively short. Under the double function of the effective stress effect and the fast diffusion effect, thus the pressure released cone would be not favorably expanded. ④The initial water drainage speed control of the coalbed methane wells in Laochang Block and Enhong Block would be one of the important contents to the drainage operation system optimization of the coalbed methane wells in the future. Enhong Block with a relative short desorption time of the coal and rock should be more important to have a slow water drainage strategy.

国家科技重大专项资助项目(2016ZX05044)；