Exploration and Development Institute,Huabei Oilfield Company,CNPC School of Energy Resources ,China University
of Geosciences(Beijing)

煤储层速敏效应直接影响煤层气井的产气效果,开发过程中在一定程度上表现为煤粉产出量的变化。在煤层气开发"五段三压"阶段划分的基础上,分析了沁水盆地樊庄区块70余口井的生产趋势与煤粉产出量变化,讨论了煤储层速敏效应与煤层气井产能的响应特征。结果表明:排水段的速敏效应主要受动液面下降速率影响,在动液面初降至煤层附近时,是煤粉的高发期;气水两相流阶段煤粉沉淀速率较排水段要快,且运移距离相对较短;在稳产阶段,气体流动会引起煤粉局部震荡,但速敏的影响效应总体变弱,煤基质收缩对煤层渗透率改善程度增加。

The velocity sensitivity effect of coalbed methane would be directly affected to the gas production effect of coalbed methane well.In development process of the well,the variation of fine coal production content would be presented in a certain degree. Based on the division of the“five stage and three pressure' in the coalbed meth ane development,the paper analyzed the production tendency and fine coal production quantity variation of over 70 wells within Fanzhuang Block of Qinshui Basin and disc ussed the response features between the velocity sensitivity effect of coal reservoir and coalbed methane well production capacity.The results showed that the velocity sen sitivity effect during the water drainage period was mainly affected by the dropping rate of the dynamic liquid level.When the dynamic liquid level initially dropped to the loc ation near the seam,there would be a high fine coal occurred period. In the gas and water phase flow stage,the fine coal settling rate would be faster than the water draina ge stage and the migration distance would be relatively shorter.In the stable production period,the gas flow would cause the fine coal in vibration locally,the velocity sensiti vity influence effect would be weak generally and coal matrix shrinking would increase seam permeability improvment.

国家科技重大专项资助项目(2011ZX05061)；教育部博士学科点基金资助项目(20130022110010)；国家自然科学基金资助项目(41272175)；