沁水盆地樊庄区块煤层气直井排采特点

Characteristics of Production of CBM Vertical Well in Fanzhuang Block,Qinshui Basin

沁水盆地樊庄区块3#煤层具有埋深适中、煤层厚度大、分布稳定、煤质好、煤层割理发育、保存条件好等诸多特点,但受地质构造、水动力条件等因素控制,平面上具有"富集成片,贫瘠成带"的分布规律,大部分区域利于煤层气规模开发。本文以樊庄区块煤层气井生产数据为基础,将煤层气直井排采生产分为排水降压、控压阶段、稳定产气、产气衰减四个阶段;综合分析了樊庄区块煤层气直井生产过程中的产气、产水变化特点,总结出各阶段控制要点,这些认识对今后煤层气排采工作具有借鉴意义。

3# seam in Fangzhuang block, Qinshui Basin is characterized by moderate burial depth, great thickness of coal seam, regular distribution, superior coal quality, well developed cleats, and good conserva- tion conditions. Controlled by factors, like the geological tectonics and dynamic conditions of water, the rule of CBM planar distribution is ＂Enrichment in stretches of land and impoverishment in zones＂. Most areas are fa- vorable to large scale development. The paper divides the production periods of a vertical CBM well into four stages ： that is, dewatering and relief of pressure, pressure control, stable production and production declining stages according to the CBM production data obtained in Fanzhuang block. The paper has made a comprehen- sive analysis of the features of gas and water production change in the production process of a CBM vertical well in Fanzhuang block and summed up the key points of control in all these stages. All these knowledge is useful for future CBM production.