屯留井田煤层气井排采主控因素研究

Study on Main Control Factors of Gas Drainage in Coalbed Methane Well of Tunliu Minefield

为提高煤层气井的产能,分析煤层气排采机理和排采阶段,并从地质构造、顶底板岩性、压裂液及井网部署等方面,探讨影响屯留井田煤层气井排采的主要因素。研究认为褶皱对煤层气井的排采效果影响较大,裂隙和顶底板也对煤层气排采有一定影响;采用压裂工艺对煤储层强化改造中,活性水+氮气压裂液体系助排效果优于活性水压裂,而清洁压裂液助排效果最差;研究区煤储层特征决定了屯留井田煤层气井难以获得高产量,但可能产气时间较长。同时研究认为,研究区煤层气井井网宜采用排间距200 m×250 m的小井网结构,且井位布置应与主裂缝延伸方向(东北方向)平行。

In order to improve the production capacity of a coalbed methane well,the paper analyzed the coalbed methane drainage mechanism and gas drainage stage.From a geological structure,roof and floor lithology,fracturing liquid,well net layout and other aspects,the paper discussed the main factors affected to the coalbed methane drainage in Tunliu Minefield.The study held that the fold would highly be affected to the drainage effect of the coalbed methane well and the breaking of the roof and floor would be certainly affected to the coalbed methane drainage.The fracturing technology was applied to the intensified reconstruction of the coal reservoir,the assistant drainage effect of the activated water + nitrogen gas fracturing liquid system was better than the activated water fracturing and the assistance drainage effect of the clean fracturing liquid was the worst.The coal reservoir features of the study zone determined that the coalbed methane well within Tunliu Minefield would be hard to have a high production,but could have a long production time.The study held that the well net of the coalbed methane wells in the study zone could be small well net structure with an inter-row distance of 200 m×250 m and the layout of well position should be parallel to the extension direction(northeast direction) of the main fracture.