煤层气井排采阶段定量化划分研究

The Research of Quantification Division of CBM Drainage Production

研究区位于鄂尔多斯盆地晋西挠褶带南段,是目前煤层气开发的主战场之一。以该区中高煤阶煤层气为该次研究对象,根据单井的排采情况,运用归纳统计的方法,先将区块内煤层气井按排采特征进行阶段划分和描述,再利用无量纲法进行定量划分,达到定量化划分排采阶段的目的。研究认为,该区煤层气井按排采特征可将其划分为排水降压阶段、不稳定产气阶段、稳定产气阶段和产气递减阶段等4个阶段,对应无量纲产气率分别为0、0.05~0.35、0.35~0.70、0.70~1.0,据此对排采阶段进行定量化划分,从定量角度优化煤层气的排采制度,对本区块煤层气井的排采管理具有重要的指导意义。

The studied area was located in the south of folded zone of Southern Shanxi in Ordos Basin,it was one of the major locations of CBM development at present.By taking the mid-high rank of CBM as the object of study,and based on the drainage-production of single well,the method of inductive and statistics was used for the phase division and description of CBM well drainage in the block and a dimensionless method was used for quantitative division of drainage phases.Study indicates that the drainage production of the CBM well can be divided into drainage and depressurization period,unstable gas production period,stable gas production period and gas production decline period.The corresponding dimensionless gas production rate is 0,0～0.35,0.35～0.7 and 0.7～1.0,based on the study,the quantitative division is carried out for the gas drainage for the optimization of CBM drainage system,it provides guidance for drainage management of CBM wells in the block.