潘河煤层气试验区产能影响因素分析

INFLUENCING FACTORS ON CBM PRODUCTIVITY IN PANHE TRIAL PRODUCTION AREA

煤层气生产过程中,为了掌握其生产动态,提高煤层气井的产能,有必要对煤层气产出特征进行综合分析,总结其变化规律,确定影响产能的主要因素。以潘河煤层气生产试验区的实际排采资料为基础,从煤层气的运移机理以及产出特征出发,利用对比、统计方法,综合分析了生产各阶段气、水产量变化趋势及其主要控制因素,把区内煤层气产出曲线划分为3种特征类型:高产—低产—高产、中高产—高产、高产—低产,其中高产—低产—高产曲线类型为主要特征类型。研究结果表明:煤层含气量、构造、煤层埋深、储层裂隙发育特征等是影响煤层气产能的重要因素,含气量、煤层埋深则影响生产曲线的阶段特征,裂隙发育的地区往往是高产井分布区,向斜部位的井对于井网的整体排水降压具有重要的意义。

In order to control the whole production activity and to enhance the capacity of CBM wells during the process of CBM production,it is necessary to have an overall study on characteristics of the produced CBM,which contribute a lot to determine main factors influencing the productivity of CBM.Therefore,with field data collected from Panhe CBM trial production area,this paper started with CBM accumulation mechanism and production features;then used methods of comparison and statistics to have a comprehensive analysis on what,how and why changes of volume happened to the produced gas and water taking place at different periods of well production,and finally described three types of production curves,which would express well how the CBM productivity was in this trial field,i.e,high-low-high,medium-high,and high-low,the first one among which was the most distinguished.The study results showed that main factors having effects on the CBM productivity were as follows:gas contend in the coalbed layers,geological structure,the burial depth of coal beds,and features on well-developed fractures,etc.Among those above-mentioned factors,gas content and the burial depth of coalbed layers would directly influence the CBM productivity at different stages of well production;while the well-developed fractures area would be the dense area for high-productivity CBM wells,and wells situated in synclines played important roles in water drainage and pressure reduction for the whole well pattern.