煤层气储层水锁损害机理及防水锁剂的研究

Research on coalbed methane reservoir water blocking damage mechanism and anti-water blocking

水锁效应是造成煤层气储层损害的主要因素之一,研究其水锁损害机理和防水锁技术有利于保护煤层气储层,从而提高煤层气采收率。以山西沁水盆地3号煤样为研究对象,实验研究了外来流体侵入对煤层气解吸时间和渗透率的影响。结果表明,外来流体侵入延长煤层气解吸时间和降低渗透率,随着含水率上升,煤层气解吸时间延长和渗透率降低。在此基础上进行了防水锁剂的研究,优选出了防水锁剂FSSJ,并对其性能进行了评价。结果表明,FSSJ起泡性弱、降低表面张力、增大接触角、降低煤芯自吸水量、减少煤层气储层水锁损害,具有较好的防水锁效果。煤层气储层水锁损害应具备自然条件、物质条件以及压力条件。

Water blocking effect is one of the main factors causing coalbed methane reservoir damage,the research of its water blocking damage mechanism and anti-water blocking technology is beneficial to protecting coalbed methane reservoir,thus enhancing CBM recovery. Taking No. 3 coal in Qinshui Basin of Shanxi Province as the research object,the influence of external fluid invasion on coalbed methane desorption time and permeability was experimentally studied. The results show that external fluid invasion prolongs coalbed methane desorption time and decreases permeability,coalbed methane desorption time prolongs and permeability decreases with the increase of water cut. The research on anti-water blocking was carried out on this basis,the anti-water blocking agent FSSJ was selected out,and its properties were evaluated. The results show that the FSSJ with weak foamability can effectively reduce surface tension,increase contact angle,decrease self adsorption water quantity of coal,reduce coalbed methane reservoir water blocking damage,and has better anti-water blocking effect. Coalbed methane reservoir water blocking damage should have natural condition,material condition and pressure condition.