清洁压裂液对煤岩储层伤害的实验评价

Experimental and mechanism research of damage of clean fracturing fluids to coalbed methane

压裂液进入煤层后会带来一定的伤害,影响煤层气的产量。通过实验研究了清洁压裂液对煤层气解吸扩散和渗流的伤害机制。以沁水盆地煤岩为实验样品,利用自主研究的煤岩解吸装置和全模拟流体模拟微观分布实验系统,测试了清洁压裂对煤岩解吸量和地层水渗透率的伤害程度。研究表明,清洁压裂液对煤岩渗透率的伤害为30%,对煤层气解吸量的伤害率为24%,并且推迟了煤层气开始解吸的时间,降低了解吸的速率。通过电镜扫描、润湿性等测试,明确了清洁压裂液对煤岩的伤害机制。

Coalbed would be damaged by fracturing fluid, which affects coalbed methane production. Clean fracturing fluid is studied through experiments on the diffusion of coalbed methane desorption and seepage damage mechanism to provide a theoretical basis for the selection of coalbed methane well fracturing fluid. Coal 3 from Qinshui basin is selected as test samples to conduct the desorption test after injecting fracturing liquids into the samples by using independently developed CBM desorption experimental apparatus and permeability test by microscopic distribution of fluid simulation experiment system. Research shows that permeability of coal is damaged by 30% and the desorption amount of damage rate is 24%. Clean fracturing fluid may postpone the coalbed methane desorption time and reduce the absorption rate. And then through the electron microscope scanning and wettability analysis, the damage mechanism of coal by clean fracturing fluid is found out.