School of Energy, China University of Geosciences (Beiing) Coal Reservoir Lab, National Engineering Center of
Coalbed Methane, China University of Geosciences (Beiing)

针对水敏效应会引起煤储层渗透率伤害,造成储层渗透率降低,从而影响煤层气井产量的问题,研究了沁水盆地南部安泽区块煤储层物性特征、水敏感性损害程度以及该区煤储层水敏损害机理,对安泽区块山西组3号煤层煤样进行了扫描电镜观察、显微组分和矿物测定以及水敏感性试验。试验结果显示:安泽区块3号煤样品水敏损害率为29.92%~54.03%,平均43.53%,水敏损害程度介于弱敏感到中等偏强之间;水敏损害率与黏土矿物含量、液体流速呈正相关关系,与煤岩渗透率呈负相关关系;煤储层水敏效应存在2种损害机制,一是黏土矿物水化膨胀而引起的静态渗透率降低机制,二是由黏土矿物颗粒分散运移而造成的动态渗透率降低机制。

According to water sensitive effect would cause a permeability failure to the coal reservoir, would reduce the permeability of the reservoir and thus would influence the production of the coalbed methane well, the physical features of the coal reservoir in Anze Block in the south part of Qinshui Basin and the water sensitivit y failure degree, the water sensitivity failure mechanism of the coal reservoir in the block was studied, and the scanning electron microscope observation, maceral, mat erial detection and water sensitivity test were conducted on the coal samples from No. 3 seam of Shanxi Formation in Anze Block. The test results showed that the wate r sensitivity failure rate of the coal samples from No. 3 seam in Anze Block was 29.92% ~ 54.03%, the average rate was 43.53% and the water sensitivity failure degree was between the weak sensitivity and the medium strong. The water sensitivity failure rate as well as the clay material content and the liquid flow velocity were in a posi tive correlation relationship and the water sensitivity failure rate and the coal and rock permeability were in a negative correlation relationship. There were two failure m echanisms existed in the coal reservoir water sensitivity effect. The first mechanism was that the water swelling of the clay material would cause a mechanism to reduc e the static permeability and the second was that the particle separated migration of the clay material would cause a mechanism to reduce the dynamic permeability.

国家自然科学基金资助项目(41530314)；高等学校博士学科点专项科研基金资助项目(20130022110010)；