使用纳米碳酸钙降低低孔低渗煤层气储层伤害  

Reducing Formation Damage to Low-Porosity and Low-Permeability CBM Reservoirs Using Calcium Carbonate Nanoparticles

作　　者：谷穗[1,2] 蔡记华[1] 常德武 维克多.费多罗维奇.契霍特金 

机构地区：[1]中国地质大学工程学院,湖北武汉430074 [2]武汉工程科技学院,湖北武汉430200

出　　处：《地球科学（中国地质大学学报）》2015年第6期1093-1100,共8页Earth Science-Journal of China University of Geosciences

基　　金：国家自然科学基金项目(No.41072111);中央高校科研业务费项目(Nos.CUG120112;CUG130612);湖北省自然科学基金(Nos.2012FFA047;2015CFA135);中国石油科技创新基金项目(No.2014D-5006-0308)

摘　　要：传统暂堵剂难以封堵低孔低渗煤层气储层中的大量纳米级别孔隙.通过煤岩显微观测、钻井液基本性能测试、泥饼清除实验、煤岩孔隙分布实验和气体渗透率实验,探讨了纳米碳酸钙降低低孔低渗煤层气储层伤害的效果.结果表明：纳米碳酸钙材料只有在水溶液中保持纳米级的分散状态,才可能对低渗煤岩起到暂堵作用;基于纳米碳酸钙的可降解钻井液既能封堵低孔低渗煤岩中微米级别孔隙,也能封堵其中的纳米级别孔隙;经过生物酶和稀盐酸双重解堵后,煤岩渗透率恢复值达77.17%~97.98%,储层保护效果好;煤岩孔隙分布实验可以在纳米尺度上研究纳米材料对低孔低渗储层的暂堵效果.研究成果可为纳米碳酸钙在低孔低渗煤层和页岩钻完井过程中的应用奠定良好技术基础.It’s difficult to block a mass of nanoscale pores in the low-porosity and low-permeability coalbed methane （CBM）res-ervoirs using traditional temporary plugging additives.The performances of reducing formation damage to low-porosity and low-permeability CBM reservoirs using calcium carbonate nanoparticles （nCaCO3 ）are evaluated in this study through micro-scope investigation of coal rocks,the basic performance tests of drilling fluid,mud cake removal tests,pore size distribution tests and gas permeability tests of coal rocks.It is found that only when nCaCO3 are dispersed to nano-scaled state in water solution could it temporally plug the low permeability coal rocks.However,nCaCO3 based degradable drilling fluid not only blocks the microscale pores in low-porosity and low-permeability coal rock,but also blocks the nanoscale pores.With the double unplugging technology of biological enzyme plus low concentration hydrochloric acid on the nCaCO3 based drilling fluid,the permeability recovery rate of coal rocks ranges from 77.17% to 97.98%.The reservoir protective effect on reservoir proves good.It is shown that the pore size distribution test could be used in the investigation on temporally plugging performance of nanoparticles to low-porosity and low-permeability reservoirs on nanoscale.This study may offer a technical support to facilitate future applications of nCaCO3 in drilling and completion process of low porosity and low permeability coal seams and shale formation.

关 键 词：纳米碳酸钙 低孔低渗煤层气储层 暂堵 储层保护 气体渗透率 孔隙分布. 

分 类 号：P634[天文地球—地质矿产勘探]