摘要
在煤储层低温条件下,二氧化氯(ClO2)不仅实现了煤层气井水力压裂时高黏压裂液的快速破胶和返排,还降低了煤的亲甲烷能力,但其强氧化性对煤储层孔隙结构的影响问题却还没有搞清楚。为此,采集了3种不同煤阶煤样(样品分别来自河南省义马市千秋矿井、焦作市中马村矿井和山西省柳林县沙曲矿井),将其粉碎(筛选粒径为2mm左右),采用浓度为4 000μg/g的ClO2溶液浸泡72h,利用压汞法分析ClO2溶液处理前后煤样的孔隙度、孔径分布、孔容、比表面积等孔隙结构的变化特征。实验结果表明:①处理后煤样的孔隙度、孔容得到不同程度的提高,大孔和中孔的孔容比增加;②进—退汞曲线的滞后现象消失及张开度变小,孔隙的连通性增强;③孔隙比表面积值降低,其中,小孔和微孔的比表面积比有所减小。结论认为:二氧化氯对煤储层具有氧化刻蚀增透作用,能够改善煤储层的孔隙结构,一定程度上增大了煤储层的渗透率,有利于煤层气的运移和产出,值得在煤层气行业进行推广应用。
With chlorine dioxide （C102） adopted under low temperatures of coal reservoirs, not only can rapid gel breaking and flowback of high viscosity fracturing fluids be achieved, but a coal＇s affinity can be lowered for methane. However, the impact of the strong oxidation of C102 on pore structure is still not fully understood. Three coal samples with different ranks were collected from different coal mines. After being crushed into grains with a diameter of about 2 mm, the samples were soaked in C102 solutions with a concentration of 4000/,g/g for 72 hours. Then the mercury injection method was used to analyze the coal samples to reveal the vari- ations of porosity, pore size distribution, pore volume and specific surface area before and after being treated with the C102 solution. The following results were obtained, a. The porosity and pore volume of coal samples both get enhanced to varying degrees, and the pore volume ratios of macropores and mesopores increase after treatment, b. The hysteresis on the mercury intrusion and extrusion curves disappears, the joint opening decreases and the pore connectivity is improved, c. The specific surface areas of pores decrease, so does the ratio of specific surface area between micro- and nano-pores. In conclusion, chlorine dioxide can improve pore structure and enhance permeability of coal reservoirs, thus is favorable for migration and recovery of CBM.
出处
《天然气工业》
EI
CAS
CSCD
北大核心
2013年第11期40-44,共5页
Natural Gas Industry
基金
国家自然科学基金项目"二氧化氯对煤储层的表面改性与增透机理研究"(编号:41002047)
河南省科学技术研究重点项目"煤储层温度下快速破胶压裂液体系开发研究"(编号:12A440005)
关键词
二氧化氯
压汞法
孔隙结构
化学增透
运移产出
亲甲烷能力
煤层气
压裂液
渗透率
chlorine dioxide, mercury injection method, pore structure, chemical permeability enhancement, migration and production, affinity for methane, coalbed methane, fracturing fluid, permeability
作者简介
郭红玉，1978年生，副教授，博士；从事煤层气地质与勘探开发的科研与教学工作。地址：（454000）河南省焦作市世纪大道2001号。E-mail：ghy1026@126．com
