煤岩氦气孔隙度测量关键参数优化  

Optimization of key parameters for helium porosity measurement of coal and rock

作　　者：张波 陈博源 马立涛[1,2] 吴鹏 刘成 陈建奇[1,2] 李洋冰 姜洋 ZHANG Bo;CHEN Boyuan;MA Litao;WU Peng;LIU Cheng;CHEN Jianqi;LI Yangbing;JIANG Yang(CNOOC Energy Technology&Services Limited Key Laboratory for Exploration&Development of Unconventional Resources,Tianjin 300452,China;CNOOC EnerTech-Drilling&Production Co.,Tianjin 300452,China;China United Coalbed Methane Corporation Ltd.,Beijing 100011,China)

机构地区：[1]中海油能源发展股份有限公司非常规勘探开发重点实验室,天津300452 [2]中海油能源发展股份有限公司工程技术分公司,天津300452 [3]中联煤层气股份有限公司,北京100011

出　　处：《非常规油气》2025年第2期25-32,共8页Unconventional Oil & Gas

基　　金：中国海洋石油集团公司科研项目“非常规油气勘探开发实验平台建设”(CNOOC-KJ PT GCJS 2021-01)。

摘　　要：煤岩氦测孔隙度是反映煤储层储集空间的重要参数,难以用常规孔隙度测量参数进行表征。为探索煤岩氦气孔隙度测量的影响因素,以鄂尔多斯盆地东部8+9号煤层为研究对象,开展了不同粒度、不同烘干温度以及不同平衡时间下的氦气孔隙度实验测试,结合低温气体吸附实验结果,对比分析了孔隙体积分布趋势,研究了颗粒样品与柱塞样品孔隙度的差异。结果表明:烘干温度、样品目数以及平衡时间对氦气孔隙度测试结果影响较大,烘干温度为80~100℃时,可有效去除煤岩孔隙中的游离水和束缚水;煤岩破碎至40~60目时,氦气分子能有效进入纳米孔隙中,更能反应岩心孔隙的真实情况;平衡时间为15~20 min时,孔隙度值逐渐稳定。优化参数后的煤岩孔隙度测试结果与低温气体吸附联合测试等精细表征手段具有较高的吻合度,且氦气孔隙度测试周期更短,相比于柱塞样品,颗粒样品孔隙度测试值更接近于真实情况。因此,煤岩干燥温度为80℃、粒度为40~60目以及平衡时间为15 min时,可准确获取孔隙度参数。该研究对于指导煤层气的勘探开发具有重要意义。It is challenging to characterize coal reservoirs with conventional porosity,so the helium porosity in coal and rock is an important parameter that reflects the storage space.Experiments were conducted on the helium porosity of coal seams 8+9 in the eastern part of Ordos Basin under different particle sizes,drying temperatures,and equilibrium times to explore the influencing factors of the helium porosity in coal and rock.Based on the result of low-temperature gas adsorption experiments,the distribution trend of pore volume was compared and analyzed,and the differences in porosity between particle samples and plunger samples were studied.The results show that drying temperature,sample mesh size,and equilibrium time significantly impact the helium porosity measurement results.The free water and the bound water in coal and rock pores could be effectively removed when the drying temperatures are between 80 to 100 ℃;helium molecules could effectively enter the nanopores when the coal and rock is broken into 40 to 60 mesh,which could better reflect the true situation of the core pores;the porosity value gradually stabilizes when the equilibrium time range from 15 to 20 minutes.The porosity measurement results of coal and rock after parameter optimization are consistent with those of fine characterization methods,such as low-temperature gas adsorption joint measurement,and the helium porosity measurement cycle is shorter.Compared with plunger samples,the porosity measurement values of particle samples are closer to the actual situation.Therefore,the porosity parameters can be accurately obtained when the drying temperature of coal and rock is 80 ℃,the particle size is between 40 to 60 mesh,and the equilibrium time is 15 minutes,which is of great significance for guiding the exploration and development of coalbed methane.

关 键 词：煤岩 孔隙度 孔隙体积 预处理 测量参数 

分 类 号：TE122[石油与天然气工程—油气勘探]