川南地区下古生界页岩气储层微观孔隙结构表征及其对含气性的影响  

Characterization of microscopic pore structure and its influence on gas content of shale gas reservoirs from the Lower Paleozoic in southern Sichuan Basin

作　　者：王哲[1,2] 李贤庆[1,2] 周宝刚[1,2] 祁帅[1,2] 张吉振[1,2] 王刚[1,2] 徐红卫[1,2] 王飞宇[3,4] WANG Zhe LI Xian-qing ZHOU Bao-gang QI Shuai ZHANG Ji-zhen WANG Gang XU Hong-wei WANG Fei-yu(State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and Technology（ Beijing ）, Beijing 100083, China College of Geo- science and Surveying Engineering, China University of Mining and Technology （Beijing）, Beijing 100083, China State Key Laboratory of Petroleum Resource and Prospecting, China University of Petroleum（ Beijing ） , Beijing 102249, China College of Geosciences, China University of Petroleum （ Beijing ）, Beijing 1022 49 , China)

机构地区：[1]中国矿业大学(北京)煤炭资源与安全开采国家重点实验室,北京100083 [2]中国矿业大学(北京)地球科学与测绘工程学院,北京100083 [3]中国石油大学(北京)油气资源与探测国家重点实验室,北京102249 [4]中国石油大学(北京)地球科学学院,北京102249

出　　处：《煤炭学报》2016年第9期2287-2297,共11页Journal of China Coal Society

基　　金：国家重点基础研究发展计划(973)资助项目(2012CB214702);国家自然科学基金资助项目(41572125);国土资源部公益性行业科研专项基金资助项目(201311022)

摘　　要：运用普通扫描电镜、氩离子抛光—场发射扫描电镜、Image J2x软件分析、高压压汞、低温CO_2和N_2吸附实验方法,对川南地区下寒武统筇竹寺组和下志留统龙马溪组两套页岩气储层微观孔隙成因类型、孔隙结构特征及其对页岩含气性的影响进行了研究。结果表明,川南地区下古生界页岩微观孔隙主要发育粒间孔、粒内孔、有机质孔和微裂缝等多种成因孔隙类型;下古生界页岩微观孔隙总面孔率为3.95%~7.48%,筇竹寺组页岩总面孔率和有机质孔面孔率低于龙马溪组页岩;下古生界页岩总孔容为(3.93~24.96)×10^(-3)m L/g,总比表面积为2.727~29.399 m^2/g,孔径为0.35~1.00,2.5~4.7和55~75 nm的孔隙是总孔容的主要贡献者,孔径为0.3~1.0,2.5~5.5 nm的孔隙主要提供了总比表面积,筇竹寺组页岩总孔容和总比表面积均较龙马溪组页岩要低;页岩微观孔隙的面孔率、有机质孔、孔容、比表面积、孔径分布均会影响页岩含气性。下古生界筇竹寺组和龙马溪组页岩在微观孔隙结构特征的上述差异,为揭示川南地区筇竹寺组与龙马溪组页岩含气性的差异提供了依据。The genetic type of microscopic pore,the characteristics of pore structure and its influence on gas content from the Lower Cambrian Qiongzhusi and Lower Silurian Longmaxi Formations shale gas reservoirs in southern Sichuan Basin were studied by using scanning electron microscope,argon ion polishing-field emission scanning electron micro-scope,Image J2 x software analysis,high pressure mercury injection,low temperature N_2 and CO_2adsorption experiments. The results show that the multiple genetic types of microscopic pores,including inter-granular pore,intragranular pore,organic matter pore and microcrack,are developed in the Lower Paleozoic shale in southern Sichuan Basin.The total surface porosity of microscopic pores is ranged from 3. 95% to 7. 48%. The total surface porosity and organic pore surface porosity of the Qiongzhusi Formation shale are lower than those of the Longmaxi Formation shale. The total pore volume of the Lower Paleozoic shale is（ 3. 93- 24. 96） × 10^- 3m L / g,total specific surface area is 2. 727-29. 399 m^2/ g in range. These pores whose pore sizes are 0. 35- 1. 00,2. 5- 4. 7 and 55- 75 nm in range are the main contribution of total pore volume,and those pores whose pore sizes are 0. 3- 1. 0 nm and 2. 5- 5. 5 nm in range account for the main total specific surface area. Total pore volume and total specific surface area of the Qiongzhusi Formation shale are lower than those of the Longmaxi Formation shale. All the surface porosity,organic pore,pore volume,specific surface area and pore size distribution of microscopic pores will affect the gas content of shale. The above differences of pore structure characteristics in the Lower Paleozoic Qiongzhusi and Longmaxi Formations shale provide a basis for revealing the difference of gas content between the Qiongzhusi Formation shale and the Longmaxi Formation shale in southern Sichuan Basin.

关 键 词：页岩气储层 孔隙结构 面孔率 含气性 下古生界 川南地区 

分 类 号：P618.13[天文地球—矿床学]