The geological conditions and exploration potential of shale oil in Chang7 Member, Upper Triassic Yanchang Formation, Ordos Basin, were studied from various aspects, including petrographic characteristics, storage ability, geochemical features, friability and mobility of hydrocarbon in the source rock, etc. A classification criterion of lithofacies for Upper Triassic Chang 7 source rock in Ordos Basin were established based on the correlation between lithology, organic carbon content and logging parameters, from which, the spatial distribution and development scale of two types of shale, black shale and dark massive mudstone, have been predicted. Qualitative and quantitative characterization of the micro-structures of Chang7 source rock using state-of-the-art microscopic facilities including argon ion milling - field emission scanning electron microscopy (FESEM), focused ion beam scanning electron microscopy (FIB-SEM) and Nano-CT reveal that the dominant pore types in Chang7 source rock are intra-granular pores and inter-granular pores; the pores and throats in the two kinds of lithofacies are both nano-scale, and the dark massive mudstone has better physical properties than the black shale. The Chang7 shale oil resources and mineability were evaluated based on the parameters from geochemical experiments on the source rock, including pyrolysis S1, chloroform bitumen ‘A’, TOC and thermal maturity, free hydrocarbon content, as well as geo-mechanical properties such as brittle mineral content and development of fractures. With large scale of favorable lithofacies, good storage ability and abundant hydrocarbon, Chang7 Member has the material basis for shale oil occurrence and accumulation, in addition, the shale oil there has accumulated greatly and has favorable properties for flowing in nano-scale pores and throats. All these show that Chang7 Member has high potential for shale oil exploration, in which, the dark massive mudstone is a more favorable target for shale oil exploration under the present technical conditions.
[1] 杨华, 张文正. 论鄂尔多斯盆地长 7 段优质油源岩在低渗透油气成藏富集中的主导作用: 地质地球化学特征[J]. 地球化学, 2005, 34(2): 147-154.
YANG Hua, ZHANG Wenzheng. Leading effect of the Seventh Member high-quality source rock of Yanchang Formation in Ordos Basin during the enrichment of low-penetrating oil-gas accumulation: Geology and geochemistry[J]. Geochimica, 2005, 34(2): 147-154.
[2] 吉利明, 徐金鲤. 鄂尔多斯盆地三叠纪疑源类及其与油源岩发育的关系[J]. 石油学报, 2007, 28(2): 40-48.
JI Liming, XU Jinli. Triassic acritarchs and its relation to hydrocarbon source rock in Ordos Basin[J]. Acta Petrolei Sinica, 2007, 28(2): 40-48.
[3] 章新文, 余志远, 黄庆. 泌阳凹陷陆相页岩油富集主控因素分析[J]. 石油地质与工程, 2013, 27(3): 5-11.
ZHANG Xinwen, YU Zhiyuan, HUANG Qing. Discussion on main controlling factors of continental shale oil enrichment in Biyang depression[J]. Petroleum Geology and Engineering, 2013, 27(3): 5-11.
[4] 王永诗, 李政, 巩建强, 等. 济阳坳陷页岩油气评价方法: 以沾化凹陷罗家地区为例[J]. 石油学报, 2013, 34(1): 83-91.
WANG Yongshi, LI Zheng, GONG Jianqiang, et al. Discussion on an evaluation method of shale oil and gas in Jiyang depression: A case study on Luojia area in Zhanhua sag[J]. Acta Petrolei Sinica, 2013, 34(1): 83-91.
[5] 邓美寅, 梁超. 渤南洼陷沙三下亚段泥页岩储集空间研究: 以罗69井为例[J]. 地学前缘, 2012, 19(1): 173-181.
DENG Meiyin, LIANG Chao. Studies on reservoir space of mud stone and shale of the lower section of Es 3 in Bonan subsag: An example from well Luo 69[J]. Geoscience Frontiers, 2012, 19(1): 173-181.
[6] 邹才能, 杨智, 崔景伟, 等. 页岩油形成机制、地质特征及发展对策[J]. 石油勘探与开发, 2013, 40(1): 14-26.
ZOU Caineng, YANG Zhi, CUI Jingwei, et al. Formation mechanism, geological characteristics and development strategy of nonmarine shale oil in China[J]. Petroleum Exploration and Development, 2013, 40(1): 14-26.
[7] MAIEK E, ZHANG H, BAI B J, et al. Submicro-pore characterization of shale gas plays[R]. SPE 144050, 2011.
[8] LOUCKS R G, REED R M, RUPPEL S C, et al. Morphology, genesis, and distribution of nanometer-scale pores in siliceous mudstones of the Mississippian Barnett Shale[J]. Journal of Sedimentary Research, 2009, 79: 848-861.
[9] LOUCKS R G, REED R M, RUPPEL S C, et al. Spectrum of pore types and networks in mudrocks and a descriptive classification for matrix-related mudrock pores[J]. AAPG Bulletin, 2012, 96(6): 1071-1098.
[10] 吴松涛, 朱如凯, 崔京钢, 等. 鄂尔多斯盆地长7湖相泥页岩孔隙演化特征[J]. 石油勘探与开发, 2015, 42(2): 167-176.
WU Songtao, ZHU Rukai, CUI Jinggang, et al. Characteristics of lacustrine shale porosity evolution, Triassic Chang 7 Member, Ordos Basin[J]. Petroleum Exploration and Development, 2015, 42(2): 167-176.
[11] 张金川, 林腊梅, 李玉喜, 等. 页岩油分类与评价[J]. 地学前缘, 2012, 19(5): 322-331.
ZHANG Jinchuan, LIN Lamei, LI Yuxi, et al. Classification and evaluation of shale oil[J]. Geoscience Frontiers, 2012, 19(5): 322-331.
[12] 卢双舫, 黄文彪, 陈方文, 等. 页岩油气资源分级评价标准探讨[J]. 石油勘探与开发, 2012, 39(2): 249-256.
LU Shuangfang, HUANG Wenbiao, CHEN Fangwen, et al. Classification and evaluation criteria of shale oil and gas resources: Discussion and application[J]. Petroleum Exploration and Development, 2012, 39(2): 249-256.
[13] 李吉君, 史颖琳, 章新文, 等. 页岩油富集可采主控因素分析: 以泌阳凹陷为例[J]. 地球科学——中国地质大学学报, 2014, 39(7): 848-857.
LI Jijun, SHI Yinglin, ZHANG Xinwen, et al. Control factors of enrichment and producibility of shale oil: A case study of Biyang Depression[J]. Earth Science—Journal of China University of Geosciences, 2014, 39(7): 848-857.
[14] PEPPER A S, CORVI P J. Simple kinetic models of petroleum formation: Part III: Modeling an open system[J]. Marine and Petroleum Geology, 1995, 12(4): 417-452.
[15] 宋国奇, 张林晔, 卢双舫, 等. 页岩油资源评价技术方法及其应用[J]. 地学前缘, 2013, 20(4): 221-228.
SONG Guoqi, ZHANG Linye, LU Shuangfang, et al. Resource evaluation method for shale oil and its application[J]. Geoscience Frontiers, 2013, 20(4): 221-228.
[16] 王香增, 高胜利, 高潮. 鄂尔多斯盆地南部中生界陆相页岩气地质特征[J]. 石油勘探与开发, 2014, 41(3): 294-304.
WANG Xiangzeng, GAO Shengli, GAO Chao. Geological features of Mesozoic continental shale gas in south of Ordos Basin, NW China[J]. Petroleum Exploration and Development, 2014, 41(3): 294-304.
[17] 林森虎, 邹才能, 袁选俊, 等. 美国致密油开发现状及启示[J]. 岩性油气藏, 2011, 23(4): 25-30.
LIN Senhu, ZOU Caineng, YUAN Xuanjun, et al. Status quo of tight oil exploitation in the United States and its implication[J]. Lithologic Reservoirs, 2011, 23(4): 25-30.
[18] WALLS J D, DIAZ E, DERZHI N, et al. Eagle Ford shale reservoir properties from digital rock physics[J]. First Break, 2011, 29(6): 97-101.
[19] BAI B J, ELGMATI M, ZHANG H, et al. Rock characterization of Fayetteville shale gas plays[J]. Fuel, 2013, 105: 645-652.
[20] 邹才能, 朱如凯, 白斌, 等. 致密油与页岩油内涵、特征、潜力及挑战[J]. 矿物岩石地球化学通报, 2015, 34(1): 3-17.
ZOU Caineng, ZHU Rukai, BAI Bin, et al. Significance, geologic characteristic, resource potential and future challenges of tight oil and shale oil[J]. Bulletin of Mineralogy, Petrology and Geochemistry, 2015, 34(1): 3-17.
