鄂尔多斯盆地张家湾地区长7页岩油气储集特征及其影响因素
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摘要
鄂尔多斯盆地张家湾地区延长组长7湖相页岩中已发现了页岩气和部分工业油流。页岩层系中的孔隙类型、孔径大小和分布特征等对页岩储层的储集能力、渗透性、页岩油气赋存状态和含量均有重要影响。利用氩离子抛光和场发射扫描电镜分析、低压CO_2与N_2吸附、XRD等测试方法,分析了长7页岩油气储层的地球化学特征、孔隙类型、孔径分布及影响因素。结果表明,该区长7页岩厚度大(30～110m),有机质丰度和含油量高(TOC值平均为4.97%,可溶烃含量平均为4.54mg/g,氯仿沥青"A"含量平均为0.80%),R_O值主要介于0.6%～1.1%之间,热解峰T_(max)值为430～469℃。页岩孔隙类型多样,残余粒间孔、粒间溶蚀孔、粒内溶蚀孔、黄铁矿集合体和黏土矿物晶间孔、有机孔等均发育,有机孔孔径多数小于50nm,为微孔和介孔,占有机孔总数的61%,部分大于100nm。刚性颗粒间孔、粒内溶孔、刚性颗粒和黏土矿物间的无机粒间孔的孔径相对较大,黏土矿物粒内孔孔径相对较小。该区长7页岩孔隙度介于0.8%～7.7%之间,平均为3.2%。孔隙孔径主要介于0.8～10μm之间,具有多峰分布的特点,不同岩性和岩石组合样品的孔径分布曲线存在较大差异。页岩中粉砂岩纹层越发育,刚性碎屑的粒度越大,石英和长石含量越高,黏土矿物含量越低,中大孔越发育,孔隙度越大;TOC、有机质热演化程度越高,有机孔越发育。
Shale oil and gas have been drilled in the Chang 7 lacustrine shale in Zhangjiawan area of OrdoBasin.The pore type,pore size and distribution of shale have important effects on the physical property,reservoir permeability,the occurrence state and content of shale oil and gas.The Chang 7 shale reservoir geochemical characteristics and pore types,pore size distribution and influencing factors were analyzed by using argon ion polishing and field emission scanning electron microscopy(SEM)analysis,the low pressurCO_2,N_2 adsorption,XRD and other test methods in this paper.Results show that the thickness of the shalranges from 30 to 110 m.The average TOCis 4.97%,the average content of soluble hydrocarbon is abou4.54 g/g,the average content of chloroform bitumen "A"is 0.80%,and R_O is between 0.6% and 1.1%Shale pore types include residual intergranular pores,intergranular dissolution pore,intragranular dissolution pore,intercrystalline pores of pyrite and clay minerals,organic pores.About 61 percent of the organipores are micro-pores and meso-pores,with diameter less than 50 nm.The pores of intergranular pores anintraplasmic dissolution pores are relatively large.The diameters of the pores of clay minerals are relativelsmall.The porosity of Chang 7 shale is between 0.8%and 6.5%,with an average of 3.2%.The pore diameter is between 0.8 nm and 10μm,and it has the characteristics of multi-peak distribution.The pore diametedistribution curves of samples with different lithology and rock composition are quite different.The mordeveloped the siltstone and fine sandstone laminar in shale,the larger the particle size of detritus,the higher the content of quartz and feldspar,the lower the content of clay minerals,the more developed the middland large pores,and the greater the porosity.The higher the total organic carbon content and organic matteevolution,the more developed the organic pore.
Shale oil and gas have been drilled in the Chang 7 lacustrine shale in Zhangjiawan area of OrdoBasin.The pore type,pore size and distribution of shale have important effects on the physical property,reservoir permeability,the occurrence state and content of shale oil and gas.The Chang 7 shale reservoir geochemical characteristics and pore types,pore size distribution and influencing factors were analyzed by using argon ion polishing and field emission scanning electron microscopy(SEM)analysis,the low pressurCO_2,N_2 adsorption,XRD and other test methods in this paper.Results show that the thickness of the shalranges from 30 to 110 m.The average TOCis 4.97%,the average content of soluble hydrocarbon is abou4.54 g/g,the average content of chloroform bitumen "A"is 0.80%,and R_O is between 0.6% and 1.1%Shale pore types include residual intergranular pores,intergranular dissolution pore,intragranular dissolution pore,intercrystalline pores of pyrite and clay minerals,organic pores.About 61 percent of the organipores are micro-pores and meso-pores,with diameter less than 50 nm.The pores of intergranular pores anintraplasmic dissolution pores are relatively large.The diameters of the pores of clay minerals are relativelsmall.The porosity of Chang 7 shale is between 0.8%and 6.5%,with an average of 3.2%.The pore diameter is between 0.8 nm and 10μm,and it has the characteristics of multi-peak distribution.The pore diametedistribution curves of samples with different lithology and rock composition are quite different.The mordeveloped the siltstone and fine sandstone laminar in shale,the larger the particle size of detritus,the higher the content of quartz and feldspar,the lower the content of clay minerals,the more developed the middland large pores,and the greater the porosity.The higher the total organic carbon content and organic matteevolution,the more developed the organic pore.
引文
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[13]Yang Junjie.Structural Evolution and Oil and Gas Distribution of Ordos Basin[M].Beijing:Petroleum Industry Press,2002:20-245.杨俊杰.鄂尔多斯盆地构造演化与油气分布规律[M].北京:石油工业出版社,2002:20-245.
[14]Wang Jianmin,Wang Jiayuan.Low-amplitude structures and oil-gas enrichment on the Yishaan Slope,Ordos Basin[J].Petroleum Exploration and Development,2013,40(1):49-57.王建民,王佳媛.鄂尔多斯盆地伊陕斜坡上的低幅度构造与油气富集[J].石油勘探与开发,2013,40(1):49-57.
[15]He Zixin.Evolution and Petroleum of Ordos Basin[M].Beijing:Petroleum Industry Press,2003:20-245.何自新.鄂尔多斯盆地演化与油气[M].北京:石油工业出版社,2003:20-245.
[16]Cheng Ming,Luo Xiaorong,Lei Yuhong,et al.The distribution,fractal characteristic and thickness estimation of siltylaminae and beds in Zhangjiatan shale,Ordos Basin[J].Natural Gas Geoscience,2015,26(5):845-854.程明,罗晓容,雷裕红,等.鄂尔多斯盆地张家滩页岩粉砂质夹层/纹层分布、分形特征和估算方法研究[J].天然气地球科学,2015,26(5):845-854.
[17]Guo H J,Jia W L,Peng P A,et al.The composition and its impact on the methane sorption of lacustrine shales from the Upper Triassic Yanchang Formation,Ordos Basin,China[J].Marine and Petroleum Geology,2014(57):509-520.
[18]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.
[19]Loucks R G,Reed R M,Ruppel S C,et al.Morphology,genesis,and distribution of nanometerscale pores in mudstones of the Mississippian Barnett Shale[J].Journal of Sedimentary Research,2009,79(12):848-861.
[20]Bernard S,Horsfield B,Schulz H M,et al.Geochemical evolution of organic-rich shales with increasing maturity:A STXMand TEM study of the Posidonia Shale(Lower Toarcian,northern Germany)[J].Marine and Petroleum Geology,2012,30(1):70-89.
[2]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(12):848-861.
[3]Sondergeld C H,Newsham K E,Comisky J T,et al.Petrophysical considerations in evaluation and producing shale gas resources[C]∥Pittsburgh:Society of Petroleum Engineers,2010.
[4]Josh M,Esteban L,Piane C D,et al.Laboratory characterisation of shale properties[J].Journal of Petroleum Science and Engineering,2012,(88/89):107-124.
[5]Chalmers G R,Bustin R M,Power I M.Characterization of gas shale pore systems by porosimetry,pycnometry,surface area,and field emission scanning electron microscopy/transmission electron microscopy image analyses:Examples from the Barnett,Woodford,Haynesville,Marcellus,and Doigunits[J].AAPG Bulletin,2012,96(6):1099-1119.
[6]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.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.
[7]Kong Qingfen.The organic maceral characteristic of Yanchang source rock in Ordos Basin[J].Xinjiang Petroleum Geology,2007,28(2):163-166.孔庆芬.鄂尔多斯盆地延长组烃源岩有机显微组分特征[J].新疆石油地质,2007,28(2):163-166.
[8]Jiang Chengfu,Wang Xiangzeng,Zhang Lixia,et al.Geological characteristics of shale and exploration potential of continental shale gas in 7th member of Yanchang Formation,southeast Ordos Basin[J].Geology in China,2013,20(6):1880-1888.姜呈馥,王香增,张丽霞,等.鄂尔多斯盆地东南部延长组长7段陆相页岩气地质特征及勘探潜力评价[J].中国地质,2013,20(6):1880-1888.
[9]Lei Y H,Luo X R,Wang X Z,et al.Characteristics of silty laminae in Zhangjiatan shale of southeastern Ordos Basin,China:Implications for shale gas formation[J].AAPG Bulletin,2015,99(4):661-687.
[10]Zhang W Z,Xie L Q,Yang W W.Micro fractures and pores in lacustrine shales of the Upper Triassic Yanchang Chang 7member,Ordos Basin,China[J].Journal of Petroleum Science&Engineering,2017,156:194-201.
[11]Zou Caineng,Dong Dazhong,Yang Hua,et al.Conditions of shale gas accumulation and exploration practices in China[J].Natural Gas Industry,2011,31(12):26-39.邹才能,董大忠,杨桦,等.中国页岩气形成条件及勘探实践[J].天然气工业,2011,31(12):26-39.
[12]Wang Xiangzeng,Zhang Lixia,Lei Yuhong,et al.Characteristics of migrated organic matters and organic pores in shale:An example from shale in the 7th member of Yanchang Formation,southeast Ordos Basin[J].Acta Petrolei Sinica,2018,39(2):141-152.王香增,张丽霞,雷裕红,等.低熟湖相页岩内运移固体沥青和有机质特征---以鄂尔多斯盆地东南部延长组长7油层组为例[J].石油学报,2018,39(2):141-152.
[13]Yang Junjie.Structural Evolution and Oil and Gas Distribution of Ordos Basin[M].Beijing:Petroleum Industry Press,2002:20-245.杨俊杰.鄂尔多斯盆地构造演化与油气分布规律[M].北京:石油工业出版社,2002:20-245.
[14]Wang Jianmin,Wang Jiayuan.Low-amplitude structures and oil-gas enrichment on the Yishaan Slope,Ordos Basin[J].Petroleum Exploration and Development,2013,40(1):49-57.王建民,王佳媛.鄂尔多斯盆地伊陕斜坡上的低幅度构造与油气富集[J].石油勘探与开发,2013,40(1):49-57.
[15]He Zixin.Evolution and Petroleum of Ordos Basin[M].Beijing:Petroleum Industry Press,2003:20-245.何自新.鄂尔多斯盆地演化与油气[M].北京:石油工业出版社,2003:20-245.
[16]Cheng Ming,Luo Xiaorong,Lei Yuhong,et al.The distribution,fractal characteristic and thickness estimation of siltylaminae and beds in Zhangjiatan shale,Ordos Basin[J].Natural Gas Geoscience,2015,26(5):845-854.程明,罗晓容,雷裕红,等.鄂尔多斯盆地张家滩页岩粉砂质夹层/纹层分布、分形特征和估算方法研究[J].天然气地球科学,2015,26(5):845-854.
[17]Guo H J,Jia W L,Peng P A,et al.The composition and its impact on the methane sorption of lacustrine shales from the Upper Triassic Yanchang Formation,Ordos Basin,China[J].Marine and Petroleum Geology,2014(57):509-520.
[18]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.
[19]Loucks R G,Reed R M,Ruppel S C,et al.Morphology,genesis,and distribution of nanometerscale pores in mudstones of the Mississippian Barnett Shale[J].Journal of Sedimentary Research,2009,79(12):848-861.
[20]Bernard S,Horsfield B,Schulz H M,et al.Geochemical evolution of organic-rich shales with increasing maturity:A STXMand TEM study of the Posidonia Shale(Lower Toarcian,northern Germany)[J].Marine and Petroleum Geology,2012,30(1):70-89.
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