Based on analysis of main controlling factors of Chang 9, the source rock, driving force of migration, migration and accumulation modes, reservoir forming stages and model and enrichment law of Chang 9 reservoir were ...Based on analysis of main controlling factors of Chang 9, the source rock, driving force of migration, migration and accumulation modes, reservoir forming stages and model and enrichment law of Chang 9 reservoir were examined. The study showed that the oil of Chang 9 reservoir in the Jiyuan and Longdong(Eastern Gansu) areas came primarily from the source rock of Chang 7 Member, but the oil of Chang 9 reservoir in the Zhidan area came primarily from the source rock of Chang 9 Member. There developed lithologic-structural oil reservoirs in Gufengzhuang-Mahuangshan area in northwest Jiyuan, structural-lithologic oil reservoirs in east Jiyuan, and lithologic reservoirs in Huachi–Qingcheng area and Zhidan area. The overpressure of Chang 7 Member was the driving force of oil migration. The burial history showed that Chang 9 Member experienced two stages of reservoir forming, the reservoir formed in the Late Jurassic was smaller in charging scope and scale, and the Early Cretaceous was the period when the source rock generated oil and gas massively and the Chang 9 reservoir came into being. Along with the tectonic movements, Chang 7 bottom structure turned from high in the west and lower in the East in the sedimentary stage to high in the east and lower in the west in the hydrocarbon accumulation stage and at last to gentle western-leaning monoclinal structure at present. In Early Cretaceous, the Chang 7 bottom structure was the lowest in the west of Huanxian-Huachi-Wuqi-Dingbian areas, so the oil migrated laterally towards the higher positions around after entering the reservoir. In the main reservoir forming period, Chang 7 bottom had an ancient anticline in Mahuangshan-Hongjingzi area of west Jiyuan, controlling the oil reservoir distribution in west Jiyuan.展开更多
In the Triassic Yanchang Formation, Jiyuan-Wuqi area, Ordos Basin, the Chang 6 reservoir is contacted to the Chang 7 high-quality source rock, but the oil pools are unevenly distributed, and complex in oil and water d...In the Triassic Yanchang Formation, Jiyuan-Wuqi area, Ordos Basin, the Chang 6 reservoir is contacted to the Chang 7 high-quality source rock, but the oil pools are unevenly distributed, and complex in oil and water distribution. Through cores observation and fracture statistics, combined with comprehensive analyses of physical property, mercury injection, logging and geochemical data, and comparisons of the sandbodies scales, reservoir physical properties, argillaceous laminae and fractures between source and reservoir in the eastern and western oil-bearing areas and in the central water producing area, it is found that the hydrocarbon accumulation patterns are different in the eastern, central and western areas, and the characteristics of hydrocarbon migration under the background of double-provenance were sorted out. The study results show that the crude oil in the eastern area has different Pr/Ph and sterane distribution from that in the western area. The oil and gas primarily migrated vertically. The high-quality source rocks and favorable source-reservoir-cap combinations lay the foundation for large-scale oil and gas accumulations. Vertically, the oil and gas enrichment is controlled by the scale of sandbody and the difference of physical properties, while on the plane, it is controlled by the connectivity of sandbodies, the argillaceous laminae between source rock and reservoir, the reservoir physical property and the fractures. The sandbodies of oil-rich zones in the eastern and western areas have large thickness, low shale content, good physical properties, weak heterogeneity, few argillaceous laminae and abundant fractures, all of which are favorable for the vertical migration and accumulation of oil and gas. In contrast, in the middle area with converging provenances, the reservoirs, composed of thin sandbodies, features rapid variation in lithology and physical properties, strong heterogeneity, poor continuity of sandbodies, abundant argillaceous laminae between source rock and reservoir, and few fractures, makes it difficult for the oil and gas to migrate vertically, and results in low oil enrichment degree ultimately. For the exploration of continental multiple-provenance tight reservoirs, not only the good-property source rocks and reservoirs, but more importantly the source-reservoir contact relationship and the effect of fractures on the hydrocarbon migration and accumulation should be considered.展开更多
An important factor to evaluate reservoir quality is the pore-throat size.However,the strong heterogeneity makes it difficult to characterize the pore-throat distribution in tight reservoirs.The field emission scannin...An important factor to evaluate reservoir quality is the pore-throat size.However,the strong heterogeneity makes it difficult to characterize the pore-throat distribution in tight reservoirs.The field emission scanning electron microscope(FESEM),high pressure mercury injection and rate-controlled mercury injection are used to investigate the pore-throat size distribution in tight sandstone reservoirs of Member 7 of the Yanchang Formation in eastern Gansu,Ordos Basin,and studies of the pore throat size controlling on physical property of the tight sandstone reservoirs are also carried out.The result shows that the pore type is mainly dominated by the residual intergranular pore,dissolution pore,micropore and a few micro-fractures;the high-pressure mercury injection experiment indicates that the pore-throat size ranges from 0.0148 μm to 40mm,the pore throat more than 1 mm is less;the ratecontrolled mercury injection experiment reveals that for samples with different physical properties,the pore radius mainly varies from 80 μm to 350 μm;the throat radius exhibits the strong heterogeneity,and is from 0.12 μm to 30μm;the pore-throat size can be effectively characterized by combination of high-pressure and rate-controlled mercury injections,and it varies from 0.0148 μm to 350 μm.The permeability is mainly controlled by the large pore throat(>R_(50))which accounts for a small proportion;in the tight sandstone with the permeability greater than 0.1 mD,the permeability is mainly controlled by the micropore and mesopore;in the tight sandstone with the permeability smaller than 0.1 mD,the permeability is mainly controlled by the nanopore and micropore;the proportion of small pore throat increases with reduction of permeability,it is important that the small pore throat influences the reservoir storage property though its effect on permeability are small.展开更多
综合利用地球化学、扫描电镜、岩心薄片、测井等资料以及油井生产数据等,对鄂尔多斯盆地陕北地区三叠系延长组7段储层特征、烃源岩特征和致密油分布特征进行了分析,从烃源岩展布、输导体系和源-储组合关系3个方面对致密油差异富集控制...综合利用地球化学、扫描电镜、岩心薄片、测井等资料以及油井生产数据等,对鄂尔多斯盆地陕北地区三叠系延长组7段储层特征、烃源岩特征和致密油分布特征进行了分析,从烃源岩展布、输导体系和源-储组合关系3个方面对致密油差异富集控制因素进行了探讨,并总结了成藏模式。研究结果表明:(1)陕北地区长7段致密砂岩储层主要分布在一亚段(长71)和二亚段(长72),以灰色—灰白色长石砂岩和岩屑长石砂岩为主,长71和长72平均孔隙度分别为5.56%和7.32%,平均渗透率分别为0.097 m D和0.110 m D,长72储层物性更好;孔隙空间以溶孔为主,发育少量粒间孔。(2)研究区烃类主要来源于本地长72顶部和长73这2套烃源岩,平均厚度大于20 m,有机质丰度高,平均TOC值为3.02%,干酪根类型以Ⅰ型和Ⅱ1型为主,处于生烃高峰期,平均生烃量为270.2×10^(4)t/km^(2),长73烃源岩生烃潜力更大,供烃至长72储层,长71致密油来源于长72烃源岩;新安边地区三角洲前缘亚相末端的长72储层中致密油由湖盆烃源岩侧向供烃。(3)研究区致密油富集受烃源岩展布、砂体连通性以及源-储组合共同控制,在长72更富集,在新安边地区分布面积最大,安塞地区无大规模致密油聚集;纵向上和平面上致密油的聚集差异受控于烃源岩厚度和源-储组合关系,下生上储、上下生油而中间储集和砂泥互层时含油性更好;新安边地区三角洲前缘亚相末端的长72致密油聚集规模大于三角洲前缘主体,是由于三角洲前缘末端发育的局部连通砂体阻碍了湖盆烃类物质的侧向运移。(4)研究区致密油为“源控-砂控”成藏模式,远源河道优势砂体尖灭处和近源局部连通的砂体是有利勘探区。展开更多
基金Supported by China National Science and Technology Major Project(2016ZX05050,2017ZX05001002-008)the PetroChina Science and Technology Major Project(2016E-0501)
文摘Based on analysis of main controlling factors of Chang 9, the source rock, driving force of migration, migration and accumulation modes, reservoir forming stages and model and enrichment law of Chang 9 reservoir were examined. The study showed that the oil of Chang 9 reservoir in the Jiyuan and Longdong(Eastern Gansu) areas came primarily from the source rock of Chang 7 Member, but the oil of Chang 9 reservoir in the Zhidan area came primarily from the source rock of Chang 9 Member. There developed lithologic-structural oil reservoirs in Gufengzhuang-Mahuangshan area in northwest Jiyuan, structural-lithologic oil reservoirs in east Jiyuan, and lithologic reservoirs in Huachi–Qingcheng area and Zhidan area. The overpressure of Chang 7 Member was the driving force of oil migration. The burial history showed that Chang 9 Member experienced two stages of reservoir forming, the reservoir formed in the Late Jurassic was smaller in charging scope and scale, and the Early Cretaceous was the period when the source rock generated oil and gas massively and the Chang 9 reservoir came into being. Along with the tectonic movements, Chang 7 bottom structure turned from high in the west and lower in the East in the sedimentary stage to high in the east and lower in the west in the hydrocarbon accumulation stage and at last to gentle western-leaning monoclinal structure at present. In Early Cretaceous, the Chang 7 bottom structure was the lowest in the west of Huanxian-Huachi-Wuqi-Dingbian areas, so the oil migrated laterally towards the higher positions around after entering the reservoir. In the main reservoir forming period, Chang 7 bottom had an ancient anticline in Mahuangshan-Hongjingzi area of west Jiyuan, controlling the oil reservoir distribution in west Jiyuan.
基金Supported by the National Natural Science Foundation of China(41872165,41572137)
文摘In the Triassic Yanchang Formation, Jiyuan-Wuqi area, Ordos Basin, the Chang 6 reservoir is contacted to the Chang 7 high-quality source rock, but the oil pools are unevenly distributed, and complex in oil and water distribution. Through cores observation and fracture statistics, combined with comprehensive analyses of physical property, mercury injection, logging and geochemical data, and comparisons of the sandbodies scales, reservoir physical properties, argillaceous laminae and fractures between source and reservoir in the eastern and western oil-bearing areas and in the central water producing area, it is found that the hydrocarbon accumulation patterns are different in the eastern, central and western areas, and the characteristics of hydrocarbon migration under the background of double-provenance were sorted out. The study results show that the crude oil in the eastern area has different Pr/Ph and sterane distribution from that in the western area. The oil and gas primarily migrated vertically. The high-quality source rocks and favorable source-reservoir-cap combinations lay the foundation for large-scale oil and gas accumulations. Vertically, the oil and gas enrichment is controlled by the scale of sandbody and the difference of physical properties, while on the plane, it is controlled by the connectivity of sandbodies, the argillaceous laminae between source rock and reservoir, the reservoir physical property and the fractures. The sandbodies of oil-rich zones in the eastern and western areas have large thickness, low shale content, good physical properties, weak heterogeneity, few argillaceous laminae and abundant fractures, all of which are favorable for the vertical migration and accumulation of oil and gas. In contrast, in the middle area with converging provenances, the reservoirs, composed of thin sandbodies, features rapid variation in lithology and physical properties, strong heterogeneity, poor continuity of sandbodies, abundant argillaceous laminae between source rock and reservoir, and few fractures, makes it difficult for the oil and gas to migrate vertically, and results in low oil enrichment degree ultimately. For the exploration of continental multiple-provenance tight reservoirs, not only the good-property source rocks and reservoirs, but more importantly the source-reservoir contact relationship and the effect of fractures on the hydrocarbon migration and accumulation should be considered.
基金The work was supported by the Natural Science Foundation of China(No.41672098,No.41602133)the National Science and Technology Major Project of China(No.2011ZX05007-003,2016ZX05006-006)PetroChina Special Projects(2011E-2602).
文摘An important factor to evaluate reservoir quality is the pore-throat size.However,the strong heterogeneity makes it difficult to characterize the pore-throat distribution in tight reservoirs.The field emission scanning electron microscope(FESEM),high pressure mercury injection and rate-controlled mercury injection are used to investigate the pore-throat size distribution in tight sandstone reservoirs of Member 7 of the Yanchang Formation in eastern Gansu,Ordos Basin,and studies of the pore throat size controlling on physical property of the tight sandstone reservoirs are also carried out.The result shows that the pore type is mainly dominated by the residual intergranular pore,dissolution pore,micropore and a few micro-fractures;the high-pressure mercury injection experiment indicates that the pore-throat size ranges from 0.0148 μm to 40mm,the pore throat more than 1 mm is less;the ratecontrolled mercury injection experiment reveals that for samples with different physical properties,the pore radius mainly varies from 80 μm to 350 μm;the throat radius exhibits the strong heterogeneity,and is from 0.12 μm to 30μm;the pore-throat size can be effectively characterized by combination of high-pressure and rate-controlled mercury injections,and it varies from 0.0148 μm to 350 μm.The permeability is mainly controlled by the large pore throat(>R_(50))which accounts for a small proportion;in the tight sandstone with the permeability greater than 0.1 mD,the permeability is mainly controlled by the micropore and mesopore;in the tight sandstone with the permeability smaller than 0.1 mD,the permeability is mainly controlled by the nanopore and micropore;the proportion of small pore throat increases with reduction of permeability,it is important that the small pore throat influences the reservoir storage property though its effect on permeability are small.
文摘综合利用地球化学、扫描电镜、岩心薄片、测井等资料以及油井生产数据等,对鄂尔多斯盆地陕北地区三叠系延长组7段储层特征、烃源岩特征和致密油分布特征进行了分析,从烃源岩展布、输导体系和源-储组合关系3个方面对致密油差异富集控制因素进行了探讨,并总结了成藏模式。研究结果表明:(1)陕北地区长7段致密砂岩储层主要分布在一亚段(长71)和二亚段(长72),以灰色—灰白色长石砂岩和岩屑长石砂岩为主,长71和长72平均孔隙度分别为5.56%和7.32%,平均渗透率分别为0.097 m D和0.110 m D,长72储层物性更好;孔隙空间以溶孔为主,发育少量粒间孔。(2)研究区烃类主要来源于本地长72顶部和长73这2套烃源岩,平均厚度大于20 m,有机质丰度高,平均TOC值为3.02%,干酪根类型以Ⅰ型和Ⅱ1型为主,处于生烃高峰期,平均生烃量为270.2×10^(4)t/km^(2),长73烃源岩生烃潜力更大,供烃至长72储层,长71致密油来源于长72烃源岩;新安边地区三角洲前缘亚相末端的长72储层中致密油由湖盆烃源岩侧向供烃。(3)研究区致密油富集受烃源岩展布、砂体连通性以及源-储组合共同控制,在长72更富集,在新安边地区分布面积最大,安塞地区无大规模致密油聚集;纵向上和平面上致密油的聚集差异受控于烃源岩厚度和源-储组合关系,下生上储、上下生油而中间储集和砂泥互层时含油性更好;新安边地区三角洲前缘亚相末端的长72致密油聚集规模大于三角洲前缘主体,是由于三角洲前缘末端发育的局部连通砂体阻碍了湖盆烃类物质的侧向运移。(4)研究区致密油为“源控-砂控”成藏模式,远源河道优势砂体尖灭处和近源局部连通的砂体是有利勘探区。
