摘要
近年来,鄂尔多斯盆地长7段页岩层系致密储层油藏勘探取得重大突破,其储层充注物性下限的大小是评价该地区致密油勘探开发潜力的关键.本次研究通过孔隙度、渗透率(简称为孔渗)含油饱和度分析以及高压压汞等实验方法,采用物性试油法、经验统计法和孔喉半径法分析不同地区、不同层位致密储层充注物性下限,并探讨其控制因素和对油气富集的影响.结果表明:陇东—姬塬地区致密砂岩以石英为主,储层孔渗平均为8.17％和0.15 ×10-3 μm2;陕北地区致密砂岩以长石为主,储层孔渗平均为8.20％和0.21 ×10-3 μm2.陇东—姬塬地区的长71段致密储层孔渗下限为4.93％和0.034 × 10-3 μm2,长72段致密储层孔渗下限为4.36％和0.027 × 10-3 pm2;陕北地区长71段致密储层孔渗下限为5.90％和0.048 × 10-3 µm2,长72段致密储层孔渗下限为5.60％和0.043 × 10-3μm2.储层充注物性下限受储层物性、源岩生烃能力和源储间距三个因素影响.储层物性好、烃源岩生烃能力强、源储间距小的地区储层充注下限低,如烃源岩厚度更大的陇东—姬塬地区储层充注下限低于陕北地区,源储间距小的长72段储层充注下限低于长71段.储层充注物性下限越低,储层含油饱和度越高.储层充注下限低的陇东地区,平均含油饱和度为31.28％,陕北地区平均含油饱和度则为28.40％,明显低于陇东地区.同理,长72段储层含油饱和度高于长71段储层.
Abstract
Recently,significant breakthroughs have been achieved in exploring tight reservoirs within the Chang 7 Member of the Yanchang Formation in the Ordos Basin.The lower limit of reservoir filling material properties is crucial for assessing the potential for tight oil exploration and development in this area.In this study,we ana-lyzed the lower limit of physical properties for filling materials in tight reservoirs across different regions and lay-ers using pore penetration analysis,oil saturation measurement,and high-pressure mercury injection.Addition-ally,we examined the lower limit of physical properties for filling materials in tight reservoirs across different regions and layers using the physical oil test method,empirical statistical analysis,and pore throat radius meth-od.We also explored the controlling factors and their influence on the oil and gas enrichment.The results indi-cate that in the Longdong-Jiyuan area,dense sandstone is primarily composed of quartz,with an average reser-voir pore penetration of 8.17％and 0.15 × 10-3µm2;in contrast,the dense sandstone in north Shaanxi is pre-dominantly feldspar,exhibiting an averages reservoir pore penetration of 8.20％and 0.21 × 10-3μm2.In the Longdong-Jiyuan area,the lower limit of physical properties for dense reservoirs in the Chang 71 submember is 4.93％and 0.034 × 10-3 μm2,while in the Chang 72 submember,it is 4.36％and 0.027 × 10-3 μm2.In north Shaaxi,the lower limit of the physical properties for dense reservoirs in the Chang 7,submember is 5.90％and 0.048 × 10-3 µm2,while in the Chang 72 submember,it is 5.60％and 0.043 × 10-3 μm2.The lower limit of reservoir filling is influenced by three factors:the physical properties of the reservoir,the hydro-carbon generation capacity of source rocks,and the distance between the sources and reservoirs.The lower lim-it of reservoir filling is lower in the areas with favorable reservoir properties,high hydrocarbon generation capaci-ty of source rocks,and minimal distance between sources and reservoirs.For example,in the Longdong-Jiyuan area,where the thickness of hydrocarbon source rocks is greater than in north Shaanxi,the lower limit of reser-voir filling is lower.The lower limit of reservoir filling is lower in the Chang 72 submember,where the distance between sources and reservoirs is smaller compared to the Chang 7,submember.A lower limit of reservoir fill-ing is associated with higher oil saturation.For example,in the Longdong area,the lower limit of reservoir fill-ing is relatively low,the average oil saturation is 31.28％.In contrast,the average oil saturation innorth Shaanxi is 28.40％,which is significantly lower than in Longdong.Similarly,the oil saturation in the Chang 72 submember reservoir is higher compared to the Chang 7,submember reservoir.
维普
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