酒泉盆地营尔凹陷下白垩统中沟组源储一体成藏条件

摘要

应用岩石热解、有机碳、有机岩石学等烃源岩地球化学分析资料,对营尔凹陷下白垩统中沟组烃源岩特征进行研究,发现烃源岩有机碳含量高,平均值达1.51%,有机质类型以Ⅰ型和Ⅱ1型为主,镜质体反射率(Ro)分布在0.5% ~1.04%之间,并结合沉积相、地层厚度,分析烃源岩平面展布特征,平面分布范围广,厚度最大达1200 m;利用铸体薄片、常规压汞等岩心分析资料对储层特征进行研究,储集空间类型原生孔隙、次生孔隙均有发育,储集物性偏差,孔隙度平均值7.42%,渗透率平均值0.75 mD;应用饱和烃气相色谱、色谱质谱等实验分析数据,对烃源岩、原油的生物标志物特征进行分析,明确油气来源,认为原油来自本身烃源岩.研究表明:烃源岩品质好,有机质丰度高,有机质类型偏腐泥型,热演化程度处于低熟-成熟阶段,主要以生油为主,厚度中心分布在南、北2次凹;储层以扇三角洲砂岩和湖相碳酸盐岩为主,碳酸盐岩分布在酒参1-营参1井一带,物性属于致密-低孔低渗型,储集空间类型以次生孔隙为主;油气分布在碳酸盐岩发育段,具备源储一体的成藏特征.%Using the source rock geochemistry analysis data of rock pyrolysis,organic carbon and organ-ic petrology hydrocarbon,studied the source rocks characteristics of Zhonggou Formation in the Lower Cretaceous Ying'er Sag,and found that the organic carbon content of the source rock is higher,the av-erage reaches 1.51%,the organic matter type is given priority to with Ⅰand Ⅱ1,and the reflectance (Ro)of vitrinite is distributed between 0.5% and 1.04%. The conventional mercury injection was used to study the reservoir characteristics,found that the space types of the reservoir developed the pri-mary pore and the secondary pore with characteristics of the plane distribution of the source rocks,the source rock is thick and widespread in the area,with maximum thickness of 1 200 m.Adpoting the casting thin sections reservoir physical property deviation,the average of the porosity is 7.42%,the av-erage permeability is 0.75 mD. Finally,the data of saturated hydrocarbon gas chromatography and chromatographic mass spectrometry were applied to study the biomarker characteristics of the source rocks and crude oil,to determine source of oil and gas,crude oil was from the autogenic resource rock. It demonstrates that the quality of source rocks is good,the organic matter abundance is high,the type of organic matter type is bias the sapropel type,the degree of thermal evolution stands in the stage of lower mature-mature,mainly based on raw oil,the thickness center is located in south and north"twice".The reservoir lithology is based on the fan delta sandstone and lake carbonate rocks,the car-bonate rocks are only distributed in the area of Jiucan 1-Yingcan 1.The reservoir physical property be-longs to the type of tight-lower pore-lower permeability.The type of reservoir space is mainly secondary porosity.Oil and gas layer is focused on the section of the carbonate rocks development with the accumu-lation characteristics of source-reservoir integration.