为明确鄂尔多斯盆地东南部长7段页岩油气富集主控因素,综合钻井、测井、岩心分析化验等资料,对研究区长7段页岩油气富集程度及其机理进行研究.页岩解析气量与烃源岩总有机碳含量呈正比,有机质含量控制页岩油气的总含量,有机质发育大量孔隙,页岩油气以吸附态和游离态赋存于有机孔隙中.储集层孔隙结构和孔隙度影响页岩油气的含量及赋存状态,吸附油气主要赋存于微孔中,游离油气主要赋存于中孔和大孔中,但中孔中游离气含量高于大孔,而孔隙度越大,页岩中油气绝对含量越高.砂岩夹层和富有机质页岩的配置关系控制着页岩油气的富集部位,根据粉砂岩、细砂岩与页岩的关系,延长组长7段页岩油气可划分为近源和源内2类,源内又可分为砂岩与页岩互层型、页岩夹砂岩型和页岩型;下伏于富有机质页岩中的砂体和透镜状砂体油气含量最高,其次是上覆于富有机质页岩的砂体和呈舌状或指状与富有机质页岩接触的砂体.
In order to clarify the main controlling factors of shale oil and gas enrichment,the degree and mechanisms of shale oil and gas enrichment in the Chang 7 member in southeastern Ordos basin were analyzed using the data of drilling,logging,and core.Desorbed shale gas content is positively correlated with the total organic carbon content(TOC)of source rocks,the organic matter content controls the total content of shale oil and gas,and abundant pores are developed in organic matter,and shale oil and gas exist in both adsorbed and free states in these organic pores.The pore structure and porosity of the reservoir affect the content and occurrence state of shale oil and gas.Ad-sorbed oil and gas mainly exist in micropores,while free oil and gas in mesopores and macropores.The content of free gas in mesopores is higher than that in macropores,and the larger the porosity,the higher the absolute content of oil and gas in shale.The configuration be-tween sandstone interlayers and organic-rich shale controls the enrichment positions of shale oil and gas.Based on the distribution of silt-stone,fine sandstone and shale in the reservoir,the shale oil and gas in Chang 7 member can be classified into two types:near-source and in-source.The in-source shale oil and gas can be further divided into hydrocarbons from sandstone interbedded with shale,shale intercalated with sandstone,and pure shale.Sand bodies underlying the organic-rich shale and lenticular sand bodies exhibit the best potential of oil and gas,followed by sand bodies overlying the organic-rich shale or those tongue-shaped or finger-shaped ones in contact with shale.