莫索湾凸起南斜坡中侏罗统红褐色砂泥岩段层位归属

Horizon Classification of Red-Brown Sandy Mudstone Interval in Middle Jurassic on the Southern Slope of Mosuowan Swell

莫索湾凸起南斜坡侏罗系与白垩系不整合面之下红褐色砂泥岩段油气显示活跃,中石化矿区已有多口井在这套地层获高产工业油流,并因此发现永进油田,但这套红褐色砂泥岩段的层位归属一直存在争议。以最新二维地震资料为基础,通过井震联合标定,开展研究区二维和三维连片精细地震地质解释,结合岩心及显微镜下微观特征的对比分析,认为在莫索湾凸起侏罗系顶部广泛发育的红褐色砂泥岩段应划归为中侏罗统头屯河组。层位的重新厘定明确了头屯河组为研究区的主要目的层,具备大规模成藏的条件,指明了莫索湾凸起南斜坡下一步勘探方向。

Oil and gas shows are active in the red-brown sandy mudstone interval under the unconformity surface between Jurassic and Cre-taceous strata on the southern slope of Mosuowan swell.High-yield commercial oil flow has been gained from several wells drilled by Sinopec in the sandy mudstone interval and then Yongjin oilfield has been discovered.However,the classification of horizon of the interval has always been controversial.On the basis of the latest2D seismic data and combining with well logging-seismic calibration,the paper performs2D&3D merging detailed seismic geological interpretation in the study area.Combined with the comparative analysis of core and microscopic features under microscope,it is considered that the red-brown sandy mudstone interval which is widely distributed at the top of Jurassic in Mosuowan swell should be classified into the Middle Jurassic Toutunhe formation.The re-classification of the horizon identifies that the major target zone in the study area is the Toutunhe formation which has favorable conditions for large-scale hydrocarbon accumulation,and indicates further exploration direction on the southern slope of Mosuowan swell.