沉积相分析在岩性油气藏勘探中的应用

Application of Sedimentary Facies Analysis in Lithologic Reservoir Exploration

针对东濮凹陷柳屯洼陷沙三中亚段储层平面变化快、纵向多期叠加、岩性油气藏潜力区不明确的问题,运用沉积相综合分析方法,利用岩心地质分析、地震综合解释及测井相分析等手段,明确了柳屯洼陷沉积体系时空展布特征。研究结果表明:柳屯洼陷西南斜坡为主要物源区,沿邢庄断层下降盘发育大型辫状河三角洲扇体;由于单斜构造,水下分流河道砂体沿上倾方向尖灭,形成岩性遮挡,发育上倾尖灭岩性圈闭,是岩性油气藏勘探的有利地区;洼陷东翼、西翼是次要物源区,其中,洼陷东翼沙三中6-沙三中12砂组局部发育浊积扇,沙三中1砂组发育厚层盐岩封盖,形成透镜体岩性油气藏,是进一步扩展岩性油气藏勘探的良好地区。

The middle Shahejie3 Member in the Liutun subsidence of Dongpu Sag is characterized by large lateral reservoir variation,longitudinal multi-stage superimposition,unclear lithologic reservoir potential zone,etc.Comprehensive sedimentary facies,core test,seismic interpretation and logging facies analyses were used to clarify the spatiotemporal distribution patterns of sedimentary system in Liutun subsidence.Research indicates that the southwestern slope zone in the Liutun subsidence is considered as the major source area,which leads to the development of large-scale braided river delta fans along the descending side of Xingzhuang fault.The underwater distributary channel pinches out along the up-dip direction and creates a lithological barrier due to the monoclinic structure.The corresponding lithologic traps with up-dip pinchout are regarded as the favorable hydrocarbon exploration zones.The east and west wings are considered as the secondary source areas.Turbidite fans locally developed within the middle Shahejie3-6 to middle Shahejie3-12 sand groups in the east wing.The Shahejie3-1 sand group is covered with thick halite caprock,forming a lenticular lithologic reservoir,which is a favorable zone for subsequent lithologic reservoir exploration.