周家湾地区前侏罗纪古地貌恢复及油气富集规律

Rebuilding Paleogeomorphology of Pre-Jurassic and Oil-Gas Accumulation Regulation in Zhoujiawan Area

前侏罗纪古地貌控制着中下侏罗统沉积发育及油气的富集规律,精确恢复刻画古地貌形态对于侏罗系油气勘探至关重要.以鄂尔多斯盆地周家湾地区为例,在沉积相、砂体展布、古流向物源、古厚度恢复、古水深校正等分析的基础上,结合地质、钻井、测井等解释资料,应用三维储层建模技术,定性定量地对前侏罗纪古地貌进行了恢复.同时建立了三维砂体、孔隙度、渗透率模型,从生、储、盖、圈、运、保等油气成藏条件,直观地解释了古地貌油气富集规律.依据以上模型,预测出油气有利储集区分布在三大斜坡储集带的河流边滩砂体和河谷内的心滩处,为勘探开发提供了可靠依据.

Pre-Jurassic paleogeomorphology controls not only the deposit and development of the Early Jurassic but also oilgas accumulation regulation. It is important to rebuild the paleogeomorphology accurately for oil-gas exploration of the Jurassic. Taking the Zhoujiawan area in the Ordos basin as an example and using 3D reservoir modeling techniques and an interpretation of the geology, drilling and logging, this paper rebuilds the paleogeomorphology of the pre-Jurassic based on analyses of sedimentary facies, sand body, flow direction, paleoburial depth reconstruction and paleobathymetric correction. At the same time, 3D sand body, porosity and permeability models are built. Using oil-gas reservoir forming conditions such as generating, storing, covering, trapping, migrating and preserving, the model visually interprets the regulations of oil-gas accumulation. According to the above models, favorable hydrocarbon accumulation areas are forecasted. They are located on the sand body of river marginal banks and the channel bars of river valleys on the three ramp reservoir regions. The models offer reliable evidence for exploratory development.