基于岩性精细识别基础上的砂砾岩储层研究——以渤海CFD油田为例

LITHOLOGICAL SCRUTINY OF A SANDY CONGLOMERATE RESERVOIR:TAKING CFD OILFIELD IN BOHAI AS AN EXAMPLE

砂砾岩体多位于陡坡带,具有纵向厚度大,粒径粗,泥岩不发育,岩相变化快,储层非均质强等特点。储层评价存在一定的困难,特别在海上油田探井较少、各项资料缺少、可类比油田较少的情况下,更增加了精细研究该类储层的难度。以渤海CFD油田的岩心、壁心、薄片、粒度、测井等资料为基础,通过岩矿与测井结合的研究,提出一套岩性判别模式,从而精确识别出储层段岩性。通过孔隙类型、孔隙结构、物性等微观特征描述,分析了沉积微相、岩性与物性的关系,指出本研究区储层物性的主控因素是岩性,从而确定了井点的优势储层。以层序地层格架为基础,井震结合,提取地震属性,在相控模式的指导下,预测出平面储层分布。这种由点到面的研究思路,为油田开发方案的合理编制提供了较为详实的地质基础。同时,为相似地质条件和资料基础的巨厚储层精细描述提供了技术和方法借鉴。

The sandy conglomerate usually has large thickness,coarse grain size,less mud,dramatic change in lithofacies and strong heterogeneity.Such properties will bring difficulties to reservoir evaluation,especially in offshore area when oil exploration wells are few.This paper takes the CFD oilfield in the Bohai Bay as an example.Data of core,thin section,grain size,and logging are integrated.Combined the logging with lithology,a set of lithology discrimination model is made for reservoir identification.By description of microscopic features of pore types,pore structures and properties,we analyzed the relationship of sedimentary microfacies,lithology and properties.It is considered that lithology is the major controlling factor of reservoir property,upon which the most favorable reservoir is identified.Finally,the prediction of the spatial distribution pattern of reservoir is made with seismic attributes extracted.The results have founded a detailed geological basis for oilfield development program and provided technical references for describing the thick reservoir formed under similar geological conditions.