椒江凹陷古新统月桂峰组“源-汇”体系及勘探意义

椒江凹陷古新统月桂峰组沉积时期发育东断西超的半地堑结构形态,具有典型的斜坡型“源－汇”系统,明确砂体优势发育区是储层预测的难点。基于最新钻井、薄片、重矿物及覆盖全区的高精度三维地震资料,以层序地层学、沉积学、地貌学和“源－汇”系统的基本理论和研究思路为指导,定量刻画了椒江凹陷月桂峰组下段“源－汇”系统要素,分析了要素间的耦合关系。研究表明：椒江凹陷月下段具有变质岩母岩供源、规模古沟槽输砂、宽缓斜坡促运、低洼地貌区利于优势堆积的“源貌共控”规模砂体成因机制,有效指导有利目标储层预测,为海上少井条件下的油气藏勘探评价提供了技术支撑。

Research on the "Source-sink" System of Paleocene Yueguifeng Formation in Jiaojiang Depression and Its Exploration Significance

Yueguifeng Formation was deposited during the period of Paleocene, in the Jiaojiang Depression. A semi graben structure was developed in this period with a typical slope type "source-sink" system, where faults gradually transited to overlaps from the east to the west. It is difficult to define the dominant development area of the sand body for reservoir prediction. Guided by the basic theory and research ideas of sequence stratigraphy, sedimentology, geomorphology and source-sink theory, the "source-sink" system elements and their coupling relationships are quantitatively characterized and analyzed within of lower member of the Yueguifeng Formation in Jiaojiang Depression, based on the latest drilling, thin sections, heavy minerals and high-precision 3D seismic data. The study shows that the lower member of the Yueguifeng Formation has a "source-control" scale sand genesis mechanism, with metamorphic rocks supplying the source, large-scale ancient grooves transporting the sand, wide and gentle slopes promoting transportation, and low-lying geomorphic areas facilitating the advantageous accumulation of the sand. These investigations are effective in guiding the prediction of the favorable target reservoirs, and providing technical support for exploration and evaluation of hydrocarbon reservoirs under the condition of few wells in the offshore.