南黄海中部隆起海相中——古生界科学钻探CSDP-2井选址

Site Selection of Scientific Drilling Well CSDP-2 for Marine MesozoicPaleozoic Strata in Central Uplift of South Yellow Sea Basin

2014年,大陆架科学钻探项目(CSDP)确定采用自主研发的轻便型海洋钻井平台"探海1号"在南黄海盆地中部隆起上实施首口科学钻探井(CSDP-2井),其科学目标是探查中部隆起的中—古生界地质结构和油气地质条件,解决南黄海中部隆起海相残留盆地长期悬而未决的地层属性问题,同时为区域地质、海陆演化与海相油气资源前景研究和评价提供基础资料。据此确定钻孔的选址原则为:钻探海域水深不超过30m,在预定2 800m的钻探深度范围内钻遇多套完整的中—古生界海相地层。根据钻探目标和选址原则,针对中部隆起没有钻探资料的状况,以区域地质特征和周边钻井对比为参考,以地震资料多属性解释为手段,标定了地震反射层位,解释并编制了反射层构造图,拟定了钻探井位,预测了钻探层位;采用地震储层预测技术预测了有利储层。上述工作形成了无井勘探区的钻探井位部署技术流程和方法,经钻探厘定了三叠纪—奥陶纪海相沉积层,并发现了多个油气显示层,达到了预定钻探目标。

In 2014,the Continental Scientific Drilling Project(CSDP)decided to adopt the selfdeveloped portable offshore drilling platform 'Tanhai 1'to deploy the first exploratory cored hole(Well:CSDP-2)in the central uplift of South Yellow Sea basin.The goal of the project is to probe the Mesozoic-Paleozoic geological structure,oil and gas geological conditions,so as to solve the longstanding stratigraphic problems of marine residual basin in the central uplift of South Yellow Sea,and to provide basic data of the regional geology,sea and land evolution and prospects of marine oil and gas at the same time.Accordingly,we determined the location principle of well CSDP-2as follows:based on safety and equipment suitability,the water depth of drilling should be no more than 30 m,the igneous rock and other special geological bodies should be avoided in the predetermined 2800 mdrilling depth,and within this depth range,several complete sets of Mesozoic-Paleozoic marine strata should be drilled through.Based on the drilling target and the principle of well location,and under the situation of no drilling data in the central uplift,we designed the technique flow and carried out the research.The seismic reflection horizons were demarcated by means of multi-attribute interpretation of seismic data,the structural maps of reflection horizons were interpreted and compiled,drilling wells were drawn up,the drilling horizons were predicted,and the favorable reservoirs were predicted by seismic reservoir prediction technology.Through the above work,the technical flow and method of drilling well location in non-well exploration area have been formed.The drilling results confirmed the Triassic-Ordovician marine sediments,and found many oil and gas layers.