摘要
大陆架科学钻探(CSDP),是一个在我国大陆架上实施的以钻探我国陆架区深部地层为目的的科学计划,是介于大陆科学钻探(ICDP)和大洋科学钻探(DSDP,ODP,IODP)之间的大陆架地球科学探索计划。首批两口科学钻探井布设在南黄海陆架上,CSDP-1井的主要目标为第四纪及其环境演化,CSDP-2井则瞄准中—古生界海相地层及其资源环境效应。CSDP-2井的科学目标为揭示中—古生界的地层时代、沉积环境、构造演化,详细标定钻遇地层的地球物理性质,系统评价其油气生储盖特征,以及开发和探索钻探与井中观测等技术。CSDP-2井完井深度2 843.18m,创造了全球陆架全取心钻探的最深记录,综合取心率97.7%,其中中—古生界取心2 198.10m,取心率99.3%,先后钻遇第四系—新近系,下三叠统青龙组,二叠系大隆组、龙潭组、孤峰组和栖霞组,石炭系船山组、黄龙组和高骊山组,泥盆系五通组,志留系坟头组和高家边组。初步建立钻遇中—古生界的岩性剖面、地球物理性质剖面、地层时代和沉积环境格架,厘定印支期和加里东期两个不整合面,以及孤峰组和龙潭组之间的断层滑脱面,并通过对烃源岩系统评价发现4套好的烃源岩。下一步工作将在进一步厘定地层年龄的基础上,深入探讨沉积环境演化、构造和热演化历史,以及结合区域资料恢复古地理环境。
Continental Shelf Drilling Program(CSDP)is a scientific plan for deep stratigraphic sequence drilling on the continental shelf of China.This plan is initially defined as the Earth Science Discovery Program between Continental Scientific Drilling(ICDP)and Ocean Scientific Drilling(DSDP,ODP,IODP).So far,two wells have been completed in the South Yellow Sea.The main target of well CSDP-1is the Quaternary and its environmental evolution,while well CSDP-2is aimed at the Mesozoic and Paleozoic marine strata and its resource and environmental effects.The scientific objectives of well CSDP-2are 1)to reveal stratigraphic sequences,sedimentary environment and tectonic evolution of the Mesozoic-Paleozoic in the South Yellow Sea;2)to calibrate the geophysical properties of the strata;3)to evaluate the hydrocarbon system;and 4)to conduct long-term in-hole geophysical observations.The depth of CSDP-2well is 2 843.18 m,the deepest record of core drilling projects in the continental shelf.The core recovery rate is 97.3%,of which the Mesozoic-Paleozoic stratum is 2 198.10 mwith a core recovery rate of 99.7%.CSDP-2borehole has drilled Quaternary-Neogene,Lower Triassic Qinglong Formation,Permian Dalong Formation, Longtan Formation, Gufeng Formation and Qixia Formation,Carboniferous Chuanshan Formation, Huanglong Formation and Gaolishan Formation,Devonian Wutong Formation, Silurian Fentou Formation and Gaojiabian Formation. The stratigraphic framework,geophysical property profile,sedimentary sequences and ages were calibrated and preliminarily established.Two unconformities developed in Indosinian and Caledonian periods,and the detachment zone between Longtan Formation and Gufeng Formation was discerned.Four sets of good source rocks indicate the oil and gas exploration potential in this area.