从扬子地区海相盆地演化改造与成藏浅析南黄海勘探方向

Exploration targets in southern Yellow Sea through analysis of tectono-depositional evolution and hydrocarbon accumulation of marine basin in Yangtze area

南黄海盆地位处下扬子地块东延部位,发育巨厚的海相中、古生界地层。通过研究扬子地区海相中、古生界的盆地原型演化及其主要烃源岩区域发育特征,指出南黄海地区海相中、古生界应发育有类似扬子地区的-C1、O3-S1、P1、P2等4套主要烃源岩,尤其要重视在扬子台内广泛发育的后3套区域烃源岩。同时,通过对扬子地区中新生代历次构造变格对海相中、古生界的改造特征及其主要油气成藏类型,以及南黄海盆地的构造特点等分析,认为南黄海盆地中部隆起—南部坳陷区是勘探海相中、古生界原生油气藏的有利区。该区海相中、古生界烃源基础好、实体保存完整、埋藏相对浅,更重要的是构造相对稳定、后期变形弱,可能发育有类似苏北黄桥地区的海相原生残留型油气藏。盆地北部坳陷因紧靠苏鲁造山带,海相中、古生界遭受了强烈变形甚至变位改造,在晚期断陷叠加区有可能形成类似苏南句容地区的重建型油气藏。而勿南沙隆起因长期处于中新生代强烈褶皱隆起带,海相中、古生界应以发育原生破坏型古油藏为主。

The Southern Yellow Sea Basin locates in the eastern extension region of the Yangtze area, where ma-rine Mesozoic-Paleozoic strata with great thickness developed. In order to investigate the petroleum geologic condi-tions and exploration direction of these marine Mesozoic-Paleozoic strata, and based on the evolution of marine Mesozoic-Paleozoic basin prototype and the regional development characteristics of main source rocks, the paper indicates that four main source rocks developed in the marine Mesozoic-Paleozoic strata in the Southern Yellow Sea Basin, similar with four source rocks （-C1, O3-S1, P1, P2） in the Yangtze area. The later three main source rocks which were widely developed in the inner Yangtze area need to be paid more attention. Meanwhile, according to the analysis of the reformation characteristics of all previous Cenozoic-Mesozoic tectonic declensions to the marine Mesozoic-Paleozoic strata in Yangtze area as well as the main petroleum formation types in the Yangtze area and the structural features of the Southern Yellow Sea Basin, it is suggested that the middle uplift and the southern de-pression area are the favorable exploration areas of marine Mesozoic-Paleozoic primary petroleum reservoirs. The marine Mesozoic-Paleozoic source rocks are in great conditions in these areas, completely preserved, and shallowly buried, and most important is that the structure was relatively stable with weak reformation in the later period. There could be some residual marine Mesozoic-Paleozoic primary petroleum reservoirs similar as those in the Huangqiao area in the northern Jiangsu. The northern depression of this basin was closely adjoining to the Sulu orogenic belt, therefore, the marine Mesozoic-Paleozoic strata was undergoing great deformation and even deflection. Similar to the Jurong area in the southern Jiangsu, the deformation petroleum reservoir could be developed in the later fault depression area. The Wunansha uplift was in the Cenozoic-Mesozoic intense fold-uplift belt for a long time, and mainly destructive primary petroleum reservoirs were developed in the marine Mesozoic-Paleozoic strata.