| HuangHai is the last one continental shelf region in China in which there is noapparent progress on the exploration and development of petroleum and gas by now.The situation was changed gradually and more and more attentions of marine geologistsand petroleum geologists are paid to the evaluation and exploration of oil-gas system ofthe Mesozoic – Palaeozoic residual marine basins. Based on the regional drilling results,It was proved that there are three important source-rock layers including Qinglongformation (T1), Dalong formation (P3) and Longtan formation (P3). Characterizing thetransverse and vertical distribution of source rocks is the key to the essential oil-gasexplorations. Early Tertiary in southern Huanghai consists of several overlapped structuralresidual basins formed between Mesozoic and Palaeozoic, especially before Taizhouformation (K3). One of the most difficult problems is to characterize the distribution of thebasins which is the prerequisite of the recovery of buried history and the evaluation ofoil-gas resource within residual basins. The current most important and anxious is todefine the distribution of P2-T1 residual basins in southern Huanghai. In the last fewyears, the discoveries of medium scale of Zhujiadun gas field and Huangqiao gas field inYancheng sub-basin in which the main source rock formed between Mesozoic andPalaeozoic in Northern Jiangsu Province implied the interesting potential explorationperspectives in Xiayangzi marine residual basin. The geophysical explorations in thisregion also exhibited that there are marine Mesozoic-Palaeozoic strata with more than5000 meters thickness below Indosinian surface. These researches during my master 4degree study focus mainly on the problems mentioned above and will contribute to theoil-gas exploration in theory as well as for economy. Geology as well as geophysics methods are employed together during research. Atthe beginning, the regional stratigraphy sequences was built up by combining thebiostratigraphy, lithologic stratigraphy and sequence stratigraphy derived from theknowledge about neighboring fields and wells drilled in marine and the stratigraphycorrelation between various well were verified. After that, based on the well seismic logsynthesized from sonic differential time log, the relationship between geologic layer andseismic layer was clarified. With the help of work station, separation of seismicsequences and the interpretation and integration of seismic profiles were achieved,further, the residual basin's spatial distribution was figured out. By combination oftectonic history, spatial distribution of residual basin, the organic material abundanceand evolution of upper Permian – lower Trias source rock, the potential gas-oilexploration prospect was predicted. The achievements were listed as follows: 1. There are two strata systems of lower Yangzi, Polaeozoic - Mesozoic marinestrata system and Mesozoic - Cenozoic terrestrial strata system in Southern Huanghai. According to the well logs, seismic, gravity and geomagnetic exploration results, thebasic geologic stratigraphic units were deduced that consist of sedimentary cover whichincludes integrated marine sequences formed during Caledonian, Hercynian andIndosinina and terrestrial sequences formed during Mesozoic-Cenozoic and regionalmetamorphic bedrock of Archean-Proterozoic. The Qinglong formation (T1), Dalongformation (P3) and Longtan formation (P3) distribute widely and have relative thickness.The terrestrial strata mainly distribute within the southern sub-basin with the maximumthickness of 8200 meter. Compared with Northern Jiangsu region, the Mesozoicterrestrial strata comprise merely of thin and limited distributed Cretaceous depositedduring the early warp-fault stage. 2. multi cyclic structural evolution Based on the study on seisms and geology structure, the regional tectonic evolutionwas divided int...
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