COMPARATIVE STUDY OF TECTONIC EVOLUTION AND PETROLEUM GEOLOGICAL CONDITIONS OF TYPICAL SUPERIMPOSED BASINS IN UPPER AND LOWER YANGTZE BLOCK

The Yangtze region in south China bears great oil potential and is now one of the important sites for petroleum exploration in marine sediments in China. Upon the basis of tectonic evolution and deposition in the Yangtze block, this paper is devoted to the comparative study of the similarities and differences of macro-geological features between the Upper and Lower Yangtzes. The results suggest that the tectonic evolution of the superimposed basins in the upper and lower Yangtze blocks is similar in Paleo-Mesozoic, but different in Meso-Cenozoic. the time boundary of differentiation is about Indosinian and the controlling factors is the interaction among the Yangtze block and adjacent tectonic units. Hydrocarbon accumulation conditions are controlled by basin tectonic evolution and have good coupling pattern with tectonic cycles. The experiences learnt from the Sichuan basin are of great significance to the oil and gas exploration in the South Yellow Sea basin. Upon the fact it is concluded that the Paleo-Mesozoic marine strata is a potential area for break-through of oil and gas exploration in the South Yellow Sea basin. More attention should be paid to the deep strata, and paleo-uplifts are prosperous exploration targets in superimposed basins.