ANALYSIS OF PALEOZOIC RESERVOIR PRESERVATION IN THE NORTH CHINA

This paper mainly studied the regional controlling effect of Meso-Cenozoic tectonic evolution to the Paleozoic reservoir preservation in the North China. Beside the analysis of the condition of Paleozoic seal rocks, this paper mainly analyzed conditions of overlying direct cap rocks, regional cap rocks and the overall sealing composed by Meso-Cenozoic basins superposition. The results show that the hydrocarbon preservation was better in the west than in the east, better in Lower Paleozoic than in the Upper Paleozoic, and better in the northen part of North China than in the souther part of North China. Benxi Formation and Shihezi Formation are the main regional cap rocks in the Paleozoic. The eastern Paleogene and the western Triassic formations provided regional cap rocks for the Paleozoic hydrocarbon preservation. The sealing condition is an important factor which caused the hydrocarbon preservation difference between the east and the west. The Central Ordos Basin and the eastern deep fault depression to inside slope in the North China are favorable units for the hydrocarbon preservation.