CHARACTERISTICS AND DISTRIBUTIONS OF MARINE PALEO-RESERVOIRS IN THE NORTHERN MARGIN OF THE JIANGNAN-XUEFENG UPLIFT, SOUTHERN CHINA

摘要

More than 156 marine paleo-reservoirs (or residual oil reservoirs) and hydrocarbon shows are found in the Neoproterozoic, Paleozoic and Mesozoic marine strata of the northern margin of the Jiangnan-Xuefeng uplift, southern China. In this paper, the characteristics and distributions of marine paleo-reservoirs are statistically analyzed. It is suggested that paleo-reservoirs and hydrocarbon shows were controlled by the ancient uplift and its tectonic evolution. These paleo-reservoirs and hydrocarbon shows in different marine strata have different characteristics and distributions. Paleo-reservoirs and bituminous shows appear mainly in the Ediacaran system of the Neoproterozoic and Lower Paleozoic, and oil and gas shows occur predominantly in the Permian and Triassic, which is obviously related to the development of source rocks and thermal evolution of hydrocarbon. The paleo-reservoir bitumen and hydrocarbons fill predominantly in the fractures and pores of carbonate and clastic reservoirs, which are controlled by the characteristics of original reservoirs and their succeeding transformation with the tectonic evolution, respectively. As estimated by the reservoir scale sequential method, the marine strata hold approximately 368 × 10~8 tonnes of total geological reserves in place of an initial crude oil in the northern margin of the Jiangnan-Xuefeng uplift.