塔里木盆地中部地区志留系油藏两期成藏特征

TWO ACCUMULATION STAGES OF THE SILURIAN HYDROCARBON RESERVOIRS IN CENTRAL AREA OF THE TARIM BASIN

塔里木中部地区志留系几个油藏原油性质存在明显差异。据油藏储层包裹体、成岩作用、沥青砂岩分布特征和志留系沉积构造背景等认为志留系油藏存在两期成藏过程 ,早期成藏时间为志留纪末 ,随即志留系抬升地表 ,油藏遭受大气淡水淋滤和细菌作用破坏 ,留下大量沥青和一定量的稠油显示。志留系油藏第二期成藏时期在白垩 早第三纪 。

There were obviously different characters in crude oil property of the hydrocarbon reservoirs in central area of the Tarim Basin. Based on the analysis of reservoir inclusions, diagenesis, asphaltic sandstone distribution and Silurian sedimentary tectonic setting, it was believed that the hydrocarbon reservoirs in central Tarim area experienced two accumulation stages. The earlier stage was at the end of Silurian. Immediately after the accumulation, the hydrocarbon reservoirs were uplifted to the earth surface and destroyed by atmospheric fresh water leaching and bacterial action. Much bitumen and some heavy oil were left. The later stage was in Cretaceous Eogene. The hydrocarbon re accumulation in this stage was an important precondition for the formation of industrial hydrocarbon reservoir in the lower sandstone member of the Silurian in central Tarim.