Petroleum Migration Direction of the Silurian Paleo-pools in the Tarim Basin, Northwest China

The results obtained in this paper indicate that carbazole-type compounds have high thermal stability and also show stability in oxidation and bio-degradation.This kind of compounds still has a high concentration and complete distribution in the analyzed dry asphalt samples,showing that they are particularly useful in studying petroleum migration of paleo-pool.During the basin's first-stage of oil-gas pool formation in the Silurian in Tazhong and Tabei areas of Tarim Basin (at the end of Silurian period)and the second-stage in the Awati area (in Permian),the petroleum experienced a long-distance migration.During the formation of the Silurian paleo-pools in Tazhong Uplift at the end of Silurian,the petroleum mainly came from the lower and middle Cambrian source rocks in the Manjiaer sag.The petroleum migrated towards the southwest-south entering the Silurian reservoir beds in Tazhong first.Then,it further migrated within Silurian from northwest to southeast along the highs of the Structural Belts to the region of the Silurian pinchout boundary in Tazhong.In Tabei Uplift,during the first-stage of pool formation,the petroleum was also from the lower and middle Cambrian source rocks in the Manjiaer sag.It migrated northwest entering the Silurian reservoir beds in the Tabei Uplift firstly,and then the migration continued in the same direction within the Silurian reservoirs and finally the petroleum was trapped in higher positions.During the second-stage pool formation in the Silurian beds in the areas around Awati sag,the petroleum mainly came from the lower-middle Cambrian source rocks in the Awati sag.The petroleum migrated from the generation center to Silurian reservoirs in all directions around the sag through major paths,and the petroleum was finally trapped in higher locations.