MECHANISM OF HYDROCARBON MIGRATION OF MARINE CLASTIC ROCKS IN WESTERN AREA OF THE NORTHERN TARIM BASIN: A CASE OF YM34 SILURIAN RESERVOIR

摘要

The oil and gas abundance in YM34 structural belt, so it is potential in exploration and develop- ment. However, due to complex geological struc- ture, it is difficult to further study in hydrocarbon 1n.igration and accumulation mechanism. Based on structural characteristics, crude property, group component characteristics, saturated hydrocarbon chromatography—mass spectrometry (GC/MS), analysis on the alkanes, steranes and terpanes of biomarkers of crude oil in YM32 buried-hill hydro- carbon reservoirs indicated that YM34 Silurian reservoir forming zonation are obviously as fol- lows: l)The western reservoir in wells YM342,YM343 as the representative of the “three low and one high” features, namely, low density and viscosity, low ratio of saturated/aromatic hy- drocarbon, followed by high fraction satLu‘ated and aromatic hydrocarbon. 2) Oil and gas migration in YM34 Silurian reservoir is from the west to the East, accumulation period of the West was later than the East. 3) The results of oil-source correla- tion from source rocks in the Kuqa depression indi- cated that source rock of the west in YM34 Silurian reservoir is superiority to the Triassic lacustrine mudstone, then that of the east is of Jurassic coal mudstone.