Abstract
Oil/gas migration in the Zhenjing region of Ordos basin had been studied through geochemical tracing based on analysis of saturated hydrocarbon, aromatic hydrocarbon, nitrogen compounds. Results revealed that hydrocarbon migrated from the north to the southeast in the research area. The reservoirs in the research area were of low porosity and low permeability, and under-compaction ubiquitously existed between the Chang-6 and Chang-8 reservoir groups, leading to the existence of abnormally high over-pressure in the Chang-7 reservoir group, which provided the main driving force for the oil/gas migration. Meanwhile, the sand body in the underwater distributary channel, the local nose structures, the faults and fractures in the region largely controlled the migration direction of the oil/gas. They were all developed in the southeast part of the region, providing advantageous delivery conditions for the oil/gas to migrate to the southeast part of the region.
