Organic geochemistry and genesis of oil and gas seeps in the southern Junggar Basin

Abstract

The geochemical characteristics of oil and gas seepages from southerm Junggar Basin were studied in order to determine the origin of complex seepages and their petroleum geology significance. The oil and gas seeps in the study area can be divided into 4 types. Type A is mainly distributed in the east section, mainly sourced from the Permian. Type B is mainly in the Qigu area, the first structural zone in the middle section and the Tuositai anticline in the west section, mainly sourced from the Jurassic. Type C is distributed in the second structural zone of the middle section, mainly from the Cretaceous. Type D is mainly distributed in Wusu-Dushanzi area of the west section, featured by mud volcanoes, with oil from the Paleogene and gas from the Jurassic. The distribution of oil and gas seeps shows a typical "source-fault" dual control mechanism, and has a good match with the main oil and gas systems, which is a direct indicator of underground oil and gas reservoirs on the surface. Further hydrocarbon exploration should be focused on gas in the upper segment in the west section, oil in the middle segment in the middle section, and favorable reservoirs in the lower segment of the east section.

Keywords

• oil-gas seeps
• mud volcano
• oil sand
• bitumen
• southern junggar basin