Research Of Fluid Inclusion And Geological Age Of Hydrocarbon Accumulation Of Ordovician Reservoir In Lungu Region, Tarim Basin

Reservoir fluid inclusions contain a large number of information of geological fluid, which can renew the history of the pool by using different research methods. Based on researching stages of regional structure and structure fracture and characters and types of association and PT simulation of hydrocarbon inclusions included in Ordovician reservoir of Lungu area, analysis about history of hydrocarbon accumulation of Ordovician reservoir was carried out. Following conclusion was reached:1) There were three stages of tectonic happened in Lungu area,which are late Caledonian-early Hercynian period, late Hercynian period and Yanshan-Himalayan period, with 11 types of structural fracture formed in Ordovician reservoir accordingly.2) There are three different species of hydrocarbon inclusions in the three types of structural fracture. The structural fracture formed in late Caledonian-early Hercynian period contains hydrocarbon inclusion with brown fluorescence, corresponding to the heavy oil components; The structural fracture formed in late Hercynian period contains hydrocarbon inclusion with yellow fluorescence, corresponding to the mature normal oil components; With hydrocarbon inclusion with light brown fluorescence associated, hydrocarbon inclusion with blue-white fluorescence is included in the structural fracture formed in Yanshan-Himalayan period, and represents high mature light oil or condensate oil and gas.3) The first stage of fluid inclusions formed in late Caledonian-early Hercynian period were trapped between 80.1 and 91.2℃ ℃,with pressure ranging from 6.3 MPa to 8.7 MPa, and whose burial depth was 1697 m~1991 m. The second stage of fluid inclusions formed in late Hercynian period were trapped between 106.9 ℃and 116.0 ℃,with pressure ranging from 18.6 MPa to 18.6 MPa, and whose burial depth was 2545 m~2774 m. The third stage of fluid inclusions formed in early Himalayan period were trapped between 154.0 and 163.3℃ ℃,with pressure ranging from 34.9 MPa to 38.7 MPa, and whose burial depth was 4660 m ~4972 m.4) History of the pool of Ordovician reservoir in the eastern part of Lungu area is different from that of the western part. Timing of hydrocarbon accumulation of Ordovician reservoir in Western Lungu and Lungu 7 area is late Caledonian-early Hercynian period and late Hercynian period. Timing of hydrocarbon accumulation of Ordovician reservoir in Eastern Lungu and Mid-platform and Western Sangnan and Eastern Sangnan area is late Caledonian-early Hercynian period and late Hercynian period and early Himalayan period. In addition, oil-gas filling in the period of Himalayan in the eastern part of Lungu area is multistage pulsatile-typed charging.