The condensate gas field geological characteristics and its formation mechanism in Tarim basin

Tarim basin has abundant of condensate gas in which about 20 condensate gas fields have been discovered, including land facies condensate gas field in Kuqia seg and marine facies condensate gas in platform basin. Reservoirs include elastic rock and carbonate rock distributing from Ordovician to Cenozoic. For these condensate gas fields, GOR is 600 similar to 19900m(3)/m(3), condensate oil is 40 similar to 750g/m(3), reservoir temperature is 78 similar to 155 degrees C, strata pressure is 37 similar to 111MPa. According to research, condensate gas in Tarim basin can be divided into primary origin condensate gas reservoir and secondary condensate gas reservoir. Dina2 condensate field in Kuqia seg is in coal series hydrocarbon source rock high evolutionary phase (vitrinite reflectance Ro is 1. 2% similar to 2. 0%). Secondary condensate gas reservoir have two kinds : multi-stage charging from land facies and late gas, mixing transformation to early oil reservoir, such as Yaha gas field; multi-stage charging from marine facies and late gas, invasion to early oil reservoir. With the conversion to the deep exploration in Tarim basin, the formation temperature and pressure gradually increased and different stages of hydrocarbon hydrocarbon hybrid system will also be more widespread and secondary condensate gas reservoirs will also be more widespread, so marine oil and gas sources of secondary origin type gas condensate reservoir will become the subject of exploration.