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Geoscience ›› 2019, Vol. 33 ›› Issue (06): 1220-1228.DOI: 10.19657/j.geoscience.1000-8527.2019.06.08

• Petroleum Geology • Previous Articles     Next Articles

Geochemical Characteristics of Paleo-fluid in Tight Sandstone from Cretaceous Reservoir in Keshen Large Gas Field, Kuqa Depression

SUN Kexin1,2, LI Xianqing1,2(), WEI Qiang1,2, LIANG Wanle1,2, ZHANG Yachao1,2, LI Jian3, XIAO Zhongyao4   

  1. 1. State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and Technology (Beijing), Beijing 100083, China
    2. College of Geoscience and Surveying Engineering, China University of Mining and Technology (Beijing), Beijing 100083, China
    3. Branch of Natural Gas Geology, Research Institute of Petroleum Exploration and Development, PetroChina, Langfang,Hebei 065007, China
    4. Research Institute of Exploration and Development, Tarim Oilfield Company, PetroChina, Korla, Xinjiang 841000, China
  • Received:2019-05-10 Revised:2019-08-20 Online:2019-12-26 Published:2019-12-27
  • Contact: LI Xianqing

Abstract:

To study the geochemical characteristics of paleo-fluids and hydrocarbon charging in tight sandstone reserviors of the Keshen large gas field, we analyzed the fluid inclusion petrography, homogenization temperature, salinity, oil inclusion abundance via quantitative fluorescence technique on the Bashenjiqike Formation sandstone in the gas field. The study shows that there were two generations of hydrocarbon inclusions: bright-blue fluorescence oil inclusions and gray-black gas ones. Homogenization temperatures of coeval aqueous inclusions show two peaks at 130-140 ℃ and 150-160 ℃, with corresponding paleo-salinity of 16%-10% and 12%-4%. This indicates two stages of hydrocarbon fluid filling, in which the high-intensity natural gas was charging since 2.5 Ma. The abundance of oil inclusions ranges from 2.1% to 13.4%, QGF index ranges from 2.2 to 9.6, QGF-E intensity are from 20 pc to 38 pc. These results reveal a weak light-oil filling in the formation of the Keshen large gas field.

Key words: Kuqa Depression, Keshen large gas field, fluid inclusion, quantitative grain fluorescence, paleo-fluid characteristics, homogenization temperature, hydrocarbon charging

CLC Number: