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Geoscience ›› 2022, Vol. 36 ›› Issue (04): 988-997.DOI: 10.19657/j.geoscience.1000-8527.2022.197

• Oil and Gas Exploration • Previous Articles     Next Articles

Geochemical Characteristics of Natural Gas and Hydrocarbon Charging History of the Tugeerming Area in the Eastern Kuqa Depression

LIU Yang1,2(), LI Xianqing1,2(), ZHAO Guangjie1,2, LIU Mancang3, DONG Caiyuan3, LI Jin3, 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. PetroChina Exploration and Development Research Institute,Beijing 100083, China
    4. Research Institute of Exploration and Development, PetroChina Tarim Oilfield Company, Korla, Xinjiang 841000, China
  • Received:2021-09-10 Revised:2021-12-05 Online:2022-08-10 Published:2022-09-09
  • Contact: LI Xianqing

Abstract:

The oil and gas geological conditions in eastern Kuqa Depression are complex. The origin of natural gas, the time and history of oil and gas charging are disputed, which hampers regional oil and gas exploration. Based on the analyses on carbon isotope composition of natural gas, fluid inclusion petrography and homogenization temperature, and integrating the sedimentary/ burial history and tectonic evolution, the geochemical characteristics of natural gas and hydrocarbon accumulation process at Tugeerming area (eastern Kuqa depression) are revealed. The results show that methane is the main natural gas component at Tugeerming, with its content ranging from 75.56% to 90.11% and the dryness coefficient from 0.79 to 0.93. The δ13C1 (-35.73% to -33.80‰) and δ13C2 (-26.41‰ to -25.30‰) values suggest that the genetic type of natural gas is mature coal-derived gas. There are two types of inclusions in the Jurassic sandstone reservoirs at Tugeerming, i.e., yellow liquid hydrocarbon inclusions and bluish-white fluorescent gas-liquid hydrocarbon inclusions and gray gas-liquid hydrocarbon inclusions. This indicates two oil and gas charging stages at Tugeerming: (1) 13 Ma to 7 Ma crude oil charging, and (2) 2.6 Ma natural gas charging. In the Lower and Middle Kangcun Formation, the crude oil formed by source rocks at Tugeerming was charged into the wide and gentle anticlinal trap for preservation. In the Upper Kuqa Formation, the Jurassic Kezilenuer and Yangxia Formations developed good source-reservoir assemblage, with natural gas being charged at close distance to form the reservoirs in the Upper Kuqa Formation.

Key words: eastern Kuqa Depression, Tugeerming region, natural gas, geochemical characteristics, fluidinclusion, hydrocarbon charging history

CLC Number: