China Petroleum Exploration ›› 2020, Vol. 25 ›› Issue (3): 121-133.DOI: 10.3969/j.issn.1672-7703.2020.03.011

Previous Articles     Next Articles

Preservation and influencing factors of ultra-deep oil reservoirs in the Shuntuoguole area, Tarim Basin: evidence from fluid inclusions

Chen Qianglu1,2,Xi Binbin1,2, Han Jun3, Xu Jin1,2,Wu Xian3, Zhu Xiuxiang3, Ma Zhongliang1,2   

  1. 1 Sinopec Key Laboratory of Petroleum Accumulation Mechanisms; 2 Sinopec Petroleum Exploration and Production Research Institute; 3 Research Institute of Exploration and Development, Sinopec Northwest Oilfield Company
  • Online:2020-05-15 Published:2020-05-15
  • Supported by:
     

Abstract: Oil and gas phase and accumulation models in ultra-deep fields are hot topics in exploration and research. Taking reservoir inclusions in the Middle-Lower Ordovician in the Shuntuoguole area of the Tarim Basin as the research object, detailed and systematic analyses have been carried out, such as inclusions petrography, restoration of paleo temperature and pressure during oil and gas charging, fluid composition, Raman spectrum, and so on. Combined with the geological conditions of oil and gas reservoirs, the preservation mechanism and influencing factors of ultra-deep oil reservoirs in the Shuntuoguole area are discussed. There are 3 types of inclusions in the Ordovician reservoirs: solid asphalt bearing hydrocarbon inclusions, gas liquid hydrocarbon inclusions, and dry gas inclusions. Solid bitumen bearing hydrocarbon inclusions and gas liquid hydrocarbon inclusions are developed in the Yuejin-Shunbei area, and solid bitumen bearing hydrocarbon inclusions and dry gas inclusions are developed in the Shunnan area. Research on paleo temperature and pressure restoration of inclusions shows that there are at least 2 stages (early and late) of oil and gas charging in the Shuntuoguole area. The early-charged crude oil transformed into light oil through thermal evolution in the reservoirs. In the late stage, light oil was charged in the reservoirs. These two processes combined together to determine the preservation of ultra-deep reservoirs in the Shunbei area. The short duration of the maximum paleo temperature (greater than 150 °C) in this area is the main control factor for ultra-deep reservoir preservation. The medium environment of the reservoirs has a certain inhibiting effect on the thermal evolution of crude oil, which is also conducive to the preservation of liquid hydrocarbons.

 

Key words: Tarim Basin, Shuntuoguole, ultra-deep formation, oil preservation, inclusion

CLC Number: