Oil & Gas Geology ›› 2023, Vol. 44 ›› Issue (1): 138-149.doi: 10.11743/ogg20230111

• Petroleum Geology • Previous Articles     Next Articles

Numerical simulation and prediction of hydrocarbon phase evolution of wells Shunnan 1 and 4, Tarim Basin

Yueyi HUANG1,2,3(), Yuhong LIAO1,2(), Chengsheng CHEN1,2, Shuyong SHI1,2, Yunpeng WANG1,2, Ping’an PENG1,2   

  1. 1.State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, CAS, Guangzhou, Guangdong 510640, China
    2.Center for Excellence in Deep Earth Science, CAS, Guangzhou, Guangdong 510640, China
    3.University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2022-06-06 Revised:2022-11-16 Online:2023-01-14 Published:2023-01-13
  • Contact: Yuhong LIAO E-mail:huangyy@gig.ac.cn;liaoyh@gig.ac.cn

Abstract:

The wells Shunnan 1 and 4 in the Tarim Basin are located close to each other and have similar geological backgrounds. The reservoirs therein are similar in burial history, thermal history and pressure history, with their crude oils having undergone severe thermal cracking. However, the two wells are significantly different in hydrocarbon phase: the reservoir in well Shunnan 1 is of gas condensate type, while that in the well Shunnan 4 is typical of dry gas type. The hydrocarbon phase evolution processes of the two wells and the reasons for the phase difference between the two wells are yet to disclose. In this study, the thermal simulation data from the gold tube closed system experiment of crude oils in combination with the actual geological setting information are applied to the numerical simulation and prediction of hydrocarbon phase evolution of wells Shunnan 1 and 4 in the Tarim Basin via PetroMod and PVTsim, and the simulation results are compared with the composition and phase of present hydrocarbon fluids. The results show that the hydrocarbon reservoir in the Yingshan Formation in well Shunnan 1 varied from liquid phase to gas condensate phase at 34 Ma and remains in gas condensate phase till now. The molar concentration of n-alkane in the gas condensates has a very good linear relationship with the carbon number, indicating that it was not affected by gas invasion, evaporative fractionation or multi-stage charging. The hydrocarbon reservoir in the Yingshan Formation in well Shunnan 4 transformed from liquid phase to gas condensate phase at 49 Ma, and probably suffered gas invasion in the Miocene (22?10 Ma) by over-mature dry gas from the Cambrian source rocks through channels of multiple NE-striking faults developed in Shunnan area. The gas invasion got weakened from east to west and disappeared in well Shunnan 1. This is the main reason for the marked difference in composition and phase between wells Shunnan 1 and 4.

Key words: gas invasion, basin modeling, PVTsim, hydrocarbon phase, crude oil, hydrocarbon reservoir, Shunnan area, Tarim Basin

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