Special Oil & Gas Reservoirs ›› 2022, Vol. 29 ›› Issue (1): 10-14.DOI: 10.3969/j.issn.1006-6535.2022.01.002

• Geologic Exploration • Previous Articles     Next Articles

Study on Identification and Main Controlling Factors of Low-resistivity Oil Reservoirs in Xijiang Oilfield, Eastern South China Sea

Liang Wei, Yan Zhenghe, Yang Yong, Huang Yujin, Xiong Qi, Dong Yifu   

  1. CNOOC Shenzhen Branch, Shenzhen, Guangdong 518000, China
  • Received:2021-03-20 Revised:2021-11-05 Online:2022-02-25 Published:2023-01-10

Abstract: In view of the complex formation of low-resistivity oil reservoirs in Xijiang Oilfield, eastern South China Sea and the difficulty in identification of low-resistivity oil reservoirs, a method for evaluating and identifying low-resistivity oil reservoirs suitable for Xijiang Oilfield was proposed on the basis of comprehensive analysis of mineral field data such as well logging, cores, scanning electron microscopy, clay minerals, and rock wettability, typical Archie′s formula was modified, the reserves of potential low-resistance oil reservoirs were predicted, and the main controlling factors of low-resistance oil reservoirs in Xijiang Oilfield were analyzed. The results showed that the main controlling factors for the identification of low-resistant oil reservoirs in Xijiang Oilfield were wettability indicator, cation exchange capacity and irreducible water saturation. On this basis, the modified Archie′s formula was used to accurately predict that the lower limit of the resistivity curve of oil reservoirs in Xijiang Oilfield, eastern South China Sea to decrease from 10 Ω·m to 2 Ω·m by using the modified Archie′s formula, and the recoverable reserves were estimated to increase by 20×104 t. The study has an important implication to the development of similar oil fields in eastern South China Sea.

Key words: low-resistance oil reservoir, main controlling factors, irreducible water, clay minerals, Archie′s formula, Xijiang Oilfield, South China Sea

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