Special Oil & Gas Reservoirs ›› 2023, Vol. 30 ›› Issue (6): 157-164.DOI: 10.3969/j.issn.1006-6535.2023.06.021

• Drilling & Production Engineering • Previous Articles    

Research and Application of Changing Rule of Fracture Flow Conductivity in Salt-Bearing Reservoirs Based on Salt Dissolution and Creep

Yu Tianxi1, Wang Lei2,3, Chen Beibei1, Sun Xize1, Li Shengxiang2,3, Zhu Zhenlong2,3   

  1. 1. PetroChina Xinjiang Oilfield Company, Karamay, Xinjiang 834000, China;
    2. School of Petroleum Engineering, Yangtze University, Wuhan, Hubei 430100, China;
    3. Hubei Key Laboratory of Oil and Gas Drilling and Production Engineering, Wuhan, Hubei 430100, China
  • Received:2022-10-07 Revised:2023-09-05 Online:2023-12-25 Published:2024-01-19

Abstract: The rapid decline of fracture flow conductivity after fracturing of salt-bearing reservoirs leads to the rapid decline of production, so the enhancement of fracture flow conductivity becomes the key to improve the development effect of this type of reservoir. By taking the salt-bearing reservoir in Mahu area of Junggar Basin as the research object, and based on the mineral component data of the reservoir, the salt content of the reservoir was classified, and based on this, the creep performance of the reservoir and the dissolution law of the salt rock, as well as the influence of the proppant particle size, the sanding concentration, and the fluid medium on the flow conductivity were investigated, and the effects of the creep effect of the reservoir, the salt dissolution effect, and the embeddedness of the proppant on the fracture width were quantitatively analyzed. The study shows that: The higher the salt mineral content of the salt rock, the more obvious the characteristics of its creep mechanical behavior; the higher the temperature, the lower the fluid mineralization and viscosity, and the higher the rate of salt dissolution; the fracture width is mainly affected by the embedment effect of the proppant, the creep effect of the salt-bearing reservoir and the salt dissolution effect on the fracture surface, and the embedment effect of the proppant and the creep effect of the salt-bearing reservoir lead to a decrease in the fracture width, and the fracture width increases due to the dissolution effect of the salt rock on the fracture surface. The fracturing fluid and high-concentration, large-size proppant prepared by using clear water can significantly enhance the fracture conductivity. The research results have been successfully tested in the field and show the direction for efficient fracturing of salt-bearing reservoirs.

Key words: salt-bearing reservoir, creep, salt dissolution, fracture conductivity, proppant, Mahu, Junggar Basin

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