Journal of Southwest Petroleum University(Science & Technology Edition) ›› 2022, Vol. 44 ›› Issue (1): 1-12.DOI: 10.11885/j.issn.1674-5086.2021.09.10.02

• ACADEMICIAN THOUGHTS •     Next Articles

Research on the Mechanism and Countermeasures of Shaft Instability in the Southern Margin of Junggar Basin

SUN Jinsheng1,2, LI Rui1,2, WANG Ren2, QU Yuanzhi2, HUANG Hongjun2   

  1. 1. School of Chemistry & Chemical Engineering, Southwest Petroleum University, Chengdu, Sichuan 610500, China;
    2. CNPC Engineering Technology R & D Company Limited, Changping, Beijing 102206, China
  • Received:2021-09-10 Published:2022-01-25

Abstract: Deep drilling in the southern margin of the Junggar Basin has problems such as high temperature and high pressure and instability of the borehole wall. The current oil-based drilling fluid technology is faced with huge challenges. According to the statistics of the complex situation of Well Hutan 1, based on the analysis of the fabric and characteristics of the rock samples of the unstable formation, the mechanism of the instability of the borehole wall is revealed. Combined with the technical requirements of deep drilling fluids in the southern margin, the self-developed nano plugging agent and super fine calcium carbonate and elastic graphite form a particle size gradation, constructing an oil-based drilling fluid system that can effectively seal the pores and fractures of the 0.05~50.00μm formation, the fluid loss of this system is only 2.8 mL after hot rolling at 180 ℃, and it is resistant to the 20% composite brine and 5% calcium sulfate pollution and can provide important technical support for deep drilling in the southern margin.

Key words: Junggar Basin, shaft wall instability, mechanism revealed, oil-based drilling fluid, treatment agent optimization, system construction

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