Abstract：

The formation of nano-micropore fractures in the Mahu well area of Xinjiang is developed, and the phenomenon of collapse and leakage in the same layer occurs many times, which leads to serious wellbore instability and seriously affects the drilling process. In this paper, 2-acrylamide-2-methylpropanesulfonic acid, polyvinyl pyrrolidone and dimethyl diallyl ammonium chloride were grafted onto the surface of mSiO2 by aqueous solution polymerization with KH570 modified nano-silica as the ‘core’. A self-adaptive strong plugging agent with high temperature resistance was prepared. The experimental results show that the morphology of XZ-APA is spherical, and the size is between 40 nm and 135 nm. The particle size of XZ-APA expanded adaptively with changes of temperature and concentration. When the temperature increased from 25 °C to 65 °C, the D50 expanded from 124 nm to 805 nm. When the concentration increases from 0.1 g/L to 10 g/L, the D50 expands from 105 nm to 3.2 μm, reaching micron level, which can realize multi-stage plugging of nano-microporous fractured formations. In the sand bed experiment, 3% XZ-APA reduced the leakage of 40~60 mesh and 60~80 mesh sand beds from 119 mL and 128 mL to 29 mL and 25 mL. In the pressure transfer experiment, 3% XZ-APA also has a good plugging effect on the core from the Mahu well area, and the pressure transfer rate is reduced by more than 72%. By adding 2% XZ-APA to the drilling fluid system, the leakage of the 40~60 mesh sand bed can be reduced from 3.2 mL to 1.2 mL, and the pressure bearing capacity can be more than 6 MPa. The leakage of the 20~40 mesh sand bed is reduced from 300 mL to 44 mL, and the pressure bearing capacity is increased from 1 MPa to more than 6 MPa, indicating that XZ-APA can be effectively blocked in WBDFs and improve the pressure bearing capacity. At the same time, its plugging effect is better than that of conventional plugging materials (such as asphalt), and can be used in combination with conventional plugging materials to achieve a better plugging effect. In this paper, XZ-APA is used as the core treatment agent to form a set of water-based drilling fluid systems with high temperature resistance and self-adaptive strong plugging suitable for the Mahu well area, which is helpful to solve the problem of wellbore instability caused by filtrate invasion in the Mahu well area.

Key words：drilling fluid; adaptive; plugging agent; nanometer materials; water based drilling fluid system

Received： 2024-03-18

Corresponding Authors：yangll@cup.edu.cn

Cite this article：贾永红, 吴家乐, 张蔚, 叶安臣, 崔新环, 杨丽丽. 一种自适应纳米封堵剂的研制在水基钻井液体系中的应用研究. 石油科学通报, 2024, 09(06): 1034-1043 JIA Yonghong, WU Jiale, ZHANG Wei, YE Anchen, CUI Xinhuan, YANG Lili. Study of the application of an adaptive nano-plugging agent in a water-based drilling fluid (WBDF) system. Petroleum Science Bulletin, 2024, 09(06): 1034-1043.

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