Junyan Liu¹, Ju Liu¹, Yan Wang¹, Shuang Liu¹, Qiao Wang¹, Yihe Du^2,*

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.1, pp. 205-218, 2024, DOI:10.32604/fdmp.2023.030645

Abstract The variation of the principal stress of formations with the working and geo-mechanical conditions can trigger wellbore instabilities and adversely affect the well completion. A finite element model, based on the theory of poro-elasticity and the Mohr-Coulomb rock damage criterion, is used here to analyze such a risk. The changes in wellbore stability before and after reservoir acidification are simulated for different pressure differences. The results indicate that the risk of wellbore instability grows with an increase in the production-pressure difference regardless of whether acidification is completed or not; the same is true for the instability area. After acidizing, the… More >

Yu Fan, Jianhua Guo, Xihui Hu, Rui Wang^*, Weiqiang Xu

FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.9, pp. 2431-2447, 2023, DOI:10.32604/fdmp.2023.027604

Abstract Drilling technologies based on oil-based drilling fluids and strong inhibitory saltwater fluids are affected by drawbacks such as downhole accidents where sticking and wellbore instabilities occur. Existing polyamine drilling fluids also exhibit problems such as easy decomposition and poor inhibition performances. In order to mitigate these issues, additives can be used, such as polyamine inhibitors and the synthesis of nanometer filtrate reducers. Tests conducted in the frame of this study with a polyamine drilling fluid and such additives show that this fluid has the same inhibitory, plugging, lubricating, and wellbore-stability performances as oil-based drilling fluids. However, it has long-term anti-wear… More > Graphic Abstract