Deep water is rich in oil and gas resources, which is of great significance to world energy. However, its reservoir geological conditions are complex, the drilling safety density window is narrow, the wellbore pressure is difficult to control, overflow, kick and other accidents are prone to occur, and there are high temperature and high pressure phenomena. In order to deal with a gas kick through managed pressure drilling in time after the gas kick, it is necessary to comprehensively consider the effects of temperature and pressure on the density and rheology of drilling fluid, and accurately calculate the bottom hole ECD after gas kick. Based on the wellbore multiphase flow model and considering the influence of temperature and pressure on the density and rheology of drilling fluid, combined with the special process flow of deep water managed pressure drilling, a more accurate ECD calculation method for deep water managed pressure drilling after gas kick is established in this paper. Verified by the data of well M in a sea area of China, the error of this method is 2% with high accuracy, which provides the basis for field managed pressure drilling.
With the development of oil and gas exploration and development technology in the world, the future exploration and development will gradually turn to deep unconventional oil and gas resources. Among them, the reserves of deep water oil and gas resources are rich, which may exceed 70 billion tons. Deepwater oil and gas resources are of great significance to world energy. However, its reservoir geological conditions are complex, the drilling safety density window is narrow, the wellbore pressure is difficult to control, overflow, kick and other accidents are prone to occur, and there are high temperature and high pressure phenomena. (Li, 2021; Li, et al, 2021; Yang, et al, 2023). Managed pressure drilling technology can accurately control the bottom hole pressure and quickly balance the bottom hole pressure difference, which is an important means to solve the drilling problem. (Yin, et al., 2020). ECD, the equivalent circulating density of drilling fluid, is a critical engineering parameter in the process of managed pressure drilling. If managed pressure is inaccurate, overflow and leakage will occur. Providing accurate ECD is the key to the successful implementation of managed pressure drilling. (Liu, et al, 2020; Fan, 2014).
