# Research Status and Development Direction of Formation Damage Prediction and Diagnosis Technologies
## 3 Laboratory Tests and Numerical Approach Method
### Numerical Simulation Methods
[PERSON] and [PERSON] [105] studied drilling fluid intrusion in horizontal wells in a two-phase flow system, proposed a numerical model that takes into account the dynamic growth of mud-cake and the role of phase percolation, determined the water content saturation distribution and intrusion depth, and evaluated the relationship between effective permeability and intrusion depth by combining the phase percolation curves. [PERSON] et al. [106] evaluated the effect of drilling fluid filtrate intrusion on acoustic logging and a formation's radial elastic parameters using numerical simulations. [PERSON] et al. [107] analyzed the effect of drilling fluid intrusion on the response of multicomponent induced resistivity logging in large-slope wells by numerical simulation. [PERSON] and [PERSON] [108] performed a quantitative comparison of water-based drilling fluid and oil-based drilling fluid intrusion processes and their respective effects on downhole resistivity logging. They found that the filtrate filtration loss rate of oil-based drilling fluids is mainly controlled by the initial mud-cake permeability and formation physical properties (capillary pressure and phase permeability), and the range of influence of water-based drilling fluid intrusion on resistivity logging is between 15% and 40% larger than that of oil-based drilling fluids. [PERSON] and [PERSON] [109] investigated the effect of drilling fluid intrusion on the response of multicomponent induced resistivity logging in large-slope wells by numerical simulation. [PERSON] and [PERSON] [108] performed a quantitative comparison of water-based drilling fluid and oil-based drilling fluid intrusion processes and their respective effects on downhole resistivity logging. They found that the filtrate filtration loss rate of oil-based drilling fluids is mainly controlled by the initial mud-cake permeability and formation physical properties (capillary pressure and phase permeability), and the range of influence of water-based drilling fluid intrusion on resistivity logging is between 1  
used the finite difference method to obtain the formation water-bearing saturation profile, solved the ion convection-diffusion equation to obtain the mineralization profile, and finally implemented time-lapse resistivity logging by the Alchian formula to analyze the effect of drilling fluid intrusion on dual lateral logging and dual induction logging. The study showed that, when the original oil saturation of the formation is greater than 70% and the ratio of the original formation water to drilling fluid filtrate mineralization is greater than 2, the intrusion will cause a \"low resistance annulus\" in the near-borehole formation. [PERSON] and [PERSON] (2010) proposed a multiple geophysical measurement method to evaluate the porosity, permeability, fluid saturation, capillary pressure, and relative permeability of water-bearing sandstone formations under oil-based drilling fluid intrusion conditions, where the radial distribution of water saturation was obtained by numerical simulation. [PERSON] et al. (2011) numerically simulated the effect of different formation properties (porosity, permeability, movable water saturation, capillary pressure, relative permeability, fluid viscosity, and wettability) on array induction logging for quantified oil-based drilling fluid intrusion conditions, and concluded that the relative permeability, capillary pressure, and filtration loss rate are the main controlling factors of oil-based drilling fluid intrusion and can affect the logging curve values and magnitude differences. [PERSON] and [PERSON] (2012) used 3D multiphase flow numerical simulations and found that, under freshwater drilling fluid intrusion conditions, the drilling fluid intrusion depth increased by 70 ft when the formation porosity was reduced from 25% to 10%.