Modeling of mud filtrate invasion and damage zone formation

In this paper, a model to estimate the invasion depth of mud filtrate from water-based mud is presented. The model includes the presence of mud cake layer and irreducible water saturation. Here, a linear flow system is considered. The filtration velocity and mud cake thickness model is derived from Darcy law and mass conservation. The invasion depth is obtained from mud filtrate profile in formation. It is found that the filtration velocity in a linear flow system depends on overbalance pressure, formation permeability, mud cake characteristics (porosity, permeability and density), and invasion time. Furthermore, the model is verified using the experimental data from literature. The invasion depth predicted by the present model is in agreement with the experimental results.

Research highlights► This paper presents a mathematical model of mud filtrate invasion into oil formation in a linear flow system. ► Here, invasion of solid particles is taken into account in the model. ► A simple criterion for estimating the invasion radius of mud filtrate is also presented. ► Furthermore, simulation and validation of the model with data from literature are conducted. ► The invasion depth predicted by the present model is in agreement with the experimental results.