Drilling mud plays an important role in drilling operations. Forming a thin layer called mudcake is one of these roles which prevents the aquatic phase of drilling mud called mud filtrate from penetrating through the reservoir rock and therefore reduces the damage caused by that work. So knowing about the mudcake characteristics such as thickness, solid contents and also filtration rate of mud filtrate will help the drilling engineer.
Factors affecting filtration process are time, temperature and pressure. In this paper, a mathematical model will be presented which estimates mudcake thickness and filtration radius in both static and dynamic conditions with consideration a radial system at constant temperature conditions. The mudcake thickness and permeability variation with time are also considered in the dynamic model.