Invaded Zone Characteristics through Logging and Invasion Modeling

The paper presents a current view of invasion and distribution of the electromagnetic field in a<br>reservoir, the processes reflecting properties of the same target - an invaded zone. Actually, as a<br>borehole is drilled, mud filtrate invades the formation and displaces oil and formation water<br>from the borehole. An invaded zone is formed in which the distribution of properties is defined<br>by hydrodynamics laws of fluids in porous media. Both the invaded zone and undisturbed formation<br>affect electromagnetic logging tools. As a result of log interpretation, the spatial resistivity<br>distribution is obtained. The same distribution can be obtained from results of invasion modeling,<br>as an example, by the generalized Archie formula.