Abstract: When drilling for oil and gas there are different physical and chemical processes. This is the result of the impact of drilling mud with rocks. This can be diffusion, filtration, heat transfer, capillary flow, etc. Filtrationis one of the most important processes that affect drilling operations. It affects the absorption of drilling fluid, the manifestation of fluids, the formation of clay cake on the walls of the hole and the emergence of other phenomena. When calling the influx phenomenon can be observed that determine the quality and efficiency of injection wells.