Evaluation of permeability of porous media consisting of calcium carbonate used as bridging agents in oil well drilling process

Abstract

The addition of calcium carbonate in drilling fluids is a common practice during the oil well drilling process. These additives commonly called bridging agents help in the formation of a layer of fine particles and low permeability called filter cake. The formation of the filter cake occurs on the surface of the walls of the well, helping to reduce the inflow of drilling fluid into the reservoir. For describing the flow in a deformable porous media, the constitutive equation for determining the permeability of the porous medium is necessary, making possible to simulate the operation. In this context, this study determined the relationship between porosity and permeability of porous media consisting of calcium carbonates 2-44 µm. The porosity distribution in the sediment was determined using the gamma-ray attenuation technique. The results showed significant differences when compared with the values ​​estimated by the correlation proposed by Kozeny-Carman.