Reservoir Permeability: Innovative Measurement Based on Novel Concept

Abstract

Abstract A new model of permeability to clarify the true behavior of fluid flow around producing wells is presented. A two-dimensional representation of fluid flow in the reservoir is inadequate in many ways. The direction of fluid flow in the reservoir is neither horizontal nor vertical, and consequently the traditional use of these two permeability components in determining fluid flow characteristics has been misleading. Rather, fluids flow from all parts of the reservoir and converge to the wellbore, a very small spot in a big reservoir. The flow pattern towards the wellbore takes a conical shape where the base of the cone at the reservoir boundary and the head is at the wellbore. In many cases, the flow reduces to the perforations which are even smaller "ports" compared to the huge reservoir. The need for a three-dimensional permeability becomes significant, and this term, complete with a technique for measuring it, is introduced here. A new method developed for determining the 3-D (conical) permeability presented and discussed. The proposed method is based on Darcy’s Law employed in a hemispherical scheme as the released gas flows from the probe through the sample in this pattern. The derivation of the model used along with the numerical technique utilized for solving are presented as well. Predictions of the model for air flow into a porous system are presented that appear to conform to the authors’ vision of fluid flow in petroleum reservoirs. This new 3-D (tapering) permeability term should enhance the accuracy of the models used to represent fluid flow in porous media.