TITLE: RESERVOIR PERMEABILITY: INNOVATIVE MEASUREMENT BASED ON NOVEL CONCEPT

This paper introduces new permeability equipment and presents a new understanding to reservoir permeability that reflects the true behavior of fluid flow around producing wells. 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 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.

The need for a three dimensional permeability becomes vital, and this term, complete with a device and techniques for measuring it, is newly introduced here. To this end, a three dimensional spot gas permeameter has been constructed in the laboratory. This device measures gas permeability with ease and precision, at any spot on the surface of the sample, regardless of shape. Two methods, developed for determining the 3 D (conical) permeability from the data generated by this device, are presented, compared and discussed. The first, based on DarcyB_s Law, employs a modification to both the length of the system and the cross sectional area exposed to the flow, enabling use of DarcyB_s equation by integrating the cross sectional area along the cone height. The second entails constructing a calibration curve of known permeability samples against their measured B_HB_ value, a parameter expressing the ratio of mass flow pressure to the mass flow rate determined by the permeameter.

This new tapering permeability term should enhance the accuracy of the models used to represent fluid flow in porous media, with this 3 D Spot Gas Permeameter and its methods of measurement likely to enjoy wide application.