A novel method is developed that allows estimation of gas recovery factor without permeability averaging. In this method recovery factor as a function of permeability is generated for each depth-interval (in a wireline log) utilising a one-dimensional (1-D) radial model. The 1-D recovery data over producing intervals is then volumetrically added to obtain recovery factor for the well. The reservoir average recovery factor is then calculated on the basis of permeability-thickness weighting of individual wells to account for lateral variations.
This is a simple technique based on a simple depletion model which allows a quick estimate of recovery from multizone, multi-well gas fields with variable permeability making recovery from different zones and different wells vary widely. This paper presents the basis of the technique and illustrates its application using several field examples.