Geochemical surveillance of gas production from tight gas fields

Abstract

Method of estimating the recovery factor for the volume drained by at least one producing gas well that penetrates a tight gas reservoir or a coal bed methane reservoir, by (a) calibrating changes in the isotopic composition of at least one component of the gas that is produced from the gas well with increasing recovery factor, (b) obtaining a sample of produced gas from the producing gas well and analyzing the sample to obtain the isotopic composition of the component of the produced gas and (c) using the calibration obtained in step (a) and the isotopic composition determined in step (b) to estimate the recovery factor for the volume drained by the gas well. The estimate of the recovery factor determined in step (c) and the cumulative volume of gas produced from the gas well is used to determine the volume drained by the gas well.

Dependencies are inferred from the claim text.