Title: Investigating reservoir stresses and strain effects during production from coal bed methane gas reservoir on reservoir properties and gas production – a numerical study

Authors: Subhashini Nainar; G. Suresh Kumar

Addresses: Department of Ocean Engineering, IIT-Madras, Chennai-600036, India ' Petroleum Engineering Program, Department of Ocean Engineering, IIT-Madras, Chennai-600036, India

Abstract: The effects of stresses and strains, occurring in a reservoir, on the cumulative gas production and the petrophysical properties are studied. Existing strain and stress model equations have been used to analyse the coupled effect of matrix shrinkage and cleat compressibility change on reservoir properties. A coal bed methane (CBM) gas reservoir, low permeable and undersaturated, is semi-analytically modelled. A nearly suitable model from among them is eventually proposed to predict the cleat permeability and gas production existing in the field using a dynamic drainage area (DDA) approach. These results vary with the production time. The strain model predicts gas production values and the stress models predict a range of cleat permeability variation values close to field values. Cleat permeability and cleat porosity both affect gas productivity but in the opposite manner. [Received: December 29, 2018; Accepted: May 14, 2019]

Keywords: stress models; strain model; cleat compressibility; sorption strain; dynamic drainage area; DDA; coal.

DOI: 10.1504/IJOGCT.2020.111150

International Journal of Oil, Gas and Coal Technology, 2020 Vol.25 No.4, pp.476 - 487

Received: 29 Dec 2018
Accepted: 14 May 2019

Published online: 07 May 2020 *

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