Study of the impact of exploitation structures on pressure distribution and adsorbed methane content in coal seams using dynamic flow models. A case study

Wiesław Szott,Krzysztof Miłek,Andrzej Gołąbek,Piotr Łętkowski

doi:10.37190/msc202710

Abstract

1. Annual Report… 2002–2011 – Annual Report (for the years 2001–2010) on the State of Basic Natural and Technical Hazards in the Hard Coal Mining Industry, Gas Hazard. Publ. Central Mining Institute, Katowice 2002–2011, p. 20–40. Google Scholar

Highlights

Polish coal mines have been extended to ever deeper levels (Annual Report...)
SUMMARY AND CONCLUSIONS On the basis of an example of a realistic structure of coal seams, the possibility of performing a detailed quantitative evaluation of pressure and reservoir fluids distributions in a selected coal seam caused by the exploitation activities in neighbouring seams as well as preparation works in the selected seam was presented
Simulations of these models have to include all the basic processes that occur in the analysed structure as a consequence of the exploitation activities, i.e., the desorption of methane from the coal matrix, its diffusion to the system of fractures of coal seam and viscous, two-phase gas and water flow in the system of these fractures as well as in the porous medium of rocks separating coal seams

Summary

INTRODUCTION

Polish coal mines have been extended to ever deeper levels (Annual Report...). As the depth of these seams increases, the amount of the methane adsorbed in them increases as well (Global methane and the coal industry, Krause et al.). The need for them, the density of the performed borehole grid, and particular stimulation techniques are strongly dependent on the initial conditions of these seams, i.e. the conditions before starting the methane drainage process This paper presents simulation results of reservoir fluids (water and methane) migration occurring in coal structures performed on a realistic model of one of the coal seams currently planned to be exploited by a national coal company (GasDrain) These results indicate the size of a typical effect of methane drainage and pressure reduction in the analysed seam due to the presence of adjacent, previously exploited seams and other exploitation elements. Based on obtained results the flow simulations including desorption, diffusion, and viscose flow were performed by EclipseTM

CHARACTERISTICS OF THE SIMULATION MODELS

Findings

SUMMARY AND CONCLUSIONS