TY - JOUR

T1 - Direct and inverse problems of gas emission and the sorptive deformation of coal beds

AU - Nazarova, L. A.

AU - Nazarov, L. A.

AU - Vandamme, M.

AU - Pereira, J. M.

PY - 2017/4/1

Y1 - 2017/4/1

N2 - Using the equations of state for fractured-porous media that describe the sorptioninduced deformation of coal, we develop a geomechanical model for radial gas influx to a borehole drilled in a coal bed with the concurrent evolution of stress field in the borehole environment. A numerical-and-analytical method is proposed for solving the corresponding system of equations for poroelastic media. A relation is found between the volume of slack withdrawn in the borehole (when opening up the gas-bearing seams), the sorption-and-storage capacities of coal, the permeability k, and the horizontal component σh of the natural stress field. We demonstrate the solvability of the inverse boundary-coefficient problem of determining k and σh on the basis of pressure in the closed borehole. We substantiate an express-method for estimating the permeability by the measurements of pressure in the borehole operating in the “pressure drop” mode.

AB - Using the equations of state for fractured-porous media that describe the sorptioninduced deformation of coal, we develop a geomechanical model for radial gas influx to a borehole drilled in a coal bed with the concurrent evolution of stress field in the borehole environment. A numerical-and-analytical method is proposed for solving the corresponding system of equations for poroelastic media. A relation is found between the volume of slack withdrawn in the borehole (when opening up the gas-bearing seams), the sorption-and-storage capacities of coal, the permeability k, and the horizontal component σh of the natural stress field. We demonstrate the solvability of the inverse boundary-coefficient problem of determining k and σh on the basis of pressure in the closed borehole. We substantiate an express-method for estimating the permeability by the measurements of pressure in the borehole operating in the “pressure drop” mode.

KW - borehole

KW - coal bed

KW - filtration

KW - fracture-porousmedium

KW - inverse problem

KW - natural stress

KW - permeability

UR - http://www.scopus.com/inward/record.url?scp=85019723794&partnerID=8YFLogxK

U2 - 10.1134/S1990478917020090

DO - 10.1134/S1990478917020090

M3 - Article

AN - SCOPUS:85019723794

VL - 11

SP - 236

EP - 243

JO - Journal of Applied and Industrial Mathematics

JF - Journal of Applied and Industrial Mathematics

SN - 1990-4789

IS - 2

ER -