Date of Graduation
The parameters affecting the hydrofracturing of coal were investigated through laboratory experiments and theoretical analyses. Effects of (i) fluid flow rate, (ii) confining stresses, (iii) orientation of material axes, and (iv) fluid viscosity were studied experimentally. Equations relating the ultimate tensile strength of coal as a function of confining stresses were developed. The expressions for crack tip stresses around a crack in an anisotropic material were used along with the results of previously performed experiments to show that the maximum normal stress criterion should be used in the fracture mechanics model of Pittsburgh coal. A computer simulation technique for crack growth inside a porous and permeable media was developed by using Darcy's law through finite difference equations. It was shown that the technique could simulate laboratory experiments within reasonable accuracy. Several field tests were simulated and the results discussed. A finite element analysis was carried out on the coal specimens, using the experimental data. It was concluded that the contribution of anisotropy was significant.
KHAN, SUBHOTOSH, "SIMULATION OF HYDRAULIC FRACTURING OF COAL." (1981). Graduate Theses, Dissertations, and Problem Reports. 9172.