An experimental study of the influence of uniaxial load on flame jet drilling

摘要

The performance of flame jet drilling on Grimsel Granodiorite cylindrical rock samples was experimentally investigated depending on applied uniaxial load. With a simple confining system for the rock samples, uniaxial load up to 47 MPa was tested in order to simulate the axial component of the stress tensor existing in a deep borehole. Provided that flame properties were unchanged, increasing the uniaxial load influenced the drilling positively. The experimental results were explained with numerically calculated stress profiles. It was concluded that tensile stresses below the heated surface increase with uniaxial load and additionally weaken the rock, which should improve the flame jet drilling with depth.