Preliminary calculations of the effects of air and liquid water-drilling on moisture conditions in unsaturated rocks

Abstract

Numerical simulation studies are perfonned to investigate the effects of air and liquid water drilling on the time-dependent moisture conditions in nearby fractures and rock matrix blocks. The results obtained suggest that drilling with liquid water will increase the liquid saturation in the matrix by one or two percentage points after one year of recovery. For the characteristic curves used, this corresponds to a 10 to 20 percent increase in the relative permeability of the liquid phase. The results also indicate that air drilling has negligible effects on the moisture conditions within the matrix blocks.