The effect of seepage on the stress–strain state of rock near a borehole

The effect of the strain-strength and seepage properties of rock and the compressibility of the percolating fluid on the dimensions of the rock fracture zones, which occur in oil and gas boreholes when the bottom hole pressure is reduced, is investigated. The seepage is considered basing on the stationary formulation of the problem, which enables the general case to be investigated. It is shown that in the case of unsteady flow, the stresses on the boundary of the rock fracture zone and, as a consequence, on its dimensions, are independent of the nature of the pressure distribution in the stratum, and are determined solely by the pressure of the percolating fluid on the boundary of this zone. It is established that an increase in the compressibility of the percolating fluid leads to an increase in the dimensions of the rock fracture zone.