The influence of deformation processes on the permeability of rocks and the stability of an oil well

The paper studies the effect of real stresses occurring in the vicinity of a horizontal well on the filtration and strength properties of rocks for the Prirazlomnoye offshore field. The rocks from two intervals of the reservoir section with different structural and lithological characteristics were studied. The experiments were carried out on the Triaxial Independent Load Test System of the Institute of Problems in Mechanics of the Russian Academy of Sciences. Modeling showed that the filtration properties of the rocks under study strongly depend on the stress-strain state. When the pressure in the well drops to a certain critical value, they deteriorate. Then there is a cracking, disintegration of the rock in the vicinity of the well, accompanied by a sharp jump-like increase in permeability. The values of the pressure at the bottom during drilling which are necessary to maintain the stability of the wellbore were defined. The density of the drilling mud was calculated, for which there is no destruction of the wellbore. The influence of the initial stress state in the formation on the deformation and fracture processes in the vicinity of the well was studied experimentally.