Most of the main types of complications in the process of drilling wells, such as collapses, taluses, collapses of the walls, the formation of caverns, etc., are associated with external mechanical and hydrodynamic effects on the walls of the wellbore. Therefore, ensuring the stability of the borehole walls is one of the urgent and difficult technological formation fluid pressure on mechanical processes in rocks when they are opened with a directional well, especially of horizontal wells. This article provides solutions to problems associated with hydraulic fracturing of a well and the condition of its prevention, calculation of generalized stresses in the rock formation for inclined well. As a result of this calculations, the necessary data are obtained for making a decision on the density of the drilling fluid to drilling the considered interval of rocks, as well as for making other technological decisions. The given calculation formulas make it possible to fully evaluate the effect of the formation fluid pressure on the mechanical processes in the rocks when they are opened by a horizontal well. Keywords: hydraulic fracturing; blade bit; steel ball-shaped toothed bit; polycrystalline diamond bit; laser drilling; impact rope drilling; rotary drilling.