When drilling exploration wells in weakly cohesive and uncohesive rocks, represented by sands, boulder and pebble and moraine sediments, by traditional methods, narrowing and collapse of the borehole occurs, which leads to sticking of drilling tools, redrilling of already passed intervals and causes complication of borehole designs (i.e., requires the placement of additional casing). All this implies additional expenditures of time and materials. At present this problem is solved by development of special flushing fluid compositions capable of keeping wellbore in steady state due to their anchoring properties. In order to determine the effect of flushing fluid on wellbore stability it is necessary to investigate the strength characteristics of rocks treated with drilling mud. An "express-methodology" of such research is offered.
