[en] THE PRESENT PAPER PRESENTS A PORTABLE APPARATUS, THE ROCK STRENGTH DEVICE (RSD), AND METHODOLOGY TO ASSESS STRENGTH OF COHESIVE GRANULAR MATERIALS 'PARTIALLY-DESTRUCTIVE' SCRATCHING TESTS.EXPERIMENTS ON SEVERAL SEDIMENTARY ROCKS SHOW THAT THE COEFFICIENT OF PROPORTIONALITY, REFERRED TO AS THE INTRINSIC SPECIFIC ENERGY IS WELL CORRELATED TO MATERIAL UNIAXIAL COMPRESSIVE STRENGTH,UCS.FURTHERMORE, THE FRICTION COEFFICIENT MOBILIZED ALONG THEWEAR FLAT OF BLUNT CUTTER IS FOUND TO BEWELL CORRELATED TO THE INTERNAL FRICTION ANGLE OF THE ROCK. THE HIGH SPATIAL RESOLUTION AND PRECISION OF THE FORCE MEASUREMENT PROVIDES FINE LOGGING OF THE TWO ROCK PROPERTIES AND THUS PERMIT TO ISOLATE WEAK OR DAMAGED INTERVALS, AND CAPTURE HETEROGENEITIES OR ANISOTROPIES.THE PAPER PRESENTS A PARTICULAR PETROLEUM APPLICATION ON CORE ANALYSIS WHERE UNDERSTANDING THE VERTICAL VARIABILITY OF ROCK PROPERTIES ALONG A RESERVOIR TICKNESS IS OF PRIMORDIAL IMPORTANCE FOR SANDING PREDICTION ANALYSIS, AND SOME OTHER FIELD APPLICATIONS FOR WHICH THE SCRATCHING TEST HAS BEEN USED.
