DEEP HOLE DRILLING IN REFRACTORY METALS USING ABRASIVE WATERJETS

A DEEP DRILLING SYSTEM FOR REFRACTORY METALS SUCH AS TUNGSTEN (W) AND MOLYBDENUM-30 WT PERCENT W IS BEING DEVELOPED THAT USES AN ABRASIVE WATERJET (AWJ) AS THE CUTTING TOOL. SEVERAL CONCEPTUAL DESIGNS OF AWJ DRILLS ARE BEING PREPARED DURING PHASE I, WHICH INCLUDES EXPERIMENTAL SIMULATION AND DRILLING TESTS TO VALIDATE THE SELECTED CONCEPTS AND TO DETERMINE THE SPECIFIC PARAMETERS, STRATEGIES, AND TECHNIQUES TO BE INCORPORATED IN A DRILLING HEAD DESIGN. A DRILLING HEAD IS BEING DESIGNED, FABRICATED,AND TESTED TO DEMONSTRATE THE FEASIBILITY OF THE AWJ DRILL AND TO IDENTIFY SPECIFIC PHASE II DEVELOPMENT EFFORTS FOR A PROTOTYPE SYSTEM. A DATA MATRIX WILL BE GENERATED ON DRILLING RATES, AWJ PARAMETERS, ENERGY REQUIREMENTS, AND GENERAL HOLE QUALITY OBSERVATIONS. TECHNICAL AND SIMPLIFIEDECONOMIC ASSESSMENTS ARE BEING CONDUCTED IN THIS PHASE, AND RECOMMENDATIONS FOR FURTHER WORK WILL BE MADE. THE ANTICIPATED DRILLING TIME FOR A HOLE 3/4 INCH IN DIAMETER AND 8 FEET DEEP IN A TUNGSTEN ROD IS APPROXIMATELY 2 HOURS.