Method for the Production of Diamond-hardfaced Titanium Carbide/titanium Bits for Geothermal Drilling

Drilling is equally important for survey purposes, for oil and natural gas exploration, and in searches for water in arid areas. Drill bits with extended service lives are needed to improve the economics of today’s drilling systems, particularly in high temperature, high pressure and erosive gases environments encountered in deep wells close to sources of hot magma. We will develop diamond-hardfaced titanium carbide/titanium (D-TiC/Ti) composites for use as rock-drill bits in deep drilling of geothermal wells where hot-corrosive wear is a major problem. Preliminary work indicates that this new class of D-TiC/Ti composites is more hot-corrosion resistant than conventional diamond-hardfaced tungsten carbide/cobalt (D- WC/Co) composites, apparently because the titanium binder phase is less prone to chemical attack than the cobalt binder phase. Oxidation and erosion resistance of D-TiC/Ti should be at least twice that of D-WC/Co. This should increase service lives of drill bits and efficiency of drilling operations by more than 50%. DoE seeks to develop advanced methods to access the subsurface, particularly for renewable geothermal energy and domestic natural gas supplies, and to increase domestic hydrocarbon resource recovery that enhances national security and economic growth. It is sought to develop tools for deep drilling through hard crystalline rocks. Proposed drilling technology will provide a pathway toward operations in high temperature (> 250 oC and even much higher) and high pressure (> 1500 bar and higher) environments. Nanostructured D-TiC/Ti composites will be prepared using a novel reactive high-pressure/high temperature process. During Phase I, we will (1) develop compositions and methodology to formulate dense superhard D-TiC/Ti nanostructured composites and (2) carry-out preliminary feasibility studies to characterize nanostructure, mechanical strength, toughness, thermal stability, erosion and oxidation resistance for rock drilling applications. It is anticipated that multiple iterations will be required to optimize the composition and nanostructure of the D-TiC/Ti composite to achieve the desired super-hardness, drilling efficiency and high temperature erosion resistance. However, since it is clear from preliminary results that D-TiC/Ti composites can be fabricated at much lower pressures and temperatures than D-WC/Co composites, manufacturing costs should also be significantly reduced. All processing work will be carried out at Diamond Materials, Inc., but characterization work will be performed at Rutgers’ Laboratory for Nanomaterials Research. Commercial applications and other benefits. These composites should increase lifetimes for rock-drill bits, thus increasing operating efficiency and reducing production costs. It is also evident that this new process will enable large monolithic articles of superhard materials, including drill bits, to be made using conventional hot pressing equipment. We will collaborate with SII Megadiamond and Baker Hughes who will perform preliminary bit testing of D-TiC/Ti nanocomposites to identify any manufacturing or performance issues that need to be addressed in Phase II and Phase III.