Oxford Catalysts Group PLC has entered into a memorandum of understanding (MOU) with Potter Drilling, Inc., a google.org funded company, to explore the incorporation of Oxford Catalysts’ Instant Steam technology (earlier post) into Potter Drilling’s hydrothermal spallation technology for drilling geothermal wells.
Geothermal wells can be slow and expensive to drill using conventional rotary drilling methods because the wells are often sunk deep into hard crystalline rocks which are difficult and slow to penetrate and which quickly wear down the drill bits. Potter Drilling’s technology overcomes these problems by using superheated fluid to drill through the rocks, rather than relying on the abrasive cutting power of a rotating drill bit.
The process applies a high-intensity fluid stream to a rock surface to expand the crystalline grains within the rock. When the grains expand, micro-fractures occur in the rock and small particles called spalls are ejected. The process is accelerated by several factors including inherent stress in the rock formation.
Although spallation drilling is not new, Potter Drilling’s technology differs from prior air based techniques in that it uses hot fluid rather than air to spall rock. Because spallation occurs in a water-filled borehole, Potter Drilling’s technology can be used to drill to depths required for universal EGS (12,000 to 30,000 feet).
Hydrothermal spallation was invented and patented by cofounder Bob Potter and Jefferson Tester of MIT. The patent is owned by MIT and licensed exclusively to Potter Drilling.
The technology that is being tested will require Oxford Catalysts’ Instant Steam catalyst to be contained within the drill head to help produce the superheated fluid that is necessary.
Oxford Catalysts’ technology involves passing a liquid fuel—a mixture of methanol and hydrogen peroxide—over a proprietary catalyst. This triggers the spontaneous and highly exothermic reaction
CH3OH + 3H2O2 → 5H2O + CO2 ΔH = -1006.5 kJ/mol methanol
and releases high temperature steam (between 100ºC and 600ºC+), along with small amounts of effluent gases. While the chemistry behind this development isn’t new—the basic reaction was known to the 19th century scientist Michael Faraday—the use of the catalyst is.
The market for geothermal energy is currently very small and supplies less than 1% of the world’s energy. With continued advances in technology, geothermal energy could potentially be used to produce enough electricity, sustainably, to meet a large portion of the world’s energy demands.
A comprehensive new MIT-led 2007 study of the potential for geothermal energy within the United States found that Enhanced Geothermal System (EGS) technology could supply a substantial portion of US electricity well into the future, probably at competitive prices and with minimal environmental impact. (Earlier post.)
Oxford Catalysts is primarily focused on the emerging market for distributed smaller scale production of synthetic fuels (via Fischer-Tropsch).