Nearly two-thirds of the oil we use comes from wells drilled using polycrystalline diamond compact (PDC) bits, originally developed nearly 30 years ago to lower the cost of geothermal drilling. Sandia and the U.S. Navy recently brought the technology fullcircle, showing how geothermal drillers might use the original PDC technology, incorporating decades of subsequent improvements by the oil and gas industry.
Sandia and the Navy's Geothermal Program Office (USN GPO) conducted the Phase One demonstration tests as part of a geothermal resources evaluation at the Chocolate Mountains Aerial Gunnery Range in Imperial Valley, Calif.
Sandia has a long history in geothermal research and drill bit technology development. Three decades ago, Sandia played a large role in developing PDCs for geothermal drilling. That work focused on resolving issues with materials, devising laboratory tests and developing data and design codes that now form the basis of the bit industry. Recently, Sandia received American Recovery and Reinvestment Act (ARRA) funding to improve PDC bits, potentially increasing access to geothermal resources in the continental U.S. by enabling the drilling of deeper, hotter geothermal resources in hard, basement rock formations.
Geothermal drilling more demanding
Because oil and gas drilling is generally less complicated than geothermal drilling, PDCs were first used to drill for oil and gas, said principal investigator David Raymond.
"Oil and gas drilling is normally done in softer and less-fractured rock, resulting in fewer problems with fluid circulation to remove debris and cool the bit," he said. "Oil and gas drilling also doesn't usually involve the higher temperatures that geothermal wells exhibit."
But as the oil and gas industry looks for new sustained resources in deeper reservoirs, it encounters more difficult drilling conditions similar to those found in geothermal drilling.
|Contact: Stephanie Holinka|
DOE/Sandia National Laboratories