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US revives research on high efficiency diamond geothermal drilling bit

Vanguard Geothermal Drill Bits, Baker Huges (source: Baker Hughes)
Alexander Richter 20 Mar 2012

The U.S. Navy in tandem with DOE's Sandia National Laboratory is reviving research, testing and evaluation of a high efficiency polycrystalline drilling bit for geothermal drilling. The research is important as it could help cut cost for drilling substantially through more aggressive drilling by those new cutters.

News in the U.S. report on efforts by a group of scientists in the U.S. to revive a rather old technology for a high performance drill bit. This time it is not looked at drilling for oil and gas, but for geothermal wells.

The group consists of the U.S. Navy and the Department of Energy’s Sandia National Laboratory. They expect to test, evaluate and improve a “polycrystalline diamond compact bit” to help lower the cost of drilling for geothermal energy projects.

The Navy has been involved in geothermal energy for decades and actually runs the China Lake research facility, which also is the site of a major geothermal power plant operating already for 15 years.

Sandia originally helped “to develop polycrystalline diamond compact (PDC) technology about 30 years ago specifically to help the geothermal industry cut costs. However, given the industry’s small size at the time, there were relatively few opportunities to refine the technology in practice, so the oil and gas industry picked up the ball and ran with it.

PDC technology is based on a process called sintering, which involves fabricating objects from powders. According to Sandia’s press materials:

“Polycrystalline diamond compact cutters on the cutting faces of bits allow more aggressive drilling than bits traditionally used for geothermal drilling. They are created by a sintering process. Graphite powder is applied to the leading face of a cutter made of tungsten carbide. The material assembly is compressed in three directions at pressures of 1 million pounds per square inch. When heated to a transition temperature, the graphite converts a to a 1-millimeter layer of synthetic diamond.”

Source: Talking Points Memo