Technology for Drilling to the Moho
The Integrated Ocean Drilling Program (IODP), in collaboration with industry partner AGR Drilling Services, has engineered an ultra-deepwater drilling technology for use by IODP drilling vessels in scientific research.
Originally developed for shallow-water oil and gas exploration, the "riserless mud recovery" technology (RMRT) holds great promise for scientists striving to reach the long-held goal of Project Mohole in the 1950s: drilling all the way through ocean crust into the Earth's mantle; a frontier not yet explored today. Drilled cores from the mantle could provide scientists with answers to questions about the structure, composition, mineralogy, and in situ physical properties of oceanic crust and the geological nature of the seismic Moho.
Implementation As Early As July, 2011
"With AGR Drilling Services' support, IODP led an engineering effort to adapt existing technology to drill very deep holes in very deep regions of the ocean," says Engineering Manager Greg Myers. "Up to now, riserless mud recovery drilling was limited to shallower water depths.
This ultra-deepwater drilling technology allows scientists to investigate subseafloor areas in great depths, where oceanic crust may be thinner-such as in waters off Hawaii." According to Myers, an ultra-deepwater RMRT system could be implemented as early as July 2011.
The RMRT technology, owned by AGR, is expected to operate in hyper-deepwater depths greater than 12,000 feet. Funding for preliminary engineering was provided by the DeepStar Consortium, a deepwater industry group that supports deepwater technology development projects and leverages the industry's financial and technical resources.
"This ultra-deepwater drilling technology is environmentally friendly," says David Hine, AGR Vice President of Sales and Marketing. "It operates with a 'zero-discharge' system, leaving no cuttings or mud behind."
Previous Near-Mantle Depth Drilling
In December 2005, scientists aboard IODP Expedition 312 approached mantle depths while drilling to investigate superfast seafloor spreading rates. The research expedition penetrated volcanic rock (gabbros) and reached a fossil magma chamber lying 1.4 kilometers beneath the seafloor. The Moho, or mantle, lies beneath the gabbros layer of ocean crust at depths that vary from about 5-10 km. beneath the ocean floor, to about 40 km. beneath the continents, to as much as 70 km. beneath some mountain ranges.
The Integrated Ocean Drilling Program (IODP) is an international marine research program led by the National Science Foundation in the U.S. with support from another 23 countries. IODP advances scientific understanding of Earth by drilling, sampling, and monitoring subseafloor environments.
Using multiple platforms and technologies, the world's preeminent scientists working in the program explore climate change, the deep biosphere, and geodynamics.
Republished from a press release from the Integrated Ocean Drilling Program issued in August, 2009.
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|One problem with drilling deep holes in ultra-deepwater is the control and recirculation of drilling mud that cools the drilling process and flushs rock cuttings out of the drill hole. In the riserless mud recovery system, drilling mud is pumped down the drill pipe, exits through the drill bit, returns to the top of the hole outside of the drill pipe and is then captured as it exits the hole and pumped back to the surface through a rigid mud return line. Image by the Integrated Ocean Drilling Program. Enlarge Image