53 AUGUST 2021 WorldWide Drilling Resource® Deep Ice Core Drilling - A Herculean Task Compiled by the Editorial Staff of WorldWide Drilling Resource® Antarctica’s next deep ice core, drilling down to ice from 130,000 years ago, will be carried out by a multi-institutional U.S. team at the western Hercules Dome, most likely beginning in January 2024. This dome, more than 650 miles from the ocean, might have been on the waterfront 125,000 years ago. By examining the cored samples for salt concentration and air bubbles with various gases, scientists hope to understand past environmental conditions and predict future sea levels. With plans to drill 1.5 miles deep, this five-year project, funded by the National Science Foundation, promises to provide key evidence about the possible West Antarctic ice sheet collapse during the last interglacial period, to better gauge its potential risk in today’s warming climate. The Hercules Dome site, remote even by Antarctic standards, lies near a mountain range dividing East and West Antarctica. In early 2020, researchers surveyed for potential core drilling locations by using ice-penetrating radar, GPS surveys, and ice-flow modeling to select final locations for core drilling. For ice coring in depths below which borehole closure in an open hole is a concern, a drilling fluid is used to make sure the pressure in the borehole is approximately the same as the surrounding ice to prevent borehole closure. All of this is temperature-dependent on the ice’s melting point at various places, so the requirement for drilling fluid may occur as early as 328 feet or as deep as 3280 feet. Typically, if drilling fluid is required, a special cable-suspended electromechanical (EM) drill system, using a pump to circulate both the drilling fluid and the chips through screens separating the chips from the fluid, is used. These drill systems are capable of cutting and retrieving cores of ice, in nine-footlong sections, to depths of up to two and a half miles. The main feature of EM ice drilling technology is the method of lowering and lifting the drill in the hole. Instead of the pipes used in conventional rotary drilling rigs to provide power for rock destruction at the borehole bottom and to retrieve the downhole unit, the EM utilizes an armored cable and a winch. The cable not only decreases the mass and power consumption of the drilling equipment; it also shortens the travel time in and out of the hole and simplifies cleaning the cuttings out of the hole. Ice coring and drilling are critical components of scientific research, but they are not simple tasks. At high altitude, cold sites, the snow never melts. It just piles up year after year, burying the older snow climate clues at the time that snow fell on the surface. By collecting vertical cores from ice sheets, evidence of the past can be obtained. The heavy-duty equipment, able to work in some of the most remote places on the planet in punishing conditions of extreme cold, wind, precipitation, and high altitude, manage the Herculean task of retrieving high-quality deep ice core samples. Photo by Peter Rejcek. ENV Gas & Oil by: Society of Petroleum Engineers Unlocking the Potential of Low Quality Reserves in Brown and Green Fields Workshop September 6-8 ~ Cairo, EGYPT phone: +971-4-457-5800 www.spe.org/events/ Irrigation by: Rain Bird Academy Training September 13-17 ~ Miami, FL September 14-16 ~ Pensacola, FL September 20-24 ~ San Diego, CA September 20-24 ~ Charleston, SC September 21-23 ~ Miami, FL phone: 800-498-1942 E-mail: training@rainbird.com More education opportunities during events can be found by clicking here online at: worldwidedrillingresource.com Education Connection Atlantis Vault • Self-Contained • Simple installation • Trouble-free operation For more information call: (270) 786-3010 or visit us online: www.geothermalsupply.com
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