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Xstrata and PathFinder applied oilfield technology to construct a pattern of vertical and horizontal wells to degassify a coal mine in Australia. A custom extended reach drilling rig was built, and a mud motor used to drill horizontal laterals of about 12,000 ft at a depth of 500 ft. Pre-job modeling, automated surface rotational controls and MWD surveys reduced risk and improved drilling efficiency.
Vol. 233 No. 2</P>
DIRECTIONAL DRILLING
Oilfield horizontal drilling technology used to degas an Australian coal mine
CLINT TODHUNTER and IAN CRANE, Xstrata; and JIM FOREMAN, MICHAEL FRANKLIN, JON HILL, JOHN PERRY and GREG MESZAROS, PathFinder, a Schlumberger company
Xstrata and PathFinder applied oilfield technology to construct a pattern of vertical and horizontal wells to degassify a coal mine in Australia. A custom extended reach drilling rig was built, and a mud motor used to drill horizontal laterals of about 12,000 ft at a depth of 500 ft. Pre-job modeling, automated surface rotational controls and MWD surveys reduced risk and improved drilling efficiency.
Purpose-built ERD rig based on a rack-and-pinion design</P></P>
Extended reach drilling (ERD) technology, widely used for oilfield applications, is now being deployed in a large underground mine to drain methane gas, enabling safe, continuous coal extraction operations. A specially designed rig has been built to facilitate drilling these horizontal wells, which are at shallower depths than would be normal for oil or gas development. Integrated services deployed include an automated surface rotation control system, and real-time analysis of drilling and advanced ranging for accurate positioning of the bottomhole assembly (BHA). Horizontal wells have been drilled successfully and cost-effectively at a depth of about 500 ft and up to 12,000-ft TD, intersecting existing vertical wells as planned, and helping achieve coal production quotas.
BULGA MINING COMPLEX
Xstrata is a diversified mining group headquartered in Switzerland with operations and projects in 20 countries. Xstrata operates the Bulga coal mining complex, 110 mi north of Sydney in New South Wales, Australia. With an annual production of approximately 16 MMt, the Bulga Complex is one of the most prolific coal mining operations in the world. Five seams are targeted for underground extraction, one of which is the Blakefield Seam.
Longwall mining. The Blakefield South development (Fig. 1) uses the longwall mining method,...