Drilling and Casing a Large-diameter Shaft in the Piceance Creek Basin.
11th Oil Shale Symp 1978 Apr; :292-310
The drilling and casing of a pioneer 8-foot-diameter vertical shaft to a depth of 2,371 feet in thick oil shale beds is described. Mining environmental research studies are planned from the shaft and samples of oil shale, nahcolite, and dawsonite will be mined. Results showed that a large-diameter shaft could be safely blind- bored through the aquifers in the basin. Problems with the drilling assembly, drilling mud, and welding of the casing can be solved with improved designs.
11th Oil Shale Symp., April 12-14, 1978, Colorado School of Mines Press, 1978, PP. 292-310