Coiled tubing velocity string set at record 20,500 ft

This paper reports that coiled tubing, set at record depth, significantly reduced costs and posed lower mechanical failure risk for recompleting a gas well in the Delaware basin of West Texas. Alternative completions such as replacing the existing tubing string with smaller diameter conventional API production tubing was deemed less economical and effective. The gas well, George M. Shelton No. 2, was recompleted on July 18, 1991, by Chevron U.S.A. Production Co. The gas is produced from the deep, low-pressure Ellenburger formation in the Gomez field. The hang-off depth of 20,500 ft set a world record for the deepest permanently installed coiled tubing. The 1-1/2 in. coiled tubing velocity string, run within the existing 4-1/2 and 4-in. tapered production tubing string, consists of seven segments that vary in wall thickness from 0.087 to 0.156 in.