Application of Recently Developed Medium-Curvature Horizontal-Drilling Technology in the Spraberry Trend Area

Abstract

Recently developed horizontal-drilling techniques have been applied in the Spraberry trend area in Midland County, TX. The desired application includes drilling horizontally at a right angle to the naturally occurring vertical fractures in one of three Spraberry zones. The result was 1,180 ft (360 m) of vertical section within 10/sup 0/ (0.17 rad) of the planned azimuth of 115/sup 0/ (2.01 rad). The W.M. Schrock 38 No. 7 was drilled vertically to 8,620 ft (8,620 ft (2627 m) through the Upper Spraberry, Lower Spraberry, and Dean formations. After the curved portion of the hole had been drilled, 3- and 1/sup 0//100-ft (1.7 x 10/sup -3/ and 0.57 x 10/sup -3/-rad/m) motors were used in both rotational and orienting modes to maintain the inclination near 90/sup 0/ (1.6 rad) and in azimuth of about 115/sup 0/ (2.01 rad). During drilling at 8,598-ft (2621-m) measured depth (MD), the motor parted and and fishing job in the near-horizontal portion of the wellbore resulted. The motor and bit were successfully retrieved on the first attempt. From 8,400 to 8,835-ft (2560- to 2693-m) MD, inclination decreased from 90 to 82/sup 0/ (1.6 to 1.4 rad), resulting in the penetration of the base of the Lowermore » Spraberry. Drilling operations ceased at 7,929-ft (2417-m) TVD and 8,930-ft (2722-m) MD with 891 ft (272 m) of formation exposed vs. a 70-ft (21-m) exposure in a standard vertical-well completion in the Spraberry trend area.« less