This paper explores the applications, benefits, and value of a high-build-rate rotary-steerable system (HRSS) capable of delivering dogleg severity (DLS) greater than 18°/100 ft. The application of this technology has led to an estimated savings of 40 days. Other benefits include better hole cleaning and smoother wellbores, leading to less wellbore tortuosity and improved post-drilling trips with drilling, logging, and casing assemblies.
Traditionally, steerable motors were used to drill an 8½-in. long-radius curve section requiring DLS of 6–7°/100 ft to land the well in the reservoir. Drilling long-radius curves required drilling through problematic and unstable formations and would require approximately 1,000–1,200 ft of vertical-section length to reach the target entry (TE). In another drilling scenario, sidetracking from a cement plug, the first run was always with a steerable motor with a measurement-while-drilling (MWD) tool to the sidetrack and then 100–150 ft followed by a second run of a rotary-steerable system (RSS) and logging-while-drilling (LWD) tools. When sidetracking from a whipstock, though, the first run was with a motor and MWD tool, a gyro shot to the sidetrack, and then 150 ft, followed by a second run of the RSS LWD bottomhole assembly (BHA).
The long-radius wells were kicked off in the Shilaif formation, and the well profiles require DLS of 6–7°/100 ft through the Shilaif and Maudud formations, 4.5°/100 ft through approximately 700-ft measured depth of Nahr Umr, and finally 6–7°/100 ft through Bab to reach TE....
Bending Rules With High-Build-Rate Rotary-Steerable Systems
17 November 2016