Operational Improvements Drilling One Million Feet at Nikaitchuq

Abstract

Abstract Nikaitchuq is the largest single-stakeholder development on the North Slope of Alaska. It is a multiyear, very shallow extended-reach drilling (ERD) project with more than 50 wells drilled from two sites, one of which is an artificial gravel island, targeting Schrader Bluff sands. A number of key drilling advances were implemented to reach the milestone of one million feet drilled as the scope of the development plan expanded to include new producer wells targeting a shallower sand, new in-fill multilateral producer branches, and a new extension plan targeting pay that is much more distant than the original development plan envisioned. The minimum slot distance of 8 ft and the increasing density of wells drilled drove the development of a systematic anticollision management plan. Significant economic value was conserved by explicitly forming shut-in/turn-on criteria for offset wells, managing surface conductor drift, controlling drilling parameters exiting the surface conductor through the kickoff, implementing a new surveying technique, and identifying and accounting for directional "deadzones." Abrasion wear occurs in the intermediate hole section bottomhole assembly (BHA) caused by high-angle well path geometry, often surpassing 85° inclination in tangent, combined with the presence of frequent hard stringers. The impact of wear has increased as the extended reach drilling ratio and directional difficulty index have increased year-on-year from 6.34 to 6.69, respectively. Well path geometry has progressed to limit the measured depth drilled through intervals where hard stringers are expected and to account for reduced directional performance at the later part of the hole section. The reduction of downhole tool repair costs and the elimination of downhole tool failures, ultimately leading to single-run, shoe-to-shoe drilling of a section 13,500-ft measured depth (MD) long—a record for Alaska—are the results of the focus on improving BHA design to limit wear. Multiple reentry laterals have been geonavigated in close proximity with the parent wellbore among offset producer grassroots wells. A point-the-bit rotary steerable system has been introduced to drill ahead and deviate from the bottom of the milling rathole, below the whipstock and window, eliminating a motor run and saving substantial rig time on each lateral. A sourceless density logging-while-drilling (LWD) tool was introduced to manage drilling risk through zones of depletion. These technical advancements demonstrate consistent improvement of the drilling learning curve over the course of 5 years drilling at Nikaitchuq. This will be the first literature that details the long-term drilling advances achieved in the project and a valuable technical reference for very shallow ERD wells where abrasion wear is a concern.