Field Testing a New Rotary-Steerable-Drilling-Liner Technology

Abstract

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 168044, ’First Field Testing of a New Rotary-Steerable-Drilling-Liner Technology on Alaska’s North Slope,’ by Greg Hobbs, Rob Stinson, and Chip Alvord, ConocoPhillips, and Okechukwu N. Anyanwu, Christian Klotz, and Muntasar Mohammad, Baker Hughes, prepared for the 2014 IADC/SPE Drilling Conference and Exhibition, Fort Worth, Texas, USA, 4-6 March. The paper has not been peer reviewed. Conventional drilling through lower intermediate intervals in the southern portion of the Alpine field on Alaska’s North Slope has posed significant challenges. While unstable shale sections can be drilled without significant issues, hole collapse has caused difficulties while tripping out of hole and running casings. In 2011, a new steerable-drilling-liner system was deployed in the field. This paper provides insights into the new technology and the field-trial program. Introduction The Alpine field, which came online in 2000, lies near the environmentally sensitive shoreline of the Arctic Ocean on the North Slope of Alaska (Fig. 1). It is the westernmost of the current North Slope producing fields and straddles the border of the National Petroleum Reserve— Alaska. The field was developed without a permanent road connection to the existing North Slope infrastructure, to address environmental and indigenous-community concerns. Much of the resupply effort for the roadless period is accomplished during the iceroad season. Field development has progressed from near-pad targets to higher-departure wells in a 6,700-ft-truevertical- depth reservoir section that has introduced drilling challenges. Background The development of the Alpine reservoir has progressed as an alternating horizontal-producer/-injector pattern for best recovery efficiency (Fig. 2). As field-pad development advanced southward, it was determined that a shale package had thickened in this direction. This thickening, compounded with progressively higher sail angles required to reach points at higher departures, led to issues that affected efficient running and cementing of intermediate liners. New techniques involving higher mud weights and managed-pressure drilling were attempted with limited success. The authors learned of a steerable-drilling- liner technology that was being developed and deployed offshore Norway to drill through and complete beyond troublesome hole sections. This system was researched, and a case was made to develop and deploy it in the Alpine field in Alaska. (For the details of the related feasibility study, please see the complete paper.) Deploying new technology in a remote, seasonally roadless Arctic development was no small commitment. Initial deployment plans used nonrotating torque reducers, premium liner connections to ensure integrity through multiple rotations in tortuous hole paths, robust solid centralizers proved in casing-drilling applications, and drilling-dynamics sensors placed above and below the liner to provide recorded and real-time data. A four-well, progressive, directionally complex pilot program was assigned by the resource asset for two reasons. First, it was not cost-effective to ship specialized equipment over ice roads for a single well project. Second, it was deemed important that the system be given a fair trial, because it could be a key to future development potential in the area. The technology could enable completion of high-departure wells in an unstable overburden where the environmental sensitivity of the area precludes the placement of more drilling pads.