Mobility and Speed in a Workover/ Completion Rig for the Arctic

Abstract

Abstract In April, 1984, ARCO Alaska, Inc. published specifications for a workover/completion rig for the Kuparuk oil fields, located on the North Slope of Alaska. ARCO was seeking a rig which could handle a static hook load of at least 300,000 lbs., with the capability of moving well-to-well within 3 hours and pad-to-pad inside a 5-mile radius within 12 hours. Nordic-Calista Rig 1, designed specifically for that contract, performed its first day of production on April 4. 1985. Subject rig has, in this entire history of operation, beaten those original move time requirements 100% of the time. From daily production reports of Nordic-Calista Services No. 1, the joint venture owner and operator of subject rig, during the one year period June 1, 1987 to May 31, 1988, well-to-well move time averaged just over 22 minutes and pad-to-pad, up to a 5-mile radius, move time averaged just under 2 hours. Built on three levels, the unit is completely self-contained, self-propelled with a top speed of approximately 2.5 miles per hour, winterized for harsh Arctic operations, and is capable of performing work-over/completion operations to a depth of 16,000 feet. Rig up and tear down time has been virtually eliminated, except where the unit is required for the Prudhoe Bay oil fields nearby. 45-foot height restrictions Prudhoe Bay oil fields nearby. 45-foot height restrictions therein require removal of the derrick and disassembly of its windwalls in such instances. Introduction In telling the story of workover and completion rigs and production in the Arctic, it is necessary to present a brief history behind the North Slope of Alaska, and its emergence as the premier oil play on the North American continent. When speaking of the North Slope we are narrowing our discussion to the on-shore production primarily consisting of two major fields: Prudhoe Bay, primarily consisting of two major fields: Prudhoe Bay, encompassing an area roughly 300 square miles: and Kuparuk River. approximately 30 miles due west encompassing roughly 225 square miles. The Prudhoe Bay discovery well was spudded in April 1967, and the Kuparuk River discovery well was drilled and tested in 1969. From the time of the original discoveries to the early seventies, little could proceed without an acceptable transportation system for the oil. Upon commencement of construction of the Trans-Alaska Pipeline, drilling and completion activities began in earnest and by the time the pipeline was completed and production began to flow through in June of 1977, many production wells were already in place in Prudhoe Bay. Kuparuk River first production was in Prudhoe Bay. Kuparuk River first production was in December, 1981.