The Beaufort Seanew Generation Drilling System

Abstract

Abstract This paper describes a new generation drilling system developed for use in the Beaufort Sea by Gulf Canada Resources Inc. The drilling fleet is comprised of a conical drilling unit named Kulluk and a mobile arctic caisson named Molikpaq. Support equipment includes two ice-breakersKalvik and Terry Fox, two ice-breaking supply shipsMiscaroo and Ikaluk, as well as shore-side administrative and marine facilities. The drilling units are unique and have been designed specifically to provide an extended season drilling capability in the Beaufort Sea. This paper describes the drilling and support equipment and highlights the novel aspects of the units. Introduction Gulf Canada Resources Inc., (GCRI) has extensive land holdings in all of Canada's frontier areas. OCRI has been a major participant in several important discoveries in the Beaufort Sea, and is operator of 1.5 million gross acres in this area. These holdings lie between 50 and 100 kilometres offshore in water depths ranging from 20 to 55 metres (Fig. 1). In GCRI's view, this acreage is geologically highly prospective, and merits aggressive exploration. This paper summarizes how GCRI intends to explore this acreage in a timely, cost effective manner. The company has developed a new generation of drilling equipment-the first such equipment to be designed and built specifically for Beaufort Sea application. The paper will outline the reasons for developing this drilling fleet, and will describe the major drilling equipment, marine components, and support systems. Background Offshore exploration in the Beaufort Sea began in 1972, with the use of an artificial sand island in very shallow water. Current methods of drilling now include the use of conventional drillships modified for an ice environment, dredged sand islands, and most recently, caisson-retained islands. Each of these systems has successfully drilled exploratory wells, however they also suffer from operational limitations. For the water depths of interest to GCRI, artificial islands are economically unattractive because of the huge quantities of dredged sand required, as well as the time necessary to place this sand, which can be in excess of two years. Conventional drillships are also not particularly cost-effective because they are limited to an open-water operating season of about Ion days -insufficient to fully drill and evaluate a well. Orderly and timely exploration of resource acreage is desirable for any company. With the advent of the National Energy Program (NEP), the frontier regions were placed under accelerated exploration requirements. The need for efficient utilization of available time was evident, and GCRI therefore reviewed all potential options for exploring its Beaufort Sea holdings. As a result, GCRI decided to develop its own new generation drilling system for this area. The primary criterion of this new system was to meet the ac? celerated exploration requirements by extending the drilling season to fully drill, complete and test a well within one year. Having established the extended season criterion, the next step was to select concepts for drilling systems which were: capable of operating in ice-infested waters; suitable for operations in the varying water depths of the acreage;