A polar gas pipeline for the Canadian Arctic

Abstract

The Polar Gas Project was established in 1972 to determine the best means of moving frontier natural gas reserves from Canada's High Arctic to southern markets. The current participants in Polar Gas include TransCanada PipeLines Limited, acting as Project Manager, Panarctic Oils Limited, Tenneco Oil of Canada Ltd., the Ontario Energy Corporation and Petro-Canada. This paper summarizes the pipeline routings investigated, present and future reserves in the Canadian Arctic and outlines methods for installing the pipelines in the Arctic channels. All the various pipeline routings investigated would be partly in continuous permafrost regions, partly in discontinuous permafrost and most cases only a portion would be in non-permafrost soils. The preferred route would be approximately 3,100 miles in length and would be buried throughout its length. The cost of constructing the Polar Gas pipeline is estimated to be $10,6 billion expressed in 1980 Canadian dollars excluding any interest charges. Even though energy exploration in these areas is relatively only a few years old, substantial natural gas reserves have been identified — approximately 15.7 Tcf in the Arctic islands excluding 1981 discoveries and 5.8 Tcf in the Mackenzie Delta excluding any gas reserves in the Beaufort Sea. The total marketable reserves of 21.5 Tcf which have already been identified in these areas are more than sufficient to make the Polar Gas Project a feasible and economic venture. In order to connect the natural gas reserves in the Canadian Arctic Islands, Polar Gas will have to install pipelines in two major marine crossings in the Arctic waters in the initial construction phase of the project. The two marine crossings are located at either end of Victoria Island — at Dolphin and Union Strait and at M'Clure Strait. Dolphin and Union Strait between Victoria Island and the Canadian mainland is about 19 miles wide and has a maximum depth of 400 feet. M'Clure Strait is between Victoria Island and Melville Island and is 76 miles wide with a maximum depth of 1650 feet. Different methods of construction are proposed for the two channels and these methods are described in the paper as well as outlining the technique for protecting the pipelines from potential ice scour. Polar Gas and its consultants have designed a full scale demonstration of the one-atmosphere welding technique closely parallelling the underwater environment faced at M'Clure Strait to demonstrate that the tie-ins which would be necessary for the actual construction of the marine crossings could be satisfactorily undertaken. The equipment required for the demonstration is outlined in the paper and the general procedures are described. The planned pipeline demonstration would significantly enhance the current state-of-the-art for deepwater pipelining worldwide as well as providing the project with invaluable information which can be used for the final design and construction of the offshore marine facilities. Therefore the demonstration should be of interest not only to participants in the Polar Gas Project but more generally to all energy companies concerned with deepwater tie-ins and marine pipeline repair.