Application of Air Cushion Technology to Offshore Drilling Operations In the Arctic

Abstract

ABSTRACT The potential for vast oil reserves under the arctic ice cap is evident. Petroleum industry activity in the arctic has been extremely limited, however, due to the transportation difficulties encountered. Existing air, surface, and subsurface craft all have limited capability in the arctic environment. It is proposed that air cushion technology be applied to help solve the petroleum industry transportation problems in the arctic. Air cushion vehicles have been used effectively in a number of military and commercial applications. For the petroleum industry, air cushion vehicles have done vibraseis and seismic survey work in addition to logistics support. These operations did not all have adequate preparation, nor was the most suitable equipment used in all cases, and consequently they varied from partial to complete success. For arctic offshore drilling, a system of air cushion platforms (barges) and air cushion vehicles is recommended. Three barges having identical main structures and mechanical systems are employed - one provides the drilling platform, one is for housing accommodations, and the third is for supplies. The system is based upon a 9000 ft drill rig and each barge has a payload capacity of 100 tons. Two air cushion vehicles of the Valiant type are proposed. These vehicles serve as tractors for the barges in addition to providing logistic support to the drilling complex. The Valiant has a normal payload capacity of 25 tons and its large flat open deck makes it a suitable carrier of all types of payloads. Over flat ground, the Valiant can tow a fully laden barge at speeds up to 25 mph, but when negotiating critical ice ridge peaks, speeds as low as 10 mph are expected. The cost of moving the drilling complex, is very sensitive to the towing speed and the annual utilization of the vehicles. INTRODUCTION If anything about the arctic is as certain as the severity of its climatic conditions, it is the inevitability that the U. S. petroleum industry will be increasingly involved there in the coming years. Relatively recent discoveries of oil within the arctic circle in both hemispheres have confirmed the potential for the long-suspected vast oil reserves under the arctic ice pack and the permafrost. Understandably, the petroleum industry is hesitant about rushing to the arctic because of the many problems associated with operating in such a severe, hazardous environment. One cannot expect to see production of arctic oil until reasonable technical, operational and, above all, economic solutions are found for these problems. The most critical problem facing the oil industry in the arctic, from an economic aspect as well as operationally, is that of transportation. From the movement of exploration crews, their equipment, and their logistic support, to the delivery of crude to the refinery, the petroleum industry is confronted with transportation challenges of enormous magnitude. Air, surface, and perhaps, subsurface transportation means will undergo a significant development effort in. the continuing evolution towards an optimum total arctic transportation system for the petroleum industry.