During the period August, 1967 to September 1970, Phillips, as operator for a group holding acreage in the Ekofisk area of the North Sea, drilled four exploratory wells. These wells, having proved the existence of a commercial field, were properly plugged and the rig moved on to exploratory work in other areas. No thought was given at the time to producing these wells, which were considered to be purely exploratory.
In June of 1971, however, it was concluded that an investigation should be made of the possibility of producing these wells. The formal program for producing the field was in the process of development and indications were that production could not be started before 1973 or 1974. As discussions on the possibility of producing the four exploratory wells progressed, it became apparent that production, in the range of 40,000 barrels per day, could be achieved perhaps by early 1971. Therefore, a serious study of the problem was set up.
The first look showed, of course, several immediate challenges. The four wells had been sealed and by this time the well heads had probably been covered by the shifting sands of the sea bottom. Merely locating them again would be like looking for the proverbial needle in the haystack. The wells were located in about 245 feet of water about 180 miles from the nearest land. Obviously, any production from the wells would have to be loaded into tankers; there would be no possibility of producing into a pipeline for delivery to a market. So the problem basically divided itself into two separate areas. The first concerned the methods to be used in completing and producing the wells as well as in separating the gas from the crude and the second, delivering the crude to the tankers at a temperature and vapor pressure which could be accepted. The way in which this challenge was met and overcome has been described in numerous papers and articles, and will not be dwelt on here. As background for the subject of this paper it should be sufficient to say that plans were made to use sea-floor completion for the wells, and to pipe the produced crude to a self-elevating drilling rig, the "Gulftide", which would be positioned in a central location between the wells, and used as a production platform, with the necessary equipment for treating the crude, flaring the gas, and pumping the crude to the tankers. So the study team split into two separate groups, one attacking the problem of producing the crude, and the other looking at the question of how to get the crude into the tankers which would take it to the users. It is the activities of the latter group which will be described in this paper.
