A permanent solution for Ekofisk was planned in parallel with trial production from Gulftide. Engineering work for the first stage of this development – or phase II – began as early as 1970, with Houston-based Brown & Root as the main contractor.
The platforms designed for phase II were relatively simple wellhead structures without process equipment. Their job was to bring up the wellstreams and send them on to a process facility.
Everything except the weather had been ready since the beginning of October 1971 for developing the Ekofisk Complex. The support which led the way was the first of three for the bridge to the southern flare stack.
Choctaw manoeuvred it into position and then set to work with piling and foundation work to secure the structure, using the same technique employed with American skyscrapers.
This meant the piles would be bored down through the jacket legs. Deep in the seabed, a hole was then made and cemented, with the cement extending right up into the steel pile itself.
An accident while installing the second support, combined with complex piling and foundation work, meant the three structures were not satisfactorily secured until the summer of 1972.The first four subsea wellsEkofisk committee reports