During the summer of 1988, Plexus Ocean Systems, Ltd. installed the first adjustable mandrel-type wellhead system on a well drilled for Occidental Offshore Pool Harbour with the jack-up rig Inter Ocean II.
The adjustable hanger technology was devised to obviate the need for removal of the BOP stack during surface hanger installation procedures. Conventional technology to that date was limited to using slip-type surface equipment when mudline hangers were required in the casing program.
The Adjustable Hanger System received formal recognition when Plexus was awarded the 1987 Scottish Offshore Achievement Technology Award and the 1989 Special Meritorious Award for Engineering Innovation presented by Petroleum International.
The paper reflects on three (3) years of operational experience gained from sixty-one installations drilled for eighteen different operators in water depths varying from 110 to 300 feet. The data offers insight into the practicality of this new technology which features time saving elements plus superior technical solutions to achieve real safety improvements. The Adjustable Wellhead Technology will be shown to be cost effective in exploration as well as production applications.