In 2008, InterAct successfully abandoned a production platform in the East Cameron field, in the Gulf of Mexico, for a leading independent operator. It has been estimated that the strategy adopted for the exercise saved the client in excess of US$700,000.
InterAct’s scope of work included the formulation of the abandonment strategy; development of the operational procedures; preparation of the submission to the Minerals Management Service (MMS) and sole supervision of the offshore work.
InterAct proposed that the topsides should be removed and the jacket then reefed on site. While this was a highly cost-effective option, it was complicated by the fact that a second structure, a wellhead jacket formerly bridge-linked to the main production platform, had been demolished by Hurricane Rita and was settled nearby on the seabed.
In the event, the entire operation went smoothly. The topsides were removed in stages using a reasonably modest derrick barge and taken to shore on a single materials barge in one trip. The jacket was cut in two using diamond wire saws, leaving the bottom section the statutory 90 feet beneath the waterline. The top section was lifted off and placed on the seabed about 160 ft away. Following a thorough seabed survey using sonar, the part jacket was then toppled in a highly controlled fashion so that it came to rest perfectly on its side in the precise spot and with the exact orientation demanded by the MMS – quite a feat given the muddy seabed, the currents, the inherent buoyancy of the jacket and the debris surrounding the site.
The key to the success of the project, from both an operational and an economic standpoint, was good strategy and planning, which minimised marine equipment needs – for a start, a project like this would normally have required a much larger derrick barge – and the length of time the equipment spread was required on site.