Taking Advantage of Vessels of Opportunity

Colin Buchan’s job at Shell is to find ways to find other vessels of opportunity—offshore construction vessels adapted to do what drilling rigs are not so well equipped to do faster and for less.

I think it was one size fits all before. A drilling rig is what you used,” Buchan said. “Now there are more options there to pick from.” His job title, well delivery manager for floating hoist at Shell, is an indication of what the options look like. Hoisting is a reference to many devices lowered to the bottom using a wireline, rather than sending them down to the well through a riser.

“We’re not seeing drilling rigs going out of business,” he said. But the high cost of repairing wells using drilling rigs and their limited number compared with the number of subsea well completions both argue for new approaches.

The goal is to do as much as possible to improve production from subsea wells by expanding the roles of vessels now doing deepwater construction work, such as installing manifolds or anchors on the seafloor. Construction vessels would play a growing role, from wellsite preparation through completions and maintenance, to plugging and abandonment.

Wireline well interventions have become common in the North Sea and will be moving to deep water. Offshore Brazil construction boats are coming in behind drilling rigs to complete wells by installing production hardware, such as subsea trees to control the flow and connecting them into the production system.

The high cost of drilling, completions, and repairs has a direct bearing on the ultimate output of reservoirs. To ensure the ultimate return exceeds the ultimate cost over the life of the well, operators will only develop discoveries with 150 million bbl of recoverable reserves or more into production, said Keith Millheim, managing director of Nautilus International. He, along with others, has started a pair of companies to commercialize a self-standing riser technology that he says will reduce costs sufficiently to change how deepwater fields are managed.

One of the companies, MEPS First Oil, is focused on reducing the cost of extended well tests and reducing the time it takes to begin production. More testing could reduce the risk that a field will fall short of expectations because of an incomplete understanding of a reservoir.

Significantly reducing the cost of field evaluation, construction, maintenance, and production could expand the universe of deepwater fields that can be profitably produced. Millheim estimates that there are 3,000 deepwater fields globally with less than 50 million bbl of reserves that cannot be produced without shifting the cost curve to allow more testing, maintenance, and artificial lift to be used.