Chevron wraps up deepwater well

Moira Baird
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Lona O-55 results will decide the future of exploration in the Orphan Basin

Chevron Canada finished drilling the deepest offshore well in Canada last Thursday, and says it did so without incidents or injuries.

The drillship Stena Carron plugged and abandoned the well 106 days after spudding it May 10.

“We drilled the well safely and without any lost-time incidents,” said Mark MacLeod, Chevron’s Atlantic Canada vice-president.

Dubbed Lona O-55, the well is 2.6 kilometres below the surface of the North Atlantic — a kilometre deeper than the ruptured Gulf of Mexico well that killed 11 people and the caused largest oilspill in U.S. history.

Drilling wasn’t entirely event-free for Chevron — it did experience three weeks of mechanical difficulties with equipment from late June to mid-July.

“We had to stop operations to make repairs,” said MacLeod. “We did have some downtime related to mechanical issues.”

That equipment, known as the forward motion compensator cylinder, controls the drill string weight. The drill string is the pipe through which drilling fluids and power are transmitted to the drill bit.

“It’s like a big, tall piston and it had to be repaired — kind of like a shock absorber on your car.”

MacLeod said the drillship also experienced small cracks in its hull and water-tight doors that were “inspected carefully.”

He said all the cracks — which were “a few inches” in length — were located about 23 feet above the water line.

“There were a number of very small cracks that were discovered on the ship itself.

“We looked at that. The board was well aware of it; they were fully briefed on the issue. There was no risk of safety to personnel or equipment.

“They did not grow and they’re being investigated.”

MacLeod said the shipbuilder, Korean-based Samsung Heavy Industries, is investigating the cause of the cracks.

The results of the Lona O-55 well will determine whether or not Chevron drills again in the Orphan Basin.

“We’ve got a lot of information to evaluate,” said MacLeod.

“We drilled the well safely and without any lost-time incidents.” Mark MacLeod, Chevron’s Atlantic Canada vice-president

“We’re going to take the time to evaluate it prior to determining our plans for the future exploration in the Orphan Basin, and we’re going to keep the results proprietary.”

Under offshore rules, Chevron can keep the results of the Lona

O-55 well confidential for up to two years.

The company isn’t saying how deep it drilled into the seabed this time.

Its first exploration well in the basin — Great Barasway F-66 — went more than 4,400 metres into the ocean floor in 2007.

That well came up dry.

Concerns about the April 20 disaster in the Gulf of Mexico prompted the Canada-Newfoundland and Labrador Offshore Petroleum (CNLOPB) to tighten up its rules for deepwater drilling.

The board created a special committee to oversee Chevron’s drilling operations, equipment testing and oil spill readiness.

“We certainly complied with all of the additional oversight,” said MacLeod.

“We certainly took more time to review with the board our plans. We had more visits … on the rig. We had more tests on the BOP, but it didn’t slow us down.”

A blowout preventer, or BOP, is installed on a wellhead. A series of valves, it’s designed to prevent potentially explosive surges of oil and gas during drilling by shutting down well and sealing it.

As part of the CNLOPB’s beefed-up drilling regulations, the BOP was tested throughout Chevron’s drilling program.

“The BOP performed as expected — no issues there.”

MacLeod also said the company expects to do seismic surveys off the coast of Labrador in future.

“Perhaps next year or the year after.”

Chevron acquired an exploration licence in the natural-gas-prone Labrador shelf for $46.5 million in 2008.

Organizations: Samsung Heavy Industries, Canada-Newfoundland and Labrador Offshore Petroleum

Geographic location: Gulf of Mexico, Atlantic Canada, North Atlantic U.S. Labrador Great Barasway

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