Could subsea drilling extend the life of the Hibernia oil field? Its owners are looking into it

The companies that own Hibernia are considering more subsea drillingto further extend the life of the iconic oil field in Newfoundland's offshore.

But right now there are far more questions than answers, with the oil companies and provincial government offering upfew details.

• A crown jewel for ExxonMobil: Hibernia a quiet workhorse in N.L.'s offshore

"It is premature to answer many of your questions below given we have not made a decision to proceed," a spokesperson forHibernia Management Development Company Ltd.(HMDC) wrote in response to a series of questions from CBCNews.

One, perhaps two drill centres

But here's what is known.

HMDC has issued an expression of interest (EOI) forcompanies who specialize in subsea dredging services in order to dig what's known as an excavated drill centrefor the placement of drilling and other equipment.

The excavation would measure 100 metres long, 50 metres wide, and 10 metres deep, and work could begin in 2021 using a specialized vessel called a "trailing suction hopper dredge" that can operate in 95 metres of water in theJeanne d'Arc Basin.

The EOI also floats the possibility of a second, smaller excavated drill centre.

The drill centres are placed in a hole in the seabed on the Grand Banks in order to protect them from passingicebergs. Flow lines connect them to the Hiberniaplatform.

The system is known as a tieback.

It's similar to the Hibernia Southern Extension, which began producing oil in 2011, but with one notable difference.

The HiberniaSouth drill centre is comprised of sixseabed wells that inject water into the reservoir in order to create pressure and move oil through five production wells drilled from the Hiberniaplatform.

This latest proposal, however, involves production wells from the excavated drilling centre, with flow lines sending the oil back to the Hibernia platform.

That kind of system would be a first for Hibernia.

Transporting a large module

In a related development,HMDCis also pre-qualifying companies who can transport and install a module of up to 1,000 tonnesonto the Hiberniaplatform, possibly in early 2022.

So what does all this mean? How much recoverable oil is involved? How far away from the platform will the drill centre, or centres, be located?Where will the equipment be fabricated? What are the benefits for the provincial government, and will government buy an equity stake in the expansion?

CBC posed those and other questions, but few were answered.

The Department of Natural Resourcessay it is "encouraging" to see HMDC pre-qualifying companies for this work and that "identifyingopportunities to advance near-field tiebacks" supports government's plan for significantly growing the offshore industry over the next decade.

"We view this as positive and await a decision" from HMDC, a department spokesperson wrote in a statement.

But the department directed questions about the proposal to HMDC.

One source said it's unlikely the province would purchase an equity position in the expansion because the drill centre will be located inside the main Hibernia field, where the province does not have an equity share.

• Hibernia pumps 1 billionth barrel of oil in Newfoundland's offshore

Subsea drilling is required, according to HMDC, because all well slots on the Hibernia platform are in use, "so this is another way to drill new wells," the spokesperson wrote.

"Subsea tiebacks are a well-established alternative to platform drilling given the Hibernia facility is slot constrained."

The Hiberniaplatform sits on the seabed315 kilometres southeast of St. John's and has been producing oil for nearly 22 years. It'sbeen described by the leadoperator, ExxonMobil Canada, as a legendary asset.

The platform produced its one billionthbarrel of oil more than two years ago, and is expected to remain in production until at least 2040, years longer than originally envisioned.

It is one of four producing oil fields in Newfoundland's offshore, and subsea drilling would be a significant investment for HMDC.

Sources say the Hibernia South expansion came at a cost of $2 billion, with the provincial government buying a 10 per cent equity stake in the project, which contains nearly 200 million barrels of recoverable oil.

Meanwhile, there are only a handful of companies throughout the world that can excavate a subsea hole for a drilling centre, with a Dutch maritime contracting company called Royal Van Oorddredging the Hibernia South drill centre using a hopper dredger called Ham 318.

According to the Canada-NewfoundlandandLabrador OffshorePetroleum Board,total oil production at the Hibernia field for 2017-18 was 51.14 million barrels, with a daily average of 140,165 barrels.

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