* Mariner field is producing less oil than expected
* Reserve estimate downgraded
* Operator Equinor holds a 65% stake
(Adds partners comment, background)
By Terje Solsvik and Nerijus Adomaitis
OSLO, Jan 12 (Reuters) - Norwegian energy group Equinor
warned on Wednesday it faces an impairment charge of
about $1.8 billion after lowering resource and output estimates
for its Mariner oilfield in the British North Sea.
Total recoverable reserves from Mariner, which is operated
by Equinor, is now estimated at about 180 million barrels of oil
equivalent, sharply down from a previous projection of 275
million barrels, the company said.
"The reserve revision is linked to an updated seismic
interpretation and experience from production of the Maureen
reservoir which led to a revised reservoir model," Equinor said.
"This revised reservoir model is further supported by
results from the first well into the Heimdal reservoir, drilled
in 2021," it added.
Equinor's partners, however, said they didn't agree with the
decision to revise estimates.
Private equity-backed Siccar Point Energy said the revision
was "premature" and pre-empted the work of a joint working group
which was established in January and is expected to deliver
results in the summer.
"The other JV partners in Mariner, JX Nippon and ONE-Dyas,
share this view," Siccar added in a statement.
The Mariner downgrade is the second blow in about a month
handed to Siccar Point by a major about a project in the British
North Sea.
Last month, Royal Dutch Shell decided to pull out
of the Cambo oilfield project, forcing Siccar to pause the
field's development.
Mariner, in which Equinor holds a 65.1% stake, is now
expected to produce about 22,000 barrels per day (bpd) for the
foreseeable future, down from an average of 30,000 bpd last
year, a spokesperson for the Norwegian company said.
Initial expectations were for the field to produce about
55,000 bpd.
JX Nippon holds 20%, Siccar Point 8.89% and ONE-Dyas 6% in
the field.
Equinor said the impairment charge would be booked in its
earnings report for the final quarter of 2021, which is due on
Feb. 9.
Located 150 km (93 miles) east of the Shetland Islands and
developed at a cost of $7.7 billion, the Mariner field began
producing https://www.reuters.com/article/uk-norway-equinor-oil-idUKKCN1V50ZG
oil in 2019, two years behind schedule https://www.reuters.com/article/equinor-britain-mariner-idUSL8N21S2AM
and significantly over budget.
The oilfield had originally been expected to pump more than
300 million barrels of oil over a 30-year period, Equinor said
when the field became operational.
"We are committed to working with our Mariner joint venture
partners to identify opportunities to improve recovery and
production," said Al Cook, Equinor's head of international
production and exploration.
"We plan to continue drilling on the field to prolong cash
flow into the future."
The Mariner field consists of two reservoirs, Heimdal and
Maureen, with estimates of the resources in place previously
subject to uncertainty because of subsurface complexity.
On Tuesday, Equinor flagged a loss on natural gas
derivatives of up to $1.5 billion, which will also be booked in
the fourth quarter earnings report.
(Reporting by Terje Solsvik and Nerijus Adomaitis
Editing by David Goodman and Mark Potter)
