The new assessment of around 180 MMbbl, down from the previous figure of 275 MMbbl, will lead to an impairment of close to $1.8 billion in net operating income for the company’s Exploration and Production International segment for 4Q 2021.
Mariner, discovered by Texaco, came onstream in 2019 and produces from the Heimdal and Maureen reservoirs. The reserves have a wide range of uncertainty due in part to the subsurface complexity: Equinor’s reassessment relates to an updated seismic interpretation and experience of production from the Maureen reservoir.
This led to a revised reservoir model, the findings of which have been further supported by results from the first well in the Heimdal reservoir, drilled during 4Q 2021.
However, drilling on the field will continue “to prolong cash flow into the future,” said Al Cook, executive vice president for Exploration and Production International.
Mariner is on the East Shetland Platform, 150 km (93 mi) east of the Shetland Islands and 320 km (199 mi) northeast of Aberdeen.
The facilities include a production, drilling and quarters platform supported by a steel jacket. Oil is exported to a floating storage unit and then transported to shore via tankers.
Other partners in Mariner are JX Nippon, Siccar Point Energy, and ONE-Dyas.