Norway’s Equinor has revised its estimate of the total recoverable reserves in the Mariner field in the UK North Sea from an earlier assessment of around 275m barrels to about 180m barrels of oil, resulting in an impairment in the region of $1.8bn.
The Mariner field began producing in 2019 and consists of Heimdal and Maureen reservoirs. According to Equinor, Mariner’s reserves have a wide range of uncertainty given the high subsurface complexity and the early production phase of the field.
The reserve revision is linked to an updated seismic interpretation and experience from the production of the Maureen reservoir, which led to a revised reservoir model. This revised reservoir model is further supported by results from the first well into the Heimdal reservoir, drilled in Q4 2021, Equinor explained.
“We are committed to working with our Mariner joint venture partners to identify opportunities to improve recovery and production. We plan to continue drilling on the field to prolong cash flow into the future,’ said Al Cook, executive vice president for exploration and production international.
The company said the write-down will be reflected in International Financial Reporting Standards (IFRS) net operating income for its exploration and production international segment in its Q4 2021 results.
Equinor is the operator of Mariner with an ownership share of 65.11%. The field is located around 150 km east of Shetland and 320 km northeast of Aberdeen. The Mariner field development includes a production, drilling and quarters platform based on a steel jacket, with oil being exported to a floating storage unit and then transported to shore via tankers.