Shearwater GeoServices has been awarded a contract for a 4D seismic monitor project at Equinor’s Mariner field offshore UK.
The geoservices firm said this will be the third Isometrix survey over the field, and its second 4D monitoring survey (3D data acquired over the same area at different times).
These “time-lapse” surveys help maximise production from existing fields by providing subsurface data to update reservoir modelling and production simulations.
The one-month project will be executed during the summer 2022, the company added.
“Time-lapse seismic acquisition is a critical activity for maximising value creation from offshore oilfield assets, which is why our clients select world leading technology for these surveys,” said Shearwater CEO Irene Waage Basili.
“We have a long-established track record of executing 4D seismic surveys for Equinor and we look forward to return to the Mariner field to capture high-quality geophysical data for our client.”
Mariner started production in 2019 after a £6.4 billion investment from Equinor. One of the largest fields in the UK sector for a decade, it was said at the time to be able to produce through to 2050.
However, in January Equinor revised down its reserve estimates from the east of Shetland field by nearly 35%, from 275 million barrels to around 180 million, prompting an impairment of £1.3 billion.
Mariner produces from two reservoirs – Heimdal and Maureen – which have “a wide range of uncertainty given the high subsurface complexity and early procution phase of the field”, Equinor said.
An updated seismic interpretation last year, and experience from production at Maureen, led to its downgrade.
Equinor operates the field and holds 65.11% equity, alongside partners JX Nippon (20%), Siccar Point (8.89%) and ONE-Dyas (6%).
In a subsequent statement on the Oslo Bors, Siccar Point said the operator’s revision was “premature” and pre-empted the findings of a joint venture working group set up that month.