BG Group’s offshore Brazil fields will produce 2.7 billion more barrels of oil equivalent (boe) than expected.

BG upgraded its reserve estimates for the Tupi, Iracema and Guara fields, which are located in the Santos Basin, to 10.8 billion boe from 8.1 billion boe, a 34% increase.

The latest analysis is based on the development of new and significantly more sophisticated reservoir models, including 3,200km² 3D seismic data, results from nine completed wells and ten drill stem tests.

BG said that 94% of Tupi’s and Iracema’s gross resources and 90% of Guara’s gross resources are recoverable during their concession periods.

Detailed development plans for the fields are subject to agreement with BG’s partners and Brazilian regulator ANP.