Revitalizing Mature Fields Through IOR

Abstract

Abstract Improved oil recovery (IOR) is the ultimate discovery in any oilfield. Equinor has a long history of evaluating and implementing IOR projects on the Norwegian Continental Shelf (NCS), where it was observed that infill drilling and well cost reduction are the most important measures, while a holistic approach from all disciplines, collaboration and integrated work is needed for achieving successful results. IOR is also relevant to the climate ambitions to reduce the carbon footprint: it enables CO2 emissions per produced barrel from field extension to be lowered due to higher production, compared to ending the production earlier. Given its history with IOR in the Norwegian Continental Shelf, Equinor brought some of its experience to Brazil, more specifically to Peregrino Field, a heavy oil asset operated by the company, and to Roncador, a partner operated license established with Petrobras in 2017. This expertise is also being applied to the pre-salt projects under development, aiming to prepare the fields for the late life since its startup. In this article, experiences from Statfjord, Troll Oil and Grane fields are used as backdrop for Equinor's IOR evaluations in Brazil. Statfjord field has had success with water and gas injection followed by pressure depletion and lifetime extension. Troll oil field has been in the forefront developing and implementing advanced well solutions and infill drilling. Grane field has introduced inflow control devices in viscous oil. Lifetime extension and challenging facility flow limitation has also been important elements to increase recovery from these fields. In Peregrino, instead of waiting for field maturity, evaluation of IOR activities began soon after field start-up in 2011 and since then several have been evaluated: some have been piloted and were not implemented in a field scale, such as the multilateral wells; some are still piloting and under evaluation and de-risking, such as polymer flooding; while others have been implemented and have become business as usual, including infill wells, water shut-off techniques and evaluation of different inflow control devices. The partnership established in Roncador aims to increase the recovery factor in the field, by applying the widely used technologies from the NCS, which combined with the deepwater expertise from the operator represent a win win scenario for both companies working together. The expected result is to maximize the value creation and longevity of the Roncador field. The ambition is to increase the recoverable volumes by one billion barrels of oil equivalent. This article presents some of the techniques used, and how they are incorporated into the company's workflow, so that they can be properly assessed and implemented, showing how it is possible to unlock extra oil from the reservoirs enabling the fields lifetime extension.