Tiebacks Expand Production Offshore Brazil

March 5, 2024
The country’s largest independent oil company is extending the production life of brownfield assets and realizing value from marginal fields
By Jean Calvi and Iuri Rossi, PRIO

International investment ramped up offshore Brazil following the approval of a legislative package introduced by President Fernando Henrique Cardoso in 1997 to modernize the oil and gas sector. This changed the face of offshore operations, ending Petrobras’ monopoly and allowing foreign companies to bid on exploration and production blocks. Although there was a shift toward a more open market, there were few domestic players other than Petrobras, and most were focused on exploring new developments. That situation changed when PRIO SA (formerly Petro Rio) began acquiring assets and expanding the use of subsea tiebacks to extend the production life of aging and marginal fields.

Building for success

Created in 2015, PRIO began extending the operational life of producing fields via a business model focused on fields with declining production. In its Campos Basin assets, the company has optimized production by installing multiple subsea tiebacks connecting groups of fields to Floating, Production, Storage and Offloading (FPSO) vessels.

The company’s first major tieback project was the Phoenix development, which began with the acquisition of a fixed platform in the shallow-water Polvo Field in block BM-C-8 in the southern part of the Campos Basin. PRIO added the Tubarão Martelo Field in the BM-C-39 and BM-C-40 blocks along with other pre-decommissioned fields, which other operators had deemed economically unattractive.

The company began carrying out its development plans, progressing its first subsea tieback project even as the COVID-10 pandemic dramatically impacted execution, introducing more stringent worker safety measures and complicating logistics. Despite these challenges, the tieback from the Tubarão Martelo field was completed in July 2021, and in October of that year, PRIO added another well from the Tubarão Martelo field increasing production by 3,000 bbl/day for a total of 16,000 bbl/day in the cluster, with Polvo and Tubarão Martelo contributing equal volumes.

The tieback connects the two fields, which are 11 km apart, with a single FPSO serving as a hub for the development. With the tieback in place, the leased Polvo FPSO was removed, and the Bravo FPSO was upgraded to handle the different types of oil from the producing fields. In addition to making modification to the Bravo FPSO, PRIO acquired a moored drilling rig to be used for workovers because the wells were developed with electrical submersible pumps, which historically have exhibited short meant time between failures and would likely need to be replaced.

The company’s next undertaking was the Frade Field, which lies 125 km (77.7 miles) offshore in 1,200 m (3,937 ft) water depth. PRIO acquired 100% interest in the field from the previous operators, Chevron (51,74%) and other partners Petrobras (30%) and INPEX (18,26%). Chevron had suspended development on the field while it determined how to address environmental sanctions on its operations. Believing it could work with local authorities to address the sanctions, PRIO bought the assets and began acquiring the necessary equipment to begin redevelopment.

A four-well campaign was designed, and drilling began in 2022. Since the wells on the Frade development produce from a similar reservoir and connect for the most part to existing infrastructure, the Valente FPSO required only minor modifications.

With a considerable amount of the subsea structure already in place, the company was able to make rapid progress. PRIO expanded the original drilling campaign, in the end, drilling nine new wells drilled and installing three new tiebacks to add more than 45,000 bbl/d in production and to once again use water injection to optimize recovery, a process that had been discontinued as a result of previous environmental sanctions.

Taking on the next challenge

The Wahoo field is next up for development, with construction expected to begin in 2024. Wahoo, which is in the C-M-101 block in 1,400 m (4,593 ft) water depth in the pre-salt Campos Basin, holds an estimated 126 MMbbl of recoverable oil.

In executing this project, PRIO is breaking new ground and achieving a number of significant “firsts.” Wahoo will be the company’s first greenfield development as well as the country’s longest subsea tieback. When the drilling program gets underway, PRIO will be the first Brazilian independent oil company to drill in the pre-salt.

Although most of the installations in the region use flexible pipe, the Wahoo design relies on rigid pipe, which was judged more suitable to provide flow assurance over a long distance.

As in its other developments, PRIO will form a production cluster for this development, sharing infrastructure between the Frade and Wahoo fields. The plan includes drilling four producer wells and two injector wells and installing the region’s longest 35 km (21.7 mi) tieback to connect the wells to the Frade FPSO.

Data is available from studies carried out by the former operator, which had drilled seven wells, but PRIO determined that Wahoo requires additional study to enable a good understanding of the reservoir, which will allow appropriate equipment to be designed and sourced to complete the development. The company anticipates that Wahoo will add 40,000 bbl/day to its total production volume. 

PRIO believes demonstrating that longer tiebacks are possible and financially viable will open the door for additional projects that could be the key to commercializing fields for which standalone economics preclude development. Success with Wahoo will lay the groundwork for future subsea tieback programs.

On the horizon

Successful projects over the past few years have proven the viability of PRIO’s approach to subsea development offshore Brazil, and the successful execution of its new deepwater, greenfield project will extend the envelope of its competencies. The company is looking for more opportunities as well as like-minded partners that will contribute to its plans to create FPSO hub developments that will transform more fields — both new fields and developments on fields with declining production — into economically viable projects.

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