ExxonMobil has increased its estimate of discovered recoverable resources for the Stabroek Block offshore Guyana from 3.2 billion to more than four billion oil-equivalent barrels.

The company has advanced its evaluation to support the third phase of development and consideration of two additional phases.

The increase comes after testing was completed at the Liza-5 appraisal well, part of the Ranger well, and after the incorporation of the eighth discovery, Longtail, into the Turbot area evaluation, and completion of the Pacora discovery evaluation.

ExxonMobil senior vice president Neil Chapman said: “Outstanding resource quality across these opportunities combined with industry-leading project execution capabilities will provide great value to resource owners, partners, and our shareholders.

“Continued success in Guyana and progress in other upstream growth projects in the US Permian Basin, Mozambique, Papua New Guinea and Brazil are giving us additional confidence in achieving our long-term earnings growth plans that we outlined in March.”

The Liza-5 well successfully tested the northern portion of the Liza field and, together with the Payara field, will support the third phase of development in the country. ExxonMobil will aim to sanction the Payara field development next year, using a floating production, storage and offloading (FPSO) vessel to produce 180,000 barrels of oil per day (bpd) from 2023.

The Stabroek Block has a total area of 6.6 million acres or 26,800 square kilometres. Esso Exploration and Production Guyana, an affiliate of ExxonMobil, operates and owns 45% interest in the offshore oil block. Hess Guyana Exploration holds 30% stake and CNOOC Nexen Petroleum Guyana owns the remaining 25%.

Hess CEO John Hess said: “The Stabroek Block is a massive world-class resource that keeps getting bigger and better. Since the end of 2016, the estimate for recoverable resources on the block has quadrupled and we continue to see multi-billion barrels of additional exploration potential on the block. We believe the investment opportunity in Guyana has the potential to be transformative for our company and create significant value for our shareholders for many years to come.”

ExxonMobil’s offshore Guyana projects

The first development project offshore Guyana, Liza-1, will use an FPSO vessel to produce 120,000 bpd, beginning in early 2020. Liza-2, which is to be sanctioned by the end of this year, will use an FPSO vessel designed to produce up to 220,000 bpd and is expected for production by mid-2022.

The Longtail well has established the Turbot-Longtail area as a possible hub for recovery of more than 500 million barrels. This estimate could increase after additional prospects are drilled in the area.

Combined, the discoveries on the Stabroek Block have thus far established the potential for up to five FPSOs producing over 750,000 bpd by 2025. There is potential for additional production from other undrilled targets, and plans for rapid exploration and appraisal drilling, including at the Ranger discovery.