ExxonMobil Advances Longtail Gas Project while Finalizing Hammerhead Plans

ExxonMobil has made significant progress in its development of Guyana’s offshore oil and gas resources by submitting an Environmental Authorization (EA) application to the Environmental Protection Agency (EPA) for its eighth project, Longtail, located in the Stabroek Block. During a recent press conference in Georgetown, Alistair Routledge, the company’s president for Guyana, emphasized that this application marks an important commitment to exploring and developing non-associated gas resources in the region.

The Longtail project is particularly significant as it represents ExxonMobil’s initial major attempt to tap into Guyana’s non-associated gas resources, which are sourced from conventional gas fields that do not yield crude oil. Routledge noted, “We have just submitted the Environmental Authorization Application for the Longtail Project, which will initiate our efforts to develop non-associated gas resources. Longtail is expected to yield a substantial amount of liquids.”

Although the project is still in the early stages of development, Routledge indicated that it is projected to be a major venture, with potential production of up to 250,000 barrels per day (bpd) of liquids and handling over 1 billion cubic feet per day (bcf/d) of gas. This marks a notable shift towards gas development in the area.

ExxonMobil’s investments in Guyana’s offshore resources have already shown remarkable results, with the company surpassing 500 million barrels of cumulative production in less than five years since first oil. Current production capacity is around 650,000 bpd, with plans to increase to 900,000 bpd.

Routledge expressed confidence in the project’s viability, citing early appraisal work that indicates sufficient reservoirs for a “cost competitive” project, which they expect to transition into a Field Development Plan (FDP). The Longtail-1 discovery in the Stabroek Block was made in 2018, revealing approximately 256 feet (78 meters) of high-quality, oil-bearing sandstone. Further drilling at Longtail-3 in June 2021 uncovered 230 feet (70 meters) of net pay.

Meanwhile, ExxonMobil is also progressing with its Hammerhead project, having submitted a draft Environmental Impact Assessment (EIA) to the EPA earlier this week. Public consultations are expected to begin soon, allowing stakeholders to review the studies and EIA findings. The Hammerhead project is projected to produce between 130,000 and 180,000 bpd, utilizing the substantial gas resources estimated at 17 trillion cubic feet in the Stabroek Block.

Routledge speculated that the Hammerhead project could receive final approval by mid-2025, with production anticipated to commence in 2029. The project will involve drilling up to 30 wells and will utilize a converted floating production storage and offloading vessel (FPSO), designed to be smaller yet efficient for resource development.

ExxonMobil, through its local subsidiary, operates the Stabroek Block with a 45 percent stake, while Hess Guyana Exploration Ltd holds 30 percent and CNOOC Petroleum Guyana Limited, a wholly-owned subsidiary of CNOOC Limited, retains the remaining 25 percent. Currently, three FPSO vessels—Liza Destiny, Liza Unity, and Prosperity—are operational in the Stabroek Block, supporting production from the Liza Phases One and Two and Payara developments, which collectively produce over 600,000 bpd. Additional FPSOs are planned to further boost production capabilities in the region.