ExxonMobil’s seventh oil project off Guyana takes step forward with EIA submission

ExxonMobil Guyana, a subsidiary of the U.S.-headquartered ExxonMobil, has handed over its environmental impact assessment (EIA) for the development of its seventh oil project in the Stabroek block off the coast of Guyana.

Following the oil discovery at the Liza field in the eastern half of the Stabroek block in 2015, ExxonMobil identified multiple additional reservoirs of crude oil with an estimated recoverable resource of approximately 1.75 billion cubic meters of oil-equivalent in the eastern half of the block.

Wheels were set in motion last year to get the required approvals for Hammerhead as the seventh deepwater oil project in Guyana to add between 120,000 and 180,000 barrels per day (bpd) by 2029, raising the country’s overall production capacity bar to nearly 1.5 million bpd.

The firm’s seventh development project in the eastern half of the Stabroek block is located in the Hammerhead field, around 160 kilometers northeast of the coastline of Georgetown in water ranging in depths of about 750 to 1,200 meters.

Upon the review of the U.S. giant’s application for environmental authorization, which was submitted to the Guyana Environmental Protection Agency (EPA) in June 2024 for the Hammerhead oil and gas development project, the EPA determined that an EIA was required to present the necessary information and analysis of potential impacts the project may have if it were to be implemented.

As a result, ExxonMobil claims that engagement with interested stakeholders has been conducted throughout the EIA’s development to ensure that the EPA can make an informed decision on the development of Hammerhead in Guyana’s Exclusive Economic Zone (EEZ).

This project will encapsulate drilling of approximately 14 to 30 development wells, including production and water injection wells; installation and operation of subsea umbilicals, risers, and flowlines (SURF) equipment; installation and operation of a floating production, storage, and offloading vessel (FPSO); installation of a 13-kilometer-long gas export pipeline from the FPSO that will connect into the gas-to-energy pipeline; and ultimately, decommissioning of the project.

While onshore logistical support facilities and marine/aviation services will be used to support each stage of the project, much of the installation and production operations activity will be offshore, with the project also making use of onshore infrastructure operated by third parties, including, but not limited to, shorebases and waste management facilities in Guyana to support drilling and installation, production operations, commissioning and start-up, and decommissioning operations.

Hammerhead is expected to employ up to 540 people during the drilling and installation stage, 600 people during the commissioning and start-up stage, and 100 to 160 people during the production operations stage. ExxonMobil is adamant that all activities and operations will be designed and conducted in alignment with good international industry practice and entailing numerous embedded controls to minimize environmental and socioeconomic impacts.

The U.S. oil major emphasizes that its preferred option, the FPSO and SURF production system, is perceived to be a proven development concept for deepwater oil recovery and will leverage both operator and industry-proven technologies and experience since the project development area (PDA) is situated in a deepwater, offshore, marine environment with physical, chemical, and geological characteristics consistent with oceanographic conditions in the region.

ExxonMobil elaborated: “Biological resources in the Stabroek block include marine birds and other migratory birds, marine mammals (whales and dolphins), marine turtles, and pelagic and demersal marine fish (including some migratory species), some of which are protected species. Although sensitive benthic features (i.e., cold-water corals) are known to exist in the block, they are not known to exist in the immediate vicinity of the work area.

“As a result of the offshore location of the project, the socioeconomic activities with which the project has the potential to interact are limited to vessel traffic and artisanal and industrial fishing. Certain key socioeconomic aspects of the onshore area of Influence (the six coastal regions of Guyana) may potentially be affected by the project, including waste management and infrastructure, ground and air transportation facilities, housing resources, and marine infrastructure.”

No major impacts from Hammerhead

While the company pointed out that none of the potential environmental or socioeconomic impacts from planned activities were found to have major significance, those of moderate significance that could occur include critically endangered and endangered offshore marine fish species during drilling and installation as a result of impulsive and non-impulsive noise and changes in water quality; and marine turtles during drilling due to potential exposure when near impulsive sound sources during the performance of vertical seismic profiling. The potential impacts on socioeconomic resources/receptors were found to be below the threshold for moderate significance based on the operator’s EIA.

However, the ones with minor significance ratings that might still occur cover the increased cost of living associated with economic growth, and potential impacts of increased marine traffic and exclusion zones on nearshore fishing; community health and well-being specific to public concerns and anxiety associated with the oil and gas industry; social infrastructure and services seeing increased traffic congestion; and waste management and infrastructure exceeding capacity.

According to the U.S. energy giant, stakeholders expressed several concerns about potential impacts on air quality, climate change, and marine fisheries; interest in business and job opportunities associated with the project; and concern about the capacity of waste management and infrastructure to address the project needs and broader economic growth. While addressing these concerns, ExxonMobil outlines that direct impacts on air quality are expected to be localized to the offshore PDA, as modeling shows no impacts to onshore areas outside already industrialized areas.

The firm acknowledges that the project is expected to increase direct greenhouse gas emissions, primarily during its production operations stage, and underlines that fish, fisheries, and fishing may be affected by planned activities. Guyanese workers and businesses are expected to see positive effects from the project through increased employment and business opportunities to support the oil and gas industry through the provision of goods and services.

Even though potential environmental and socioeconomic impacts could occur during unplanned events such as a hydrocarbon spill, vessel collision, discharge of untreated wastewater and off-specification water from the FPSO, underwater release of drilling fluid and seawater injection fluid, vehicle collision, or collision between marine animals and a project component, the firm considers it unlikely that such events will occur.

While no residual risks from unplanned events were rated negligible or major, moderate risk ratings were assigned to unplanned event scenarios involving environmental and socioeconomic impacts on the marine geology and sediments; marine water quality; protected areas and special status species, including vulnerable and near threatened coastal birds; coastal habitats; marine mammals; riverine mammals; marine turtles; socioeconomic conditions, employment, and livelihoods; community health and wellbeing; and Indigenous Peoples.

Oil spill preparedness

ExxonMobil also commissioned an oil spill modeling study to evaluate the risk of a large oil spill using oceanographic conditions and the characteristics of the project crude oil to determine the expected trajectory and rate of movement of oil in the event of a spill. The modeling results indicate that oil from an unmitigated worst-case discharge scenario, defined as an open-well condition in which no flow restrictions, well-control technologies, or response measures are in place for 30 days, would move to the northwest.

The probability that oil from such a large spill could reach the coast of Guyana is 5 to 70% for Region 1 and 5 to 20% for Region 2, depending on the oceanographic conditions at the time of the spill and the time of year. This modeling also indicated that a mitigated and unmitigated spill could reach the coastline of Trinidad and Tobago, Venezuela, the Lesser Antilles, and the Greater Antilles.

The firm has developed an oil spill response plan for Guyana operations (OSRP) to address the potential impacts of an oil spill, which would significantly reduce them within Guyana, as well as transboundary impacts in areas northwest of the spill location.

“With the adoption of such embedded controls, mitigation measures and plans, and requirements for emergency response preparedness, the Project is expected to pose limited risks to the environmental and socioeconomic resources/receptors of Guyana while potentially offering significant economic benefits to the residents of Guyana,” concluded ExxonMobil.