At end of Yellowtail development, oil company could leave equipment underwater


By Vishani Ragobeer

Concerns have been raised about oil equipment that could be left underwater after work is completed on the Yellowtail development, which has been identified at ExxonMobil’s fourth oil production project.

ExxonMobil is seeking environmental authorisation for the project which will actually extract oil from both the Yellowtail and Redtail fields in the giant Stabroek block where Exxon has so far made over 20 oil discoveries.

The start-up of the Yellowtail project is expected to begin in late 2025 and is anticipated to produce 220,000 barrels of oil per day from a Floating, Production, Storage and Offloading (FPSO) vessel that would be able to store up to two million barrels.

“The plan, which is preliminary in nature, envisions that subsea equipment will be disconnected after it is flushed and prepared, and potentially left on the seafloor,” Todd Hall, an environmental consultant revealed at a public consultation recently.

Hall is attached to the Environmental Resources Management (ERM), the firm which prepared the Environmental Impact Assessment for ExxonMobil Guyana to submit to the Environmental Protection Agency (EPA).

The consultation was required after Esso Exploration and Production Guyana Limited (EEPGL), ExxonMobil’s local affiliate, submitted its Environmental Impact Assessment (EIA) for Yellowtail to the EPA.

Among the equipment that could be left on Guyana’s seafloor, where oil is being produced, are Subsea Umbilicals, Risers and Flowlines. These kinds of equipment are used to connect the topside vessel- that is, the FPSO vessel- to the wellheads and pumps on the seafloor, in order to extract the oil.

The Yellowtail project is expected to last for 20 years. It will come onstream and produce oil at the same time as the earlier projects, namely Liza phases One and Two and Payara.

It was reported that the exact locations of the Yellowtail development fields have not yet been finalized; however, the wells will be drilled from six drill centers. ERM consultants indicate that there could be between 41 and 67 oil wells – the largest number of wells within the four developments.

Stakeholders who were part of the public consultations stated their concerns about this equipment being disconnected at the end of the development and simply discarded underwater since it may adversely affect the marine environment.

Dr Jerry Jailall, a member of the Guyana Oil and Gas Governance network, asked what international studies the company was using to justify that action.

Another participant pointed out that the government is currently spending millions (the exact amount of $787.6 million) of dollars to remove wreckages from the Demerara River, and questioned whether that would become necessary with the oil equipment left underwater.

Hall, however, emphasised that this decommissioning plan was only preliminary. In the process of producing oil and gas, decommissioning (or closure) is the last phase of the process, following exploration, development and operations.

He said all of the hydrocarbon material (such as oil) would be cleaned off from the equipment at the time of closure.

He also pointed out that in the preliminary decommissioning plan, there is scope for alternative strategies to be considered.

“… if we’re talking about something that will happen 20-plus years from now, then I think the state of the science (and) the state of international guidance will continue to evolve,” Hall explained.

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