ExxonMobil Guyana’s proposed Haimara development is introducing a new technical term to Guyana’s oil and gas industry: retrograde gas.
The term appears in the company’s project summary for Haimara, which has been submitted for environmental review. The project has not been approved.
Haimara is being proposed as a natural gas development in the Stabroek Block, offshore Guyana. The project summary said the primary produced fluid would be retrograde gas.
ExxonMobil invites public input as proposed Haimara project enters EPA process | OilNOW
Retrograde gas is a gas-rich hydrocarbon mixture that can form liquid condensate when reservoir pressure drops during production. In simple terms, it is gas that can also produce liquid.
Condensate is a light hydrocarbon liquid that can be separated from the gas and produced as part of the project. The term matters because retrograde gas does not behave like dry gas. As pressure falls in the reservoir, heavier parts of the gas mixture can turn into liquid. If too much liquid forms within the reservoir, it can affect how easily gas flows to the well. It can also affect how much condensate is recovered.
That is why ExxonMobil Guyana’s proposed plan for Haimara includes gas reinjection.
The project summary said condensate would be separated from the produced gas on a floating production, storage and offloading vessel, or FPSO. The remaining gas stream would then be reinjected into the reservoir.
The summary said this would be done “for pressure maintenance and increased recovery of condensate.”
ExxonMobil Guyana said the proposed plan would use gas reinjection with no water injection. The summary said this process is referred to as gas-cycling. Gas-cycling means gas is produced, processed, and reinjected into the reservoir. For Haimara, the process would support pressure maintenance and condensate recovery.
Haimara is expected to join Longtail, ExxonMobil Guyana’s first proposed non-associated gas development in Guyana. The Longtail project is expected to develop the Longtail, Tripletail, and Turbot discoveries.
The summary said “gas may be exported from Haimara as market demand materializes.”
Once gas reinjection is no longer needed for condensate recovery, the summary said the gas resource value could be captured through primary depletion and gas export.
The proposed FPSO is expected to produce between 1-1.5 billion standard cubic feet per day of natural gas. It is also expected to produce 160,000 to 220,000 barrels per day of condensate separated from the produced gas.
ExxonMobil Guyana operates the Stabroek Block with a 45% interest. Hess, now part of Chevron, holds 30%. CNOOC holds 25%.
Read more about Haimara here: What we know about ExxonMobil’s proposed Haimara project | OilNOW
