Patterson releases information on Liza gas composition

Sep 02, 2021 News

Kaieteur News – Former Minister of Public Infrastructure, David Patterson, on Wednesday released information he received in 2017 from ExxonMobil’s local subsidiary, Esso Exploration and Production Guyana Limited (EEPGL), on the composition of the gas from the Liza operation.

Opposition Member, David Patterson

This comes after a member of the Transparency Institute Guyana Inc. (TIGI), Alfred Bhulai, rapped the Department of Public Information and officials from the Environmental Protection Agency (EPA) for making statements about expected reduced emissions from the gas-to-energy project, even as the Government refused to provide information on the gas composition when requested by the anti-corruption body.
“The gas-to-energy project proposed to be located at Wales estate continues to raise questions in the public sphere while several remain unanswered,” Patterson said.
“One such question relates to the composition of the gas that will be piped to shore. My records reveal that a similar question was asked of Exxon in May 2017 by the then Minister of Natural Resources (Raphael Trotman).”
Patterson posted a table on Facebook, which he said was provided to the Government from Exxon’s then project manager.
The table indicates that Methane (79.1%), Ethane (7.3%) and Propane (6.7%) make up the natural gas constituency, with some other components.
The note attached from the Exxon project manager states, “This composition reflects composition at the outlet from the Liza Destiny FPSO early in the life of the field production.”
It is stated in the note that the Liza gas is expected to contain significant quantities of natural gas liquids (NGL) such as propane and butane, and that these products can be used to supply liquefied propane gas (LPG) for cooking. It is on this premise that the project manager advised that it may be of commercial interest to extract the NGLs for separate sale while the remaining gas (methane and ethane) could be used for power generation.
The project manager added that the gas composition will change over time, particularly as a result of gas and water injection which is done during oil production. He said, for example, that hydrogen sulfide (H2S), which is not even 0.1 percent of the quoted constituency, is expected to increase over time.
“Gas at the outlet of the FPSO will have received some processing insofar as it has had limited treatment through the FPSO topsides. It has also been dehydrated to meet the requirements of future gas use,” the project manager wrote in the note.The official further stated that when it comes to subsequent processing, Liza gas would be delivered to shore at relatively high pressures, and that onshore facilities would be required to reduce the pressure to a level suitable for downstream use.
“Beyond that, Liza gas does not require significant processing as it is expected to be high in hydrocarbon content and low in impurities.”