Under the FOI release, the government was pushed to make public an internal report Chevron commissioned outlining an annual update on its CCS project alone.
It shows that the project has stored 2.26 million tonnes of CO2 during the 2020-2021 financial year; despite the facility having a nameplate capacity of 4 million tonnes, spread across nine wells. It also noted some reservoir pressure decline.
Chevron has also revealed operational expenditure on its CSS project: A$13.2 million on "reservoir management," A$2.4 million on maintenance and A$3.2 million on wells maintenance. Labour cost a further A$5.6 million.
The documents also show that the budget for the project has been revised upward from A$3.092 million to A$3.147 million.
Including other operational expenditure, it brings Chevron's total spend on the project to A$25.6 million. It must pay more than half of this to make up for a payment arrangement of A$40 million to the WA government following its failure to sequester as much CO2 as originally claimed in initial project documentation.
"In late 2020, the (WA) Department of Mines, Industry Regulation and Safety (DMIRS) imposed an injection limit on the Asset which reduced the injection rate to 70 MMscfd due to issues with starting up the pressure management sites. This was initially flagged in the 2020 annual report," Chevron wrote.
The project ran at nameplate for the first half of the reporting period, it said.
"During the first half of the reporting period, injection rates matched the CO2 volume extracted from the feed gas, essentially meeting its functional objective."
The report was issued to the department of industry, science, energy and resources on Thursday September 30 2021.
In its report, Chevron notes that it is still determining whether to make public monitoring data for the CSS project, further claiming "it's likely that appropriate data submitted to the Western Australian department of mines...may be made available to the public."
The CCS facility was shut down for a six week period through 2021 due to maintenance.
Chevron also states on page three of its internal report that "a de-sanding project was initiated to remediate the issue through an upgrade of the surface facilities to remove sand from the process stream."
