Coal seam gas wells owned by companies including Origin Energy and Shell are corroding beneath the ground and threatening groundwater relied on by Queensland farmers.
The evidence of corrosion was identified in newly obtained Right to Information documents by Lock the Gate Alliance (available here).
The Alliance fears the examples captured in the documents are likely to be just a small example of a much wider and deeply concerning industry problem across QLD’s many thousands of operating and legacy gas wells.
Environmental Engineering Associate Professor Gavin Mudd said the onus was now on the gas industry to prove corrosion was not occurring at more wells.
“The CSG industry in Queensland has drilled tens of thousands of wells to date, with as many more planned – but where is the audit of the entire collection of wells?
“The fact that significant corrosion was found to be occurring raises serious concerns about the potential for cross-aquifer contamination. Full transparency is required on the condition assessment of the entire collection of wells to date, nothing less.”
Lock the Gate Alliance Queensland Coordinator Ellie Smith said, “These documents show the corrosion is occurring from the outside in, suggesting bacteria is eating away at the well casings, leading to a high risk of groundwater contamination.
“This is what we’ve always feared - that piercing the underground water layers that sustain the Western Downs like a pin-cushion with thousands of CSG wells is putting water quality at risk if well corrosion occurs.
“We know that well corrosion is a major risk in the long-term, but it’s even more shocking to see that it is already occurring in Qld gasfields - this is a serious threat to farmers who rely on shallow aquifers to grow the food and fibre for Queenslanders.”
The discovery of corroding gaswells supports concerns raised by scientists in the United States, where the unconventional gas industry has existed longer than in Queensland.
“In particular, Cornell University Professor Anthony Ingraffea has long argued that all gaswells fail eventually, and states that allow unconventional gas projects need to monitor their well casings in perpetuity," Ms Smith said.
The documents also reinforce industry communications suggesting coal seam gas well corrosion is a “system” issue in Queensland, likely caused by bacteria present in underground water systems.
As well, the RTIs identified gas wells leaking methane, adding further weight to scientific concerns raised late last year that fugitive emissions from Inland QLD’s gasfields were two to three times worse than expected.