Australia Pacific LNG, through Origin, has undertaken research and monitoring of methane seeps in the Condamine River in various forms since 2012, engaging independent technical experts whose recommendations have informed this ongoing work.
Previous reports and studies have found no gas safety risk and no evidence of any adverse environmental impact on the plant or animal life of the river and its surroundings1, 2.
Australia Pacific LNG continues to refine and adjust how it responds to the seeps. In recent years, a combination of production and targeted intercept wells have proven effective in capturing and reducing the amount of gas migrating towards the river through naturally occurring geological pathways.
1 Summary Technical Report – Part 1; Condamine River Gas Seep Investigation, Department of Natural Resources and Mines, 2012
2 Methane seeps in the Condamine River, CSIRO Fact Sheet, 2017
Seeps have been observed and monitored at five locations downstream from the Chinchilla weir.
These locations are monitored visually and where it is considered that sufficient flows or flux exist, measured using methodology developed by CSIRO that involves placing floating capture apparatus over the seeps in a defined grid pattern to record the amount of gas collected in a defined time period.
The results are presented in the graph below. Volumes are shown in litres per minute averaged per quarter. The total flux rate is an aggregate of all seep locations where measurement is undertaken for that quarter.
Flow rates across individual seep locations continue to vary over time due to a range of factors.
Flow rates at the most recognisable seep location have reduced significantly. It was last measured in August 2020 and continues to be monitored visually.
For more information about the seeps:
Dec 2011: Condamine River experiences major flooding, heavily scouring the riverbed.
Apr 2012: Condamine River seeps are first identified. Historical evidence of shallow gas and natural gas in the area is well known. There is no coal seam gas development in the immediate area.
Aug 2012: Origin, as Upstream Operator for Australia Pacific LNG, initiates a program of monitoring, research and independent technical review by international scientific experts focussing on four methane seep locations in an area centred ~4km downstream of the Chinchilla weir.
Feb 2014: Independent technical review (Norwest) finds several possible factors including the underlying geology, natural events such as drought and flood cycles as well as human activity (water bores and future coal seam gas development).
Jan 2015: Increasing seep flow rates are observed. Measurement of flow rates begins using a new methodology developed by CSIRO.
Jun 2015: A further fifth seep location was identified by a landowner and added to ongoing monitoring.
Jan 2016: Flow rates peak over 2,000 litres a minute.
Apr 2016: The seeps are deliberately set on fire amid claims nearby CSG development and fracking is the cause (despite no gas development in the area at this time and the nearest fracked gas well over 15km away). The actions gain widespread attention.
Jun 2016: Informed by research, local seismic studies and technical review recommendations, three specifically designed intercept wells are drilled as a first step towards intercepting and reducing the volume of gas heading towards the river.
Aug 2016 onwards: Flow rates fall significantly.
Jun 2017: A further 12 gas wells directly south of the river are brought into production.
Oct – Dec 2017: Measurements confirm the downward trend and a reduction of over 90% compared to the peak in early 2016. Work commences on a second larger package of wells adjacent to the river, made up of 14 production wells and eight wells specifically designed to intercept gas heading towards the seeps through an identified natural fault and pathway.
Apr 2018 – Jul 2018: Flow rates increase as the 12 wells south of the river come offline for maintenance and upgrade work, reducing their mitigating effect. Flow rates plateau and fall as these wells are progressively brought back into production.
Sep 2018: Flow rates fall further after the second, larger package of mitigation wells adjacent to the river come on-line. Gas migrating towards the river is intercepted and directed into production.
Sep – Nov 2019: Flow rates rise briefly and fall, as intercept compression facilities come offline for maintenance for a period of time.
Jan 2021 – 2022: COVID limitations, combined with a series of flooding events in the Condamine River impact the ability to physically access and measure the seeps. Visual monitoring is maintained during this period.
April 2023 – In river measurement using CSIRO methodology continues at locations where measurable levels are present.