|
“Unconventional gas” describes gas that is more difficult or less economical, generally because the technology to extract it has not been developed or is too expensive.
Shale gas is that found in very fine-grained sedimentary rock which breaks easily into thin, parallel layers.
Tight gas is that found in unusually impermeable hard rock or in a sandstone or limestone formation that is unusually impermeable or non-porous. |
Hydraulic fracturing of gas reserves, more commonly known as fraccing, has been the subject of much community interest in recent months.
Some of this interest has arisen from reported adverse impacts associated with unconventional gas extraction projects in Queensland, New South Wales and the United States.
Fraccing is a process that pumps fluid and other materials under high pressure into wells to open channels in the rock formations, which increases the flow of gas to allow extraction.
Potential risks and impacts associated with fraccing include the use, storage and disposal of water, potential chemical contamination of groundwater, and disruption to aquifer connectivity.
The situation in WA is materially different to that in Queensland and New South Wales. According to the Department of Mines and Petroleum, WA resources are primarily shale and tight gas which differs from the coal seam gas being targeted in the eastern states. The shale and tight gas resources in WA are typically more than 2000 metres below the surface. In contrast, coal seam gas is generally found between 600 and 1000 metres below the surface. The greater depth of gas resources in WA limits the potential for fraccing to interfere with water supplies, which are typically drawn above 1000 metres.
Avoidance and mitigation of environmental risks and impacts and best practice management is important for projects where fraccing is used, and the impact associated with the full scale production of unconventional gas reserves in WA needs to be better understood. The EPA also considers that community confidence about the effective management of fraccing is best achieved through open and transparent regulatory processes.
In September this year, the EPA released Environmental Protection Bulletin No. 15 – Hydraulic fracturing of gas reserves, to outline its approach to fraccing proposals.The Department of Mines and Petroleum (DMP) is the lead agency responsible for the regulation of unconventional gas activities in WA. DMP is proposing to improve its regulatory processes to ensure it is well placed to manage the issues associated with the unconventional gas industry.
The EPA will determine whether to assess fraccing projects that are referred to it on a case-by-case basis, depending on whether the proposal is likely to have a significant effect on the environment.
To date, only a few fraccing related proposals have been referred to the EPA. In these cases the EPA determined that it would not assess the proposals, on the basis that they were small scale ‘proof of concept’ proposals that were not likely to have a significant impact on the environment.
The EPA will continue to work with the Department of Mines and Petroleum to ensure that the potential environment impacts of fraccing related proposals are fully considered, and that the community and industry has appropriate information and guidance on fraccing.
The EPA believes a strategic and science-based approach to informing assessment and regulatory policy and decision-making on fraccing is vital.