FAQS and Fact Sheets
- Coal seam gas is natural gas held in coal seams beneath the earth's surface.
- CSG extraction is a low impact and low risk industry that can help meet the growing demand for a low emissions energy source.
- AGL uses the best available science and technology to explore for and extract natural gas safely and to protect the surrounding enviroment.
- Gas exploration activities are compatible with the Hunter's thriving tourism industry and famous wineries. In fact, AGL owns and maintains a working vineyard and agricultural land and is proudly part of the to the region's annual grape harvest.
Project Fact Sheets
Gas well investigation and construction
- Q: What is Coal Seam Gas?
A: Coal seam gas (CSG) occurs naturally within coal seams and is also known as natural gas. Natural gas has been identified as the optimum transitional fuel for power generation in response to climate change. Traditionally NSW has relied on importing its gas supplies from interstate. There are significant CSG reserves in NSW which can help secure gas supply to NSW residents and businesses.
Find out more about Coal Seam Gas.
- Q: Why Natural Gas?
A: Natural gas is used to power hot water systems, stoves and heaters in homes. It is used as a direct source of power in hospitals and is also used extensively in industry for chemical and fertiliser manufacturing, aluminium smelters and it is used as a fuel for electricity generation.
- Q: What is a 2D seismic survey?
A: Two dimensional (2D) seismic surveys area non-intrusive exploration method used to create a map of the structures beneath the earth's surface. The method sends sound waves into the Earth, where the different rock formations then reflect the waves back to the surface. The information is recorded over a period of time measured in seconds.
Geologists and geophysicists can then interpret this data to understand where possible gas reserves might be located, to identify areas that are unsuitable for coal seam gas exploration and to gain a regional understanding of the geology of the Hunter region.
- Q: What is coal seam gas water?
A: CSG water is deep groundwater that is contained in micro-fractures and the pore spaces of coal seams. When it is pumped to the surface it is generally referred to as "produced water", "associated water" or "extracted water".
- Q: How did this water reach the coal seams?
A: Similiar to groundwater, this water in the coal seams was recharged from rainfall. Studies have shown that this water is many tens of thousands of years old.
- Q: Is it connected with overlying water resources?
A: There is no evidence from scientific studies in the Hunter area at Broke and Bulga that surface water or shallow aquifers (that occur to depths of 70m) are connected with the target coal seams generally located at depths between 150m and 750m. Groundwater monitoring networks are in place to monitor both water levels and water quality.
- Q: How can you be sure that gas wells do not cross connect different aquifers?
A: Gas wells are fully cased with steel and pressure cemented when drilled to ensure that all overlying aquifers are sealed off and do not leak groundwater upwards or downwards.
- Q: Will CSG water extractions drain overlying aquifers?
A: No. Even though CSG extractions are based on removing water from the coal seams and substantially lowering pressure levels and water levels within the coal seams, there is no evidence that shallow aquifers will drain. There are many low permeability rocks located above the coal seams that are not disturbed by the CSG drilling or extraction process hence shallow water resources are effectively separated from deeper saline groundwater.
- Q: Will CSG water extractions contaminate local shallow aquifers and streams?
A: No. CSG water that is brought to the surface is fully contained and then either treated, blended (before reuse) or disposed of at a licensed offsite facility.
- Q: Is the water toxic?
A: No. The produced water is generally slightly saline (about 5,000 to 15,000 EC) which is 10-25% the salinity of seawater which is normally around 55,000 EC. The water is generally elevated in sodium and bicarbonate. The poor water quality generally makes the CSG water unsuitable for any consumptive uses (without treatment).