But coal seam gas, just like conventional gas, can be used to power water and space heating. Coal seam gas is shaping up as an issue in the nsw election. Fact sheet coal seam gas extraction and coproduced water. A short primer on benzene, toluene, ethylbenzene and xylenes. Coal seam gas extraction and their potential effects on. Coal seam gas extraction coal seam gas is found in cracks, pores and micropores in coal seams, where it is held in place either as free gas, or adsorbed onto coal surfaces figure 3. These coal seams are drilled down into, releasing the associated gas which is extracted and can be used to generate electricity. Groundwater modelling tools can simulate the potential groundwater impacts from coal seam gas production. The development of australias coal seam gas resources. Coal seam gas extraction and coproduced water, fact sheet. Fraccing involves injecting a mix of water, sand and chemicals. Public perception of the extraction of these sources of gas, particularly the process of fraccing, has been influenced by recent media attention.
Hence, the gas extraction rate is increased, and the permeability of coal seam is enhanced. Extracted water and gas is diverted to surface infrastructure treatment and processing plants. It is an unconventional gas as opposed to the conventional resources commonly found offshore in many parts of australia. With such abundant planes of land stretching from the coral sea to the indian ocean, there is much to be discovered of australias. Nsw have focused attention on the extraction of shale gas and coal seam gas together known as unconventional gas resources. It supports high standards for both industries and aims to maximise the safe and optimal extraction of resources. Rational boreholes arrangement of gas extraction from. Fraccing is a process that breaks up the coal seam to improve gas and water flow. Apr 10, 2014 learn more about coal seam gas csg and the technology arrow energy uses to extract it. This chapter focuses on the development of the coal seam gas industry in australia. The gas and liquid are brought to the surface via a pipe which is encased in layers of concrete and metal to prevent any leakage into permeable layers, including aquifers.
The modelling process is influenced by, objectives, conditions, data and scale of impact. Hydraulic fracturing is one such technique which has made gas extraction both feasible. These pillars can be up to 40% of the total coal in the seam although this coal can sometimes be recovered at a later stage. Pdf on jun 26, 2016, tianhang bai and others published impact of flow regimes on coal fines generation during coal seam gas production process. Farmers are protesting over safety concerns and threats to the countrys food security. On the surface, the gas is separated from the water. Using the typical gas extraction from high gas coal seam group songzi moutain mine as example, to give the basic parameters of coal seam, and elaborate the measures and design process of gas extraction from coal seam group to provide a referential engineering case for other gas mines with similar conditions.
By dr sara bice, melbourne school of government, university of melbourne. Petroleum division publication regulation of shale, coal. Fact sheet coal seam gas extraction and coproduced. This can be achieved in what is known as retreat mining, where coal is mined from the pillars as workers retreat. A csg project can spread across hundreds of thousands of hectares of land. Water and coal seam gas how coal seam gas is extracted in nsw. Well stimulation is used to increase production in oil and gas wells by improving the flow of hydrocarbons into the oil well. Constraining surface deformation predictions resulting from. The assessment examined 1 chemicals used by companies in australia between 2010 and 2012 in drilling and hydraulic fracturing for coal seam gas, to develop a stronger understanding of the. Coalbed methane cbm or coal bed methane, coalbed gas, coal seam gas csg, or coalmine methane cmm is a form of natural gas extracted from coal beds. Coal seam gas csg or coal bed methane cbm is primary coal seam gas collected from unmined coal seams. But coal seam gas, just like conventional gas, can be used to power water and space heating for industrial, commercial and domestic users, as well as in gas turbines to generate electricity.
National assessment of chemicals associated with coal seam. Michael fibbens, michael y mak, and anthony p williams. It was first identified when coal mining began in the early 1900s. Coal seam gas is a natural gas held in coal seams under pressure by groundwater. The extraction of natural gas from low permeability unconventional reservoirs requires methods to improve access to the reservoir. An analysis of coal seam gas production and natural resource. Research on gas extraction from high gas coal seam group. Coal seam gas extraction usually involves tens of thousands of gas wells, with roads. National assessment of chemicals associated with coal seam gas extraction in. This process reduces pressure in the seams which allows csg to be released. The coal seams are generally filled with water and it is the pressure of the water that keeps the gas as a thin film on the surface of the coal.
Abstract coal seam gas csg extraction is set for expansion in new south wales. Coal seam gas doctors for the environment australia. To produce coal seam gas csg, wells are drilled into underground coal seams, bringing water csg water from the seams to the surface. To extract the gas via wells drilled into a coal seam, the hydraulic pressures exerted by water in the seam andor overlying aquifers must be reduced. Csiro is working on a range of research projects to enhance the characterisation, production and stimulation of coal seam gas reservoirs and address the environmental. The quality of csg water quality varies greatly, however it is generally rich in salts and other minerals. To access the coal seams, a well is created by drilling a hole to the required depth. Coal seam gas wells release the gas by reducing the pressure through groundwater extraction.
Coal seam gas, also known as coal bed methane, is a natural, colorless, odorless mixture of various gases primarily methane that is extracted from coal at a depth of. The process has also been used in nsw to enhance water flows from water bores. Thus, the coal seams are merely a new source for an old and valued fuel. Pdf impact of flow regimes on coal fines generation. A new approach to overlapping tenure in queensland may 2012 pdf, 1. To simplify the gas extraction process and reduce the production cost, the use of the three. Effect of coal maturity on co2based hydraulic fracturing. Coal seam gas debate is more than hot air pursuit by the.
Coal seam gas extraction and their potential effects on surface subsidence. Based on the multiphysics field theory, the hydraulicmechanical coupling model of gas extraction in the unloading coal seam was established, and the gas extraction process by drilling borehole in. The rapid development of unconventional energy resources since the mid2000s has left the community divided with regard to the benefits and risks involved, and has risen to prominence in the australian policy debate. Influence radius of gas extraction borehole in an anisotropic. Coal seam gas, shale and tight gas extraction methods. Coal seam gas extraction, fraccing and groundwater. The water trigger allows coal and coal seam gas developments that are likely to have a significant impact on water resources to be comprehensively assessed at a national level. Fraccing is the process of pumping high pressure fluids into a coal seam to fracture the seam and allow gas to flow into the gas well, thus maximizing extraction. Until recently, the natural gas or methane used in australia and elsewhere was nearly all supplied from reservoir gas that is, conventional gas that occurs in underground porous sedimentary rock reservoirs gas fields rather than in coal seams.
Pdf coal seam gas extraction and their potential effects on. Hydraulic fracturing in coal seam gas mining national toxics. The rapid expansion of csg production on the east coast has been the topic. In order to enhance gas extraction from unloaded coal seam by drilling borehole in the floor roadway, the mechanism of stress relief improving permeability by protective coal seam mining was analyzed. Coal seam gas csg mining is a risky, invasive form of unconventional gas mining. In recent decades it has become an important source of energy in united states, canada, australia, and other countries. Coal seam gas extraction usually involves tens of thousands of gas wells, with roads, pipelines, compressor stations, wastewater dams, and other infrastructure. The process of extracting gas from the coal seam has come under considerable scrutiny in recent times. To extract coal seam gas csg a well is drilled into the target coal seam. The process depressurises the coal seam, allowing the gas in the pores of the coal to be released and flow to the surface. Reservoirs are typically porous sandstones, limestones or dolomite rocks, but also include unconventional reservoirs such as shale rock or coal beds. Coal seam gas extraction and coproduced water what is coproduced water. Coal seam gas water environment department of environment. Maximising utilisation of queenslands coal and coal seam gas resources.
Did community opposition have a role in agls decision to quit exploration of natural gas. Coal seam gas extraction and coproduced water pdf 294. However, in csg production fracturing is becoming less common as companies. But where are the coal seam gas wells in nsw, how is the gas extracted and what are the concerns. Natural gas in coal seams in australia is not a new discovery. Based on the multiphysics field theory, the hydraulicmechanical coupling model of gas extraction in the unloading coal seam was established, and the gas extraction process by drilling borehole. Learn more about coal seam gas csg and the technology arrow energy uses to extract it. An analysis of policy, pollutants and protests abstract australia is undoubtedly one of the most resourceful countries in the world. Aug 15, 2011 debate is intensifying over the extraction of coal seam gas, particularly in nsw and queensland. Coal seam gas csg is primarily methane a colourless and odourless gas, found in coal deposits formed over millions of years from fallen trees and other plant matter. Hydraulic fracturing enables the extraction of natural gas and oil from rock formations deep below the earths surface generally 2,0006,000 m 5,00020,000 ft, which is greatly below. Influence radius of gas extraction borehole in an anisotropic coal. The chemical composition of csg and conventional gas is the same.