Hydraulic fracturing

Hydraulic fracturing or “fracking” is a well established, tightly regulated technology. It has been used safely to enhance oil and gas production for 65 years in more than 2 million wells worldwide.

Fracking increases the flow of oil and gas to wells, which increases production per well and reduces the total number of wells needed to develop resources. It also allows commercialisation of “tight” (low permeability) reservoirs in which oil and gas do not easily flow.

This technology is now used in about 90% of new US gas wells. Other industries also use reservoir stimulation – artificial geothermal energy production relies on fraccing and even water bores are sometimes fracced to increase water production.

The Cooper Basin (in northeast south Australia and southwest Queensland) has for 50 years been one of Australia’s premier oil and gas regions. Since 1969, about 700 wells have been hydraulically fractured in the Cooper without problems. Some of these wells have been fracked several times.

How fraccing is done

Fracking involves stimulating tiny fractures in a rock layer in order to increase the flow of gas, oil or other substances, such as geothermal fluids.

Fluid is pumped down the well at high pressure to produce cracks in the target rock reservoir.

Hydraulic fracturing fluid is mostly water and sand or ceramic beads (between 96 and 99.9 per cent). The sand or beads (known as “proppants”) enter the fissures and hold them open to make the fracturing process more effective.

The chemicals in the fluid reduce friction, remove bacteria from the formation, dissolve some minerals, prevent build-up of scale and enhance the fluid’s ability to transport sand.

The chemical additives used are familiar products found in most households. They are subject to similar strict regulations applying to responsible chemical use on farms or in factories.

 Typical chemical additive used in hydraulic fracturing fluids

Compound Purpose Common application
Acids Helps dissolve minerals, initiate fissure in rock (pre-fracture) and manage pH Levels Swimming pool cleaner
Sodium Chloride Allows a delayed breakdown of the gel polymer chains Table salt
Polyacrylamide Minimises the friction between fluid and pipe Water treatment, soil conditioner
Ethylene Glycol Prevents scale deposits in the pipe Automotive anti-freeze, de-icing agent, household cleaners
Borate Salts Maintains fluid viscosity as temperature increases Laundry detergent, hand soap, cosmetics
Sodium/Potassium Carbonate Maintains effectiveness of other components, such as cross-linkers Washing soda, detergent, soap, water softener, glass, ceramics
Glutaraldehyde Eliminates bacteria in the water Disinfectant, sterilisation of medical and dental equipment
Guar Gum Thickens the water to suspend the sand Thickener in cosmetics, baked goods, ice cream, toothpaste, sauces
Citric Acid Prevents precipitation of metal oxides Food additives, food and beverages, lemon juice
Isopropanol Used to increase the viscosity of the fracture fluid Glass cleaner, antiperspirant, hair colouring

For more information, see this list of chemicals used in CSG fraccing operations.