Chemicals play an important role in the oil and gas industry and should be handled, stored, transported and disposed of in a safe and environmentally responsible manner.
The use of chemicals is regulated by the Commonwealth and State Governments to ensure petroleum activities are performed responsibly on Western Australian lands and in WA waters.
Why are chemicals used in hydraulic fracturing?
During hydraulic fracturing, fluid is pressure pumped down a well to create small fractures (cracks) in gas-bearing rock formations to release trapped petroleum. In Western Australia, these rock formations are typically two to five kilometres underground.
The fluid typically contains up to 90 per cent water, up to 9.5 per cent sand/proppants and up to 0.5 per cent chemicals. Water is used to create pressure to fracture the rock. It is also used to transport sand and chemicals through the well.
Sand/proppants hold the fractures open and increase the amount of petroleum that can flow through the rock. Typically, chemicals are added to improve the transportation of sand, prevent the growth of bacteria, reduce mineral or chemical blockages and to avoid well corrosion.
How are chemicals assessed?
Chemicals are regulated by the Commonwealth Government of Australia through the National Industrial Chemicals Notification and Assessment Scheme (NICNAS). This regulatory body assesses the risks of all chemicals made or brought into Australia and sets conditions about their safe use to protect people and the environment.
The State Government assesses the chemicals proposed in hydraulic fracturing, including the risks to safety, environment and public health, and checks that the chemicals used in hydraulic fracturing have been approved for use in Australia. There are arrangements in place between the Environmental Protection Authority (EPA), the Department of Energy, Mines, Industry Regulation and Safety (DEMIRS), the Department of Health, and the Department of Water and Environmental Regulation to obtain advice on the risks.
Hydraulic fracturing proposals are not allowed to proceed if the chemicals pose unacceptable public health, safety and/or environmental risks (including risk to groundwater).
The chemicals are assessed against:
- toxicity to humans;
- toxicity to the environment;
- biodegradation, bioaccumulation potential and persistence;
- potential chemical routes and exposure pathways; and
- health and environmental standards.
What types of chemicals are used during hydraulic fracturing?
The chemicals are typically used in very low concentrations by volume (between 0.1 to 0.5 per cent). Exact chemical mixtures will vary and depend on several factors, including the depth and the properties of the rock being targeted.
The types of chemicals and their purpose in the hydraulic fracturing operation are detailed below:
| Chemical Types | What is it used for |
|---|---|
| Biocide, microbial controls | Limits the growth of bacteria in the water which may reduce flow rates and contribute to well corrosion |
| Breaker | Breaks down the gelling agents and releases the proppant into rock fractures |
| Clay inhibition, stabiliser | Counters clay swelling in the well when drilling and in the rocks being fractured to optimise drilling and flow rates |
| Friction reducer | Reduces the friction forces of fluids being pumped into the well to increase flowrates |
| Gelling agent, binder, crosslinker | Increases the thickness of fluids which allows more proppant to be carried into rock fractures |
| Iron control, scale control | Limits the build-up of iron precipitates and mineral scale which can reduce the flow rate of fluids and contribute to well corrosion |
| Oxygen scavengers, corrosion inhibitors | Removes or deactivates oxygen and other corrosive material in fluids which contribute to well corrosion |
| Proppants | Tiny solids (e.g. sand) are used to physically hold open tiny rock fractures or cracks, and allows fluids and gas to move around them |
| pH control, buffers, acids, salts, stabilisers, solvents | Adjusts the chemical and physical properties of the fluid to achieve optimal flowrates |
| Surfactants | Reduces the stickiness of fluids to improve flow rates |
How can I find out what chemicals are being used in hydraulic fracturing?
The State Government publishes this information on the relevant department’s website.
If a proposal is being assessed by the EPA, the information will be available from the EPA's website. If the proposal is being assessed by DEMIRS, the information will be available in the Environment Plan Summaries.
Petroleum companies are also required, under the Petroleum and Geothermal Energy Resources (Environment) Regulations 2012, to consult with relevant interested persons and organisations. For hydraulic fracturing, companies are expected to engage with their stakeholders about the chemicals they propose to use.
How are chemicals stored onsite and disposed of?
All chemicals stored on an oil or gas site must comply with the management practices specified in the Safety Data Sheets. This ensures safe chemical storage, transport, use and disposal when dealing with potentially harmful chemicals.
The requirements typically include storage of chemicals in purpose-built lined and bunded areas designed to Australian Standards, to contain any potential spills or leaks.
A bund is a structure with a floor and retaining wall that envelopes the area where chemicals are handled, processed or stored. Its purpose is to minimise the risk of unintended escape of undiluted chemicals into the environment, and to retain any spillages for clean-up.
After fluid has been used down a well, the wastewater (flow-back water) that returns to the surface can be re-used in another hydraulic fracturing operation or be stored in lined water evaporation ponds. This prevents wastewater from seeping into groundwater and allows left-over material to be tested and then removed by a licensed waste contractor for disposal at a waste facility licensed under the Environmental Protection Act 1986.
Chemicals used in hydraulic fracturing
A range of chemicals are used in the hydraulic fracturing process and many of them are used in industrial processes and household products. Some of the substances, or active ingredients, may be hazardous and can be dangerous if used in high concentrations and/or unsafely.
The number of chemicals used in hydraulic fracturing depends on the specific well location and characteristics of the target formation. Hydraulic fracturing fluid typically contains very low concentrations of between three and 12 chemical products. The tables below describe some of the substances that may be used in hydraulic fracturing, and other common applications.
Proppants
| Chemical name | Other applications |
|---|---|
| Crystalline silica (Quartz) | Cat litter, tile mortar, arts and crafts, glass manufacture, ceramic glaze, glaze, concrete, paint |
| Crystalline silica (Cristobarite) | Sand, gravel |
| Ceramic | Dinnerware, glassware, tiles, pottery, electronic devices |
Biocides
| Chemical name | Other applications |
|---|---|
| Glutaraldehyde | Medical and dental disinfectant, wart treatment |
| THPS Tetrakis(hydromethyl) phosphonium sulphate | Fabric treatment, leather tanning |
| Quaternary ammonium chlorides (e.g. benzoalkonium chloride, benzethonium chloride) | Disinfectants, anti-mould removal, throat lozenges, swimming pool algaecide |
| Chloromethylisothiazolinone (CMIT) | Cosmetics, shampoos, conditioners, body washes, disposable wipes |
| Methylisothiazolinone (MIT) | Toiletries, cosmetics, dishwashing liquids |
| Sodium hypochlorite | Disinfectant, bleaching agent, cleaners, milk production, water treatment, dental sterilisation, medical use, wood cleaner/deck wash, mildew remover, phosphate free dishwasher gel, anti-bacterial cleanser |
Oxygen scavengers/corrosion inhibitors
| Chemical name | Other applications |
|---|---|
| Zinc carbonate | Shampoos, skin protectants and cosmetics |
| Isopropanol | Cleaning agent for electronic components, whiteboard cleaner, hand sanitiser |
| Methanol | Petrol additive |
| Formic acid | Clothing dye, cleaning products |
| Acetaldehyde | Preserving fish and fruit; perfume production, plastics and dyes |
| Gelatine | Capsules for medicines, desserts, jellies, ice cream |
| Sodium sulphite | Food preservatives, making dyes, making paper and textiles |
Iron control/scale control chemicals
| Chemical name | Other applications |
|---|---|
| Citric acid | Flavour enhancer, cleaning products, pharmaceutical applications |
| Acetic acid | Vinegar, found in citrus fruits, descaling products |
| Thioglycolic acid | Hair perming and straightening, leather processing |
| Sodium erythorbate | Used in processed meats, poultry and soft drinks |
| Acrylamide copolymer / sodium acrylate | Used in paper making, dyes and plastics |
| Sodium polycarboxylate | Detergents |
| Phosphoric acid salt | Anticorrosion products |
pH control, buffers, salts, stabilisers, solvents
| Chemical type or name | Other applications |
|---|---|
| Potassium carbonate | Soaps, glass and china production |
| Sodium acetate | Food flavouring |
| Sodium hydroxide (caustic soda) | Food preparation, household drain cleaner, paper, soaps, detergents |
| Sodium bicarbonate | Baking soda, cleaning product |
| Sodium carbonate (soda ash) | Water softener, swimming pools, food additive, glass |
| Hydrochloric acid | Household cleaning, food additive, swimming pools, drinking water |
| Carbonic acid | Soda drinks |
| Citric acid | Flavour enhancer, cleaning products, pharmaceutical applications |
| Sodium acid pyrophosphate (SAPP) | Food preservative |
| Acetic acid | Vinegar, found in citrus fruits, descaling agent |
| Carbonic acid, sodium salt | Food additive |
| Calcium chloride | Detergents, cosmetics, deodorant, pet products, dessicant (moisture absorber), food additive, sports drinks |
| Gypsum (calcium sulphate) | Fertiliser, plasterboard |
| Ethylene glycol | Clothing manufacturing, car coolant, cooling systems |
| Magnesium silicate hydrate (talc) | Talcum powder, cosmetics, food additive, soaps, paper, paints, rubber, pottery |
| Tetrasodium ethylenediaminetetraacetate | Cosmetics |
| Magnesium oxide | Cements, antacid medicine |
Friction reducers
| Chemical type or name | Other applications |
|---|---|
| Polyacrylamide | Water absorbing toys |
| Hydrotreated light petroleum distillate | Mineral turpentine |
| Methanol | Petrol additive |
| Ethylene glycol | Clothing manufacturing, car coolant, cooling systems |
| Sodium lignosulphonate | Food preservative, used in ceramics, making paper and leather |
| Glycerine | Food and pharmaceutical industry, hair products |
Clay management chemicals
| Chemical type or name | Other applications |
|---|---|
| Sodium chloride | Table salt |
| Isopropanol | Cleaning electronics, whiteboard cleaner, hand sanitiser |
| Tetramethyl ammonium chloride | Batteries, antiseptic agent, plastic manufacturing |
| Potassium chloride | Table salt substitute, some medical treatments, garden products, pet supplements, various hair products |
| Polyacrylamide | Water absorbing toys |
| Choline chloride | Poultry feed additive |
| Polydimethydiallyl ammonium chloride | Water treatment (drinking and wastewater), textiles, cosmetics, paper making, soil treatment, drinking, bathing, cooking |
| Trimethylammonium chloride | Dyeing |
| Magnesium nitrate | Facial care, home garden uses, ceramics |
| Magnesium chloride | Food industry (e.g. tofu from soy milk), vitamin supplements |
| Silica gel | Cat litter, packaging, food preservative |
| Poly(ethylene glycol co-propylene glycol) monobutyl ether | Lubricants, plastic manufacturing |
Gelling agents/binders/crosslinker
| Chemical type or name | Other applications |
|---|---|
| Bentonite | Cement, adhesives, ceramics, cat litter, wine making |
| MEA borate | Cosmetics, hair texturiser, hairspray, antiseptic, laundry detergent |
| Boric acid | Cosmetics and skin care products |
| Triethanolamine | Cosmetics and skin care products |
| Sodium tetraborate | Detergents, cosmetics, texturing agent in cooking |
| Vinylidene chloride / methylacrylate | Plastic wrap |
| Sodium chloride | Food production, food additive, detergents, hair products, water softener |
| Hydrogen peroxide | Hair bleach, food processing |
| Diammonium peroxidisulphate | Hair bleach |
| Sodium thiosulphate | Personal care, pet care, food production, aquaculture food |
| Sodium sulphate | Textiles |
| Sodium sulphite | Paper industry |
| Carboxymethyl cellulose (cellulose gum) | Thickener in dressings, sauces, ice cream, cosmetics, eye drops, icepacks |
| Welan gum | Food additive |
| Guar gum | Thickener in dairy products, sauces and dressings, cosmetics, baked goods, ice cream, toothpaste |
| Xanthan gum | Thickener in dressings, sauces, ice cream, cosmetics |
| Polysaccharide blend (starch) | Naturally present in all plants and animals |
Breakers
| Chemical type or name | Other applications |
|---|---|
| Sodium persulphate | Hair bleach |
| Hemicellulase enzyme | Food industry, washing powder |
| Hemicellulase enzyme carbohydrates | Food additive |
| Ammonium persulphate | Hair bleach |
| Sodium chloride, salt | Table salt |
| Magnesium oxide | Cements, antacid medicine |
Surfactants
| Chemical type or name | Other applications |
|---|---|
| 2-Butoxyethanol | Cleaning agents, jewellery cleaner |
| Ethanol | Present in beer, wine and spirits |
| Propan-2-ol | Cleaning agents |
| C6-C10 Alcohol ethoxysulphate | Laundry detergents |
| Alcohols C6-C10 ethoxylated (surrogate C6-C12) | Cleaning agents |
| Lauryl sulphate | Detergent |
Terms used
hydraulic fracturing: also known as hydraulic fracture stimulation or ‘fracking’, this means the underground petroleum extraction process that involves the injection of fluids under high pressure into low permeability rock to induce fractures for the purpose of increasing the rock’s permeability. This term is as defined in the Petroleum and Geothermal Energy Resources (Hydraulic Fracturing) Regulations 2017.
permeability: the ability, or measurement of a rock’s ability to transmit fluids.
petroleum: a complex mixture of naturally occurring hydrocarbon compounds found in rock in liquid, gaseous or solid form (i.e. crude oil, natural gas, or bitumen).
proppant: small particles, usually sand, mixed with fracturing fluid to hold fractures open after a hydraulic fracturing treatment.
