Chemicals used in hydraulic fracture stimulation

The use of chemicals in the oil and gas industry is regulated by the Commonwealth and State government agencies to ensure chemicals are managed, stored, transported and disposed of in an appropriate, safe and environmentally responsible manner.

This information sheet details chemicals used during hydraulic fracture stimulation (fraccing), their regulation and management.

Why are chemicals used in hydraulic fracture stimulation?

Petroleum sites must be equipped with spill kits for response to potential spills or leaks
Petroleum sites must be equipped with spill kits for response to potential spills or leaks

During hydraulic fracture stimulation, fracture fluid is pumped, at pressure, down a well to create small fractures (cracks) within gas-bearing rock formations (located 2 to 5 km underground) and allow trapped natural gas to flow.

Fracture fluid typically contains 90% water, 9.5% sand (or proppants) and up to 0.5% chemicals.

Water (fresh, salt, bore or recycled) is used to create pressure to fracture the rock. It is also used to transport sand and chemicals through the well.

Sand is used to hold the fractures open and allow the natural gas to flow.

Chemicals are used to improve the transportation of sand, prevent the growth of bacteria, reduce mineral blockages and prevent well corrosion inside the well.

How are chemicals assessed?

Chemicals proposed for use during hydraulic fracture stimulation are thoroughly risk-assessed on a case-by-case basis by the Department of Mines, Industry Regulation and Safety (DMIRS) under environment and safety regulations before they are approved or rejected.

DMIRS assesses chemicals against the following criteria:

  • Toxicity to humans
  • Toxicity to the environment
  • Biodegradability
  • Geology of the area (e.g. potential chemical routes and exposure pathways)
  • Australian health and environmental standards

Petroleum companies must demonstrate the use of chemicals selected does not pose an unacceptable risk to human health, the environment or groundwater resources.

If significant risks or potential impacts are identified, the proposal is referred to the Environmental Protection Authority for independent environmental assessment.

What chemicals are used during hydraulic fracture stimulation?

Chemicals used in fracture fluid depend on the properties of the rock being targeted.

Types of chemicals and their use in hydraulic fracture stimulations are detailed below.

Chemical types

What it is used for

Proppants

Proppant or tiny solids (e.g. sand) are used to physically hold open tiny rock fractures or cracks and to allow fluids and gas to move around them

Microbial controls, biocide

Limits the growth of bacteria in fluids which may reduce flow rates and contribute to well corrosion

Oxygen scavengers, corrosion inhibitors

Removes or deactivates oxygen and other corrosive material in fluids which contribute to well corrosion

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

pH control, buffers, salts, stabilisers, solvents

Adjusts the chemical and physical properties of the fluid to achieve optimal flow rates

Friction reducer

Reduces the friction forces of fluids being pumped into the well to increase flow rates

Clay inhibition, stabiliser

Counters clay swelling in the well when drilling and in the rocks being fractured to optimise drilling and flow rates

Gelling agents, binders, cross linker

Increases the thickness of fluids which allows more proppant to be carried into rock fractures

Breakers

Breaks down the gelling agents and releases the proppant into rock fractures

Surfactants

Reduces the stickiness of fluids to improve flow rates

 

How can I find out what chemicals are being used for hydraulic fracture stimulation?

Example of a typical fracture fluid composition
Example of a typical fracture fluid composition

DMP regulations require petroleum companies to publicly disclose all chemicals and additives introduced to a well or formation during hydraulic fracture stimulation. Chemicals and additives introduced to a well or formation are publicly listed on the department’s website.

These transparency requirements, introduced by the department in August 2012, are the strongest of any Australian jurisdiction.

How are chemicals stored on-site and disposed?

All chemicals stored on an oil or gas site must comply with their corresponding Material Safety Data Sheets (MSDS) which identify management practices to ensure safe chemical storage, transport, use and disposal.

Before use down a well, hydraulic fracturing chemicals need to be stored in a lined and bunded area which is designed to contain any potential spills or leaks.

After fluid has been used down a well, the waste water returned to the surface can be re-used during further hydraulic fracture stimulations or stored in lined and bunded evaporation ponds or tanks. This prevents waste water from seeping into groundwater until it is removed by a licensed waste contractor and disposed of offsite at a licensed waste facility.

DMP conducts regular site audits of hydraulic fracture activities to ensure operators are complying with assessed and approved plans for chemical use, storage and disposal.

For more information check out Natural gas from shale and tight rock,  Email: shaleandtightgas@dmirs.wa.gov.au or Telephone +61 8 9222 3333

Chemicals used in hydraulic fracture stimulation - 924 Kb

Find out what chemicals are used during hydraulic fracturing and how they are assessed by the State Government

Examples of proppants

Chemical name

Common applications

Crystalline silica (quartz)

Cat litter, tile mortar, arts & crafts, glass manufacture, ceramic glaze, glaze, concrete, paint

Crystalline silica (cristobalite)

Sand, gravel

Ceramic

Dinnerware, glassware, tiles, pottery, electronic devices

 

Examples of biocides

Chemical type or name

Common applications

Glutaraldehyde

Medical and dental disinfectant, wart treatment

THPS tetrakis(hydroxymethyl) phosphonium sulphate

Fabric treatment, leather tanning

Quaternary ammonium chlorides (eg. 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

 

Examples of oxygen scavengers / corrosion inhibitors

Chemical name

Common 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 sulfite

Food preservatives, making dyes, making paper and textiles

 

Examples of iron control / scale control chemicals

Chemical name

Common 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 making paper, dyes and plastics

Sodium polycarboxylate

Detergents

Phosphonic acid salt

Anticorrosion products

 

Examples of pH control, buffers, salts, stabilisers, solvents

Chemical type or name

Common 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, desiccant (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

Tetrasodiumethylene diaminetetraacetate

Cosmetics

Magnesium oxide

Cements, antacid medicine

 

Examples of friction reducers

Chemical type or name

Common applications

Polyacrylamide

Water absorbing toys

Hydrotreated light petroleum distillate

Mineral turpentine

Methanol

Petrol additive

Ethylene glycol

Clothing manufacturing, car coolant, cooling systems

Sodium lignosulphate

Food preservative, used in ceramics, making paper and leather

Glycerin

Food and pharmaceutical industry, hair products

 

Examples of clay management chemicals

Chemical type or name

Common 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

Polydimethyldiallyl ammonium chloride

Water treatment (drinking and waste-water), 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

 

Examples of gelling agents / binders / cross-linker

Chemical type or name

Common applications

Bentonite

Cement, adhesives, ceramics, cat litter, wine making

MEA borate

Cosmetics, hair texturizer, 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 thiosulfate

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, ice-packs

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

Naturally present in all plants and animals

 

Examples of breakers

Chemical type or name

Common applications

Sodium persulfate

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

 

Examples of surfactants

Chemical type or name

Common applications

2-Butoxyethanol

Cleaning agents, jewellery cleaner

Ethanol

Present in beer, wine and spirits

Propan-2-ol

Cleaning agents

C6-C10 Alcohol ethoxysulfate

Laundry detergent

Alcohols C6-C10 ethoxylated (surrogate C6-C12)

Cleaning agents

Lauryl sulphate

Detergent