Chemical use in hydraulic fracturing

Certain chemicals are needed to ensure that the hydraulic fracturing process is efficient and effective. The primary chemicals used for hydraulic fracturing operations are gelling agents, friction reducers, biocides, corrosion inhibitors, oxygen scavengers, and acids – all commonly used in other sectors of the petroleum industry and elsewhere in everyday life.

In the UK, approximately 0.25% of the total volume of fracturing fluid consists of chemicals, the rest being water (~95%) and proppant (~5%). Regulators such as the Environmental Agency (EA) and Scottish Environment Protection Agency (SEPA) require operators to disclose the chemical constituents in fracturing fluids.

In the US, the concentration of chemicals can reach up to about 2% of the total volume of fracturing fluid. The exact constitution of fracturing fluid depends on the characteristics of the formation. A growing number of states currently require operators to divulge the chemicals used; to increase transparency, most operators disclose the chemicals used through the publically available FracFocus Chemical Disclosure Registry.


Acid
Reasons for use: Cleans mineral deposits from rock formations enabling more efficient production
Consequences of not using chemical: Higher treatment pressures required, reduced production efficiency
Other uses: Used as swimming pool cleaner, household cleaner, and in cosmetics

Friction reducers
Reasons for use: Decrease pumping friction
Consequences of not using chemical: Significantly increased surface pressure and hydraulic fracture pump engine emissions
Other uses: Used in cosmetics, including hair, make-up, nail and skin products

Oxygen scavenger
Reasons for use: Prevents corrosion of well tubing and casing by oxygen
Consequences of not using chemical: Corrosion sharply increased, well integrity (containment) potentially compromised
Other uses: Used in food packaging to aid preservation; aids in the protection of boilers from corrosion

Corrosion inhibitor
Reasons for use: Used in conjunction with acid to prevent corrosion of pipes
Consequences of not using chemical: Sharply increased risk of pipe corrosion from acid, well integrity potentially compromised
Other uses: Used in pharmaceuticals, acrylic fibres and plastics

Biocide
Reasons for use: Control bacterial growth which causes blockages
Consequences of not using chemical: Higher treating pressure, possible growth of bacterial sludge within the well causing plugging of perforations
Other uses: Used in drinking water, cosmetics and wipes, cleaning products, toothpaste, laundry detergents and general disinfectants

Gelling agent
Reasons for use: Improves proppant placement
Consequences of not using chemical: Increased water use, natural gas recovery may decrease in some cases by 30 to 50% when fracturing fluids are not gelled
Other uses: Used as a thickener in cosmetics, ice cream, toothpaste, sauces



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