What health considerations are there?

Table 4: Fracturing fluid additives and main compounds 1

Additive Type

Main Compound(s)

Purpose

acid

hydrochloric or muriatic acid

Helps dissolve minerals and initiate cracks in the rock

Antibacterial agent

Glutaraldehyde

Eliminates bacteria in the water that produce corrosive byproducts

Breaker

Ammonium persulfate

Allows a delayed breakdown of the fracturing gel

Clay stabilizer

Potassium chloride

Brine carrier fluid

Corrosion Inhibitor

N,n-dimethyl formamide

Prevents the corrosion of pipes

Crosslinker

Borate salts

Maintains fluid viscosity

Defoamer

Polyglycol

Lowers surface tension and allows gas to escape

Foamer

Acetic acid (with NH4 and NaNO2)

Reduces fluid volume and improves proppant carrying capacity

Friction Reducer

Petroleum distillate

Minimizes friction in pipes

Gel guar gum

Hyroxyethyl 

Helps suspend the sand in water

Iron Control

Citric Acid

Prevents precipitation of metal oxides

Oxygen Scavenger

Ammonium bisulfate

Maintains integrity of steel casing of wellbore; protects pipes from corrosion by removing oxygen from fluid

pH Adjusting Agent

Sodium or potassium carbonate

Adjusts and controls pH of fluid

Proppant

Silica, sometimes ceramic particles

Holds open (props) fractures to allow fluids (oil and/or natural gas) to escape from shale

Scale Inhibitor

Ethylene glycol

Reduces scale deposits in pipe

Solvents

Stoddard solvent, various aromatic hydrocarbons

Improve fluid wettability or ability to maintain contact between the fluid and the pipes

Surfactant

Isopropanol

Increases the viscosity of the fracture fluids and prevents emulsions

Notes:

  1. Adgate, Goldstein, and McKenzie, “Potential Public Health Hazards,” 8311.