Why Chemicals Are Used

Chemical additives are present in most fracture fluids. These additives serve primarily to increase viscosity, which helps the fluid to carry proppant more effectively, and reduce friction, which allows the fluid to flow more easily to and into the target formation. Additives tend to make up less than 1% of fracture fluids and can serve several purposes, from corrosion inhibitors, which prevent the metal in a wellbore from deteriorating, to anti-bacterial agents. The table depicts generic hydraulic fracturing chemical additives by type, purpose, downhole result, common use (outside of oil and gas) and typical usage in unconventional reservoirs.

Used in Unconventional ReservoirsTypePurpose Downhole ResultCommon use
YesAcidHelps dissolve minerals and initiate cracks in the rockReacts with minerals present in the formation to create salts, water, and carbon dioxide (neutralized)Swimming pool chemical and cleaner
YesCorrosion InhibitorPrevents the corrosion of the pipe Bonds to metal surfaces (pipe) downhole. Any remaining product not bonded is broken down by micro-organisms and consumed or returned in produced water.Used in pharmaceuticals, acrylic fibres and plastics
RareIron ControlPrevents precipitation of metal oxides (in pipe)Reacts with minerals in the formation to create simple salts, carbon dioxide and water all of which are returned in produced waterFood additive; flavouring in food and beverages; lemon juice
YesAnti-Bacterial AgentEliminates bacteria in the water that produces corrosive by-productsReacts with micro-organisms that may be present in the treatment fluid and formation. These micro-organisms break down the product with a small amount of the product returning in produced water.Disinfectant; sterilizer for medical and dental equipment
RareScale InhibitorPrevents scale deposits downhole and in surface equipmentProduct attaches to the formation downhole. The majority of product returns with produced water while remaining reacts with microorganisms that break down and consume the product.Used in household cleansers, de-icer, paints, automotive antifreeze
RareClay StabilizerPrevents formation clays from swellingReacts with clays in the formation through a sodium - potassium ion exchange. Reaction results in sodium chloride (table salt) which is returned in produced water.Used in low-sodium table salt substitute, medicines, and IV fluids
YesFriction Reducer“Slicks” the water to minimize friction in the pipeRemains in the formation where temperature and exposure to the "breaker" allows it to be broken down and consumed by naturally occurring micro-organisms. A small amount returns with produced water.Used in cosmetics including hair, make-up, nail and skin products
Common, but often over usedSurfactantUsed to increase the viscosity of the fracture fluidGenerally returned with produced water, but in some formations may enter the gas stream and return in the produced natural gasUsed in glass cleaner, multi-surface cleansers, antiperspirant, deodorants and hair-color
Only in hybrid hydraulic fracturing programsGelling AgentThickens the water in order to suspend the sandCombines with the "breaker" in the formation thus making it much easier for the fluid to flow to the borehole and return in produced waterCosmetics, baked goods, ice cream, toothpaste, sauces, and salad dressings
Only with gelBreakerAllows a delayed break down the gel polymer chainsReacts with the "crosslinker" and "gel" once in the formation making it easier for the fluid to flow to the borehole. Reaction produces ammonia and sulphate salts which are returned in produced water.Used in hair coloring, as a disinfectant, and in the manufacture of common household plastics
In some hybrid hydraulic fracturing programsCrosslinkerMaintains fluid viscosity as temperature increasesCombines with the "breaker" in the formation to create salts that are returned in produced waterUsed in laundry detergents, hand soaps and cosmetics
Only with gelpH Adjusting AgentMaintains the effectiveness of other components, such as crosslinkersReacts with acidic agents in the treatment fluid to maintain a neutral (non-acidic, non-alkaline) pH. Reaction results in mineral salts, water and carbon dioxide; a portion of each is returned in produced water.Used in laundry detergents, soap, water softener and dish washer detergents,washing soda
YesOxygen scavengersRemoves oxygen from the water to protect the pipe from corrosion Cosmetics, food and beverage processing, water treatment