Water, Land & Air

 

What chemicals are used in hydraulic fracturing?

Fracture fluid is a mixture made of approximately 99.5% water and sand. The remaining 0.5% is comprised of additives, many of which are found in household products.

Fracture Fluid

Graph: BC Oil & Gas Commission

The number and type of chemical additives used in a typical hydraulic fracture treatment depends on the conditions, such as depth or location, of the specific well being fractured, as well as the characteristics of the formation, such as thickness and type of rock.

ProductsSome common additives include the same additives found in consumer goods and household items we use every day. For example, one commonly used material is a substance known as “guar.” It’s actually an emulsifying agent more typically found in ice cream.

Other additives include citric acid, used in lemon juice; sodium chloride, used for table salt; borate salts, used in laundry detergent, hand soaps and cosmetics; and petroleum distillates, used in make-up removers, laxatives and candy.

See other chemicals commonly used in hydraulic fracturing.

Canada’s oil and gas industry fully supports the public disclosure of fracture fluid additions. For example, the Canadian Association of Petroleum Producers (CAPP) has developed guiding principles for hydraulic fracturing that guide water management and improved water and fluids reporting practices for shale gas development in Canada.

Further, the Frac Focus website provides Canadians with listings of the ingredients that make up hydraulic fracturing fluids for every well in BC and Alberta. The New Brunswick government has outlined plans to create a publicly available online registry for fracturing fluid disclosure. PSAC is advocating for FracFocus to become the standardized national reporting tool for fracture fluid use.

What risk does hydraulic fracturing pose to groundwater?

More than 175,000 wells have been hydraulically fractured in Western Canada over the past 60 years with no evidence of groundwater contamination, according to regulators in BC and Alberta.

Wellbores are carefully constructed to efficiently recover gas or oil, while protecting the surrounding environment, in particular the underground drinking water or aquifers.

Drilling and completing a well has much the same stringent regulatory and construction guidelines as putting up a tall office building, only upside down and underground! All wells require a similar level of attention to the environment above and below ground: safety, design, materials, construction and clean-up.

Here’s how it’s done. A wellbore is drilled to allow steel pipe to be sunk deep into the ground. This pipe is surrounded with cement in the bore hole to ensure that both the pipe and the underground area it travels through are completely separated.

Trican Well Service

Graphic: Trican Well Service

During well construction, the wellbore is cased and cemented. This seals and isolates all fresh water zones from the oil and gas zones, and isolates the oil and gas zones from each other. All these steps are highly regulated and require reporting on.

All the pipe (or casing) used in the well is manufactured and certified to established standards. The cement used in wellbore construction is so far advanced versus the cement used in sidewalks it is tough to compare – it’s like comparing a computer to a calculator.

In addition to wellbore construction to protect groundwater, numerous other protective measures are in place at well sites to control any potential runoff, including:

  • Liners under well pads
  • Rubber composite mats under rigs
  • Storage tanks with secondary containment measures and barriers.

Spill prevention, response and cleanup procedures are implemented before drilling begins, and they are continually updated as operations progress.

Further, hydraulic fracturing is only conducted at safe distances from fresh water aquifers. In fact, the resource (oil or gas) is typically beneath 2,000 to 4,000 metres of solid rock, several hundred metres below the deepest fresh water aquifers. Innovative technologies ensure that the fissures created by hydraulic fracturing extend only 50 to 100 metres from the wellbore and are contained within the source rock.

wellbore

Graphic: AER (formerly ERCB)

How much water is used in hydraulic fracturing? Where does the water come from? Who monitors water use in hydraulic fracturing?

Regulators in each province allocate water for industry and other use. In 2009, In Alberta for example, the oil and gas industry is allocated about 8.5% of the province’s available surface and groundwater. Municipal use is allocated 11.3% and agriculture is allocated 44.3% (Alberta Environment). Government regulators monitor water use carefully.

For a shale well, the demand for large amounts of water usually lasts about one week during the initial fracturing stage. A well is typically only fractured once, then will produce for 20 to 30 years.

Fluid volumes required depend on many factors, including rock characteristics and pressures, horizontal well length and number of fracturing stages. As an example, shale gas and tight gas resources currently being developed in BC, using horizontal wells with multistage fracturing, need anywhere from 5,000 to 100,000 cubic metres (m3) of water per well (BC Oil and Gas Commission). To put this into perspective, an unconventional gas well that requires 20,000 m3 of water will have used the same amount of water as a golf course uses about every 28 days (CSUR).

For more information, read:

What alternatives are there to using fresh water for hydraulic fracturing? How is industry trying to reduce its fresh water usage?

Industry is working to reduce its use of fresh water for hydraulic fracturing by using or recycling a variety of poorer quality alternatives, such as:

  • Brackish groundwater: water from slightly saline (salty) aquifers
  • Saline groundwater: water from deep saline aquifers
  • Flowback: water injected during fracturing that flows back to the wellbore
  • Produced water: water naturally present in the reservoir or injected into the reservoir to enhance production
  • Municipal wastewater

Of course, these types of water must be – and are – treated before being reused.

After hydraulic fracturing is completed, what happens to any fluid or waste water?

After the fluid/proppant mixture is forced into the target rock unit, the well bore is flushed out and all fluids are flowed back to the surface and collected at the wellsite. Commonly between 50 to 90 per cent of the fluid is recovered.

Most fracturing fluid is recovered at the wellhead during flowback testing and production operations. In some cases this fluid may be stored, treated and re-used. When the fluid is to be disposed, it is generally trucked to an approved disposal well or facility. At this point it must be pumped into a deep underground formation using a wellbore reviewed and approved by the regulator.

Source: Hydraulic Fracturing and Disposal of Fluids (BC Oil and Gas Commission)

Are gases flared during hydraulic fracturing?

During hydraulic fracturing, no gases are flared. However, once the hydraulic fracturing process is complete, the fluid is flowed back to surface during clean-up. Natural gas that flows back at that time may be flared for a few days, as per industry recommend practices.

For more frequently asked questions about hydraulic fracturing, visit:

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