Hydraulic fracturing is a government-regulated technology
What is hydraulic fracturing or "fracking"?
Hydraulic fracturing is a government-regulated technology used safely for more than 60 years to recover shale or tight natural gas that is trapped in deep underground rock. After a well has been drilled, hydraulic fracturing fluid is injected into the well at high pressure to create tiny finger-like fractures in the rock. The fractures are propped open by grains of sand to allow the natural gas to flow to the surface.
Photo Courtesy of Devon Energy
Hydraulic Fracturing: How it works
- Drilling the Well- Unconventional natural gas reserves are typically located between two and three kilometres below the earth’s surface and hundreds of metres deeper than the deepest drinkable groundwater.
- Surface Casing- Steel casing is inserted and cemented in place creating a solid barrier between the well and any underground water sources. Cement is pumped into the wellbore where it surrounds the casing. This creates a solid barrier around the well.
- Intermediate Casing- Intermediate casing extends even deeper below any fresh water sources and provides an additional layer to the production casing.
- Horizontal Drilling- Horizontal drilling techniques extend the well hundreds of metres into the formation to maximize the production zone and allow more natural gas to be extracted from each well, reducing surface impacts.
- Perforating the Wellbore- Prior to fracturing, the wellbore casing is perforated to provide an entry point for the natural gas to flow. When the perforations are made, the rock cracks.
- Fracturing- Once the cracks in the shale have been created, fracturing fluid is pumped down the well under pressure which fractures the shale rock. These factures extend between 50 and 100 metres from the horizontal leg of the wellbore. When the fracturing is complete, the sand props open the fractures to provide a pathway for the natural gas to flow into the wellbore more easily.
Hydraulic fracturing fluids
Hydraulic fracturing fluids are comprised primarily of water and sand (~98.5%) and a small amount of additives (~1.5%). Additives are used in part to limit bacterial growth and prevent corrosion. The make-up of fracturing fluid varies from one rock formation to another.
Managing the use of hydraulic fracturing fluids
All additives used must comply with provincial and federal regulations where applicable. Industry also follows best practices to assess and manage the use of hydraulic fracturing additives including having risk mitigation plans in place in the unlikely event of a spill.
In Alberta and British Columbia, disclosure of the additives used for hydraulic fracturing operations must be publicly disclosed. For each well, operators must describe the function of additives used and the trade name of the additive as well as the name of the additive ingredients as listed on the Material Safety Data Sheet (MSDS) and the Chemical Abstract Service registry number (CAS number). This information is stored in a public database that can be found at FracFocus.