Because unconventional oil and natural gas is trapped in low-permeability rock, pathways need to be created to allow oil and natural gas to move through the rock to the well and to enable it to be pumped to the surface. A common method of doing this is to use hydraulic fracturing to “fracture” or crack the rock and create the paths required.
|Hydraulic well fracturing (“fracking”) is the process of pumping fluid into a wellbore to create enough pressure to crack, or fracture, the rock layer. The fluid usually contains a “proppant,” like sand, that helps keep the fractures open to allow oil and gas to be produced to the well.
To produce unconventional oil and natural gas, horizontal wells and multistage fracturing are used. These wells start by drilling vertically (straight down) and then turning the drill bit so that it drills horizontally through the formation.
Typically, the formations being targeted with horizontal multistage fracturing are between 650 and 3500 metres below ground. While horizontal well drilling has been around for decades, improvements in the technology have made it possible to combine horizontal drilling with hydraulic fracturing to help coax oil and natural gas out of tight rock.
WHAT ARE IN THE FLUIDS USED FOR HYDRAULIC FRACTURING?
In some areas, concerns have been raised about the chemicals that might be used in hydraulic fracturing fluids, leading to requests that this information be made publicly available. Effective December 2012, AER rules require that licensees comply with enhanced requirements to report amounts and sources of water and chemicals used in every hydraulic fracturing job. Summary information is posted to www.fracfocus.ca.
The AER requires that any hydraulic fracturing fluids used above the base of groundwater protection (BGWP) be nontoxic and that the operator reveal the contents of the fluids to the AER upon request. The AER also requires that the type and volume of all additives used in fracturing fluids be recorded in the daily record of operations for any well. This information must be submitted to the AER.
The AER’s regulatory requirements are designed to prevent any hydraulic fracturing fluid from mixing or entering groundwater or surface water regardless of whether or not it contains toxic chemicals. These requirements include ensuring the use of steel casing and full cementing of the wellbore so that any fluid inside the casing cannot mix with water in the formations through which the well passes. Any produced fluids that are returned to surface, such as hydraulic fracturing fluid and salt water from the producing geologic formation, must be handled, stored, and disposed of under the strict regulations of the AER. No fluids, including those that have been treated, are ever allowed to be released into a natural water body.