Hydraulic fracturing, known as fracking, is a technology and process used to recover oil or natural gas trapped in non-porous or “tight” rock formations such as shale – these formations were previously too expensive to produce efficiently.
This process is also called “unconventional” recovery. Hydraulic fracturing is a government-regulated technology that has been used safely for more than 60 years and has more recently been applied to oil and natural gas reservoirs in tight rock formations.
How Hydraulic Fracturing Works
First, the well is drilled vertically. Unconventional natural gas reserves are typically found two to three kilometres below the earth’s surface, hundreds of metres deeper than drinkable groundwater. Once the vertical well reaches the target formation, the well is turned to drill horizontally through the formation. Horizontal drilling can extend through the resource-bearing formation for a kilometre or more.
Near-surface layers including soil and groundwater are protected by steel casing and cement that create a solid barrier between the well and underground water sources. Intermediate casing extends even deeper below any fresh water sources and provides an additional protective layer.
Perforating the Wellbore
Prior to fracturing, the wellbore casing is perforated so fracturing fluid can be forced out of the wellbore and into the rock formation, and so oil or natural gas can flow into the wellbore and be brought to the surface. Perforating causes initial cracks in the formation that are extended during the fracturing process.
Fracturing | Fracking
Fluid comprised of water, sand and a small volume of additives is pumped down the well under high pressure that further fractures the rock after perforation. These fractures extend between 50 and 100 metres from the horizontal wellbore. The sand holds the fractures open to provide pathways for natural gas to flow into the wellbore for extraction. A well is typically fractured once and may produce for up to 20 to 30 years.
IS FRACKING BAD?
Fracturing technology has transformed the Canadian energy market, providing an alternative means to recover oil and natural gas from “tight” rock formations previously uneconomic to develop. While there is nothing inherently bad about hydraulic fracturing, there are concerns around fracturing practices and the potential environmental impacts, specifically around water contamination, fracturing earthquakes and the venting and flaring of methane and other gases.
As well, there are overall benefits. In Canada, hydraulic fracturing is highly regulated and has led to the creation of thousands of jobs, and generates government revenues through taxes and royalties. Fracking also provides a ready source of natural gas for current and proposed LNG projects on Canada’s West Coast.
Hydraulic Fracturing Fluids
About 98.5% of the hydraulic fracturing fluid is water and sand. Additives that provide special properties to the fracturing fluid make up the other 1.5%. Additives are used to limit bacterial growth and prevent corrosion. The make-up of fracturing fluid varies from one rock formation to another.
All additives used must comply with provincial and federal regulations. In Alberta, the Alberta Energy Regulator (AER) regulates the use of water for tight oil and natural gas development. Industry also follows best practices to manage hydraulic fracturing additives including risk mitigation plans in the unlikely event of a spill.
In Alberta and British Columbia, the additives used for hydraulic fracturing must be publicly disclosed, including function of additives used, the trade name of the additive, additive ingredients and the Chemical Abstract Service registry number (CAS number). This information is stored in a public database that can be found at FracFocus.
PROTECTING GROUNDWATER DURING HYDRAULIC FRACTURING
Regulations and industry best practices ensure groundwater resources are protected during hydraulic fracturing.
Drinking water aquifers are usually found at depths less than 300 metres. A well that is hydraulically fractured is typically drilled to a depth of 2,000 to 3,000 metres, far below any aquifers used for drinking water.
All wells are constructed to protect groundwater, using multiple layers of steel casing, which are inserted and cemented in place to create a solid barrier between the wellbore and the water source.
Water Use in Hydraulic Fracturing
Today, industry is focusing on increasing the use of alternatives and reducing the overall amount of surface water and fresh groundwater used in hydraulic fracturing. New hydraulic fracturing technologies developed require less water.
How Much Water is used in Fracking?
The volume of water used in hydraulic fracturing depends on the well specifications and geology. On average, a hydraulic fracturing operation takes 5,000 to 30,000 cubic metres of water. Water may be sourced from surface water or fresh groundwater, or from alternative sources.
Minimizing Water use in Fracking
Industry is focusing on increasing the use of alternatives and reducing the amount of surface water and high-quality groundwater used in hydraulic fracturing and other operations. Low-quality or otherwise unusable sources of water, such as saline groundwater, flowback, produced water and municipal or industrial wastewater, are used where possible. New hydraulic fracturing technologies are also being developed that require less water.
INDUSTRY GUIDING PRINCIPLES FOR HYDRAULIC FRACTURING
Canada’s shale gas, tight gas and tight oil industry supports a responsible approach to hydraulic fracturing and water management, and is committed to continuous performance improvement. Protecting water resources during sourcing, use and handling is a key priority for the industry, which supports and abides by all regulations governing hydraulic fracturing operations, water use and water protection.
In addition to following regulations governing hydraulic fracturing operations, water use and water protection, Canada’s oil and natural gas industry is guided by CAPP’s Guiding Principles for Hydraulic Fracturing and Operating Practices
Industry in Action
An example of industry best practices for effective water management is the work done by Shell Canada. Shell Canada is continually seeking opportunities to reduce fresh water use in its oil and gas operations. Opportunities for reduction are sought through improvements to completion design as well as the use of alternative water sources and water reuse.
In 2014, to support these objectives, Shell and the Town of Fox Creek signed an agreement to allow Shell use of the town’s treated wastewater as an alternative water source in its operations. In return, Shell funded the engineering and design to upgrade the town’s raw water facilities. To date, this alternative source of water has allowed Shell to replace the use of approximately 400,000 cubic metres of fresh water per year in their Fox Creek asset.