RESOURCEFUL APPROACH
HYDRAULIC FRACTURING
As Canadians expect a transition to a less carbon-intensive energy future, partnering becomes an essential piece of the renewable picture.
Natural gas is the cleanest-burning hydrocarbons, making it an ideal partner to intermittent renewable options. It offers a reliable energy source during periods when intermittent renewable energy sources, such as wind and solar, are unable to provide adequate capacity, and it can be used to reduce greenhouse gas emissions in a variety of ways, including transportation and electricity generation.
“Renewables almost always need a partner,” says Kevin Heffernan, president of the Canadian Society for Unconventional Resources, a Calgary-based not-for-profit organization.
“I believe that natural gas is a foundation energy source for the shift to a renewable future.”
Canada is the world’s thirdlargest producer of natural gas, and natural gas provides almost one-third of the energy used by Canadians. Based on current demand levels, Canada’s natural gas resources are estimated to last for at least the next 100 years.
Over the past decade, the share of natural gas production from unconventional reservoirs has been increasing.
Natural gas trapped in unconventional formations is typically located two to three kilometres below the Earth’s surface and thousands of metres below drinking water aquifers. Drinking water aquifers are typically found less than 300 metres below the surface.
Available technologies, including hydraulic fracturing, are continually adapted to safely and economically produce natural gas from these challenging geological formations.
While many believe hydraulic fracturing is a new technology, it has been used to recover natural gas and oil from geological formations including unconventional reservoirs for decades. In fact, the first commercial use of hydraulic fracturing took place in 1949.
Over the course of the past 60- years- plus, more than 175,000 wells have been hydraulically fractured in Canada, including in Alberta, British Columbia, Saskatchewan, Quebec and New Brunswick.
“About 85% of current oil and gas activity in British Columbia, and 70% in Alberta, involves hydraulic fracturing. It is a common practice in the industry,” Mr. Heffernan says.
Hydraulic fracturing uses water-based fluid which is injected at high pressure to create new, or to connect existing, cracks in the rock.
In most instances the fluid contains sand used to hold the cracks open. This allows natural gas to flow more easily from the rock formation to the well. When hydraulic fracturing is completed, the fluid is recovered for reuse or disposal.
Once well has been hydraulically fractured, it can typically produce natural gas for up to 30 years without having to be hydraulically fractured again.
The Canadian natural gas industry is one of the most regulated in the world. In addition to regulations specific to individual provinces, all have laws to minimize impact, protect freshwater aquifers and ensure responsible development. That said, public concerns remain around environmental risk, water use and chemical additives used in hydraulic fracturing.
To address these concerns, and as part of its commitment to continuous performance improvement, the Canadian Association of Petroleum Producers (CAPP) and its members recently developed a series of operating practices for hydraulic fracturing.
Implementation of these practices in 2012 will be reported for the first time in the annual CAPP Responsible Canadian Energy Report, scheduled for release at the end of 2013.
In addition to groundwater testing, fluid handling and seismic assessment, CAPP’s operating practices for hydraulic fracturing address water use, wellbore construction and the disclosure and risk assessment of chemical additives used in the process.
WATER USE
One of the most contentious issues in hydraulic fracturing is the amount of freshwater used. A major goal of the oil and gas industry is a reduction in freshwater required per barrel of oil or volume of natural gas it produces.
To that end a water sourcing, measurement and reuse practice has been implemented by CAPP to safeguard surface water and groundwater quantity by assessing and measuring water sources, monitoring for sustainability and publicly disclosing water use data.
New methods for the use of non-potable water sources are also helping to lower freshwater use, says Markus Ermisch, spokesperson for CAPP.
In particular, the use of saline groundwater from deep aquifers is reducing the use of freshwater at operations in northeastern B.C.
WELLBORE CONSTRUCTION
Sound wellbore design and construction are critical to ensure an impermeable barrier exists between the wellbore and the surrounding geology, including aquifers.
Every wellbore has an engineered steel casing system that is cemented externally, to prevent any fluids from migrating from the wellbore to groundwater aquifers. In the unlikely event that a wellbore is compromised, remedial plans to restore its integrity are developed for each location.
CHEMICAL ADDITIVES
Hydraulic fracturing fluid is typically more than 98% water and sand, and less than 2% chemical additives. Chemical additives are used to suspend the sand evenly throughout the fluid, ensure the fluid flows evenly and with limited friction, and reduce bacterial growth in the wellbore.
CAPP members have committed to publicly disclose additives used in hydraulic fracturing fluid. The disclosure includes the trade name, general purpose and concentration for each ingredient used. Information is posted on the operator’s website or that of a third party.
In British Columbia and Alberta, additives are disclosed through the publicly accessible chemical disclosure registry at fracfocus.ca.
“We must be transparent about our operations and the processes that we use,” Mr. Ermisch says. “The public deserves to know this information.”