Wells are designed to protect fresh water sources.
Today, most natural gas wells are drilled at a depth of between one to four kilometres below the surface (2,000 to 3,000 metres). Drinking water aquifers are typically located less than 18-150 metres from the surface.
Natural gas wells are constructed to protect our water
Wells are designed and constructed to ensure underground water sources are protected. When a natural gas well is drilled, multiple layers of steel casing are inserted into the full length of the well and cemented in place. This creates a solid barrier between the well and any underground fresh water sources. With multiple layers of steel casing and cement in place, the ‘integrity’ of the well should be not be compromised.
Regulations are in place to ensure a well is properly engineered to maintain its integrity over its full lifecycle. Industry uses several tools to assure the quality of and proactively monitor the steel casing and cement for early detection of degradation including:
- Production packers - create a seal between the well and the casing
- Corrosion logs - identify pits, cracking, holes in the steel casing
- Cement bond logs - measure the bond between casing and the cement determined by acoustic sonic and ultrasonic tools
- Production log tools - record casing thickness and whether the casing has undergone any corrosion
SOUND WELL CONTRSTRUCTION IS THE KEY TO PROTECTING GROUNDWATER
- Understanding Well Construction
- CAPP’s Operating Practice: Wellbore Construction and Quality Assurance
The Alberta Energy Regulation has strict requirements for well construction:
- Directive 008: Surface Casing Depth Requirements
- Directive 009: Casing Cementing Minimum Requirements
- Directive 083: Hydraulic Fracturing - Subsurface Integrity