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Hydraulic fracturing process

Until late in the 20th century, unconventional gas production was deemed uneconomical, as special well completions were needed to access and extract the resources. Commercial production began on a small scale in the 1980s but did not become significant until the late 1990s/early 2000s with the combined application of two existing technologies - horizontal drilling and hydraulic fracturing.

Before any wells are drilled, extensive surveillance is carried out to study the locations of the underground natural gas reservoir and the nature of the local topography, so as to ensure minimal impact of operations on the local community.

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  • Hydro facility
    1. Preparing for drilling (4 to 8 weeks)

    The first step is to clear the designated drill site area and develop the infrastructure for water and electricity supply for the site.

    A pit is then dug close to the drill site and lined with thick plastic to prevent any potential soil contamination. All the rock, soil and mud removed from the well site can then be placed in the pit to prevent the contamination of the soil and water table.

  • Hydraulic fracturing site in winter
    2. Rig work (4 to 8 weeks)

    Once the infrastructure is in place, the rig is assembled and inspected to ensure it meets all specifications and safety standards. Only then can drilling begin.

    As the well is drilled through a groundwater aquifer, only water is used in the drilling mud. Subsequently, multiple layers of cement and steel casing are used to ensure the integrity of the wellbore and provide an impermeable barrier between the well and the water source. This process is carried out for both conventional and unconventional gas wells.

    Once the casing is properly set, drilling continues vertically until the well reaches the target formation. At this point, the drilling of a conventional well typically ends.

  • Gas coming out from a hydraulic site
    3. Hydraulic fracturing (2 to 5 days)

    In many unconventional wells, however, the drill bit then turns and drills horizontally through the gas-bearing rock. Hydraulic fracturing fluid is then pumped down the well and into the target reservoir, creating small fractures in the rock.

    The fractures are held open by grains of sand that are mixed into the hydraulic fracturing fluid, allowing the natural gas to escape from the tight rock and flow up through the well.

    Hydraulic fracturing fluid is typically comprised of approximately 98 - 99.5 per cent water and sand, and 0.5 - 2 per cent chemical additives. Most of these additives can be found in common household items.

    The chemicals in hydraulic fracturing fluid serve various functions, such as reducing friction and protecting the rock formation, thereby making the hydraulic fracturing process safer and more efficient.

    Hydraulic fracturing is a time-tested, proven technology that has been safely used in more than a million wells worldwide since the 1940s.

  • Hydraulic fracturing site with trees in the background
    4. Producing natural gas (25 to 40 years)

    Once a well is drilled and completed over the course of a few months, it is ready for production. Everything is dismantled except for a one- to two-meter high well-head and the local processing facilities that connect to gas lines that eventually run to the national distribution network. A natural gas well can produce gas for up to four decades, and all the while it’s monitored to ensure continual well integrity.