Water is an important part of oil and gas development.
How water is used in unconventional oil and gas developmentWater plays an important role in unconventional oil and natural gas development. When a well is drilled, water is added to the drilling mud to help move rock and rock chips away from the drill bit and to keep the drill bit cool. If the natural gas and oil trapped in the rock cannot flow easily to the surface, the well is “completed” with a hydraulic fracturing operation, which uses large volumes of water.
Once a well is producing, large amounts of water are no longer needed, but some water may be used on site for other secondary purposes such as dust control or washing equipment. Water is also used for construction purposes such as freezing winter roads.
How is water used in hydraulic fracturing?After a well has been drilled, a mixture of mainly water and sand, and a small amount of additives, is injected into the well at high pressure to create tiny, finger-like fractures in the rock. The fractures are propped open by the grains of sand so that the oil or natural gas can flow to the surface. The additives each perform a specific purpose such as to limit bacterial growth or prevent corrosion. Alberta and British Columbia regulations require producers to publicly disclose the additives used in hydraulic fracturing on a well-by-well basis.
How much water is used in hydraulic fracturing?The amount of water used to hydraulically fracture a well depends on the well specifications and the geological formation of the well but on average, a hydraulic fracturing operation takes 5,000-30,000 cubic meters of water. In some cases (exploration or early field development), this water is sourced from surface water or fresh groundwater, and in other cases (in full-field development scenarios), water is sourced from alternative sources such as saline water, non-potable groundwater, flowback, produced water and municipal or industrial waste water.
According to the British Columbia regulator, the Oil and Gas Commission (OGC), an average of 13,000 cubic metres of water was used per well hydraulically fractured in 2014. To put water used in natural gas development into perspective, OGC data shows that water withdrawn for natural gas development is small compared to the total amount of water available in northeastern B.C. In 2015, 0.004 percent of the annual runoff in that part of the province was used for water licenses and short-term approvals. (Source: BCOGC Annual Report, 2015).
Reducing water useReducing the amount of surface water and fresh groundwater used in hydraulic fracturing is a priority for industry. There are several approaches to reducing fresh water use including:
- using alternative, low quality or otherwise unusable sources of water such as saline groundwater
- reusing produced and flowback water in subsequent hydraulic fracturing operations
- sharing sources of water in multiple operations or with other operators
- working with communities to use treated municipal wastewater
- investing in research to develop hydraulic fracturing technologies that require less water
An example of industry best practice for effective water management is Shell Canada’s efforts to reduce its overall fresh water footprint by using municipal wastewater as the first priority water in its operations. In late 2014, Shell entered into an agreement with the Town of Fox Creek to use the town’s treated wastewater in its completions operations. In return for the use of the water, Shell funded the engineering and design to upgrade the town’s raw water facilities. This alternative source of water is a key component of Shell’s overall water strategy in the Fox Creek area and replaces the use of about 400,000 cubic metres of fresh water a year.