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Water is used for various stages of unconventional gas development. It is used during geophysical exploration, for washing equipment, to freeze winter ice roads, for dust control, for drilling wells, as part of the hydraulic fracturing injection process and for hydrostatic testing of pipelines.
During the hydraulic fracturing stage of unconventional gas development, water is mixed with sand and chemicals and pumped down the wellbore. Fractures are then created in the target formation, allowing natural gas to flow up the wellbore.
The BC Oil and Gas Commission (Commission) has delegated authority to issue short-term water use permits under Section 8 of the Water Act. The Commission looks at a number of key points when reviewing water applications, such as runoff levels in rivers, other users and ecological values of the area. Community and ecological needs must be able to be sustained before a permit is issued and conditions may be attached to the permit. The Commission is a proactive regulator with the authority to intervene when necessary.
In most river basins, the total approved short-term water use is a fraction of the mean annual runoff. In 2012, 3.77 million m3 of water was reported as used. The water reported as used was 18.5 per cent of the total approved for use in 2012.
The volume of water used per well ranges from 10,000 to 70,000 m3 depending on the targeted formation. For the majority of basins, approved water use corresponds to less than 0.2 per cent of mean annual runoff. Actual water use as reported by the approval holders in individual basins is a small fraction of the approved water use, and was less than 0.075 per cent of mean annual runoff in all river basins between January and December 2012. Basins with the largest total approved water volumes as a percentage of mean annual runoff are listed in the Annual Report on Water Use in Oil and Gas Activities.
Provincial laws outline how the oil and gas industry must ensure water resources are protected during drilling and production operations. A number of measures are required to protect the water supply such as setbacks to maintain distance between water wells and drilling operations. Pressure-tested steel casings are cemented in place to prevent hydraulic fracturing fluids from migrating into freshwater aquifers, and the integrity of the casing can be evaluated to ensure it is maintaining an impermeable barrier. There has never been an instance of groundwater contamination due to hydraulic fracturing in British Columbia.
The water table is in most cases thousands of metres above unconventional gas target zones. Potable water is found between 18 and 150 metres down while unconventional gas target zones are typically at a depth of 2,000 to 3,200 metres.
When the well is no longer being used it is plugged with dense impermeable cement. The casing is cut off below ground and the well is capped.
Provincial laws ensure produced water never comes into contact with the environment. Currently, about 40 per cent of produced water is reused in hydraulic fracturing operations. Produced water is disposed of in deep injection wells or stored temporarily, both which are subject to strict regulations.
To ensure river and lake levels are conserved for community water supplies and fish and aquatic resources are not impacted, the Commission can and does issue suspensions of short-term water use by the oil and gas industry during drought conditions.
Currently, 65 per cent of water used for oil and gas activities comes from surface water such as lakes and rivers. The remaining 35 per cent comes from recycled water such as flowback fluids from operations or deep groundwater aquifers located more than 800m below the surface. Some water comes from shallow groundwater aquifers between 0-200m underground.
There is an abundance of water in northeast B.C. but it needs to be managed carefully, for example by halting industry water withdrawals during periods of seasonal low flow and drought as the Commission did in both 2010 and 2012. The Commission has also launched hydrology modelling for Northeast B.C. and created a tool that gives water license and permit decision-makers access to stream flow data, water approval data and recognizes water availability for every river or lake in Northeast B.C.
The Commission publishes an annual water report and quarterly water data. The latest quartlerly water use summary can be found here. The 2012 Annual Report on Water Use in Oil and Gas Activities can be found here.
For each basin, the mean annual discharge and runoff are listed. A list of current Section 8 permits is also available on www.bcogc.ca and is updated daily.
The Northeast Water Tool provides information for decision makers on current stream flow data and other water approvals. http://www.bcogc.ca/northeast-water-tool-newt
If you have further questions about water use for oil and gas activities in B.C. or the Commission in general, please email email@example.com.