Water Use, Recycling and Injection
Water is used in many oil and gas related activities from routine drilling to advanced stimulation techniques. The use of water in drilling and servicing a well is vital to many oil field practices. A common water use is for secondary recovery schemes referred to as a “water flood” whereby water is pumped down one or more wells to push or “sweep” the oil out of the reservoir so it can be pumped to the surface from other wells.
One of the main uses for water today is for hydraulic fracturing. This technique is a critical component used in both conventional and unconventional oil and gas activities. Hydraulic fracturing is used to create fractures that extend from a wellbore drilled into targeted rock formations to optimize oil and natural gas recovery. With the realization that advances in hydraulic fracturing techniques were the key to unlocking Canada’s vast unconventional resource potential, water has become a vital fluid for oil and gas development across the country.
Fracture return water is the fluid flowed back to surface after the hydraulic fracturing program is completed and is a combination of the original fracture fluid and the natural formation found in oil and gas reservoirs that is extracted along with the targeted oil and gas resource. The fracture return water can follow a number of different paths, which may include being recycled and used for further hydraulic fracturing, or disposal by injection into deep subsurface formations, through a disposal well. Surface discharge of produced water regulation varies across Canada, but is prohibited in British Columbia. Fracture return water is not introduced into surface waters, such as lakes and streams, and is not introduced into near surface aquifers that are used for potable water supply.