What is a flowing artesian well?
Artesian aquifers are often encountered when drilling wells. An artesian aquifer is a confined aquifer containing ground water under pressure. When the artesian zone is encountered the water level will rise in the well to a level above the point it was encountered. If it is a flowing artesian well the aquifer is under enough pressure to force the water up and out of the well. Some flowing artesian wells can seasonally flow depending on the time of year or demand on the aquifer. Other wells can flow year round sometimes with considerable pressure and volumes.
Flowing Artesian Control
Our groundwater resources are finite and need to be protected. Uncontrolled flow from a well can cause erosion, flooding, property damage and even ground subsidence or sinkholes to form. A flowing artesian well discharging to waste can also impact neighbouring wells, reducing their capacity and in some cases rendering them no longer productive.
Recent changes in provincial regulations require that all flowing artesian wells are controllable. This means the well needs to be constructed in a way it can be shut in and able to withstand the pressure of the aquifer without leakage. If a well isn’t constructed properly this can be problematic as shutting the well in may cause uncontrolled flow around the outside of the casing.
Flowing Artesian Experience
The geology in the areas we operate is highly variable and we encounter dozens of flowing wells every year. Some of the wells we’ve worked on have had artesian flows of over 500GPM and well head shut in pressures over 20psi. Most of the time these conditions can be expected and planned for but an experienced drilling contractor needs to be ready to implement the appropriate measures when flowing artesian conditions are encountered unexpectedly.
Drillwell has extensive experience controlling and closing flowing artesian conditions. Our management team has over 100 years of drilling experience, a P Eng, and a senior partner who is a member of the British Columbia Ground Water Association (BCGWA) Flowing Artesian Well Working Group. We’ve developed effective tools and techniques to deal with these variable conditions and have successfully completed challenging programs throughout the province.
One recent program completed directly for the Provincial Government was nominated for Premier’s award. The program involved closing a well in Westwold that was drilled by others and was flowing at 500GPM creating concerns about damage to the adjacent Highway. A relief well with shut in pressure of approx. 30’ above grade was constructed and the uncontrolled well was permanently decommissioned on time and under budget.
BC Groundwater Association Presentation: