Shallow gas fracturing is very prevalent in Western Canada. Several thousand wells are typically drilled and completed in the shallow gas fields every year. All these wells are typically hydraulically fractured. Prior to 1999, after testing for micro-toxicity, the flowback fluid was allowed to be land farmed in Southeastern Alberta. In that year, the Alberta Energy and Utilities Board began more stringent enforcement of Guide 58, which required that flowback fluid be disposed in a disposal well. More recently, several years of drought conditions in the shallow gas areas of Southeastern Alberta have caused water shortages.
Prior to 1999, the flowback from a particular surfactant-based fracturing fluid could be successfully land farmed. One operator typically had a project of 300 to 400 wells with an average of 5 fracs per day during spring/summer. When the fluid could no longer be land farmed, attempts were made to recycle the flowback fluid. The chemistry of the surfactant gel fluid was insensitive to the water quality, which made the recycling concept successful. Several cost advantages were achieved, which will be detailed in the paper. These included fresh water costs, disposal costs and chemical costs. An additional advantage that was realized involved a 50% reduction in the fresh water requirements for a project.
The paper will detail the chemistry of the fracturing gel, its field application, the optimized recycling operation and the details on cost advantages achieved as well as future direction for further reduction in fresh water usage on a project basis.