The Industry Challenge:
Primary recovery from sandstone reservoirs bearing heavy oil in Western Canada often includes producing massive quantities of sand throughout the life of a well.
Early efforts at producing these reservoirs attempted to prevent sand production by using various sand retention strategies but economic oil rates could not be achieved without producing sand.
The process, often referred to as Cold Heavy Oil Production with Sand (CHOPS), involves producing as much as 5% sand by volume continuously.
This volume of sand causes increased well operating costs associated with reduced equipment life due to wear and erosion, production interruptions due to well plugging, and frequent well cleanouts.
In addition, the large volume of sand prevents the use of flow lines due to the risk of plugging, so that the produced fluids and sand must be stored temporarily in lease tanks, and trucked to centralized fluid treating and sand disposal facilities such as salt caverns.
These lease tanks are generally heated to encourage separation of the fine sand from the produced fluids.
Trucking the produced oil and water adds to the operating costs and makes it impractical to operate the wells as they mature and the rate of water production increases.
This limited economic operating life generally limits total oil recovery to less than 10% of the original oil in place. The high operating costs of CHOPS caused by sand handling and disposal plus the high energy intensity due to heating lease tanks and trucking fluids can make primary heavy oil recovery uneconomic in many reservoirs.
How We Help:
C-FER has proposed a process called SuperSump where a small disposal cavern is created below the producing heavy oil reservoir and drainage wells are drilled through the producing zone to intersect the cavern.
This arrangement allows the oil, water and sand to flow by gravity into the cavern, where the sand settles, allowing the oil and water to be produced.
This eliminates all sand handling costs and results in essentially sand-free oil to be produced so that lease tanks can be eliminated and flow lines used to transport the produced fluids to a central facility.
The elimination of heated lease tanks and fluid trucking will also significantly reduce greenhouse gas emissions. The lower operating costs and more efficient transportation of produced water should extend the well life and result in improved recovery.