Tertiary Recovery

The movement and accumulation of oil by ASP

The addition of chemicals allows the oil to coalesce and flow through the reservoir pore structures, increasing reservoir recovery factors.

 

 

Tertiary, or enhanced recovery, typically involves the injection of chemicals or other fluids to improve oil production and increase the amount of oil that can be recovered by secondary recovery methods. At our Little Bow property, we are preparing to implement an Alkaline Surfactant Polymer (“ASP”) tertiary flood.

How ASP works

With an ASP project, chemicals are diluted in water and then sequentially injected into a reservoir. This sets up a process that is very similar to how typical household cleaners deal with grease, dirt and grime. Alkali is the base for typical household liquid or crystalline drain cleaners.

The Alkali also preconditions the reservoir preventing the surfactant from being absorbed by the rock. When the alkaline solution contacts certain types of oil, a chemical reaction occurs that creates a small quantity of surfactant. The surfactant works to reduce the surface tension between the oil and water. (We see this same ‘cleaning’ reaction when washing dishes at home). The reduced surface tension allows small oil globules to coalesce and flow through the reservoir pore structures.

The final chemical, polymer, is added to water and injected into the reservoir. The polymer thickens the water (same consistency as maple syrup) which then helps push the oil through the reservoir to producing wells. The final stage is another flush from water injections, essentially rinsing the remaining mobile oil from the reservoir.

ASP tertiary flooding can only be used in selected reservoirs.  The candidate reservoirs should have thick oil columns with limited water legs or gas caps and must also have superior flow capacity (measured as permeability). The reservoir oil must have certain specific chemical and flow properties such that the chemistry of ASP will mobilize the oil. Also, because of the overall project costs, a minimum resource size is required to support the implementation of ASP.

Learn more about our ASP project at Little Bow