Cyclic Steam Stimulation
How high pressure CSS works
Steam Injection phase
- Steam is injected at high pressure into oil sand formation for several weeks
- Steam heats bitumen (reduces viscosity)
- High steam injection pressures create fissures in formation thereby maximizing bitumen contact and production
Production phase
- Steam injection is stopped and heat dissipates in reservoir (soak)
- Well produced for several months until temperature and production rates decline
Steaming and production cycle is repeated
Why CSS?
- Robust commercially proven technology
- Depositional environment is that of a coarsening up sequence with improved permeability & oil quality towards top of reservoir
- Thin discontinuous minor clay laminations inhibit vertical flow paths, CSS pierces through these
- Absence of thief zones
- Thick continuous capping shale (45m+)
- Comparable commercial producing analogue at CNRL’s Primrose South CSS project
- The right recovery method for our resource
Companies currently using CSS commercially in Alberta:
Imperial Oil (Cold Lake) – 140 mbbl/d (CSS)
Shell Canada (Peace River) – 12 mbbl/d (CSS)
CNRL (Primrose, Wolf Lake) – 80 mbbl/d (approx. 90% CSS, 10% SAGD)
