Wettability alteration & gravity drainage by surfactants: Depleted reservoir pressure would be low with non-zero gas saturation. Increase reservoir pressure during the injection of surfactant solution. Produce at high back pressure. Compression of gas imbibes surfactant solution into the matrix, decreases the distance/time for diffusion.
- Traditional surfactant processes were aimed sandstone reservoirs; the new process is for fractured carbonates
- Traditional surfactant processes were aimed for tertiary recovery
- Target oil saturation ~ 0.3 PV (Current target ~0.5-0.7)
- Oil recovery ~ 0.2 PV (Target recovery ~ 0.3-0.4)
- Surfactant concentration: Traditional 1-5 wt%(0.05 - 0.1 wt %) & Surfactant slug – 0.2 PV (1PV)
- Flow process vs. gravity drainage process: slower process
- Decrease in diffusional barrier by compression of gas leads to faster oil recovery
Chemical manufacturers, oil recovery equipment manufacturers.