Subsurface foam injection

Tank Farm Liquid Spill Gas Release NFPA30 1. Hydrants 2. Monitors 3. Water Deluge Cooling Spray 4. Subsurface Foam Injection 5. Foam Topside Delivery 1. NFPA 24 2. NFPA 24 3. NFPA 15 4. NFPA 11 5. NFPA 11... 

The foam concentrate used with subsurface systems should be a fluoroprotein type for best results, although some AFFF foams are listed for substitutable application (because of their "fuel shedding" properties). The minimum foam solution rate should be 0.3 gpm/ft (12 Ipm/m ). The supply of foam liquid should be adequate to operate the system for 20 minutes. The foam injection point must be above the level of any residual water in the bottom of the tank. Subsurface foam application is not recommended for open or covered floating roof tanks or cone roof tanks with internal floating covers. 

Not all foam systems can be tested. There are some conditions where discharge of foam in the protected area during testing is undesirable, such as for subsurface injection or placing foam on an internal floating cover. 

The reports of the enhanced oil recovery projects concluded that the reservoir heterogeneities is the most frequent cause for failure of enhanced oil recovery processes which involve foam and surfactant flooding. It was deserved that the reservoir heterogeneity was much more dominant than expected. Geologic and permeability heterogeneities were the most probable cause of the low recovery efficiency realized by Goodrich and Watson The wettability of the pore surface affects the recovery efficiency, but this effect is poorly understood because it is almost impossible to determine which portions of the surface are oil-wet and which ones are water-wet in the subsurfaces. The wettability of the reservoir rocks can be influenced by the injection of surfactant solution for foam flooding. 

---