Foam injection processes

A major challenge is the proper selection of foam-forming surfactants. 

Results from field testing have suggested that foams may achieve lower gas mobility reductions than anticipated because of the defoaming action of residual crude oil [120], which has led to an interest in the formulation of oil-tolerant foams. Although crude oils tend to act as defoamers, it turns out that foams actually exhibit a wide range of sensitivities to the presence of crude oils, as discussed in Section 5.6.7. Overall, it is clearly possible to make foams 

Good solubility in the brine at surface and reservoir conditions 

Good thermal stability under reservoir conditions 

Strong ability to promote and stabilize foam lamellae 

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For cyclic steam-foam injection, it is important that the foam breaks down in the presence of oil or after prolonged exposure to high temperature. In this way, the resistance to the flow of production fluid will not be substantially increased. A concern with a cyclic foam injection process is that the low mobility foam will displace oil further (as compared to steam-only injection) from the well during the injection portion of the cycle. The oil will then have a greater distance to flow to the well during production. Thus, initial water cuts may actually increase in cyclic steam-foam tests (26). The oil recovery may also be low initially but then increase to a level higher than that obtained from a steam-only cycle. 

Foam Injection Processes. Foams can be injected in to a reservoir for mobility control or for blocking and diverting. The foam can thus act to reduce the effects of ... 

Structural foams are made of a cellular core with a dense skin. The technique is used for industrial and aesthetic goods for the automotive, electronics, household appliance and aeronautics sectors, such as housings of machines, TV cabinets, computer housings, roofs for caravans or ships, hard tops of 4WD (Jeep), luggage boxes, parts for washing machines. Structural foams are processed by thermoplastic injection moulding using ... 

Foam sandwich has seemed for many years to have had much to offer, and yet has rarely been exploited commercially. Details are given of how a foam sandwich bootlid for the Ford Escort CE14 Cabriolet was designed, manufactured and tested. During the project, much was learned about the injection process as well as the properties and failure modes of composite foam sandwich panels. 

To safeguard future operations, additional reliability was built into the design of the permanent anti-foam injection unit. This included separate power supply sources ior the running and standby injection pumps with low-flow arid pump-failure alarms in the process control room... 

Polydispersity. If a liquid is injected into polydisperse cellular foam (a process which decreases the foam multiplicity) until the foam becomes spherical with the same size distribution of bubbles, then the obtained spherical foam is said to be equivalent. The equivalent foam is characterized by the multiplicity called the minimum multiplicity Kmjn. Obviously, the minimum multiplicity of polydisperse foam is larger than that of monodisperse foam, since in gaps between densely packed spheres of the same largest size, spheres of smaller sizes can be located. Thus the value K a can be used as a quantitative measure of polydispersity [214], While K a = 3.86 for monodisperse foam, for actual polydisperse foam we have 10 to 15 in practice Kma never exceeds 20 [480],... 

Emulsification—imbibition greatly increases the oil—aqueous contact area in the foam and is possibly an important process when constant quality foam injection into waterflooded media at residual oil saturation is practiced, and when the amount of interfadal area constituted by pseudoemulsion films is a rate-determining factor for foam sensitivity. This emulsification—imbibition can act in favor of or against foam stability, depending upon whether the pseudoemulsion films, once formed, are quite stable or quite unstable. 

Application of Foams. Foam injection is a simple addition to a steam process. It basically requires a surfactant storage tank or drums, a surfactant pump, a gas compressor, and methods of measuring surfactant-injection rates(e.g., changes in liquid level) and gas -injection rates (e.g.,... 

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