Use of foams in petroleum and gas industries

An important and perspective application of foams is its use in petroleum and gas industries in drilling wells, in developing oil pools, in cleaning out wells from sand cork [142-148], in foam enhanced oil recovery (EOR) from underground formations [149-154]. 

EOR process requires a detail study not only of foam behaviour in porous media but also of the options to control it. Foam flow in porous media during EOR is a complex, multifaceted process. A number of papers are dedicated to that topic, including some reviews [e.g. 13,14,18] which describe the experimental set-up used in the study of foams in porous media. We will focus on those illustrating the efficiency of EOR from oil pools and the role of some important factors, involving the effect of foam properties, especially of the critical capillary pressure. 

The studies indicated that for all foaming agents the efficiency of oil recovery increased with the rise in foam quality. The authors explained this with the apparent viscosity of the foam. The analysis of other studies of the same authors showed that similar increase was observed in unconsolidated porous media with high porosity (0 0.35) and high permeability (K 10 mm2). For consolidated pores with low porosity (0 0.25) and low permeability (K 0.2 pm2) a decrease in oil recovery with the increase in foam quality occurred. 

The presence of salts (10% NaCl and 1% CaCh) and petroleum strongly accelerate foam decay, leading to decrease in gas permeability [161]. The increase in permeability due to crude oil depends significantly on the type of the foaming solution. For a more stable foam the decrease in permeability is much less and the foam action pertains for over a month without continuos injection of the agent [161]. 

Foam mobility has been proven to be strongly dependent also on bubble size and bubble distribution by size (foam texture) [162,163]. The latter is affected by the dispersion technique used, solution concentration, etc. (see Chapter 1). 

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