Formation of emulsions and sludges

Emulsions and sludges can form as a consequence of incompatibilities between the combined acid, formation fluids, and acid reaction products. Proper planning, additive selection, and fluid-compatibility testing will prevent these damage problems to a great extent. 

Water blocking and wettability alteration are related acidizing damage mechanisms, especially useful in sandstones. In tight formations, water that is introduced to the formation may be retained by capillary forces. Gas or oil production rates may be severely impaired. Proper selection of surfactant additives is necessary to avoid water blocking. This is quite often difficult to assess without the benefit of core flow testing with a representative formation core. 

In most cases, though, proper additive selection will greatly reduce the potential for water blocking. Water blocks may be removed by subsequent 

Aqueous treatments exist as well. Water (or brine) containing a surfactant and mutual solvent or alcohol may be effective in removing water blocks. 

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The presence of water in turbine systems tends to lead to the formation of emulsions and sludge containing water, oil, oil oxidation products, rust particles, and other solid contaminants that can seriously impair lubrication. The lubricating oil, therefore, should have the ability to separate from water readily and to resist emulsification during passage of steam into the oil until... 

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