What are the main methods currently used for dehydration and desalination in oil fields?
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I would appreciate some guidance from experts: I want to know the main methods used to remove water and salt from crude oil produced in oil fields at present, as well as the advantages and disadvantages of each method.
Generally, electrical dehydration and desalination are used; there are other methods as well, such as centrifugal dehydration and desalination, but they are expensive and are only used at sea, as the equipment for electrical dehydration and desalination is quite large.
For ordinary light oils, a three-phase separator is generally used, along with one or two stages of thermochemical dehydration； For EOR produced fluids, some use a two-stage three-phase separator for dehydration, while others employ one-stage thermochemical dehydration followed by two-stage electrical dehydration ； For heavy oil, large-tank sedimentation dehydration, electrical dehydration, or dehydration by dilution with light oil are generally used; there are also advanced technologies that employ one-stage or two-stage dehydration using three-phase separators.
Oil fields only remove water, not salt. Thermochemical precipitation is mainly used, while electrodeposition is increasingly less utilized