Last technology surfactants to oil dehydration process (W/O emulsion) and treatment of associated water to production (O/W emulsions).
Emulsions are difficult to treat and create many operational problems, such as:
The emulsions, dispersed in the mass of the crude, must be treated to remove the water and its associated inorganic salts. It is needed to bring the crude to the storage, transportation, and delivery specifications, as well as, to reduce corrosion and problems in downstream processing facilities.
The emulsions are stabilized by emulsifiers (active surface agents or surfactants) that tend to concentrate at the crude/water interface where they form interfacial films (surrounding the droplet). This generally leads to a reduction of interfacial tension and promotes the dispersion and emulsification of water droplets in the crude.
Emulsifiers can be:
The demulsification is the breaking of an emulsion into oil and water phases.
From the process point of view, the crude oil producer is interested in two aspects of demulsification:
Usually, crude oil cannot contain more than 0.5% BSW and 10 lbs of salt per thousand barrels of oil (PTB). This low content of BSW and salt is required to reduce corrosion and salt deposits, in pipelines and processing facilities.
The demulsification process takes two steps:
Any of these steps can determine the speed of the separation process.
By far the most common method of treating emulsions is through the application of chemical additives called demulsifiers or emulsion breakers. These chemicals are designed to neutralize the emulsifying effect of the agents that stabilize the emulsion.
The demulsifiers are active surface compounds, when they are added to the emulsion migrate to the crude/water interface, break or weaken the rigid film and improve the coalescence of the water droplets.
Selection of demulsifying chemicals
Test procedures for the selection of appropriate demulsifiers include bottle tests, dynamic simulators, and real field tests.
The amount of demulsifier chemical to be applied is also important because very little will leave the emulsion unbroken, however, a very high dose (overtreatment) can be adverse to the treatment process because the demulsifiers are also surfactants such as emulsifiers.
During the treatment of heavy oil emulsions and emulsions produced by tertiary recovery, especially with the injection of surfactants, injection rates can typically reach thousands of ppm in the most extreme cases.
Demulsifiers are generally specific to a given emulsion and may be completely ineffective for another emulsion.
Due to the wide variety of components present in the crude oil, it is not surprising that the effectiveness of a given demulsifier is sensitive to the type of crude oil, the adsorption and displacement process, as well as being dependent on pH, salt content, and temperature.
In SMART FLUID, we continuously develop breaker emulsion additives based on our experience, seeking to adjust to the specific conditions of each type of crude.