Nov-2022

Sulzer’s VIEC technology provides the solution with single-stage early separation

The principle of “easiest first” applies as much in the oil industry as in most other enterprises. This in no more evident than in the state of the reservoirs that are currently being produced and even more so in future production.

Article Summary

The low hanging fruit of easily producible reservoirs is depleting ever-increasingly and what remains are mature reservoirs with high water content and/or a high tendency for forming stable “emulsions” of water-in-oil that are difficult to separate by conventional means in three-phase production separators. These challenges dictate the use of new and innovative solutions.

Sulzer Chemtech Norway has developed a unique separation technology that is ideally suited for this task. VIEC™ (Vessel Internal Electrostatic Coalescer) is a technology comprising of a system of advanced separator internals that utilizes high-voltage and high frequency electrostatic fields to promote and accelerate separation of water-in-oil emulsions in three-phase production separators. It has unique patented features that ensure that optimal electrical field distribution is maintained over the emulsions to enable the most efficient separation effect. The design and materials of the internals have been developed specifically to tolerate very high water content while maintaining efficient electrical field distribution. This makes the VIEC technology ideally suited for addressing and resolving the above-mentioned challenges.

The Middle-East sees no exception to the increasing separation challenges despite its abundance of crude oil supply. In light of this, Sulzer’s VIEC technology has been selected by one of the major oil producers in the region to debottleneck several existing production facilities. Being a field proven technology for close to twenty years and having a comprehensive track record with 54 installations for all the major oil producers, VIEC is the natural technology of choice for the operators.

A total of eight production facilities were chosen for retrofitting with VIEC technology. These facilities had been in operation for several decades and have been producing a combined total liquid rate of more than 1.5 million barrels per day. In the later years, the water content of the inlet feed started to increase rapidly and was expected to reach values up to 75% within short time. Combined with a low process temperature of down to 10 °C, the high water content was expected to give rise to inherently more stable emulsions. The existing mature production facilities cannot cope with the increased water cut and stable emulsions.

To prevent overloading of the existing facilities, with a corresponding negative impact on oil production rate, a solution was designed utilizing Sulzer’s VIEC technology. The solution consists of a single-stage separation unit installed upstream of each of the eight existing production facilities. It uses a single three-phase separator with VIEC technology for enhancing the separation and removing excess water without need for additional heating or increased chemical consumption. The target was to reduce the water content of the inlet feed from up to 75% down to a guaranteed value of less than 15%, which is then routed to the existing facilities for further treatment.

The VIEC systems were started smoothly with no reported issues and the ensuing performance achieved proved the VIEC solution to be an unconditional success. The field results show that the technology is delivering a crude oil outlet stream averaging approximately 1% water-in-oil at the lowest temperatures, as opposed to the target value of less than 15% water-in-oil. Furthermore, the same was achieved with a high liquid flow rate of approximately 200 000 barrels liquid per day per each production facility with water cuts up to 75%.

An additional benefit of the excellent performance of the VIEC systems was that the operator was able to reduce the consumption of demulsifier chemicals by more than 80% and still maintain better separation than the target. This represents a major environmental benefit as well as economic benefits for the operator in terms of reduced operating costs.

The VIEC success story allows the operator to safeguard the oil production and also enables future increase in line with its stated strategy. It also places Sulzer in a favorable position to supply similar solutions in the future, both in the Middle East region and to the rest of the oil producing world.

For details about the VIEC system, please see the following link: https://www.sulzer.com/en/shared/products/vessel-internal-electrostatic-coalescer