The challenge
Naphthenic oil is produced from reservoirs in conjunction with natural formation water and injection water used to maintain or increase production. This mixture of oil and water is subject to shearing (pump), and contributes to creating complex and difficult-to-break emulsions that are well stabilised with natural emulsifiers. Naphthenate salts present in the oil are liable to enhance the stability of the emulsion and induce a very thick oil/water interface, thereby exacerbating problems with water-in-oil emulsion and the production of quality water meeting the regulatory oil-in-water specification (< 40 ppm).
The solution: increase the performance with dedicated solutions.
To treat tough emulsions like these and produce high quality water, a demulsifier is injected both at the wellhead and in the process, together with a huge quantity of acetic acid, which is used to fight against the naphthenate salt and related problems mentioned above.
CECA’s Technical Support Team was invited offshore in Africa by an Oil Operator to design solutions to:
- Reduce or eliminate the quantity of acetic acid which was inducing logistics and safety problems offshore
- Improve the quality of the water produced (< 40 ppm oil in water)
- Improve the oil quality (< 0.3% BSW).
Crude oil production is 13,000 m3/day, containing 52% water. The process removes this water first in a three-phase separator (FWKO), and then with electrostatic desalters. An initial demulsifier is first injected at the wellhead. In the process, a second demulsifier as well as acetic acid are injected before the desalter to remove the naphthenate salt interface. The water is then treated with a deoiler before discharge in the environment.
CECA’s Technical Support Team designed a bottle test campaign offshore to allow the formulation of a number of innovative demulsifier molecules. This led to a dedicated product referred to as PROCHINOR CM 5. After testing in our laboratory the stability of the newly-developed formulations, several tonnes of this new customised product were manufactured in CECA’s plant in France.
The benefits:
6 month's later, CECA’s Technical Support Team was invited offshore to run an industrial field test in order to validate the dedicated solutions developed in July 2005 during the bottle test campaign. Several weeks of an industrial offshore application of CECA’s PROCHINOR CM 5 technology achieved the following benefits:
- Very good oil quality (less than 0.1% BSW / better than the target of 0.3%)
- Very good water quality (less than 30 ppm oil in water compared to 150 ppm without CECA’s technology)
- Quantity of acetic acid substantially reduced by a factor of two, thereby improving logistics and safety problems.
Our customer found the CECA PROCHINOR CM 5 technology to be an efficient solution to achieve high quality water and hence environmental regulatory compliance, while allowing the safer production of higher quality oil.
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