A European based E&P Operator approached Aubin for support as they were experiencing difficulties sourcing a REACh compliant pH responsive emulsification additive.
The Operator’s technical specialists were keen to improve upon the performance of non inhibited HCl acid stimulation treatments by deploying an inhibited emulsified acid fluid system. The key to this was to source an effective emulsifying agent.
Recognised for our specialist technical knowledge, speed of delivery and diverse portfolio, Aubin was requested to review the challenge and propose a suitable additive.
The Challenge
Our client required a stable HCl in light condensate emulsion to inhibit the rapid spending of acid when in contact with the formation. This delay would promote the propagation of an extended network of wormhole penetrations along a lengthy perforated interval and increase injectivity rates.
SAE-05 needed to be readily soluble and create an emulsion that would remain stable for a period upto 60 mins and be effective upto temperatures of 100 deg C.
Typically 50m3 to 100m3 of emulsified acid would be pumped per well during stimulation operations. Although the fluids could be prepared in advance of pumping, it would be beneficial if the fluids could be mixed on the fly.
What Happened?
Additive SAE-05 was specifically developed to effectively emulsify HCl (15-28% concentration) in light condensates and crude oils and is REACh compliant. It has excellent compatibility and thermal stability characteristics and was therefore recommended to the Operator for their internal evaluation.
SAE-05 is an amine-based proprietary surfactant mixture that is added to light hydrocarbon phases prior to mixing with aqueous acid. The resultant low pH environment causes the amine to protonate and increase polarity to form stable, structured emulsions between hydrocarbon and aqueous phases.
A sample was prepared and forwarded to the customer within the week.
The Result
Significant injectivity improvements upto 70% were achieved compared to uninhibited acid matrix treatments.
SAE-05 was fully compatible with all other additives used in the system and the emulsion was seen to be stable for over 60 mins.
An added benefit that was observed was that the excellent solubility characteristics of SAE-05 also supported the ability to blend the fluids on the fly.
Our client was delighted with the performance and has confirmed that SAE-05 will be the default emulsifier for ongoing operational requirements.
