Use of micelle detection for Corrosion inhibitor screening

Corrosion inhibitors, applied to mitigate internal corrosion across oil and gas production systems, are subjected to a series of corrosion mitigation and secondary properties tests to determine the most suitable candidate. A balance is sought between the product which is most effective for preventing corrosion and that which does not contribute to unwanted effects of dosing such a product, including: emulsion tendency, foaming tendency, water haziness, etc. The process of determining the most suitable candidate may begin with simple corrosion rate testing, these tests are routinely sequentially dosed and the candidates which show the best inhibition at the lowest dose are advanced to secondary property testing. Due to the nature of sequential dosing, this dose may be higher than the true optimal dose. This could lead to candidate inhibitors being applied above this dose, leading to false failures in the secondary property testing phase and otherwise good candidates being dismissed. This paper describes a method of exploiting the critical micelle concentration (CMC) of the corrosion inhibitors to show that the use of CMC can be used as a laboratory screening method for corrosion inhibitor selection.