Development of a Test Protocol for the Evaluation of Underdeposit Corrosion Inhibitors in Large Diameter Crude Oil Pipelines

Pipelines carrying heavy crude oil from oil sand developments may be subject to corrosion caused by deposition of oil sand sediments, a sludge containing oil, water, and bacteria in a particulate matrix.  A standard testing protocol was developed with the participation of five inhibitor vendors.  The test protocol includes inhibitor evaluations based on (1) Filming Effectiveness, (2) Partitioning Studies, (3) Sludge Corrosivity and Inhibitor Tests, and (4) Bacterial Kill Studies.  The results of the different tests and the relevance of each test with regard to the application are discussed.  A successful bacterial kill test approach was established.  Initial exposure tests of coupons covered with inhibited sludge in oil are most representative of the pipeline environment, but results were variable.  Improvements to the test procedure are presented and explored.