Abstract
Corrosion inhibitor applied with a tubing displacement technique is used in the Prudhoe Bay field to control corrosion of downhole tubulars. In this application a "pill" of corrosion inhibitor/crude oil mixture is pumped into the tubing and then displaced down the tubing string by pumping crude oil into the tubing. The inhibitor forms a protective film on the tubing wall which protects the tubular until the next treatment is done. Currently there are no reliable methods for predicting film life. Optimizing a treatment schedule based on corrosion monitoring or well corrosion history is very expensive and can easily exceed the cost of the treatments. Fluid velocity is widely believed to be an important factor in the removal of inhibitor films. However, other well characteristics such as water cut could be important. This paper presents the results of a test program aimed at developing more cost effective treatments for the Prudhoe Bay field. Laboratory and field test methods were used to measure the film life of several commercial corrosion inhibitors. These tests also provided some insight into what factors are important in the removal of inhibitor films.
