Chemical Inhibitors

In many service applications excursions in solution chemistry, temporary loss of inhibitor, or transient increases in temperature may give rise to localised corrosion. To test the return of inhibition when the loss is remedied, the use of an artificial pit has been investigated using simulations of cooling water and of of oil production formation water.

Results of inhibitor performance at slug flow in a 101.6 mm inner diameter horizontal pipeline. Electrochemical Impedance Spectroscopy (EIS) and scanning electrom microscope (SEM) techniques are used to reveal that the strong bubble impact, high shear stress and turbulent intensity are the reasons for a poor performance of inhibitor.

 A novel evaluation technique, based on an artificial pit electrode, has been developed for inhibitor studies. The first example is of three generic inhibitors, against localised corrosion. The second is of three industrial inhibitors against existing localised corrosion on a north sea production platform

A convenient protocol for screening the potential efficacy of scale inhibitors is described. All of the techniques used require relatively inexpensive equipment. Two types of scale are addressed in this paper, calcium carbonate and calcium oxalate, but the general procedures are expected to be applicable to inhibitor screening for others as well.

Pipeline quality gas is normally dried in Triethylene Glycol (TEG).  This paper explores how TEG vapor can exist in a pipeline in a similar manner to water, and possibly lead to corrosion. TEG vapor can condense at long distances down a gas pipeline as the line cools.

The effectiveness of organic commercial migrating inhibitors on steel reinforcements corrosion. Four series of concrete specimens were cast. Two organic migrating inhibitors were applied. Free corrosion potential and corrosion rate of steel rebar were periodically monitored for five years.  Results show that migrating inhibitors are not effective in reducing corrosion rate.

An elbow leak was encountered after 3 years of operation of a carbon steel flow line from an artificial lift (rod pump) well.  Methods for prevention of similar failure are discussed in terms of design and inhibition.

This paper will provide a review of the specific methods for deactivating the various oxidizing and non-oxidizing biocides commonly used today. Examples of lab and field data will be presented.

The Thunder Horse project’s sub-sea flow-lines were installed in 6,000’ water depths and filled with chemically treated seawater. After 2 years, investigations were done to determine continued effectiveness of the chemical treatments. 

In this paper the compatibility of the biocide tetrakis(hydroxymethyl) phosphonium sulfate (THPS) and the oxygen scavenger ammonium bisulfite (ABS) were explored.  Performance testing of both the biocide in the presence of the oxygen scavenger and the oxygen scavenger in the presence of biocide are reported.

 The new passivation mechanism in steam-assisted gravity drainage (SAGD) process is discussed through theoretical approach in this paper.  A corrosion mitigation program was implemented that included the pigging both slug and batch corrosion inhibitors chemistry analysis corrosion rate (CR) monitoring and non-destructive tests.

Previously, precipitation of SI and Ca2+ was investigated. Similar work has also been performed by other researchers. The current paper presents corresponding experimental results where the binding of divalent cations Ca2+ and Sr2+ to 9 phosphonate SIs at pH 8.5, 95oC is investigated.