Attempts to Improve the Performance and Biodegradation of Kinetic Hydrate Inhibitors–More Lessons Learned

Kinetic hydrate inhibitors (KHIs) have been used for over 25 years to prevent gas hydrate formation in oil and gas production flow lines but are some of the most expensive oilfield production chemicals. The main component in industrial KHI formulations is one or more water-soluble polymers with many amphiphilic groups. In our quest to develop improved and more environmentally acceptable KHIs for practical use in the oil and gas industry, we have carried out several projects that in our hands, only led to partial success. However, as with most laboratory research projects, useful data have been obtained, and some important lessons have been learned. These lessons can be helpful in several ways. First, to understand the scope and limitations of chemicals that could be used as KHIs, from a performance, environmental, or practical application viewpoint. Second, to highlight mechanistic aspects of KHI theory. Finally, the work may help inspire others to develop related, but more successful, research projects. In this paper, the results of five partially successful KHI research projects are presented and explanations given as to why each of these projects was undertaken, the results obtained, and the lessons learned. Four of the projects concern new classes of polymer, and the remaining project describes what was hoped to be a new class of nonpolymeric synergists for KHI polymers. All new KHI products were investigated for their performance in high pressure multiple steel rocking cells using a synthetic natural gas blend (76 bar) and the slow (1 degrees C/h) constant cooling test method.