High pressure high temperature resistant coatings

Due to rapid depletion of oil reserves, the oil and gas industry is gradually shifting focus towards High Pressure High Temperature (HPHT) wells for extraction of crude oil and natural gas. Unlike ordinary oil wells, extremely high pressure and high temperature conditions are required in HPHT wells. Anticorrosive coatings are generally applied as linings inside metal equipment such as downhole piping and pressure vessels to protect metal substrates against corrosion.

While the general presence of moisture and other chemicals deteriorate coatings, the introduction of higher pressure and higher temperature will lead to accelerated break down of the coating system and corrosion of the steel substrate. The typical maximal dry service temperature of e.g. epoxy linings is approximately 180 to 200 °C. In addition to this, rapid decompression imposes high stress on the internal lining.

Prevention of coating break down under these extreme conditions calls for more optimized and efficient formulation of coatings. Only very limited data is currently available regarding the degradation of anticorrosive coatings under HPHT conditions.

Disciplines involved in understanding the working mechanisms of high temperature, high-pressure linings are chemical reaction kinetics, thermodynamics and mass and heat transport phenomena.