Introducing a Patent-Pending Revolutionary High-Temperature Corrosion Inhibitor: TETRA X
By Phillip Vincent | Engineering Services Manager | October 23rd, 2024
Corrosion
The development of the hydrocarbons that fuel our world almost always entails contact with a host of corrosive species: water, carbon dioxide (causing sweet corrosion), hydrogen sulfide (causing sour corrosion), organic acids like formic acid and acetic acid, and salts like sodium chloride, calcium chloride, magnesium chloride, and ammonium chloride, all of which can cause corrosion of the metal tubulars used in wells (Perez 2013). [1]
Corrosion is dangerous, as more than 25% of safety incidents in the oil and gas industry are reportedly due to corrosion-related failures (Solovyeva, et al 2023). [2] The rupture of metal piping or couplings can send metal debris flying and release hot fluids and gases.
Corrosion is also expensive, as shown in the latest NACE Impact study which estimated the global cost of corrosion in the oil and gas industry to be US$1.372 trillion in 2013; that was 11 years ago, so the cost is surely more by now (Solovyeva, et al, 2023). Corrosion can necessitate not only the costly replacement of individual well components like metal tubing, drill pipe, and casing string, but also the far costlier scenario of a premature end to a productive well’s lifespan.
The Limits of Inhibition
The industry employs a number of solutions to mitigate the corrosion of downhole components: specialized corrosion-resistant alloys, protective coatings, cathodic protection, non-metal composites, and corrosion inhibiting additives, the last of which are compounds added to the various fluids used in wells. Owing to their low cost and ease of use, particularly in contrast to costly specialized alloys, corrosion inhibiting additives are the most commonly used method.
Additive corrosion inhibitors, however, have limiting parameters. They must be specially formulated to be compatible with the fluids and geology in which they’ll be used, and they have temperature boundaries. With the industry drilling ever-deeper, and consequently hotter, wells, the upper temperature limit of an additive can take it off the menu and thus require the operator to resort to expensive specialized metal tubulars.
Another limitation is that most currently available corrosion inhibitors are formulated with morpholine residues, the supply of which is increasingly constrained by dwindling sources and increasing regulation of use.
Expanding Inhibition
Addressing the challenge of mitigating corrosion in deeper, hotter wells, TETRA scientists set out to develop a corrosion inhibiting additive that could withstand high temperatures, especially when used with the high-density and extra-high-density bromide-based fluids needed to counteract the high hydrostatic pressures of very deep wells.
We were researching for an ‘out-of-the-box’ approach, which is one long standing practice at TETRA. After identifying two candidate chemistries, we conducted extensive testing over a period of three years.
The result was the development of TETRA X high-temperature corrosion inhibitor, a patent-pending revolutionary additive, that provides enhanced corrosion protection in high-temp/high-pressure conditions up to 400°F (204°C). Extensive testing has shown the additive to have an efficacy and thermal stability far beyond conventional legacy inhibitors, and it can reduce the need for auxiliary inhibitors and other additives. Additionally, TETRA X has no effect on fluid pH and is compatible with most elastomers and formation fluids, as well as with high-density and extra-high-density bromide-based fluids (up to 17.5 lb/gal), like TETRA CS Neptune.
All testing conducted on N80 mild steel coupons with 0.5% by volume inhibitor loading.
To address the supply chain and regulatory constraints of other inhibitors, we’ve formulated TETRA X with plentiful, regionally sourced ingredients, which also reduces its carbon footprint. The additive requires no special blending or storage equipment and is environmentally safe. What’s not to love?
“Build a better mousetrap and the world will beat a path to your door.” The ‘mousetrap’ of today’s oil and gas operations is corrosion inhibition, and we believe we’ve pioneered a game-changing product. The chemistry is permitted to be used in the North Sea, and we’re looking forward to seeing its success in wells in every offshore (and onshore) environment around the world.
Endnotes
[1] Perez, T.E., 2013, “Corrosion in the Oil and Gas Industry: An Increasing Challenge,” JOM, Vol. 65, No. 8., pp. 1033–1042.
[2] Solovyeva, V.A., K.H. Almuhammadi, W.O. Badeghaish, 2023, “Current Downhole Corrosion Control Solutions and Trends in the Oil and Gas Industry: A Review,” Materials, Vol. 16, No. 5.
