Abstract
As one scans the market today, it is noted that the vast majority of drill pipe is internally coated with a polymeric coating system. One also notes that completion pipe, landing strings, etc are increasingly utilizing internal coating technology to provide corrosion, hydraulic and scale mitigating benefits. Transitioning from simple drilling operations in the 1950’s to the ability to withstand drilling, fracing, cementing, gravel packing, acidizing, and mechanical intervention at high temperatures and pressures. There has been a transition in technology from those very early coating systems to the newest technology available today. Several milestones define the technological advances in internal coating capabilities.
Initial versions of these drilling coating systems utilized a liquid applied epoxy phenolic coating systems. As the industry developed, there became a need for a powder version of the traditional drill pipe coating systems. From there, the market showed a need for a more abrasion resistant system to handle not only drilling applications, but also completion operations. A third era was ushered in with this new abrasion resistant technology, but transitioned back from a powder application to a liquid application due to the market experienced performance benefits of a liquid applied material. We now stand in a new era of coating technology in the drilling and completion market. While still focusing on a liquid applied material, the traditional epoxy phenolic is being left behind. This new coating utilizes a high temperature, multi-functional epoxy resin as its backbone. This system also deviates from the norm in that specialized additives are used to improve characteristics such as coating toughness and flexibility. Historically, the use of additives would reduce the final glass transition of the coating system, reducing its overall performance in a given environment. These new additive systems in conjunction with this multi-functional epoxy allow for them to be used in concert without reducing the glass transition temperature. This new system increases the chemical resistance over traditional liquid applied systems, doubles the flexibility over other industry available systems, exhibits greater performance at temperature over traditional coating systems, and now possesses the most abrasion resistance available in the market.
