Precision and Price Advantages of Laser Cladding
The total cost of ownership is an important and often overlooked factor in selecting wear protection technologies and materials for components used in demanding modern drilling applications. This paper presents a critical analysis for the cost of ownership of a drill string stabilizer, a single component of a multicomponent downhole tool assembly that is used in modern drilling applications. Subjected to extreme in-service conditions, drill string stabilizers require special protective coatings to ensure performance and survivability in some of the most severe environments on earth. Technical decisions regarding coating type and deposition technology can have a significant impact on the run time hours for new components, the expected repair cycles, and overall service life of a drill string stabilizer, all of which affect ownership costs.
Looking at the Big Picture
The cost of ownership for a generic drill string stabilizer can be broken down into three cost categories: initial manufacturing, repair, and replacement costs. Drill string stabilizers are manufactured from high strength, non-magnetic stainless steel. The base material is very expensive, and hardfacing is applied to maximize the total service life and to reduce operational cost of early replacement. Wear protection coatings applied to the surface of the stabilizer can be repaired, in some cases multiple times, resulting in substantial financial benefits. Employing wear protection systems can maximize the lifetime of the stabilizer based on application costs and potential for multiple repair cycles.
Lowering Costs While Ensuring Results
The five most industrially relevant process-material combinations are laser clad manufacture with laser clad repair, plasma transfer arc welding manufacture with plasma transfer arc welding repair, plasma transfer arc welding manufacture with laser clad repair, tungsten carbide brick oxy-fuel brazing manufacture with laser clad repair, and tungsten carbide brick oxy-fuel brazing manufacture with tungsten carbide brick oxy-fuel repair.
Laser cladding of nickel tungsten carbide powders is a proven high-quality overlay coating process that can be done efficiently and repeatedly using automation in the form of CNC or robotic welding.
Laser cladding manufacture with laser clad repair has shown to be the lowest cost of ownership option of the five potential combinations—at a 50% cost compared to brazed brick with brazed brick repair option. This takes into account the following: initial manufacturing costs, repair costs, repair cycles and a total target service life of 1000 hours.