Drilling string sub is made up of high-strength alloy constructional steel and processed by heat-treatment. Its structure is suitable to the connected drilling string and the sub connections at the both ends are up to API standard. It is mainly used for conversion, and connection of the drilling string components in/natural gas operation.
Description | Upper connection | Lower connection | Size | Type |
Kelly crossover sub | Kelly | Drill pipe | All size | A or B |
Drill pipe crossover sub | Drill pipe | Drill pipe | All size | A or B |
Crossover sub | Drill pipe | Drill collar | All size | A or B |
Drill collar Crossover sub | Drill collar | Drill collar | All size | A or B |
Drill Bit crossover sub | Drill collar | Drill bit | All size | A or B |
Swivel crossover sub | Swivel lower sub | Kelly | All size | C |
Fishing crossover sub | Kelly | Drill pipe | All size | C |
Drill pipe | Fishing tool | All size | C |
Drill string crossover sub for oilfield
