The Research Of The Connecting Types And Tools Of Casing And Drill Pipe In Casing Drilling

Casing drilling is a revolutionary new technology in the field of drilling around the world, it changes conventional drilling way .Compared with conventional drilling, casing drilling could effictively reduce about 10% of drilling costs and has good future. However the development and improvement of supporting equipment, especially the technology of connections of casing and drill pipe is the key of casing drilling . In this paper, three kinds of connecting tools were developed and applied in casing drilling technology.In this paper, the connections of casing and drill pipe were analysed and studied.,articulated crossover joints was used in 133/8″casing drilling in the surface for connection of casing and drill pipe, which comprised above joint and underlying joint, above joint and underlying joint were connected by drill pipe thread or articulated connecting rod to ensure connected effectively. Casing holder,articulated crossover joint and articulated link chain crossover joint were used in 103/4″casing drilling in the surface for connection of casing and drill pipe. casing holder could effectively transmit driving force of the table to casing by limit cam slip clipping casing collar surface, hang casing under the collar end to avoid the dropout of drill tools. Articulated crossover joint and articulated link chain crossover joint comprisd above joint and underlying joint, above joint and underlying joint were connected by drill pipe thread,articulated connecting rod or t articulated link chain to ensure connected effectively. Crossover joint was used in 7″production casing drilling for connection of casing and drill pipe,which comprisd above joint and underlying joint, above joint and underlying joint were connected by drill pipe thread. Liner hanger with the functions of drilling and completion. was developed in liner drilling for connection of casing and drill pipe, which had very high reliability. The surface stmiulation test and industrial per-formance detection have been completed successfully.The special pipe thread of casing drilling was studied. Through the thread was appximated with the tooth angle and angle of taper, it could be achieved the same connections and disassembly with conventional drill pipe. Through the face of cylinder was sealed with external thread and the sphere was metal sealed with internal thread, it could be secured the relative displacement in seal adaptation and meet the need in the seal. Through the outside end face of external thread and the inside shoulder of internal thread were sticked together with the special angl e, it could be avoided the buckle of casing continue process due to discontinuity load. Field tests showed that: Articulated crossover joint, crossover joint,liner hanger and special casing thread met the design specifications and the application requirements...