Development Experimental Study on Double-start Thread Connection for Tubing and Casing

Described here in the paper is the devel opment activities of the a double-start thread connection for tubing and casing. The make up speed of the said double-star thread connection is at least two times higher than that of the conventional thread connection,and therefore the downhole efficiency can be significantly improved. The FEA,the processing technology research and the physical test are carried out for the said double-star thread connection with specific sizes. As a result it is identified that the double-star thread connection features uniform stress distribution,high make-up speed,and properties satisfactory to the application requirements,which proves the rationality of the doublestart thread structure.