The sleeve consists of a coupling and a tube body. The casing coupling is an internal thread that is machined at both ends to connect the casing tube body to form a casing string. The sleeve collar is threadedly attached to one end of the sleeve body to form an internally threaded end of the sleeve. The casing tube body is the main body of the casing structure, and is a steel pipe with specific size and performance requirements. The pipe body is made of rolled seamless steel pipe and processed by threading at both ends after proper heat treatment.
1, the specifications of the casing. The casing is formed into a series of casing specifications depending on the size of the rolling. The casing size refers to the design size of the outer diameter of the casing body. The size of the casing is expressed in millimeters of the outer diameter of the pipe.
2.Casing wall thickness. The wall thickness of the casing is the thickness of the casing body, and the casing size of the uniform specification has different wall thicknesses of the casing required. For example, a casing with a size of 139.7 mm has a wall thickness of 6.20 mm, 6.98 mm, 7.72 mm, 9.17 mm, and 10.54 mm.
3. Casing steel grade. The casing steel grade determines the strength characteristics of the casing. The steel grade of the casing consists of two parts. The upper capital letters represent the steel grade, and the latter numbers represent one thousandth of the minimum yield strength of the steel grade. Pounds per square inch. Casing thread is a special thread for petroleum pipe. Commonly used casing threads are round thread and trapezoidal thread. Among them, round thread is the most widely used. The casing round thread is divided into a short round thread and a long round thread. Long round threads are often used in production, and the casing thread gauges used in the field are generally short round thread gauges.