I. Different standards
(1) API 5CT: It is a standard for oil casing issued by the American Petroleum Institute.
(2) API 5L: It refers to line pipe API 5L line pipe, which is a pipeline steel pipe standard jointly issued by ISO and API.
II. Different processes
(1) API 5CT: The main materials are B, X42, X46, X56, X65, X70, etc. From raw materials to products before leaving the factory, flattening tests, tensile tests, impact tests, tensile tests and other related inspections must be carried out.
(2) API 5L: The micro-alloying heat treatment process is adopted. The production cost of seamless pipe is significantly higher than that of welded pipe, and with the improvement of steel grade, such as the restriction on carbon equivalent of steel grade pipeline pipe above X80.
3. Different working conditions
Working pressure and temperature
(1) The 5CT casing is located in the oil well. Its working pressure must meet the requirements of lifting oil and gas from thousands of meters underground to the ground, and the temperature must meet the requirements of not solidifying paraffin and chemicals during transportation. The working pressure and temperature are determined by the natural conditions inside the earth's crust, and under certain conditions, humans will also use artificial means to change them.
(2) The working pressure and temperature of the 5L surface pipe are determined and manually controlled by humans according to the requirements of the conveying medium.
Contact medium
(1) The medium that the 5CT casing contacts in the oil well is very complex, including drilling fluid, sand, oil and gas, artificially injected acidizing fluid, hydrogen sulfide in the earth's crust, etc.;
(2) The medium that the 5L surface pipe contacts is relatively simple. The initial oil and gas have been purified, and the drilling fluid, sand, acidizing fluid, etc. have been removed. There is no need to send these wastes to the refinery.
API 5CT Casing and Piping
