Different types of oil casing used in oil production: surface oil casing protects the well to protect it from shallow water and shallow gas pollution; supports the wellbore equipment and maintains the weight of other casings. Technical oil casing: Separate different pressure layers, make the limit of drilling fluid in a normal circulation state, protect production casing, and install anti-cracking devices, leak-proof devices and exhaust pipes in drilling. Reservoir oil casing: the export of oil and natural gas from underground reservoirs, used to protect drilling and layered drilling mud. When producing oil casing, the outer diameter is usually 114.3 mm to 508 mm.

J55 oil casing is a kind of pipe material necessary for oil and natural gas drilling, and it needs to have good performance in use. Petroleum casing can choose different temperature control in different temperature ranges. It needs to be heated according to a certain temperature. For 27MnCrV steel AC1=736℃, AC3=810℃, quenching and tempering temperature 630℃, tempering heating holding time 50min. The heating temperature during sub-temperature quenching is between 740°C and 810°C. The sub-temperature quenching heating temperature is 780min, and the holding time is 15min. As the sub-temperature quenching is heated in the α+γ two-phase region, and quenched while retaining part of the insoluble ferrite, the toughness is improved.

Cement should be used to cement the oil casing after it is down. Unlike tubing and drill pipe, it cannot be reused and is a disposable consumable. Therefore, casing consumption accounts for more than 70% of all oil well pipelines.