First, classification and anti-corrosion of oil casing
Oil casing can be roughly divided into 1. Surface casing according to different usage methods. 2. Intermediate casing. 3. Production casing. 4. Drilling casing. Surface casing is mainly: through the casing head installed on the top, to hang and support the subsequent layers of casing. Another is to isolate the shallow water layer on the surface from the complex formation in front to protect the drilling from the pollution of the shallow water layer. Intermediate casing or technical casing is used to isolate the layers with different formation pressures or complex formations that are prone to collapse and leakage. Production casing is used to protect the production layer and provide a channel for transporting oil and gas from the production layer to the ground. Drilling liner is used to reduce the load of the drilling rig and the load after the casing during and after cementing, saving casing and cement, and reducing the cost of cementing. In the use of industries and fields, oil casing has shown important roles and good performance.
The anti-corrosion of oil casing is mainly divided into: 1. Apply anti-corrosion coating on the outer wall. 2. Apply anti-corrosion coating on the inner wall. 3. Apply anti-corrosion cooling coating. With the use of oil casing in harsh oil extraction industries such as polar regions and oceans. It requires that the material and structure of the oil casing must have good node properties, excellent physical properties, stable chemical properties, and a wide temperature adaptability range. If the oil casing cannot do this, it should be coated with an anti-corrosion coating. To help him cope with the harsh use environment. Applying a coating on the outer wall is used to reduce external erosion. The anti-corrosion coating on the inner wall reduces friction, reduces corrosion in the pipe, and increases the amount of oil delivered. The anti-corrosion and thermal insulation coating is to transport crude oil and fuel oil and reduces the heat dissipated from the pipeline to the soil.
Second, heat treatment technology of oil casing
After the oil casing adopts this heat treatment method, it can effectively improve the impact toughness, tensile strength, and anti-destruction performance of the oil casing, ensuring good value in use. Oil casing is an essential pipe for drilling oil and natural gas, and it needs to have good performance during use. Oil casing uses different temperature controls in different temperature ranges, and heating needs to be produced according to a certain temperature. The AC1 of 27MnCrV steel is 736℃, AC3 is 810℃, and the selected temperature for tempering after quenching should be 630℃, and the tempering heating holding time is 50 minutes; the heating temperature for sub-temperature quenching is selected between 740 and 810℃. The heating temperature for sub-temperature quenching is 780℃, and the holding time for quenching heating is 15 minutes. Since sub-temperature quenching is heated in the α+γ two-phase region, the quenching is carried out in a state where the local ferrite is not dissolved, and the toughness is improved while maintaining high strength. The heat treatment of oil casing must be strictly implemented to ensure that the produced oil casing has excellent product quality and performance, can show good use value and performance during use, maintains high strength and toughness, and perform heat treatment in different ways. At the same time, low-temperature quenching is lower than the conventional temperature, which reduces the quenching stress and the quenching deformation, thus ensuring the smooth operation of the oil casing heat treatment production and providing good raw materials for subsequent threading processing. At present, this process has been applied in different steel pipe processing plants. The quality assurance data shows that the tensile strength Rm910-940MPa yield strength Rt0.6820-860MPa of the steel pipe after heat treatment is 100% qualified, and the impact toughness Akv65-85J data indicate that 27MnCrV steel pipe is already a high-grade oil casing of high quality. On the other hand, it also shows that the sub-temperature quenching process is an excellent method to avoid high-temperature brittleness in the production of steel products.
Post time: Jan-09-2025