Oil casing is a type of large-diameter pipe that serves to secure the walls or boreholes of oil and natural gas wells. The casing is inserted into the wellbore and fixed with cement to help isolate rock layers, prevent wellbore collapse, and ensure the circulation of drilling mud, facilitating drilling and extraction.

Steel grades for oil casing include H40, J55, K55, N80, L80, C90, T95, P110, Q125, V150, etc. The end machining types for casing include short round thread, long round thread, buttress thread, and special connections. During oil well drilling, casing is mainly used to support the wellbore during drilling and after completion, ensuring the drilling process goes smoothly and the proper functioning of the well after completion.