Oil Country Tubular Goods(OCTG) involve a collection of rolled metal products, more commonly known as Drill pipe, Casing and Tubing for petroleum industry. Both of them are used in the drilling process. Do you know the difference between casing pipe and drill pipe?
Drill pipes are durable steel pipes that conduct the force to the drill bit when drilling process. In many cases the seamless drill pipe turns the drill bit, which cuts into the rock until it reaches the deposits. Drilling with drill pipe is the first phase of every wellbore.
Casing,refers to seamless casing pipe which is tubing that is set inside the drilled well to protect and support the wellstream.The Casing lines the wellbore and thus protects the layers of soil and above all the groundwater from being contaminated by the drilling mud and frac fluids. It also stabilizes the wellbore, so casing must be able to withstand especially high loads.
According to the API standards, Spec 5D is a combination of the drill pipe requirements. The purpose of this specification is to provide standards for drill pipe suitable for use in drilling and producing operations. API 5D specification covers Group 1(Grade E drill pipe) and Group 3 (All high strength grades of drill pipe:Grades X-95, G-105, and S-135) in the designations and wall thicknesses.
APT 5CT specified the requirements of Casing and tubing for the purpose of oil or gas production, must be cased with material with sufficient strength and functionality. The standard involving requirements for three Product Specification Levels (PSL-1, PSL-2, PSL-3) and several grades(API 5CT J55, K55,N80,L80,P110).
There are too many drilling connection types to choose,but limited for casing pipe.