OCTG, which full name is oil country tubular goods, is special oil pipes that are a kind of special pipes for oil and gas exploration. Many OCTG pipe is seamless pipe, though the welding pipe is also accounted for considerable proportion. OCTG is a family of seamless pipes products consisting of drill pipe, casing and tubing, sucker rod subjected to loading conditions depending on their specific applications.
Drill pipe: it is a heavy seamless steel pipe which rotates the drill bit and circulates drilling fluid. Pipe segments 30 ft long are coupled with tool joints. Simultaneously drill pipe is subjected to high torque by drilling, axial tension by its dead weight and internal pressure by purging of drilling fluid. Moreover, because of non-vertical or deflected drilling alternating bending loads may be superimposed on these basic loading patterns.
Casing pipe lines: casing pipe lines is used to drill the borehole. It is subjected to axial tension by its dead weight, internal pressure by fluid purging and external pressure by surrounding pressure by the pumped oil or gas emulsion.
Tubing: it is the pipe by which the oil or gas is transported from the wellbore. Oil tubing segments are usually around 30ft long with a threaded connection on each end.
Typical OCTG Processes include Three Stages:
Continuous mandrel-rolling and the push bench for sizes between 21 and 178 mm Outer Diameter;
Plug mill rolling for sizes between 140 and 406 mm Outer Diameter;
Cross-roll piercing and pilger rolling for sizes between 250 and 660 mm Outer Diameter;
These processes do not allow the thermo-mechanical processing customary for the strip and plate products which is used for welded pipe. So, high strength seamless pipe must be made by increasing the alloy contents together with a suitable heat treatment like quench or tempering.
Generally, OCTG grades are carbon-manganese steels (up to the 55-ksi strength level) or Mo-containing grades up to 0.4% Mo. In recent years, deep well drilling and reservoirs containing contaminants causing corrosive attack have created a strong demand for higher strength materials resistant to hydrogen embrittlement and SCC. Highly tempered martensite is the structure most resistant to SSC at higher strength levels and 0.75% is the Mo concentration that produces the optimum combination of yield strength and to SSC resistance.
API SPEC 5CT for casing and tubing
API 5DP/API SPEC 7-1 HWDP for drill pipe
API 5L for pipeline pipe
API 11B for steel sucker rods
API 5B for thread processing, measurement and test of casing and tubing and line pipe.
Specializing in various kinds of OCTG pipes production and supplying, Anson steel subsidiary of AGICO is a professional OCTG manufacturer and supplier in the international trade. We keep enough in stock in the warehouse every month. Besides, we keep a good relationship with every big steel factory in China, so we can guarantee the delivery time and competitive prices for customers. Therefore, if you have any inquiry on OCTG, please don‘t hesitate to contact us by e-mail or ring us!