Oil Country Tubular Goods (OCTG)

Oil country tubular goods (OCTG) is a family of seamless rolled products consisting of drill pipe, casing and tubing subjected to loading conditions according to their specific application.

Oil Country Tubular Goods (OCTG)

Corrosion resistance under sour service conditions is a very important OCTG characteristic, especially for casing and tubing.

Supply Range

SunnySteel supplies API 5CT casing pipes with the following sizes and specifications:

Standard and Grades: API 5CT J55 / K55, N80-1, N80Q, C90, T95, P110, Q125 and 13Cr

Casing Pipe Size range: 5 1/2 “to 20” Length usually in R3.

Tubing Pipe dimensions range: 1.0 “, 1.315”, 1.66 “, 1.9”, 2.063 “, 2 3/8”, 3 1/2 “and 4 1 /2”, Length in R2.

Type of connections for Casing: BTC (thread coupling buttress), LTC (long round thread coupling), premium connection.

Types of connections for Tubing: BTC, NUE, EUE, Premium

Each wellbore proceeds in multiple phases, during which

The American Petroleum Institute (API) stipulates precisely standardized specifications that define the properties of Oil Country Tubular Goods and classify them into ten grades. These properties are achieved through the chemical composition of the steel and subsequent heat treatment.

Oil Country Tubular Goods are used both onshore and offshore. In the industry, they are also referred to by the acronym OCTG (for “Oil Country Tubular Goods”).

Typical OCTG manufacturing processes include (all dimensional ranges are approximate)

These processes typically do not allow the thermomechanical processing customary for the strip and plate products used for welded pipe. Therefore, high-strength seamless pipe must be produced by increasing the alloying content in combination with a suitable heat treatment such as quench & tempering.

Schematic deep well completion
Schematic deep well completion

Meeting the fundamental requirement of a fully martensitic microstructure even at large pipe wall thickness requires good hardenability. Cr and Mn are the main alloying elements used to produce good hardenability in conventional heat-treatable steel. However, the requirement for good sulphide stress cracking (SSC) resistance limits their use. Mn tends to segregate during continuous casting and can form large MnS inclusions that reduce hydrogen induced cracking (HIC) resistance.

OCTG includes threaded casing and tubing that are used in equipping and operating oil and gas wells.

Higher levels of Cr can lead to formation of Cr7C3 precipitates with coarse plate-shaped morphology, which act as hydrogen collectors and crack initiators. Alloying with Molybdenum can overcome the limitations of Mn and Cr alloying. Mo is a much stronger hardener than Mn and Cr, so it can easily recover the effect of a reduced amount of these elements.

OCTG Tubing Pipe

OCTG Tubing pipe goes inside the casing pipe because it is the pipe through which oil makes its way out. Tubing is the simplest part of OCTG and it is normally found in the segment of 30 ft (9 m), with threaded connection at both ends. The pipe is either used to transport natural gas or crude oil from the producing formation to the facilities where it will be processed after drilling is complete.

Tubing (pumping pipe) goes inside the casing because it is the pipe through which oil makes its way out. Pipe of production is the simple part of OCTG and it is normally found in the segment of 30 ft (9 m), with threaded connection at both ends. The pipe is either used to transport natural gas or crude oil from the producing formation to the facilities where it will be processed after drilling is complete.



Tech & Service of Seamless pipe

Seamless pipes are extensively applied for the nuclear device, gas, petrochemical, ship building and boiler industries. Seamless pipes dominates 65% of market share in Chinese boiler industry.

How to make seamless pipe(seamless pipe process)?
Hot Piercing Workshop
Piercing process
The cross roll piercing and pilger rolling process in the size range from approx. 250 to 660 mm outside diameter.
Precision cold drawn steel tube production process
Pipe weld cracks
often follow different mechanisms can be divided into two types of thermal cracking and cold cracking.
How to calculate a steel pipe and tube theoretic weight
Calculate a steel pipe?
Pipe fittings are necessary to join together pipes, or to change the direction of an existing pipe.
Pipe beveling
Pipe beveling is the process where an angle is formed between the edge of the end of a pipe or tube and a plane perpendicular to the surface.
Steel pipe cutting machine
Pipe cutting
Cutting tools have a grinding wheel piece cutting machine (also known as toothless saw), hand saw, cutter and other hand tools.
How to calculate a steel pipe and tube theoretic weight
Packing the steel pipes
There are probably hundreds of different methods for packing a pipe, and most of them have merit, but there are two principles that are vital for any method.
Condition on delivery:

It refers to the state of final plastic deformation or final heat treatment of the delivered product. The hot-rolled or cold drawn (rolled) state or manufacturing state generally delivered without heat treatment; the heat-treated state after heat treatment delivery, or the normalizing, tempering, solid solution, annealing according to the type of heat treatment status.

Delivery status Abbreviation Description

Cold-finished/hard
(cold-finished as-drawn)

BK No heat treatment after the last cold-forming process. The tubes therefore have only low deformability.
Cold-finished/soft
(lightly cold-worked)
BKW After the last heat treatment there is a light finishing pass (cold drawing) With proper subsequent processing, the tube can be cold-formed (e.g. bent, expanded) within certain limits.
Annealed GBK After the final cold-forming process the tubes are annealed in a controlled atmosphere or under vacuum.
Normalized NBK The tubes are annealed above the upper transformation point in a controlled atmosphere or under vacuum.

Delivery according to actual weight or delivery according to theoretical weight

  • Actual weight - at the time of delivery, the weight of its product is delivered according to the weighing (weighing) weight;
  • Theoretical weight - The weight of the product at the time of delivery is calculated from the nominal size of the steel.
 


SUNNY STEEL

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