OCTG Tubing Pipe Manufacturers and Suppliers

OCTG Tubing: The Complete Guide for Importers and Buyers

What is OCTG?

OCTG or oil country tubular goods is a collection of rolled metallic products that many people know as pipes and other accessories used in the process of manufacturing and processing them. They include drill, casing/tubing pipes, thread protectors, stabbing guides, bumper rings, and pipe chocks.

Thus, to give you a simple and informational guide into OCTG, this post will discuss pipes, which are the commonly known and essential part of OCTG.

The piping products get a nod in this article as they qualify to be OCTG because of some specifications regarding their accepted loading conditions, their applications, strength, and composition.

Types of Oil Country Tubular Goods (OCTG pipes)

The int’l standard has standardized specifications that can be used to group OCTG pipe into different performance grades.

Such specifications have been used by experts in the manufacturing and oil and gas industry, to categorize OCTG pipes into three different types, namely, OCTG Drill pipe, OCTG Casing pipe, and OCTG Tubing pipe.

To give you a better understanding of these three types of OCTG pipes, we will explain each in the sections that follow.

• OCTG Drill pipe

OCTG drill pipes are often heavy, seamless tubes with rotating drill bits used to circulate drilling fluid.

These pipes are used to pass the drilling fluid to and from the annulus.

An OCTG drill pipe is capable of withstanding internal pressure, axial tension, and very high torque.

One of the characteristics of an OCTG drill pipe is that it is durable, making it suitable for such applications.

An OCTG drill pipe comes with the durability of a steel pipe that can be used for drilling. Additionally, the standard drill pipe comes in two grades; int’l standards.

Expert tip: the annulus of drilling well is the space found between the case and the pipe. The annulus is the hollow part of the pipe that allows fluids to pass through.

• Steel Casing pipe

An OCTG steel casing pipe is used as a lining for the oil well or borehole that is drilled into the ground. The steel casing pipe is designed to withstand axial tension in the same way that an OCTG drill pipe is.

The steel casing pipe comes with a large diameter because it goes straight into the well. In most cases, the steel casing pipe is often held into place using a durable adhesive material, such as cement.

Steel casing pipe is often subject to axial tension, and this is made possible due to its dead weight.

Additionally, the rocks surrounding the pipe exert external pressure, while the fluid passing through it creates internal stress.

The casing pipe can balance between the two due to its design and material strength.

A well-cemented steel casing pipe helps make the drilling process straightforward through the following ways:

• It prevents the contamination of water well zones.
• The OCTG steel casing pipe allows internal bore for the installation of other equipment used in the production of oil.
• The pipe prevents the contamination of production zones and loss of fluids through seepage.
• The steel casing pipe firmly holds the drill string and creates the stability that prevents upper formation from caving in.
• The pipe seals off higher pressure zones.

In summary, the steel casing pipe is exceptionally heavy-duty, which makes it fit the specifications for OCTG.

OCTG Casing Pipe standard

The steel casing pipe standards is commonly known as the int’l standards.

An OCTG casing pipe is typically used to end the connection in the piping system, and in most cases, they come in BTC and LTC or STC.

Any project that involves the drilling of oil and gas that requires a premium connection often call for the use of many standard casing pipes.

The cost of a steel well casing pipe

OCTG steel casing pipes are more affordable compared to OCTG drill pipes.

In most cases, you will find steel casing pipes at $200 higher than a regular int’l standardspipe.

The cost may not be that high, especially if you consider the threading and coupling cost and other post-processing, such as heat treatment.

There is no fixed cost for any OCTG product due to variations in designs.

Additionally, most OCTG manufacturers have their pricing mechanisms. You need to compare various grades from different manufacturers if you want to get the best deal.

In a nutshell;

• Drill pipes are heavy, tubular, seamless pipes used in rotating the drill bits and the drilling fluids. They are joined together using toll joints.
• Casing pipes are used in lining the borehole dug into the ground leading to the oil. Unlike drill pipes, casing pipes handle both internal and external pressure. They are extremely heavy-duty.
• Tubing pipes are those that run into the casing pipe. This is the pipe that allows the passage of oil. It is the simplest of the OCTG family and can be found in a segment of up to nine meters. Additionally, they are connected end to end and protected with tubing pipe protectors during transportation and storage.

Drill protectors are used to protecting pipes against corrosion that could take place when the pipes are stored. Corrosion can be a major problem when tons of oil is pumped through the pipes.

In some cases, it is wise to use anti-corrosion pipes.

OCTG Tubing Pipe Applications

OCTG tubing pipes are the ones that go inside the casing pipe. They are used to transfer oil from the wells going up to the surface.

In other words, the OCTG tubing pipes allow the oil to make its way through from the ground. They are simple in design, unlike other OCTG pipes.

In some cases, the OCTG tubing pipes are used to transport natural gas and crude oil from the wells to the processing facilities after the drilling process is complete.

The tubing pipe is designed to withstand internal pressure during the extraction process.

Additionally, they are modeled to resist loads and deformation during production or workovers.

OCTG tubing pipes are manufactured the same way as casing pipes.

However, the tubing pipes go through a process of additional upsetting to make them thicker.

The thickness differentiates various OCTG tubing grades, depending on where they are to be used.

How steel casing pipe and tubing work together

As said before, steel casing and tubing pipes are used together in drilling oil.

The tubing pipe goes into the casing pipe, and it lets oils make its way from the ground.

On the other hand, the casing pipe offers shelter to the tubing pipe and is mostly used to create a pathway for the tubing pipe.

In that way, they both go deep into the well or borehole to reach surface oil in the ground.

These pipes are connected end to end until they reach the desired length deep into the well.

Drive, structural, and conductor casing

This is the first string of pipes, and its primary purpose is to protect the unconsolidated shallow formation from being eroded by the drilling fluid.

Other functions of the casing pipes include:

• They allow for the installation of full mud systems, especially when the formation is stable enough.
• They are used to guide the drill string and other pipes into the borehole.
• They sometimes form part of the piling system offshore.
• They support the wellhead system in subsea wells.
• They help limit potential buckling of the subsequent casing strings by providing centralization for the innermost casing strings.
• Conductor casings minimize shallow lost returns.
• Finally, they provide support in onshore applications for various diverter systems that would be used in case of any shallow influx.

The conductor casing pipe is, therefore, the first foundation that is driven or jetted deep into the hole. The casing is then cemented to hold it firmly into the ground.

Surface casing

Surface casing pipes are installed for the following reasons:

• The surface casing pipes prevents unstable formations from caving in the well.
• It enables the full circulation of mud.
• Prevents the contamination of freshwater sands by the drilling mud.
• Protects other equipment from hydrocarbons found in shallow ends.
• The surface casing pipes support the blowout preventers.
• The pipes enhance kick resistance to enable deeper drilling.
• The surface casing pipes support all subsequent strings and the entire wellhead system.

The surface casing pipes are usually cemented to the ground and the well walls. They form the first layer for the installation of blowout preventers.

The extent of protection that surface casing pipes provide depends on the internal pressure, and it can only be as effective as the strength of the formation at the casing shoe.

Intermediate casing

Intermediate casing pipes are used to ensure adequate blowout protection to enable deeper drilling and to isolate unstable formations that would cause problems during the drilling process.

Intermediate casing pipes are often set in the transition zones, especially in areas of overpressure.

These casing pipes can also be placed in below loss zones if the borehole encounters severe lost circulation zones.

Intermediate casing pipes can also be applied as a plan to prevent hydrocarbon-bearing intervals from any form of lost circulations.

When installed well, the pipes control lost circulation problems in drilling wells.

Additionally, the pipes can be used as a backup plan to reduce the cost of drilling by isolating various intervals that have experienced mechanical defects.

OCTG tubing pipe features and specifications

All OCTG pipes are designed and manufactured with standard toughness and strength that enable them to run into the ground through hard rocks.

Whether it is OCTG tubing, OCTG drill pipes, or OCTG casing pipes, they all meet specific standard requirements, which in most cases are about hardness.

OCTG tubing pipes are made using manganese and chromium as the primary alloys. The alloys confirm cohesion and durability in the mechanical structure of all OCTG tubing pipes.

The only problem with using manganese and chromium alloys is that they generate sulphide stress cracking.

However, various OCTG manufacturers are currently using a blend of the alloys with molybdenum to overcome the limitations of manganese and chromium.

Convectional level manufacturing is enhanced by a 4% addition of molybdenum to produce close to 75% of the desired level.

Therefore, the current crop of OCTG tubing pipes is harder without the limitations imposed by the fear of sulphide stress cracking.

Typically, the OCTG manufacturing process includes a continuous rolling of mandrel and push bench processes for various tubular products between 21 mm and 178 mm OD.

Plug mill rolling process is used for products of sizes between 140 mm and 406 mm OD.

Accordingly, cross-role piercing processes are used for sizes between 250 mm and 660 mm OD.

All these processes are backed up with post-processing activities such as various thermo-chemical processes that are used to strip and plate the products.

Heavy-duty, high strength seamless pipes are manufactured by increasing the alloy content and incorporating heat treatment in the manufacturing processes.

Heat treatment is used to add more strength to pipes such as temper and quench.

Oil country tubular goods have standard strength requirements that are usually referred to as martensitic structures.

This structure helps the pipes overcome the pressure exerted during the drilling processes and when the oil is pumped through them at high pressure.

The bottom line

Sulphide stress cracking has been a significant issue in the manufacture of OCTG tubing pipes.

However, recent advancements have seen them become harder and well-protected from cracking.

If you are looking for the best OCTG tubing pipes supplier, your search is over because we are the most reputable OCTG Tubing Manufacturer.

We ensure that our OCTG tubing pipes are designed to the best quality from raw steel materials.

Accordingly, our pricing is competitive. All the OCTG tubing pipes we have distributed comply with international standards and are certified for use to help you save costs in the long run.

As a reputable manufacturer, supplier, and distributor, and exporter, we offer the best OCTG piping solution for the oil and gas industry.

Contact us today for high-quality OCTG tubing pipes.

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