Differences between Oil Casing Pipe and Oil Drill Pipe

Oil casing pipe and oil drill pipe must not be new terms for you if you’re associated with the petroleum industry. OCTG involves an array of rolled metallic products,...
Oil Casing Pipe

Oil casing pipe and oil drill pipe must not be new terms for you if you’re associated with the petroleum industry.

OCTG involves an array of rolled metallic products, including pipes, casing, and tubing that helps simplify the drilling process.

OCTG pipes are available in three different types:

  1. Drill pipe
  2. Casing
  3. Tubing

In this post, we’re going to highlight the differences between oil casing pipe and oil drill pipe.

Casing Pipe Explained

Casing pipe is also called an encasement pipe. These pipes are mainly used in underground construction.

They’re used for a variety of purposes, including providing security to water mains, gas lines, high-voltage electric lines, and all other utilities that are vulnerable to natural and human elements.

You must have seen these types of pipes used in horizontal underground boring, or welded under highways, lakes, and rivers.


Casing pipes are made up of steel that is melted in electric furnaces and treated in casters and synthetic slag. The pipes made with this procedure are durable, corrosion-resistant, and ductile.

As far as specifications are concerned, casing pipes must boast a minimum yield strength of 35k psi. Also, their walls must be smooth and round.

To maintain quality, the welding step must be done by experienced welders. There is no need to conduct hydrostatic testing, though.


The casing is critical to oil drilling equipment. It is used to support the oil and gas wall of the pipe. How many layers should be included in the casing depends on the depth and geological conditions of the well.

Drilling Explained

Drill pipes are mainly used to bore wells. There is a thread at the end that links the surface equipment of the rig with the grinding equipment.

The purpose of these pipes is to transport mud to the drill bit. These pipes must be able to withstand pressure and bend during the drilling process.

Tubing Explained

There are many applications in which tubing can be used. Tubing is long-lasting and you can use it over and over again depending upon your needs.

Steel tubing must be treated to ensure it stays rust-proof. It is the best option for heavy-duty tubing that needs reliable and durable piping options.

Many commercial and industrial applications use tubing to transport fluids and gases. Tubing is generally available in cylindrical form, but there are other shapes available too.

Tubing can be either rigid or flexible. Besides steel, tubes are available in different materials, including aluminum, copper, and even plastic. Apart from that, rubber, silicone, and glass tubes are also available.

Differences Between Oil Casing Pipe and Oil Drill Pipe


Oil casing is basically a steel pipe that is primarily used to support the well (wall) of oil and gas. Its purpose is to ensure the smooth operation of the well during the drilling process.

As a general rule, each well uses multiple layers of casing. In most cases, cement is used as a binding agent. The casing process is different from the tubing, as you cannot reuse it.

The casing is available in different types, including surface casing, oil layer casing, and technical casing.

The drill pipes, on the other hand, are responsible for transporting force to the drill bit. The drill pipes can be used multiple times during the extraction/refining process.

Drill rods are also available in different types, including square rods, drill rods, and weighted drill rods.


The oil casing pipes are available in a wide range of materials. From basic carbon steel to 3CR, 9CR, and 13 CR, you can find them all in the market.

Drill pipes are also available in different materials – API Standard E75, double shoulder joint drill pipes are just to name a few.


The purpose of casing pipes is to reinforce the wall. The drill pipes, on the other hand, are used to link the drill collar and the drill bit.

The drill string includes components like a collar, joint, rod, and a stabilizer. These components work together to transmit power.


Both these pipe options also come with different standard requirements. For instance, according to API standards, 5D represents drill pipe requirements. This specification includes Group 1 and Group 3 pipes.

APT 5CT represents casing and tubing standards required during the oil and gas production process. According to this standard, casing pipes and tubing must come with high-end and durable material that provides optimum strength and performance.

This standard covers three specification levels, along with different grades.

The selection of casing or drilling pipes depends on your project requirements. If you’re looking for a long-term and reliable solution (which you don’t have to reuse again), the casing can be your safest bid.

But if you’re looking for a cost-effective solution that you can use multiple times during the drilling process, drill pipes or tubing should be on top of your list.

Pipes & Fittings
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