How to improve the performance of oil casing pipe?

As an important petroleum engineering pipe, oil casing pipe meets the API SPEC 5CT standard. Casing pipe steel grades cover a variety of material options from H40 to V150, meeting the needs of different geological conditions and drilling depths. Its performance characteristics are mainly reflected in the following aspects:

‌1. High dimensional accuracy‌: The nominal outer diameter and wall thickness of oil casing have high precision, ensuring its application accuracy and stability in oil drilling.
‌2. Structural uniformity‌: Oil casing has good structural uniformity, which is the basis for ensuring its stable and reliable mechanical properties.
‌3. Excellent toughness‌: Oil casing has excellent toughness and can withstand pressure and impact in complex and changeable underground environments, ensuring the safety and stability of oil wells.

‌4. Anti-extrusion and anti-explosion properties: Oil casing (Seamless casing and ERW casing) combines the common advantages of ERW welded pipes and seamless pipes, has excellent anti-extrusion and anti-explosion properties, and can cope with challenges in extreme working environments.

The performance characteristics and parameters of oil and casing jointly ensure the effective application of oil and casing in oil drilling and the smooth exploitation and transportation of oil and natural gas. So, what aspects can be started for efficient development of oil fields and sustained and stable production? How to improve the performance of oil casing pipe?

Improving the performance of oil casing pipe can be achieved through a variety of methods, including optimizing design, using appropriate materials, enhancing maintenance and upkeep, and adopting new technologies. Here are some specific methods:

‌1. Optimize casing design‌
The design of casing should take into account its load analysis and strength design to ensure that the casing can withstand downhole pressure and temperature conditions‌.
The size, steel grade and wall thickness of the casing should be selected based on the specific application scenario to ensure that its performance meets the requirements.

‌2. Use appropriate casing material‌
Choosing the right material is critical to improving the performance of oil casing. For example, for gas flooding technology, corrosion-resistant alloy coiled tubing and non-metallic coiled tubing should be used to take into account both anti-corrosion and gas sealing functions.

‌3. Adopt new technologies‌
In view of the problem of the accuracy of the make-up torque on oil casing, the accuracy of the make-up torque can be improved by improving the calibration method and sampling frequency, thereby improving the strength of the threaded connection of oil and casing. For gas drive technology, the use of corrosion-resistant alloy coiled tubing and non-metallic coiled tubing is the future development direction, which will help improve the integrity of the wellbore and the efficiency of the gas drive process‌.

4. Strengthen casing maintenance and upkeep‌
Perform regular maintenance and upkeep on oil casings, such as using oil casing corrosion inhibitors, to reduce corrosion and wear and extend service life.

How to improve the external pressure resistance strength of casing pipe?

The external pressure resistance strength of casing is one of the important factors to ensure the safety of wellbore. Methods to improve the strength of casing against external pressure include selecting high-strength materials, increasing casing wall thickness, optimizing casing design, etc. In practical applications, different measures need to be selected to improve according to different situations.

The significance of casing resistance to external pressure:
The role of casing in oil wells is very important. It carries the weight of the well wall and the pressure of the external environment. Therefore, the strength of the casing against external pressure is directly related to the stability and safety of the wellbore. Improving the strength of casing against external pressure is one of the key measures to ensure well safety.

Measures to improve the strength of casing against external pressure:
1. Use high-strength materials
Selecting high-strength casing materials is an effective way to improve the strength of casing against external pressure. At present, with the continuous advancement of science and technology, more and more high-strength casing materials have emerged, such as high-strength steel and composite materials. These materials not only improve the strength of the casing against external pressure, but also have the advantages of corrosion resistance and extended service life.

2. Increase casing wall thickness
Increasing the thickness of the casing wall is an effective method to improve the strength of the casing against external pressure. It should be noted, however, that increasing wall thickness increases the cost and weight of casing manufacturing, so a balance needs to be struck between economy and safety.

3. Optimize casing design
Reasonable casing design can maximize the strength of the casing against external pressure. For example, you can use reasonable welding joints, reduce joint length, increase taper, etc. In addition, factors such as wellbore temperature and wellbore pressure must also be considered in casing design.

Read more: What are the grades of OCTG casing? or Oil well casing size selection