What is API 5CT P110 Casing Pipe?

P110 casing pipe is a steel pipe used for oil and gas well drilling and completion operations. It is part of the API 5CT standard, which specifies the technical delivery conditions for steel pipe used in the petroleum and natural gas industries.

"P110" designates a minimum yield strength of 110,000 psi (approximately 758 MPa), meaning it can withstand extremely high axial loads and internal/external pressure differentials in deep and high-pressure oil and gas well environments. Compared to lower steel grades (such as N80, J55 and K55), P110 casing pipe offers superior mechanical properties.

P110 Casing Pipe Dimensions

1. P110 Casing Pipe Outer Diameter

Common P110 casing pipe outer diameters include 139.7 mm, 177.8 mm, and 244.5 mm. In practical applications:

139.7mm OD—commonly used in medium-shallow oil wells;

177.8mm OD—suitable for medium-depth wells with high requirements for wellbore stability;

244.5mm OD—generally used in deep wells or wells requiring high formation pressure.

2. P110 Casing Pipe Wall Thickness

P110 casing pipe comes in a variety of wall thicknesses, including 7.72mm, 9.19mm, 8.94mm, 10.03mm, and 11.05mm.

Thinner 7.72mm wall thickness casing pipe—lower cost and lighter weight, suitable for environments with low formation pressure and simple well conditions;

Heavier wall thicknesses, such as 11.05mm, are suitable for wells with high formation pressure and complex geology, enhancing collapse resistance and internal pressure resistance.

3. P110 Casing Pipe Length

According to API regulations, there are three types of casing pipe lengths. R-1—Lengths range from 4.88 to 7.62 meters, suitable for shallow wells or where transportation and construction conditions are limited;

R-2—Lengths range from 7.62 to 10.36 meters, suitable for conventional well depths;

R-3—Lengths start at 10.36 meters and are commonly used in deep wells. They reduce the number of casing pipe connections and improve sealing and stability.

API 5CT P110 Casing Pipe Specifications Chart

Mechanical Properties of P110 Casing Pipe

P110 steel grade casing pipe has a minimum yield strength of 110,000 psi (approximately 758.6 MPa). During tripping, this strength ensures the casing pipe can withstand tensile forces generated by its own weight, drilling fluid buoyancy, friction, and other factors, preventing fracture due to tension.

Chemical Composition of P110 Casing Pipe

Sulfur and phosphorus are detrimental elements in steel. Sulfur can cause hot brittleness, reducing toughness and fatigue resistance; phosphorus can cause cold brittleness, reducing plasticity and toughness. Controlling the content of these two elements ensures the quality of the casing pipe steel and improves its overall performance.

P110 Casing Pipe Thread Parameters

1. Thread Type

Common thread types for P110 casing pipe include round threads (STC/LTC) and buttress threads (BTC).

Round threads (STC/LTC) offer simple processing, low cost, and a certain degree of sealing and connection strength, making them suitable for wells where sealing requirements are not extremely high.

Buttress threads (BTC) offer a unique thread profile, high connection strength and excellent sealing, and can withstand significant axial tension and torque. They are commonly used in deep wells, high-pressure wells, and other locations where connection performance requirements are high.

2. Thread Pitch

Round thread pitches include 8 threads/25.4mm and 10 threads/25.4mm.

The 8-thread/25.4mm thread pitch is larger, resulting in a relatively small number of threads on the casing pipe, allowing for faster installation and removal.

3. Thread Angle

Round threads generally adopt the API standard 60° thread angle, which facilitates machining and assembly and ensures a certain degree of connection tightness. The trapezoidal thread angle is typically 3°/30°.

Applications of P110 Casing Pipe

P110 casing pipe, as an OCTG pipe, is commonly used in various applications in oil and gas well operations, including:

1. Wellbore Support

Maintaining wellbore stability and preventing collapse.

2. Fluid Isolation

Separating layers to prevent cross-flow of oil, gas, and water between different strata.

3. Pressure Control

Withstands high differential pressures to ensure safe well control.

4. Corrosion Protection

Suitable for corrosive environments containing sulfur and CO₂. Can be used with internal coatings or alloy casing pipe to extend service life.

5. Deep/Ultra-Deep Well Applications

Reduces the number of joints and improves overall sealing.

Summary

P110 casing pipe, as API 5CT high-grade steel casing pipe, is widely used in medium-deep wells, high-pressure wells, and complex wellbore conditions due to its high yield strength, excellent collapse and tensile properties, and diverse specifications. Compared to lower-grade steel casing pipe, it significantly improves wellbore safety and service life, making it a key piece of equipment in modern oil and gas field development.