High Collapse Casing

HIGH COLLAPSE CASING

In the ever - evolving landscape of oil and gas exploration, where wells are being drilled deeper and in more challenging environments, the need for robust and reliable casing solutions is paramount. OAK, a trusted name in the industry, presents its high collapse casing, engineered to withstand extreme external pressures and ensure the integrity of wellbores.

1. What is Collapse and Influencing Factor

1.1 What is Collapse

Collapse resistance is a property of pipe body and defined as the limit exceeding which pipe fails in the circumferential direction when external pressure is applied.

Collapse calculation formulas were addressed in the API 5C3 or ISO 10400. Four failure modes have been defined based on failure pattern observation and mechanical rules (refer to figure below). These four domains are continuously positioned as a function of the ratio of the outside diameter to the wall thickness, or D/t ratio.

1.2 Influencing Factor

Collapse resistance is influenced by a complex combination of geometrical characteristics, material properties, applied loads, and load conditions:

Geometry: Outer Diameter(D), Wall thickness(t),Ovality, Eccentricity or wall thickness variation.

Mechanical properties: Yield strength, Residual stress

Applied loads: Tension-Compression, Bending ,Torsion

Testing parameters: Length / D of tested sample, Parasite load due to testing equipment, Pressure gradient.

OAK high collapse casing covers full range from 4-1/2" to 13-3/8”in O.D.

Grades from 80ksi to 130ksi .

HC-T Series: the collapse value greater than API 5C3.

HC-TT Series: the collapse value greater than OAK-T Series for the same size.

2. Technology Parameters

2.1 Dimensions

Outer Diameter: OAK high collapse casing is available in a diverse range of outer diameters, typically spanning from 4-1/2 inches (114.3 mm) to 13-3/8 inches (339.72 mm). This wide selection enables seamless adaptation to different wellbore sizes, whether it's a moderately-sized onshore well or a large-scale offshore operation.

Wall Thickness: The wall thickness varies according to the specific grade and the operational requirements of the well. Thicknesses can range from as low as 0.25 inches (6.35 mm) to 1.0 inches (25.4 mm). This flexibility ensures that the casing can endure the intense external pressures exerted during oil and gas production.

2.2 Grades

OAK L-80: With a minimum yield strength of 80,000 psi (552 MPa), a maximum tensile strength of 110,000 psi (758 MPa), and a minimum collapse resistance that is guaranteed to be 20% more than API values calculated by the API formula, this grade is suitable for wells with moderate to high external pressures. It offers a good balance between cost-effectiveness and performance.

OAK T-95: Boasting a yield strength of 95,000 psi (655 MPa), a tensile strength of 125,000 psi (862 MPa), and a substantial collapse resistance as per the API formula, this grade is designed for deeper wells where higher pressures are encountered. It provides enhanced strength and durability.

OAK P-110: This high-strength grade has a yield strength of 110,000 psi (758 MPa), a tensile strength of 140,000 psi (965 MPa), and a significant collapse resistance following the API formula. It is engineered for extremely deep and high-pressure wells, capable of withstanding the harshest conditions.

OAK Q-125: With an impressive yield strength of 125,000 psi (862 MPa), a tensile strength of 150,000 psi (1034 MPa), and a robust collapse resistance according to the API formula, this grade is ideal for the most demanding well environments, such as ultra-deep wells with extremely high external pressures.

OAK R-130: With an impressive yield strength of 130,000 psi (896 MPa), a tensile strength of 155,000 psi (1068 MPa), and a robust collapse resistance according to the API formula, this grade is ideal for the most demanding well environments, such as ultra-deep wells with extremely high external pressures.

•  OAK high collapse casings are designed by selecting and controlling the most influential parameters.

•  OAK high collapse casings are  delivered with the guarantee of their minimum  high collapse rating,for example : HC Q125TT .

•  On average ,OAK casing provides guaranteed High collapse performance values that exceed API by 20% to 35%.

2.3 Thread Connections

Premium Connections: OAK high collapse casing is equipped with premium thread connections, similar to those used in our standard casing products. These connections, such as Tenaris Hydril CS, TSH W511, and Hunting Seal-Lock-Flush (SLX), offer enhanced torque resistance, pressure integrity, and corrosion resistance. The design of these connections ensures a secure and leak-free joint, even under high-stress conditions, which is crucial for maintaining the integrity of the casing in high-pressure wellbores.

3. Performance

3.1 Exceptional Collapse Resistance

OAK high collapse casing is specifically designed to resist the high external pressures that are commonly encountered in deep wells. Through a unique production technique that includes strict mill control, quenching, and tempering, our casing has significantly improved collapse properties well beyond API ratings. This means that it can withstand the horizontal pressures exerted by the surrounding rock formations without deformation, ensuring the long-term stability of the wellbore.

3.2 High Tensile and Internal Pressure Resistance

In addition to its outstanding collapse resistance, the casing also exhibits a very high resistance to tension load and internal pressure. This allows it to endure the forces generated during the installation process, as well as the internal pressures from the flowing oil, gas, or injection fluids. The combination of high tensile and internal pressure resistance, along with its collapse resistance, makes OAK high collapse casing a reliable choice for a wide range of well conditions.

3.3 Corrosion Resistance

For wells operating in corrosive environments, OAK offers high collapse casing made from corrosion-resistant alloys. For example, our HC-95 SS grade is highly resistant to sulfide stress corrosion cracking, making it suitable for deep wells producing sour gas and oil. This corrosion resistance helps to extend the lifespan of the casing, reduce maintenance costs, and minimize the risk of failures due to corrosion.

4. Application Scenarios

4.1 Deep and Ultra-Deep Wells

The primary application of OAK high collapse casing is in deep and ultra - deep wells, where the external pressures can be extremely high. As wells are drilled deeper, the hydrostatic pressure from the overlying rock formations increases significantly. Our high collapse casing is designed to withstand these elevated pressures, providing the necessary support and integrity to the wellbore. It is crucial for ensuring the safe and efficient extraction of hydrocarbons from these deep-seated reservoirs.

4.2 High-Pressure Zones

In wells that encounter high - pressure zones, whether due to geological factors or the nature of the reservoir, OAK high collapse casing is the ideal choice. The casing's ability to resist both high external and internal pressures makes it well - suited for containing the high-pressure fluids and preventing blowouts. It can maintain its structural integrity in these challenging conditions, allowing for the successful production of oil and gas.

4.3 Offshore Wells

Offshore wells present unique challenges, including the corrosive nature of the marine environment and the need to withstand the high pressures associated with deep-water drilling. OAK high collapse casing, with its corrosion-resistant options and exceptional collapse resistance, is well-equipped to meet these challenges. It can endure the harsh conditions of the offshore environment, ensuring the long-term performance and reliability of the well.

5. Applied Oil Fields and Companies

OAK high collapse casing has been successfully applied in numerous oil fields around the world. In the deep-water oil fields of the Gulf of Mexico, where the external pressures can be extremely high, many oil companies rely on OAK high collapse casing for their well construction. The casing's ability to withstand these pressures and resist corrosion in the salty marine environment has made it a preferred choice in this region.

In the ultra - deep wells of the Middle East, which are known for their challenging geological conditions, OAK high collapse casing has also proven its reliability. The high-strength grades of our casing, such as HC P-110 and HC Q-125, have been used to great effect in these wells, ensuring the safe and efficient production of oil and gas.

Among the companies that have chosen OAK high collapse casing are major international oil and gas corporations such as ExxonMobil, Chevron, and BP. These companies recognize the importance of high - quality casing in ensuring the safety and efficiency of their operations and have trusted OAK to provide them with the products they need to meet the challenges of modern oil and gas exploration and production.

In conclusion, OAK high collapse casing offers a combination of outstanding technology parameters, exceptional performance, and wide - ranging application scenarios. Its use in major oil fields and by leading companies is a testament to its quality and reliability. Whether it's a deep - water offshore well or an ultra - deep onshore well, OAK high collapse casing is the ideal solution for ensuring the long - term success of oil and gas production.

If you have a need for an high collapse casing, don't hesitate to get in touch with the OAK team for high-quality products and technical support.