Core Diameter (coiled tubing reel)

Core Diameter: The Heart of a Coiled Tubing Reel

In the oil and gas industry, coiled tubing (CT) is a crucial tool for a variety of operations, from well stimulation to downhole intervention. The CT is stored on a specialized reel, and a key parameter of this reel is the core diameter.

What is Core Diameter?

The core diameter is simply the diameter of the central cylindrical space within the coiled tubing reel. This space is where the CT spool is located, and its size directly impacts the amount of CT that can be stored on the reel.

Why is Core Diameter Important?

• Capacity: A larger core diameter allows for a greater length of coiled tubing to be stored on the reel. This is essential for operations requiring long reaches or extensive deployments.
• Tension Control: The core diameter affects the tension applied to the CT during deployment. A larger core diameter results in lower tension, minimizing the risk of CT damage or stretching.
• Reel Design: The core diameter is a fundamental factor in the overall design of the reel, influencing its size, weight, and transportability.

Understanding the Relationship between Core Diameter and CT Length:

The amount of CT that can be stored on a reel is directly proportional to the core diameter. A larger core diameter equates to a greater length of CT that can be accommodated. This relationship can be expressed as follows:

• CT Length = (Reel Diameter² - Core Diameter²) * π / (4 * CT OD)

Where:

• Reel Diameter: The outer diameter of the reel.
• Core Diameter: The diameter of the central space within the reel.
• CT OD: The outer diameter of the coiled tubing.
• π: The mathematical constant pi (approximately 3.14159).

Conclusion

Core diameter is a critical parameter in the design and operation of coiled tubing reels. Understanding its significance and the relationship between core diameter and CT length is essential for maximizing the efficiency and effectiveness of coiled tubing operations in the oil and gas industry.