1. Structure & Design
Function: The coupling connects adjacent casing sections via threaded joints, transmitting torque and axial loads while providing sealing.
Types:
Short Coupling: Shorter length, used for standard casing connections.
Long Coupling: Longer length, employed for adjusting casing run-in depth or repairing damaged casing.
Thread Types:
API Standard Threads (e.g., STC, LTC, BTC), compliant with American Petroleum Institute (API) specifications.
Premium Threads (e.g., VAM, Hydril), designed for high-pressure gas wells or complex geological conditions.
2. Material & Manufacturing
Material: Typically made of carbon steel matching or exceeding casing strength (e.g., API 5CT Grades J55, N80, P110), with corrosion-resistant alloys (e.g., 13Cr) used for sour environments.
Manufacturing Processes:
Forging: Enhances material density and strength.
Heat Treatment: Improves toughness and fatigue resistance in threaded zones.
Coating: Zinc plating or epoxy powder coating for corrosion protection.
3. Technical Standards
API 5CT: Specifies dimensions, thread parameters, and pressure ratings for casing couplings.
ISO 11960: International standard defining connection protocols for casing and couplings.
Testing Requirements: Must pass pressure tests (e.g., gas tightness), torque testing, and tensile strength testing.
4. Applications
Drilling Phase: Connects casing strings to ensure sealing and stability during installation.
Completion Phase: Forms part of the wellbore structure, enduring long-term formation pressure, temperature, and fluid corrosion.
Specialized Uses:
Re-entry Casing: Repairs damaged well sections using long couplings for length adjustment.
Multilateral Wells: employs special couplings to connect multiple wellbore branches.
Key Features Highlighted:
Precision Threading: Ensures leak-proof connections under high axial loads.
Corrosion Resistance: Alloy grades and coatings extend service life in harsh environments.
Compliance: Meets API/ISO standards for global drilling operations.
Specification
Standard & Grade : API 5CT, SY/T 6194, BS EN ISO 11960, NF M87-207, JIS G3439, IS:4270, H-40, J55, K-55, N-80, N80Q, C-75, L-80, C-90, T-95, P110, Q-125
API 5CT K55 LTC Casing Couplings, N80 BTC Casing Couplings Manufacturer, J55 BTC Casing Couplings Supplier, API 5CT L80 BTC Casing Mill, API 5CT K55 EUE Tubing Couplings,
Surface: Corrosion proofing water based paint;
Packing: Bundled or bulk , seaworthy packing or for the client's requirement
