Coiled tubing has become a critical tool in modern oil and gas operations, but its performance in extreme environments such as polar regions, deep corrosive wells, and offshore platforms is often challenged by severe temperature, pressure, and mechanical conditions. Among these, ultra-low temperatures in high-latitude regions create some of the harshest operational constraints. Below is a breakdown of the core challenges and how KWKSTEEL coiled tubing solutions are engineered to overcome them.
Challenges in Ultra-Low-Temperature Environments
1. Low-Temperature Brittleness and Toughness Loss
Steel materials naturally suffer a steep reduction in toughness at low temperatures, making them prone to brittle fracture. In conditions below minus 40°C, many conventional high-strength steels exhibit impact toughness values under 27 J, significantly increasing the risk of cracking. This risk is amplified under bending or cyclic loading conditions where fatigue life drops sharply.
Welded joints present even greater concerns. Due to microstructural differences between the weld metal and base metal, these areas show higher brittleness at low temperatures and often become the origin point for fracture.
2. Fluid Freezing and Flowability Issues Inside the Tube
Fluids containing water or wax components tend to thicken or solidify at low temperatures, blocking internal pathways and compromising operational efficiency, especially during fracturing or drilling fluid circulation.
Mitigation through antifreeze agents or heating systems increases operational cost and may introduce corrosion risk to the tubing's inner wall.
3. Equipment Compatibility and Operational Limitations
Low temperatures reduce the flexibility of coiled tubing, requiring a larger bending radius and limiting operations in complex well geometries such as multi-stage horizontal fracturing. At the same time, surface equipment like injectors, reels, and lubrication systems experience increased hydraulic oil viscosity, leading to higher failure rates.
Performance Advantages of KWKSTEEL Coiled Tubing
KWKSTEEL coiled tubing is engineered specifically to handle extreme cold environments with outstanding impact toughness at subzero temperatures. For example:
• TS-90 coiled tubing achieves 84 J of impact energy at minus 50°C.
• TS-110 delivers 74 J at minus 50°C.
• High-strength RC-110 reaches 103 J at minus 50°C.
• According to API Spec 5ST Section 6.2.6, fracture toughness requirements at 0°C must meet a minimum of 41 J.
KWKSTEEL coiled tubing far exceeds these requirements even at temperatures much lower than the standard testing conditions. This exceptional low-temperature toughness significantly enhances operational reliability, safety, and stability in extremely cold regions, reducing downtime and improving overall performance.
