Capillary Tubing Strings: Functions, Applications, Installation and design

--Comprehensive Guide to Capillary Tubing Functions, Design, and Industrial Applications

Explore how Capillary Tubing Strings enable precise control and monitoring in oil, gas, and chemical systems—engineered to meet ASTM and industrial standards.

Capillary Tubing Strings are used in downhole systems for oil and gas wells. 

Understanding Capillary Tubing Strings provides precise selection and usage reference for EPC engineering companies and industrial users, helping to achieve efficient and stable operation under harsh working conditions.

Definition

Capillary Tubing Strings are composed of multiple precision tubes with outer diameters typically ranging from 0.5-6mm. They are made of corrosion-resistant materials such as austenitic, duplex steel, or nickel alloy, and can achieve fine fluid control at small diameters. They have compressive properties.

Core Functionality

Precision fluid transmission: delivering chemical agents to the production layer at the bottom of the well with low loss, reducing the risk of leakage;

Real time parameter monitoring: Cooperate with sensors to provide real-time pressure and temperature monitoring data underground;

Efficient heat exchange: The multi tube parallel design can expand the heat exchange area, resulting in high thermal efficiency and meeting the heat exchange performance requirements of ASTM A269 standard;

Key Application

Oil and gas: used for long-distance control pipeline connections in oil and gas extraction, and has been applied in international oil and gas projects such as the KUG project;

Chemistry and process industry: instrument sampling, hydrogen/corrosive medium transportation, suitable for nickel based alloy materials that can withstand high temperature conditions above 200 ℃;

Aerospace: used for hydraulic control to meet operational requirements;

Power plants and seawater desalination: resistant to chloride and high-pressure scenarios.

Installation and Design

1. Installation specifications: Adopt stress free installation technology and comply with the minimum bending radius specification;

2. Material selection: 316L/2205 is preferred for conventional/chlorine containing environments, while Nickel Alloy 825/625 is recommended for high temperature/high pressure/acidic environments;

3. Packaging and Quality Control: Choose FEP/HDPE/PP/PA outer cover or flat tape packaging according to the working conditions, and conduct a 100% airtightness test after installation.

MTSCO Professional Solutions

MTSCO's Siri Tubing factory focuses on the production of Capillary Tubing, supporting the full process service from material selection to customized production. Siri welded capillary tubing can be up to 50,000fts per coil， After 100% water pressure testing, it ensures structural integrity even under pressures up to 100MPa, making it a reliable partner for industrial precision transmission scenarios.