Slim logging tools have become increasingly important in the oil and gas industry, particularly for accessing narrow-diameter wells and for deployment through drill pipes to log horizontal and high-angle wells. Reliable and effective components are key for developing efficient downhole tool systems. To address these needs, a specialized slip ring was required that could meet the compact size requirements and withstand extreme well conditions for advanced formation-evaluation tools. The solution was found in a product developed by UEA and our Alpha Slip Ring line.
A market demand for advanced slim logging tools emerged, enabling service providers to collect high-quality data in real-time or memory mode using cutting-edge conveyance systems. In the creation of a tool suite with a 2 1/4-inch outer diameter, UEA initiated to engineer a slip ring that met size and environmental requirements for a downhole swivel tool.
A slip ring, which transfers electrical current between stationary and rotating components, consists of two main parts: the conductor ring core and the brushes with housing. The conductor rings are made from electrically conductive metals, mounted on a shaft and insulated, while the brushes maintain a continuous electrical connection as the assembly rotates. The Alpha Slip Ring’s integration in the downhole swivel allowed the top section to rotate independently from the lower section, thus preventing wireline cable damage caused by twisting.
Due to the project’s specialized requirements, the Alpha Slip Ring needed to have a custom solution, addressing multiple hurdles:
- Compact Design: The slip ring required a very small size.
- Harsh Environment Tolerance: The slip ring needed to function reliably in extreme conditions.
- Oil Flow Compatibility: The design had to allow oil to flow through the unit.
- Resistance to Shock and Vibration: The slip ring had to meet rigorous shock and vibration standards.
The Solution
Size Optimization
The slip ring’s design called for a diameter of less than 1 1/4 inches and a length under 6 inches. UEA addressed this by modifying standard brush rods and brushes with a new unibody design, which enhanced the compactness and efficiency of the assembly.
High-Temperature Resilience
The slip ring was designed to operate within a temperature range of -40°C to 180°C. High-temperature-resistant materials, such as specialized plastics and solder, were utilized to provide performance in extreme environments. The slip ring was engineered for dependable electrical connections even during rotation at elevated temperatures.
Oil Flow Integration
To accommodate oil flow, we added holes to the slip ring’s cover and openings at both ends. This allowed oil to clean the unit by carrying away debris. A stainless-steel housing was used to prevent corrosion, and the cover was designed to be removable for easy inspection and maintenance.
Shock and Vibration Resistance
The Alpha Slip Ring met rigorous shock and vibration requirements, including a shock rating of 500 G’s for 2 milliseconds and a vibration requirement of 10 GRMS at 400 Hz. UEA conducted detailed testing, such as drop tests from 1 foot onto a hard surface, monitoring electrical continuity throughout. The slip ring passed these tests, demonstrating its durability.
Minimized Torque
The slip ring was designed to operate with a starting torque of less than 16 inch-ounces. This was achieved while maintaining low contact resistance between the brushes and rings, enabling longevity and reliability within the compact design.
Results
UEA delivered the first custom Alpha Slip Ring meeting all the specified requirements for the downhole swivel project. The unibody design accommodated the compact size while integrating oil flow and debris removal features. These innovations allowed the slip ring to function effectively in harsh environments, solidifying its role in advanced slim logging tools.