Downhole Power Cable With Steel Core Copper Cladding
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Solution Overview
Problem
Existing methods for deploying cables in coiled tubing for downhole tools face challenges in high-temperature environments and require complex anchoring or buoyancy support, making them inconvenient and costly to install.
Innovation Solution
A cable design featuring a steel core with copper cladding and insulating layers, where the copper makes up between 20% and 40% of the total metal content, allowing the cable to support its own weight and withstand high temperatures without internal anchoring, and a termination member with a gripping element for secure connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If anchor devices or dimples are provided in coiled tubing to support the cable, then the cable is frictionally supported at intervals, but the installation becomes more complex and costly
Solution Approach 1:
The invention extracts the anchoring function from the coiled tubing system by using a self-anchoring cable construction. The cable incorporates a tensile member that actively engages with the coiled tubing inner surface through friction, eliminating the need for separate anchor devices or dimples in the tubing. This removes the complexity of installing anchoring mechanisms while maintaining reliable cable support.
2Reliability
If dense liquid is used to provide buoyancy for the cable, then the cable is supported, but the installation and handling becomes more complex
Solution Approach 1:
The invention extracts the buoyancy support mechanism and replaces it with a self-anchoring cable construction. The cable uses its own tensile member to actively engage with the coiled tubing through friction, eliminating the need for dense liquid fillers. This simplifies installation and handling operations while maintaining reliable cable support throughout the deployment.
3Reliability
If copper content is increased to improve electrical conductivity, then power transmission improves, but cable weight increases
Solution Approach 1:
The invention uses a composite conductor construction with a steel core providing tensile strength and copper cladding providing electrical conductivity. This composite structure optimizes the weight-conductivity trade-off by combining materials with complementary properties, achieving sufficient electrical performance for power transmission while maintaining manageable cable weight through the high-strength steel core.
4Stability of the object's composition
If the cable is secured along its length to the inside of coiled tubing, then cable position is stabilized, but installation complexity increases
Solution Approach 1:
The invention implements a self-service mechanism where the cable's own tensile member actively engages with the coiled tubing inner surface through friction. This self-anchoring construction stabilizes cable position without requiring external anchoring devices or complex installation procedures, as the cable secures itself during deployment through the interaction between its tensile member and the tubing surface.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The cable effectively supports itself and high-voltage power transmission over long distances in high-temperature environments, reducing installation complexity and costs by eliminating the need for internal anchoring and ensuring reliable electrical insulation and mechanical protection.
Implementation Method 1
a conducting member which carries the majority of the tensile stress on the cable
Implementation Method 2
the cable incorporating a conducting member which carries the majority of the tensile stress on the cable
Implementation Method 3
The coiled tubing and power cable have very similar coefficients of thermal expansion, so when exposed to high temperatures limited differential stress is applied to the electrical insulation
Implementation Method 4
coiled tubing may be supplied with anchor devices to frictionally support the cable at intervals
Data Source
AI summary
A cable and tubing suspends an electrically powered tool in a borehole and provides the tool with electrical power. The cable is disposed in the tubing, and the cable incorporates a conducting member which carries the majority of the tensile stress on the cable without the cable being secured along its length to the inside of the tubing. The cable may be capable of supplying high voltage electrical power, in which case the cable comprises a conducting member having a steel core, an outer cladding of copper, and at least one insulating layer surrounding the outer cladding of copper. The copper makes up between 20% and 40% of the total metal content of the cable, the cable being able to support at least its own weight.