Stranded Wire Strength Members for Wellbore Cables
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Solution Overview
Problem
Traditional wellbore armored logging cables face issues with corrosion resistance and torque balancing, leading to weakened armor wires and potential gas migration hazards, which compromise their strength and safety during high-pressure well operations.
Innovation Solution
The use of polymer jacketed stranded filaments as strength members, with multiple filaments bundled and encased in a polymer jacket, provides improved corrosion resistance and torque balancing, while minimizing gas migration by filling interstitial spaces with polymeric materials to prevent fluid and gas infiltration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional zinc-coated steel armor wire is used, then the cable provides initial corrosion protection, but the zinc passivation at elevated temperatures leads to rapid strength loss and cable failure
Solution Approach 1:
The patent applies composite materials by combining polymer-coated steel strands with traditional armor wire layers. The polymer coating (such as polyethylene or polypropylene) provides continuous corrosion protection that does not suffer from passivation issues like zinc coating. This composite structure maintains both the mechanical strength of steel and the corrosion resistance of polymer, resolving the contradiction between initial protection and long-term strength retention at elevated temperatures.
Solution Approach 2:
The patent changes the material parameter from zinc-coated steel to polymer-coated steel. This parameter change fundamentally alters the corrosion mechanism from electrochemical (zinc) to physical barrier (polymer), eliminating the passivation problem that occurs at elevated temperatures. The polymer coating maintains its protective properties across a wider temperature range, preserving armor wire strength.
2Strength
If armor wire is used to carry cable weight, then structural support is provided, but torque imbalance and helical arrangement cause torsional loads and cable damage
Solution Approach 1:
The patent segments the armor structure into multiple independent layers with different functions. The inner layer provides structural support and weight carrying, while the outer layer is specifically designed for torque balancing. This segmentation allows each layer to optimize its performance for its specific function, reducing the harmful effects of torque imbalance on the overall cable structure.
Solution Approach 2:
The patent introduces an intermediary torque-balancing layer between the load-bearing inner layer and the external environment. This intermediate layer acts as a mediator that absorbs and distributes torsional stresses, preventing them from transferring to the load-bearing armor wires. The intermediary layer protects the structural support elements from harmful torque effects.
3Ease of manufacture
If conventional cable construction is used, then manufacturing is straightforward, but annular gaps allow corrosive fluids and gas to infiltrate, causing continuous damage
Solution Approach 1:
The patent applies flexible polymer shells (coatings) over the armor wire strands. These thin film polymer layers conform to the helical arrangement of the wires while providing continuous sealing. The flexible nature of the polymer shell allows it to accommodate cable movement and deformation without cracking, maintaining the barrier against fluid infiltration throughout the cable's operational life.
Solution Approach 2:
The patent creates a composite structure by combining the metal armor wires with polymer coating materials. This composite approach fills the annular gaps between wires while maintaining the mechanical integrity of the cable. The polymer material provides the sealing function against corrosive fluids and gas, while the steel wires provide structural strength, achieving both gap sealing and ease of manufacture.
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 solution enhances the cable's durability and safety by maintaining strength and preventing gas migration, allowing for efficient data transmission and power conduction with reduced risk of explosion hazards and increased cable lifespan.
Implementation Method 1
a polymer jacket encasing the central filament and filaments disposed adjacent the central filament
Implementation Method 2
at least three (3) filaments helically disposed adjacent the central filament
Implementation Method 3
minimizing gas migration by filling interstitial spaces with polymeric materials to prevent fluid and gas infiltration
Data Source
AI summary
Disclosed are high strength wellbore electric cables, which are formed from a plurality of strength members. The strength members are formed from several stranded filament wires which may be encased within a jacket of polymeric material. The strength members may be used as a central strength member, or even layered around a central axially positioned component or strength member, to form a layer of strength members. Cables of the invention may be of any practical design, including monocables, coaxial cables, quadcables, heptacables, slickline cables, multi-line cables, etc., and have improved resistant to corrosion, torque balancing, and gas migration from a wellbore to the surface.