Metal-Encapsulated ESP Cable Assembly for Gas-Tight Power Feedthroughs
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Solution Overview
Problem
Existing Electrical Submersible Pumping (ESP) systems face high failure rates due to power cable issues, particularly at high pressures and temperatures within oil wells, where gases can penetrate the cable jacket and cause connector failures, attributed to 69% of failures as identified by Saudi Aramco.
Innovation Solution
The system eliminates electrical connectors by using pre-assembled cable assemblies with a low-temperature alloy like bismuth for encapsulation, including a penetrator body, splice, and pot head, with metal-to-metal seals and a pressure test port to ensure integrity, and utilizes bismuth to fill void spaces for enhanced sealing and disassembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrical connectors and bulkheads are used in high pressure and temperature environments, then electrical connections can be established, but gas penetration through cable jackets causes connector failures and high system failure rates
Solution Approach 1:
The invention removes electrical connectors and bulkheads from the system entirely. Instead of using conventional connectors that are susceptible to gas penetration, the patent employs a direct metal-to-metal encapsulated connection where the cable itself becomes the sealing element, eliminating the vulnerable connector components that were the failure point
Solution Approach 2:
The invention uses composite construction with the cable jacket serving as both electrical insulation and pressure barrier, combined with metal encapsulation at critical junctions. This composite approach creates a unified structure that simultaneously provides electrical conduction, pressure containment, and gas sealing without requiring separate connector components
2Reliability
If multiple barriers and connectors are used to protect against high pressure and temperature, then electrical connections are established, but the system complexity increases with bulkheads and penetrators
Solution Approach 1:
The invention merges the functions of electrical insulation, pressure containment, and gas sealing into a single integrated cable assembly structure. The cable jacket and metal encapsulation work together as a unified barrier system, eliminating the need for separate bulkheads, penetrators, and connectors that would increase structural complexity
Solution Approach 2:
The cable jacket serves multiple functions simultaneously: it provides electrical insulation for the conductors, acts as a pressure barrier against high downhole pressures, and serves as a gas seal to prevent gas penetration. This multi-functional design eliminates the need for separate specialized components for each function
3Reliability
If conventional cable assemblies with connectors are used, then electrical power can be transmitted, but failure rate reaches 69% due to connector and cable issues in high temperature environments
Solution Approach 1:
The invention changes the material parameters and design specifications of the cable assembly to withstand high temperature environments. This includes using high-temperature resistant insulation materials, heat-resistant metal encapsulation, and designing the cable structure to maintain its mechanical and electrical properties at elevated temperatures where conventional assemblies would fail
4Ease of operation
If electrical connectors and bulkheads are used to establish electrical connections, then power can be transmitted through the wellhead and packer, but the number of failure points increases
Solution Approach 1:
The invention removes electrical connectors and bulkheads from the system entirely. Instead of using conventional connectors that are susceptible to gas penetration, the patent employs a direct metal-to-metal encapsulated connection where the cable itself becomes the sealing element, eliminating the vulnerable connector components that were the failure point
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
This solution significantly reduces failures by creating a sealed, reliable electrical connection that withstands high pressures and temperatures, with bismuth's melting point allowing for selective use based on wellbore temperatures and enabling easy disassembly, thus improving the durability and reliability of downhole electrical connections.
Implementation Method 1
the void between the splice tube and cable being encapsulated in a low temperature alloy
Implementation Method 2
metal-to-metal seals and a pressure test port to ensure integrity
Implementation Method 3
bismuth's melting point allowing for selective use based on wellbore temperatures and enabling easy disassembly
Data Source
AI summary
1. A pre-assembled cable assembly for a penetrator body or pothead comprises at least one cable located in a volume of the penetrator body or pothead, the volume around the cable being encapsulated in a low temperature alloy. The cable or cables may include a spliced electrical connection located a volume of the penetrator body or pothead such that the volume around the spliced electrical connection being encapsulated in a low temperature alloy.