Tubing-Encased Conductor Welding With Insulation-Protecting Spacer
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Solution Overview
Problem
Conventional methods for welding electrical tools to tubing-encased conductors (TECs) risk damaging insulation due to heat and can lead to short circuits from conductor expansion, necessitating improved joining techniques that prevent insulation damage and short circuits.
Innovation Solution
A method involving the removal of a section of electrical insulation from the TEC, followed by welding an end member to the outer tube, and inserting a spacer with insulative material to protect the insulation and prevent short circuits, allowing for secure and heat-resistant connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If welding is performed directly on the TEC outer tubing, then electrical tools can be securely connected, but the insulation material inside the TEC is damaged by heat
Solution Approach 1:
The outer tubing is segmented into a welded portion and an insulated portion. The insulation is removed only at the specific location where welding is required, while the rest of the insulation remains intact to protect the conductor from heat damage during the welding process.
Solution Approach 2:
The insulation removal is applied locally only at the welding zone rather than throughout the entire TEC. This localized modification allows welding to proceed without compromising the overall insulation protection, maintaining different properties in different regions of the TEC.
2Object-affected harmful factors
If insulation is removed prior to welding to prevent heat damage, then insulation is protected, but the conductor can short circuit by contact with the outer tube due to thermal expansion
Solution Approach 1:
An intermediary component (such as a ceramic bead or insulating sleeve) is introduced between the conductor and the outer tubing at the welding zone. This intermediary maintains electrical isolation even when the insulation is removed, preventing short circuits while allowing the welding process to proceed without damaging the remaining insulation.
Solution Approach 2:
The intermediary insulating component is pre-installed or pre-positioned at the welding location before the welding process begins. This preliminary action ensures that electrical isolation is already in place before any heat is applied, preventing potential short circuits from conductor expansion during welding.
3Ease of operation
If connections are made on the rig floor, then field assembly is possible, but the process is time-consuming
Solution Approach 1:
The TEC is pre-prepared with the insulation removed at the welding zone and intermediary components positioned before deployment to the rig site. This preliminary preparation enables rapid assembly and welding operations to be performed in the shop, eliminating time-consuming field assembly operations while maintaining the ability to make connections in the field if needed.
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
Enables reliable and durable connections of electrical tools to TECs without damaging insulation, preventing short circuits and accommodating thermal expansion, allowing shop-based assembly rather than rig-floor connections.
Implementation Method 1
welding an end member to an outer surface of the outer tube at a weld joint that is axially between the end of the TEC and the end of the electrical insulation
Implementation Method 2
electrical insulation layered radially between the conductor and the tubing to prevent short circuits between the tubing and the conductor
Data Source
AI summary
A method includes removing a section of electrical insulation proximate an end of a tubing-encased conductor (TEC) to form an end of electrical insulation that is axially recessed relative to the end of the TEC. The method includes welding an end member to an outer surface of the outer tube at a weld joint that is axially between the end of the TEC and the end of the electrical insulation to protect the electrical insulation from heating damage from welding. The method includes replacing the section of electrical insulation proximate the end of the TEC by inserting a spacer into the end of the TEC between the outer tube and the electrical conductor after welding the end member to the outer surface of the TEC. A tool can be electrically connected to the electrical conductor and the tool can be welded to the end member.