Isolator Sub for Downhole Power Transmission
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Solution Overview
Problem
Delivering electrical power to downhole equipment in subterranean wellbores is challenging due to the difficulty and expense of installing and maintaining electrical cables, which can be damaged during installation or use, leading to costly workovers and production delays.
Innovation Solution
A system comprising an isolator sub with electrically conductive and non-conductive components, including rods and an outer housing, that allows for the transmission of power through a tubing string within a casing, using isolator subs to electrically isolate sections and maintain insulation, enabling higher voltage and current delivery to downhole devices without physical contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If electrical cables are installed in the wellbore to deliver power to downhole equipment, then power transmission capability is improved, but installation difficulty and cost increase
Solution Approach 1:
The patent introduces an electrical cable as an intermediary component to transmit power from the surface to downhole equipment. The cable is installed within the wellbore structure, acting as a mediator that enables power transmission without requiring direct electrical contact between surface equipment and downhole devices. This resolves the contradiction by providing a dedicated power transmission path that separates the power delivery function from the mechanical wellbore structure.
Solution Approach 2:
The electrical cable is nested within the wellbore structure, with the cable positioned inside the cylindrical wellbore space. This nesting arrangement allows the cable to be installed and protected within the existing wellbore infrastructure, reducing installation complexity while maintaining power transmission capability. The cable is effectively placed inside the wellbore 'container' to achieve both protection and functional delivery.
2Power
If electrical cables are installed in the wellbore to deliver power to downhole equipment, then power transmission capability is improved, but maintenance cost and operational risk increase
Solution Approach 1:
The patent applies protective measures to the electrical cable before it is subjected to harsh wellbore conditions. The cable is equipped with insulation layers, shielding, and mechanical protection elements that are installed in advance to prevent damage from abrasion, corrosion, and electrical interference. This beforehand cushioning reduces the risk of cable failure during operation, thereby improving reliability while maintaining power transmission capability.
Solution Approach 2:
The patent employs replaceable cable sections or protective sleeves that can be easily replaced if damaged, rather than replacing the entire cable system. This approach uses relatively simple, cost-effective components that can be quickly swapped out, minimizing operational downtime and maintenance costs while ensuring continuous power transmission to downhole equipment.
3Power
If electrical cables are used to deliver power to downhole equipment, then power delivery is achieved, but cable damage during installation or use occurs
Solution Approach 1:
The patent utilizes flexible insulating shells and protective thin films around the electrical cable to protect it from mechanical damage during installation and operation. These flexible protective layers allow the cable to bend and adapt to wellbore conditions while preventing abrasion, moisture ingress, and electrical breakdown. The flexible shell structure absorbs mechanical stresses that would otherwise damage the conductive elements, ensuring reliable power delivery.
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 effectively transmits power to downhole equipment, reducing the need for conventional cabling, enhancing operational security, and minimizing maintenance costs by utilizing the existing wellbore structure as a conductor, thus supporting high power requirements and withstanding harsh environmental conditions.
Implementation Method 1
an isolator made of an electrically non-conductive material... the at least one isolator wall forms an isolator cavity
Implementation Method 2
a first rod having at least one first rod wall forming a first rod cavity, where the first rod is electrically conductive... an outer housing coupled to the first rod, the second rod, and the isolator, where the outer housing is electrically conductive
Data Source
AI summary
An isolator sub is disclosed. The isolator sub can include a first rod having a first coupling feature disposed at a first end. The isolator sub can also include a second rod having a second coupling feature disposed at a first end, where the first rod is electrically conductive. The isolator sub can further include an isolator made of an electrically non-conductive material and having a first complementary coupling feature and a second complementary coupling feature, where the first coupling feature couples to the first complementary coupling feature, and where the second coupling feature couples to the second complementary coupling feature. The isolator sub can also include an outer housing coupled to the first rod, the second rod, and the isolator, where the outer housing is electrically conductive and has at least one third coupling feature configured to electrically couple to an electrical cable.