Downhole Metallic Structure Signaling via Cathodic Protection Current
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Solution Overview
Problem
The presence of a platform in well installations complicates the transmission of electrical power and signals using electromagnetic wireless communication, leading to issues such as shorting and noise, and existing systems require costly and hazardous cable installations or significant modifications.
Innovation Solution
A well installation electrical transmission system utilizing an impressed current cathodic protection system to modulate current for transmitting power and signals through the downhole metallic structure, minimizing the need for additional connections and modifications by integrating with existing systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If EM wireless communication is used to transmit electrical power and signals through the well installation metallic structure, then power and signal transmission is achieved, but the presence of a platform causes shorting and noise that degrade transmission quality
Solution Approach 1:
The patent introduces an intermediary coupling mechanism between the platform and downhole metallic structure that allows electromagnetic signals to be transmitted without direct electrical contact. This intermediary approach prevents shorting while enabling signal transmission through the metallic structure, resolving the conflict between achieving transmission and avoiding harmful shorting effects.
2Reliability
If cables are installed in hazardous or difficult to access areas to transmit power and signals, then reliable transmission is achieved, but the installation becomes hazardous and difficult
Solution Approach 1:
The patent replaces the mechanical cable installation system with an electromagnetic field-based transmission system. Instead of physically installing cables in hazardous areas, the system uses electromagnetic coupling through the existing metallic structure, eliminating the need for difficult cable routing while maintaining transmission reliability.
3Adaptability or versatility
If significant and expensive workover activities are performed to retrofit signal application systems, then transmission capability is achieved, but the cost and complexity increase significantly
Solution Approach 1:
The patent makes the existing metallic structure serve multiple functions: it continues to provide its original structural and flow containment functions while simultaneously acting as a transmission medium for electromagnetic signals. This multi-functionality eliminates the need for separate cable systems or complex retrofitting activities.
4Ease of operation
If connections are made to the platform metallic structure for signal transmission, then power and signals can be applied, but shorting occurs at the platform
Solution Approach 1:
The patent employs an intermediary coupling mechanism that allows electromagnetic energy to be transferred to the downhole metallic structure without creating direct electrical connections at the platform that would cause shorting. This intermediary approach enables signal application while preventing harmful shorting effects.
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
Facilitates convenient and effective transmission of electrical power and signals while avoiding hazardous areas and costly modifications, allowing for wireless control and power to downhole devices like subsurface safety valves.
Implementation Method 1
a transmitter in such a system may be connected between the well installation metallic structure and a reference connection to earth
Implementation Method 2
a circuit is formed by the well installation metallic structure acting as the signal channel in combination with an earth return path
Data Source
AI summary
Well installation electrical transmission system for use in a well installation having a downhole metallic structure (2) and a platform (3) provided above the level of a borehole (B) for the transmission of at least one of electrical power and electrical communication signals between an out of hole station (4) and a downhole station (5). In some instances, the out of hole station is arranged to modulate current applied to the downhole metallic structure by an impressed current cathodic protection system. In some instances the out of hole station is connected electrically between a portion of the platform or of the metallic structure galvanically connected to the downhole metallic structure, and a downhole connection location on a second set of downhole metallic structure in a second borehole.