Electromagnetic Telemetry Across Cement Plugs
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for monitoring conditions within a plugged subterranean wellbore are inadequate, particularly across a surface cement plug, as they lack effective means for continuous communication of parameters like pressure and temperature due to the absence of conductive casing or tubing.
Innovation Solution
The use of electromagnetic telemetry systems, including induction and galvanic telemetry, to transmit information through the surface cement plug and surrounding earth, employing transmitter and receiver coils, and insulated gaps or toroidal coils to facilitate communication across the plugged wellbore.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If conductive casing or tubing is used for transmitting information, then information transmission is enabled, but the wellbore cannot be permanently plugged with cement
Solution Approach 1:
The patent replaces the mechanical/electrical conduction system (casing or tubing) with an electromagnetic field-based transmission system. Transmitter and receiver coils generate and detect electromagnetic signals that can penetrate the cement plug, eliminating the need for conductive physical pathways while maintaining information transmission capability.
Solution Approach 2:
The patent introduces electromagnetic fields as an intermediary medium to transmit information through the cement plug. The transmitter coil converts electrical signals to electromagnetic fields, which then pass through the cement barrier, and the receiver coil converts them back to electrical signals, enabling communication without direct conductive contact.
2Reliability
If a surface cement plug is emplaced to permanently close the wellbore, then permanent closure is achieved, but information transmission from below the plug becomes impossible
Solution Approach 1:
The patent replaces the need for physical conductive pathways (which would compromise the cement plug) with electromagnetic field transmission. This allows the cement plug to maintain its permanent closure function while electromagnetic signals pass through it to enable information transmission.
Solution Approach 2:
The patent changes the transmission medium from requiring physical conductive contact to using electromagnetic field propagation. This parameter change allows information to pass through the cement plug by utilizing the electromagnetic properties of the cement and surrounding formation rather than requiring electrical conductivity through casing or tubing.
3Reliability
If continuous monitoring is implemented to detect potential breaches, then safety is improved, but the system complexity increases due to installation requirements
Solution Approach 1:
The patent creates a system where the same electromagnetic transmission infrastructure serves multiple functions: transmitting information from sensors below the cement plug and providing a means to power the downhole electronics. This multi-functionality reduces overall system complexity compared to separate systems for each function.
Solution Approach 2:
The electromagnetic field acts as a universal intermediary that enables both information transmission and power transfer across the cement barrier. This single intermediary mechanism simplifies the system architecture compared to requiring separate conductive pathways for each function.
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 continuous monitoring and duplex communication of information and power across the surface cement plug, allowing for real-time parameter detection and potential breach identification, even in permanently plugged wells.
Implementation Method 1
The transmitter coil is operably associated with one or more sensors that are configured to detect or monitor particular conditions or parameters within the wellbore below the surface cement plug. In accordance with preferred embodiments, a controller is operably associated with the transmitter coil and causes the transmitter coil to create a time-varying voltage signal which is indicative of the detected parameter or parameters. Current is induced into the receiver coil by the transmitter coil.
Implementation Method 2
In accordance with alternative described embodiments, galvanic telemetry is used to transmit information uphole to surface across a surface cement plug. In accordance with one described embodiment, an insulated gap is provided at the lower end of the surface cement plug which separated the surface cement plug from the completion plug and casing below. An electrical potential is applied across the insulated gap causing current to flow upwardly through the surface cement plug.
Data Source
AI summary
Systems and methods for communicating information relating to at least one wellbore condition across a surface cement plug in a plugged off wellbore. Induction telemetry or galvanic telemetry are used to transmit electromagnetic signals across the axial length of a surface cement plug.