Monitoring Well Sealing Plug With Electromagnetic Data Transmission
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Monitoring well installations in oil and gas fields face challenges in maintaining a seal to prevent fluid escape while allowing for data collection from below cement plugs, as traditional sealing methods like cement plugs can create leak paths and hinder data extraction.
Innovation Solution
A monitoring well installation with a metallic casing and a sealing material plug featuring an axial spacing to allow the plug to seal against the formation, combined with a downhole sensing tool and electromagnetic communication apparatus to transmit data across the plug, minimizing fluid escape and enabling effective parameter monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a cement plug is used for sealing the borehole, then sealing effectiveness is improved, but data extraction capability deteriorates
Solution Approach 1:
The cement plug is segmented by creating a hollow cavity within it, dividing the solid sealing mass into functional zones: the outer cement matrix provides sealing, while the inner hollow space accommodates the sensor and communication devices, enabling both sealing and data extraction functions simultaneously
Solution Approach 2:
The sensor device and communication apparatus are nested within the hollow cavity of the cement plug, allowing the monitoring system to be contained within the sealing structure itself, thus achieving data extraction without compromising the seal
2Loss of information
If a cable is passed through the cement plug for data transmission, then data extraction capability is improved, but sealing effectiveness deteriorates
Solution Approach 1:
The communication function is extracted from traditional cable-based systems and repositioned into the hollow cavity of the cement plug. The electromagnetic communication device transmits signals through the formation rather than through a cable passing through the seal, eliminating the leak path while maintaining data transmission capability
Solution Approach 2:
The hollow cavity acts as an intermediary space that allows electromagnetic signals to be transmitted through the formation without requiring a physical cable to penetrate the cement seal, thus mediating between the need for communication and the need for sealing
3Ease of manufacture
If the outer cement seal is made by pumping cement into the gap between casing and borehole wall, then installation ease is improved, but sealing effectiveness deteriorates
Solution Approach 1:
The casing is prepared in advance by creating an axial spacing or gap at the intended plug location before the cement plug is installed. This preliminary action ensures that when the cement is pumped, it will form a proper seal against the formation rather than simply filling an existing annular space, thereby improving sealing effectiveness while maintaining installation simplicity
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 monitors downhole parameters while minimizing fluid escape risks, providing a reliable and efficient means to collect data from below the sealing plug without creating additional leak paths.
Implementation Method 1
a transmitter or transceiver for applying signals via the spaced contacts to generate a voltage dipole in the casing to cause electric field in the formation in the region of the plug such as to result in current flow, in use, in the casing portion above the axial spacing
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A monitoring well installation comprising metallic casing (2) and a sealing material plug (6) provided downhole in the borehole for sealing the borehole against the egress of fluid from a zone below the plug. There is an uncased length of borehole at least 10m in length in which the plug seals against the formation. There is provided a downhole sensing tool (3) located below the plug (6) and a communication arrangement (31, 5, 4) for use in transmitting data from the sensing tool towards the surface, which comprises an across plug communication apparatus (5) comprising a pair of spaced contacts (51) contacting the casing and/or the formation and a transmitter located below the plug (6) for transmitting signals carrying data across the plug towards the surface.