Bridge Plug Sensor for Bottom-Hole Pressure Monitoring
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Solution Overview
Problem
In subterranean well drilling and completion, accurate bottom hole measurements are challenging due to obstructions within the well casing, such as packers and bridge plugs, which prevent the installation of fiber optics and hinder communication with downhole sensors during hydraulic fracturing and initial shut-in periods.
Innovation Solution
Incorporating sensors and an acoustic signal generator within bridge plugs that communicate with a fiber optic cable, using electro-acoustic technology to transmit pressure measurements as acoustic signals through the optical fiber, allowing for real-time monitoring of multiple stages despite casing obstructions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bridge plugs and packers are installed to isolate zones for fracturing operations, then zone isolation is achieved, but fiber optic cable passage is blocked preventing downhole measurements
Solution Approach 1:
The fiber optic cable is integrated within the bridge plug structure itself, with the cable running through the interior of the plug. This nesting approach allows the fiber to be positioned inside the isolation device, enabling measurements at the isolated zone while maintaining the plug's sealing function.
Solution Approach 2:
The bridge plug is designed to perform multiple functions simultaneously: it provides zone isolation through its sealing elements, while also serving as a measurement platform by housing sensors and fiber optic cables. This multi-functionality eliminates the need for separate measurement devices and allows continuous monitoring during fracturing operations.
2Productivity
If bridge plugs are deployed to seal off well portions, then fracturing operations can proceed, but communication with downhole sensors is hindered
Solution Approach 1:
Sensors and fiber optic cables are pre-installed within the bridge plug structure before deployment into the well. This preliminary action ensures that measurement capabilities are already in place at the target zone, eliminating the need for subsequent wireline or coiled tubing operations to install measurement equipment.
Solution Approach 2:
The fiber optic cable acts as an intermediary transmission medium, carrying measurement data from sensors located within the bridge plug to the surface. This intermediary approach allows information to be transmitted through the plug structure itself, bypassing the need for separate communication pathways.
3Measurement precision
If fiber optics are run on the outside of tubing to surface, then optical sensing can be performed, but structures in the well prevent fiber installation over entire length
Solution Approach 1:
Instead of requiring a single continuous fiber optic cable running from surface to the deepest measurement point, the system segments the fiber installation by integrating cables within individual bridge plugs at different depths. Each plug contains its own fiber and sensor assembly, allowing measurements at multiple zones without needing one continuous cable installation.
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 accurate bottom hole pressure monitoring during fracturing and shut-in periods, facilitating the identification of isolation issues between zones and optimizing fracturing operations by conveying data through the optical fiber cable external to the casing.
Implementation Method 1
Incorporating sensors and an acoustic signal generator within bridge plugs that communicate with a fiber optic cable, using electro-acoustic technology to transmit pressure measurements as acoustic signals through the optical fiber
Data Source
AI summary
Example apparatus, methods, and systems are described for performing bottom hole measurements in a downhole environment. In an example system, a bridge plug is deployed at a downhole location of a cased well, An optical fiber cable is deployed exterior to the casing of the well. The bridge plug includes a sensor and an acoustic signal generator, which transmits acoustic signals through the casing to the optical fiber cable.