Casing-Mounted Electrodes for Water Flood Location Monitoring
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Solution Overview
Problem
Existing monitoring techniques fail to detect water floods approaching producing wells until they are close, leading to hydrocarbon contamination and significant financial losses.
Innovation Solution
Measuring potentials between a well casing and circumferentially mounted electrodes by injecting current into the formation, which reflects resistivity changes caused by the water flood, allowing for the determination of water flood locations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing electric field measurement techniques are used, then monitoring is possible, but detection is delayed until water floods are close to the producing well
Solution Approach 1:
The monitoring system is segmented into multiple independent measurement zones along the wellbore, with each zone having its own electrode pair. This allows detection of water floods at different locations and stages of approach, providing early warning before the water flood reaches the producing well.
Solution Approach 2:
The patent introduces an intermediary measurement approach by measuring electric potentials between casing and electrodes rather than directly measuring electric fields. This intermediary measurement method is more sensitive to resistivity changes caused by approaching water floods, enabling earlier detection.
2Device complexity
If water flood detection is delayed, then monitoring complexity is reduced, but hydrocarbon contamination and financial losses occur
Solution Approach 1:
The wellbore casing serves multiple functions: it acts as both the production well structure and one electrode in the monitoring system. The electrodes mounted on the casing serve dual purposes as both structural components and measurement sensors, reducing the need for separate monitoring infrastructure.
Solution Approach 2:
The existing wellbore infrastructure (casing, cement sheath, formation) serves the monitoring function without requiring additional external structures. The system uses the wellbore's own electrical properties and existing components to detect water floods, eliminating the need for complex external monitoring equipment.
3Measurement precision
If current injection is used to measure potentials, then water flood location can be determined, but energy consumption increases
Solution Approach 1:
The system uses low-level current injection sufficient only to create measurable potential differences, rather than high-current operations. The measurement current is kept minimal while still providing adequate signal strength for accurate location determination, optimizing the balance between measurement precision and energy consumption.
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 early detection of water floods, preventing contamination and financial losses by accurately determining their proximity and location.
Implementation Method 1
measuring potentials between a well casing and electrodes circumferentially mounted on the casing... which reflects resistivity changes caused by the water flood
Data Source
AI summary
A system for locating water floods, in some embodiments, comprises: multiple transducers for coupling to a borehole casing to inject current into a formation within which the casing is disposed; and multiple electrodes, each of the electrodes coupled to a different one of the multiple transducers when coupled to the casing, wherein each of the multiple transducers is used to determine a potential between the casing and a corresponding one of the multiple electrodes to which the transducer is coupled, wherein the potentials from the multiple transducers are used to determine a water flood location.