Casing-Mounted Electrodes for Water Flood Detection
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Solution Overview
Problem
Existing monitoring techniques fail to detect water floods approaching a producing well until they are close, leading to hydrocarbon contamination and significant financial losses, as they often cannot accurately measure the proximity of water floods until they begin to dilute hydrocarbons.
Innovation Solution
The technique involves injecting current into the formation surrounding a well and measuring potentials between casing-mounted electrodes to detect resistivity changes caused by the approaching water flood, allowing for the determination of its location.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing electric field measurement techniques are used, then monitoring is possible, but detection occurs too late when water flood has already diluted hydrocarbons
Solution Approach 1:
The patent performs preliminary action by measuring potentials at multiple electrodes before the water flood reaches the producing well. The system continuously monitors potential differences at various distances from the wellbore, enabling early detection of the water flood's approach. This allows operators to take preventive actions before hydrocarbon dilution occurs, resolving the timing issue where detection was previously too late.
2Measurement precision
If current injection and potential measurement between casing-mounted electrodes is used, then early water flood detection is enabled, but device complexity increases
Solution Approach 1:
The patent applies universality by using the well casing as a multi-functional element: it serves both as the structural well casing and as an electrode for potential measurements. The casing-mounted electrodes utilize the existing casing structure, eliminating the need for separate measurement infrastructure. This reduces device complexity while enabling precise water flood proximity detection through potential difference measurements between multiple electrode locations.
3Reliability
If multiple casing-mounted electrodes are deployed for early detection, then financial losses are prevented, but manufacturing and installation complexity increases
Solution Approach 1:
The patent merges the monitoring function with the existing well casing structure. Instead of installing separate measurement devices, the system integrates electrodes directly onto the casing, combining the structural and monitoring functions. This approach simplifies manufacturing and installation by utilizing the already-present casing infrastructure, reducing the need for additional components and installation steps while maintaining reliable hydrocarbon protection through early water flood detection.
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 method enables early detection of water floods, preventing contamination and financial losses by accurately determining their proximity and location, thereby optimizing hydrocarbon extraction.
Implementation Method 1
measuring potentials between multiple casing-mounted electrodes... detect resistivity changes caused by the approaching water flood
Data Source
AI summary
A system for locating water floods, in some embodiments, comprises: multiple non-reference electrodes with insulative pads for coupling to a borehole casing; a reference electrode with an insulative pad for coupling to the borehole casing; and multiple transducers coupled to the reference and non-reference electrodes, each of said electrodes coupled to one or more of the multiple transducers, wherein each transducer coupled to a non-reference electrode determines a differential non-reference potential between that non-reference electrode and the reference electrode, and wherein a transducer that couples to the borehole casing determines an absolute reference potential between the borehole casing and the reference electrode; wherein the differential non-reference potentials are mathematically combined with the absolute reference potential to produce absolute non-reference potentials; wherein scaling weights are applied to said absolute non-reference potentials to produce scaled absolute potentials that are used to determine a water flood location.