Borehole Fluid Interface Tracking via Electric and Gravity Sensors
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Solution Overview
Problem
Current methods for tracking the water-to-hydrocarbon interface in hydrocarbon reservoirs require knowledge of formation porosity, which is not always available, making it challenging to monitor hydrocarbon extraction efficiently.
Innovation Solution
A method and apparatus that use electric field and gravitational field measurements, taken before, during, and after fluid injection, to estimate the displacement of the fluid-to-hydrocarbon interface without requiring porosity data, involving an electrode for voltage application, electric field sensors, and gravity sensors in boreholes to process these measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional methods using porosity data are used to track the water-to-hydrocarbon interface, then measurement precision can be maintained, but the method becomes inapplicable when porosity information is unavailable
Solution Approach 1:
The patent changes the measurement parameters from porosity-based electrical properties to gravity field measurements. By measuring gravitational field variations caused by density differences between water and hydrocarbons, the system can track the fluid interface without requiring porosity data, thus resolving the contradiction between adaptability and measurement precision
Solution Approach 2:
The patent replaces the traditional electrical measurement system (which requires porosity information) with a gravity-based measurement system. The gravity sensor detects density variations in the formation, providing interface tracking capability that is independent of porosity data, thereby achieving versatility without sacrificing accuracy
2Adaptability or versatility
If only gravity measurements are used to track the fluid interface, then porosity data is not required, but measurement precision and reliability are reduced
Solution Approach 1:
The patent merges gravity measurements with electrical resistance measurements into a combined monitoring system. The gravity sensor provides interface location information independent of porosity, while the electrical measurements provide complementary data about fluid saturation and formation properties, together enhancing overall system reliability
Solution Approach 2:
The system uses feedback from multiple measurement sources (gravity and electrical) to continuously update and refine the fluid interface position estimate. The processor integrates data from both sensor types, using the gravity measurements as a reliable baseline that does not depend on porosity assumptions, thereby improving measurement reliability
3Measurement precision
If a combination of electric and gravity measurements is used, then reliability and precision are improved, but device complexity increases
Solution Approach 1:
The patent designs the monitoring system with multi-functional sensors that can perform both gravity measurements and electrical resistance measurements. The processor is configured to handle both types of data, integrating them into a unified fluid interface tracking solution, thereby managing complexity through universal design
Solution Approach 2:
The patent segments the measurement functions into distinct sensor modules (gravity sensor, electrical sensors) and processes them separately before integration. This modular approach allows each sensor type to be optimized independently while maintaining overall system precision, managing complexity through functional segmentation
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 estimation of the fluid-to-hydrocarbon interface displacement, allowing for improved hydrocarbon extraction monitoring without needing porosity information, thereby enhancing oil/gas production efficiency.
Implementation Method 1
a voltage source coupled to the electrode and configured to apply a voltage to the electrode in order to apply the voltage to the reservoir
Implementation Method 2
an electric field sensor configured to be disposed in the injector borehole and to measure a magnitude of a time-varying electric field to provide electric field measurements
Implementation Method 3
a gravity sensor configured to be disposed in at least one of the injector borehole and a producer borehole offset a distance L from the injector borehole and to measure a magnitude of a time-varying gravitational field
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
A method for estimating a displacement of a fluid-to-hydrocarbon interface in a reservoir in the earth includes: disposing an electrode in an injector borehole that is 5 configured to inject a fluid into the reservoir; energizing the electrode with a voltage source to apply a voltage to the reservoir; disposing an electric field sensor in the injector borehole; disposing a gravity sensor in at least one of the injector borehole and a producer borehole that is offset a distance L from the injector borehole; injecting fluid into the reservoir; measuring a magnitude of a time-varying electric 10 field due to the injecting using the electric field sensor to provide electric field measurements; measuring a magnitude of a time-varying gravitational field due to the injecting using the gravity sensor to provide gravitational field measurements; and estimating the displacement using the electric field measurements and the gravitational field measurements.