Downhole Tool Measuring Magnetic Permeability for Reservoir Analysis
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Solution Overview
Problem
Accurate measurement of permeability in oil and gas reservoirs is challenging due to the difficulty in obtaining representative rock samples and reconstructing fluid distributions and wettability in laboratory settings, leading to inaccurate production predictions.
Innovation Solution
A system and method that deploy a downhole tool to measure magnetic permeability by injecting a fluid with elevated magnetic permeability into the reservoir, using mutual inductance between coils to determine phase permeabilities, allowing for in-situ measurements that correlate with the permeability of the geological formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If laboratory measurements on small rock samples are used to determine permeability, then the measurement process is standardized and controllable, but the samples may not be representative of the reservoir and fluid distributions and wettability cannot be accurately reconstructed
Solution Approach 1:
The patent extracts the measurement process from the laboratory setting and places it directly in the reservoir environment. By using a downhole tool that measures magnetic permeability in-situ, the method eliminates the need to extract physical rock samples, thereby avoiding representativeness issues while maintaining measurement precision through controlled electromagnetic measurements.
Solution Approach 2:
The patent introduces magnetic fluid as an intermediary substance to enable permeability measurement. The magnetic fluid is injected into the formation, and its magnetic properties serve as a mediator that allows the downhole tool to indirectly measure permeability through magnetic field interactions, avoiding direct contact with and potential contamination of the rock matrix.
2Reliability
If in-situ measurements are made in the reservoir, then fluid distributions and wettability are correct and representative, but the measurement process becomes more complex and requires specialized downhole tools
Solution Approach 1:
The downhole tool is designed with multi-functionality, combining magnetic field generation, magnetic permeability measurement, and formation evaluation capabilities in a single instrument. This universal approach reduces the need for multiple separate tools and operations, thereby managing device complexity while enabling reliable in-situ measurements that capture actual fluid distributions and wettability conditions.
Solution Approach 2:
The patent utilizes changes in magnetic fluid properties (magnetic permeability) as the fluid moves through the formation to infer permeability characteristics. By monitoring parameter changes in the magnetic field response rather than directly measuring physical flow properties, the system simplifies the measurement approach while maintaining reliability in representing in-situ conditions.
3Measurement precision
If magnetic fluid is injected into the formation, then permeability can be measured in-situ, but the injection process and fluid recovery add operational complexity
Solution Approach 1:
The measurement process employs periodic action through a sequence of discrete operational phases: injection of magnetic fluid, measurement of magnetic permeability, and recovery of the fluid. This structured periodic approach breaks down the complex process into manageable, repeatable steps that can be systematically executed and monitored, improving ease of operation while maintaining measurement precision.
Solution Approach 2:
The system incorporates feedback mechanisms where the measured magnetic permeability data is used to adjust and optimize subsequent injection and recovery operations. Real-time monitoring of magnetic field responses provides feedback on formation properties, allowing operators to adapt injection rates and measurement parameters to maintain optimal measurement conditions and simplify overall operation.
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 approach enables more reliable and accurate determination of permeability in real-time, reducing the need for laboratory samples and improving the accuracy of oil and gas production predictions by directly measuring permeability in the reservoir.
Implementation Method 1
measuring, via the downhole tool, a radial profile of magnetic permeability of the geological formation around the downhole tool
Implementation Method 2
measuring, via the downhole tool, the mutual inductance between pairs of inductive coils where the magnetic field of the coils extends beyond the borehole and into the formation
Implementation Method 3
a magnetic-permeability doped fluid to diffuse through the formation surrounding the downhole tool
Data Source
AI summary
The present device and technique relates to measuring geological formation permeability, such as by injection/withdrawal of conductivity-permeability doped fluid and measuring the magnetic permeability and/or conductivity of the surrounding formation. Before, during and/or after injection or withdrawal, pluralities of electromagnetic measurements of the radial distribution of magnetic permeability and/or conductivity of the surrounding formation may be made. The rate of change of the radial distribution of magnetic permeability and/or conductivity of the formation is generally directly proportional to the permeability of the surrounding formation. In implementations, magnetic permeability and electrical conductivity can be measured independently in time domain or frequency domain, such that the magnetic permeability mapping is not disturbed by other confounding electromagnetic parameters.