Compensated Crosswell Tomography for Sensor Gain and Phase Errors
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Solution Overview
Problem
Crosswell tomography in oil field operations is limited by noise and inaccuracies caused by mismatches in sensor gains and phases, which traditional methods fail to adequately address, leading to degraded image quality in subsurface reservoir mapping.
Innovation Solution
The method involves combining data from multiple transmitters and receivers to form compensated values that account for gain and phase inaccuracies, followed by an inversion process to create a subsurface structure model, using software to output accurate images of the reservoir.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional crosswell tomography methods are used, then the system is simpler to operate, but image quality deteriorates due to sensor gain and phase mismatches
Solution Approach 1:
The patent implements a feedback mechanism where sensor gain and phase information is continuously measured and used to compensate for mismatches in the tomography data processing. The system measures actual sensor characteristics and adjusts the inversion process accordingly, creating a closed-loop system that maintains image quality despite sensor variations.
Solution Approach 2:
The patent changes the parameters used in the tomography inversion process by introducing compensated data that incorporates gain and phase correction factors. Instead of using raw sensor data directly, the system transforms the data parameters to account for sensor mismatches, thereby improving image quality without requiring more complex hardware.
2Measurement precision
If compensated crosswell tomography methods are used, then image quality improves, but data processing complexity increases
Solution Approach 1:
The patent performs preliminary compensation of the tomography data before the inversion process. By pre-calculating and applying gain and phase corrections to the sensor data, the system prepares compensated data that can be directly used in the inversion. This preliminary action separates the compensation step from the inversion step, making the overall process more manageable and not significantly more complex.
3Measurement precision
If more sensors are used to improve measurement coverage, then image quality improves, but sensitivity to sensor mismatches increases
Solution Approach 1:
The patent uses feedback to measure and correct sensor characteristics for each sensor in the array. By continuously monitoring and adjusting for individual sensor gains and phases, the system maintains reliability even as the number of sensors increases. The feedback mechanism ensures that each sensor's contribution is accurately accounted for, preventing increased sensitivity to mismatches.
Solution Approach 2:
The patent transforms the data parameters by incorporating sensor-specific compensation factors into the tomography inversion. This parameter transformation adjusts the data to account for individual sensor variations, thereby maintaining measurement reliability and reducing sensitivity to mismatches even in systems with many sensors.
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 significantly improves image quality by compensating for sensor errors, allowing for more accurate subsurface structure identification and fluid distribution mapping, even in diverse borehole and environmental conditions.
Implementation Method 1
the focus has been on the use of electromagnetic (EM) transmitters and receivers
Data Source
AI summary
A method and system to compensate for inaccuracies in crosswell tomography is presented. The method includes obtaining data from at least two receivers in response to transmissions from at least two transmitters. Next, at least one compensated value is derived based on the responses of the receivers to the transmitters. Finally, an inversion is performed based at least in part on the compensated value derived. This method eliminates inaccuracies that can be caused by sensor gain and phase variations in the inversion process. Inversion results with gain and phase compensation produce better imaging results that can better help determine the shape and boundaries of the reservoir.