Formation Evaluation Tool Noise Compensation
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Solution Overview
Problem
Conventional formation evaluation tools do not effectively compensate for noise originating from within the outer tool housing, leading to significant measurement errors due to variables such as borehole fluid and mudcake between the inner and outer housings.
Innovation Solution
The implementation of additional sensors within the inner housing, positioned in a shielded portion of the outer housing, allows for the measurement and compensation of noise within the tool, using techniques such as perturbation to correct for background interference from the borehole fluid and drilling mud, and the use of high-density materials for shielding to minimize external noise impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional compensated tools are used, then compensation for borehole fluid and mudcake is achieved, but noise from within the outer tool housing remains uncorrected causing significant measurement errors
Solution Approach 1:
The tool housing is segmented into inner and outer housings, with sensors strategically positioned in the inner housing to distinguish between noise sources from borehole fluid/mudcake (affecting outer housing sensors) and formation signals (detected by inner housing sensors), enabling selective compensation
Solution Approach 2:
An intermediate compensation signal is introduced by using outer housing sensors to detect noise from borehole fluid and mudcake, which then serves as a reference for compensating the formation property measurements from inner housing sensors through signal processing
2Measurement precision
If additional sensors are added within the inner housing for noise compensation, then measurement accuracy improves, but device complexity increases
Solution Approach 1:
Multiple sensors within the inner housing serve dual functions: detecting formation signals for primary measurements and detecting noise from borehole fluid/mudcake for compensation, allowing a single sensor array to perform multiple measurement tasks simultaneously
Solution Approach 2:
The tool uses its own sensor array to self-diagnose and self-correct measurement errors by detecting and compensating for noise from borehole fluid and mudcake, eliminating the need for external calibration or correction systems
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 reduces measurement errors by isolating and correcting for noise within the tool, enhancing the accuracy of formation property measurements by distinguishing between internal and external environmental effects.
Implementation Method 1
an emitter disposed within the inner housing; a first sensor disposed within the inner housing; a first window in the outer housing, positioned about the emitter, to permit signals from the emitter to pass out of the outer housing; a second window in the outer housing, positioned about the first sensor, to permit signals to reach the first sensor from out of the outer housing
Implementation Method 2
positioning a sensor in an inner housing of the apparatus within a shielded portion of an outer housing of the apparatus
Data Source
AI summary
An apparatus for compensated formation evaluation has an outer housing; an inner housing disposed within the outer housing; an emitter disposed within the inner housing; a first sensor disposed within the inner housing; a first window in the outer housing, positioned about the emitter, to permit signals from the emitter to pass out of the outer housing; a second window in the outer housing, positioned about the first sensor, to permit signals to reach the first sensor from out of the outer housing; a second sensor disposed within the inner housing.