Piezoelectric Mud Property Measurement for Resistivity Imaging
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Solution Overview
Problem
Oil-based muds used in borehole drilling operations interfere with resistivity imaging by contributing to measured impedance, leading to skewed measurements, especially when the standoff between the borehole tool and the wall is high, and existing methods require accurate mud angle determination to remove this effect effectively.
Innovation Solution
A system and method that accurately determine the mud angle using the Z90 processing algorithm and piezoelectric materials to eliminate the mud effect from resistivity images, ensuring high-quality imaging by accounting for mud properties and standoff variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If oil based mud is used for drilling operations, then higher performance and better stability in high temperature and pressure environments are achieved, but the mud contributes to measured impedance and degrades the quality of resistivity images
Solution Approach 1:
The patent extracts and removes the mud contribution from the measured impedance data through processing methods. By separating the mud effect component from the total measured impedance, the system isolates and eliminates the harmful mud contribution, leaving only the formation resistivity information for accurate imaging.
Solution Approach 2:
The patent changes the parameters of the impedance measurement by introducing the mud angle parameter and using multi-frequency measurements. By measuring impedance at different frequencies and analyzing the phase angle (mud angle), the system can characterize and remove the mud effect, transforming the measurement parameters to achieve accurate formation resistivity values despite the presence of oil-based mud.
2Measurement precision
If processing methods are used to remove mud effect, then resistivity image quality is improved, but accurate determination of mud angle is required which increases measurement complexity
Solution Approach 1:
The patent makes the imaging tool multi-functional by enabling it to perform both standard resistivity imaging and mud property measurements using the same hardware platform. The tool can operate in different modes (imaging mode and mud measurement mode) and the data acquired can be used for multiple purposes, reducing the need for separate specialized equipment.
Solution Approach 2:
The patent uses periodic action by measuring impedance at multiple frequencies periodically. The system acquires impedance data at different frequency points and uses this periodic multi-frequency measurement approach to characterize the mud properties and enable effective mud effect removal through the Z90 processing algorithm.
3Measurement precision
If multi-frequency impedance measurements are performed to determine mud angle, then mud effect removal accuracy is improved, but measurement time and data processing complexity increase
Solution Approach 1:
The patent performs preliminary action by measuring mud properties and determining the mud angle in advance before acquiring the formation resistivity imaging data. By characterizing the mud effect beforehand, the system can apply the appropriate correction factors during the imaging process, eliminating the need for time-consuming real-time mud effect removal calculations.
Solution Approach 2:
The patent creates a model or copy of the mud effect characteristics through multi-frequency measurements and uses this model to represent and remove the mud contribution from the imaging data. By measuring the mud properties separately and creating a mud effect model, the system can efficiently apply this model to correct the imaging data without repeated complex calculations.
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
The system enhances the accuracy of resistivity imaging by reducing the mud effect, providing a more reliable and precise characterization of formation properties, even at varying standoff distances, thereby improving the quality of the resistivity images obtained.
Implementation Method 1
a pad, wherein the pad comprises: a material, where the material expands or contracts from an external electromagnetic field
Implementation Method 2
Taking a first impedance measurement with the electrode at a first operating frequency; taking a second impedance measurement with the electrode at a second operating frequency
Data Source
AI summary
A downhole tool may comprise a mandrel, wherein the mandrel is a structural support for the downhole tool; one or more arms, wherein the one or more arms are attached to the mandrel; and a pad, wherein the pad is connected to the one or more arms. The pad may comprise a material, where the material expands or contracts from an external electromagnetic field; an insulator, wherein the insulator is connected at a first end to the material; and an electrode, wherein the electrode is connected to the insulator. A method may comprise applying a time varying biasing voltage to a material, wherein the material exhibits mechanical strain; taking a first measurement and a second measurement with at least one operating frequency with an electrode; calculating a mud property based at least in part on the first measurement and the second measurement; and applying a mud effect removal algorithm to the mud property.