Logging Tool Dip Correction for Anisotropic Formation Accuracy
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Solution Overview
Problem
Existing logging technologies face challenges in accurately determining the dip and azimuth of anisotropic earth formations away from a borehole, particularly when formation angles change laterally, leading to inconsistencies between multi-component measurements and borehole imaging logs.
Innovation Solution
A method and apparatus utilizing a multicomponent logging tool with a specific depth of investigation to estimate formation dips, resistivities, and porosities, comparing these measurements with local dip data from borehole imaging tools, and using the estimated dip angles for drilling offset wells, while accounting for the ratio of undulation height to wavelength in the formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If multi-component logging measurements are used to determine formation dip and azimuth, then the depth of investigation is increased, but measurement precision deteriorates when formation angles change laterally
Solution Approach 1:
The system dynamically adjusts the anisotropy ratio parameter based on the detected dip angle. When the dip angle exceeds a predetermined threshold, the system automatically corrects the anisotropy ratio to account for lateral formation angle changes, thereby maintaining measurement precision across varying geological conditions
Solution Approach 2:
The invention changes the anisotropy ratio parameter from a fixed value to a dynamically adjusted value based on dip angle measurements. This parameter modification allows the system to compensate for lateral variations in formation geometry, resolving the contradiction between deep investigation and measurement accuracy
2Device complexity
If standard anisotropy ratio values are used for dip correction, then the processing complexity is reduced, but measurement precision worsens due to underestimation of formation anisotropy
Solution Approach 1:
The system performs self-correction by using its own dip angle measurements to adjust the anisotropy ratio parameter. The logging tool automatically detects the dip angle, compares it to threshold values, and modifies the anisotropy ratio accordingly, eliminating the need for external correction data or complex manual processing
Solution Approach 2:
The system implements a feedback mechanism where dip angle measurements feed back into the anisotropy ratio determination process. This closed-loop approach allows continuous refinement of the anisotropy ratio based on actual formation conditions, improving dip measurement precision without significantly increasing processing complexity
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 allows for accurate characterization of geologic formations away from the borehole, improving the reliability of dip and azimuth measurements, and enabling precise estimation of formation properties such as porosity and shale volume, facilitating more effective drilling operations.
Implementation Method 1
Electromagnetic induction and wave propagation logging tools are commonly used for determination of electrical properties of formations surrounding a borehole
Data Source
AI summary
A method, apparatus and computer-readable medium for evaluating an earth formation includes making measurements with a logging tool having a first depth of investigation in a borehole in the earth formation. A first dip of the formation is estimated using multi-component measurements. The estimated dip is compared with a second dip measurement in the borehole. The results of the comparison are stored on a tangible medium.