3D Array Laterolog Tool for Deviated Well Resistivity
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Solution Overview
Problem
Conventional array laterolog tools, which are widely used in oil and gas exploration for measuring formation resistivity, face limitations in accurately determining resistivity in high resistivity formations and deviated wells due to their two-dimensional nature, leading to difficulties in computing accurate formation resistivity, dip angle, and distance to boundaries in horizontal wells.
Innovation Solution
A three-dimensional array laterolog tool is developed, equipped with a main electrode and azimuthal electrodes arranged around the axis, allowing for the generation and control of current patterns to determine resistivity across different radii, azimuthal angles, and depths, thereby providing more accurate 3D formation resistivity profiles and reducing the shoulder effect of measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a two-dimensional array laterolog tool is used, then the device complexity is reduced, but the measurement precision of formation resistivity in deviated wells and horizontal wells deteriorates
Solution Approach 1:
The patent transitions from a conventional two-dimensional array laterolog tool to a three-dimensional array laterolog tool. The 3D tool includes electrodes arranged in multiple planes along the longitudinal axis, with both axial and azimuthal spacing, enabling measurements in three dimensions. This dimensional enhancement allows accurate resistivity measurement in deviated and horizontal wells where 2D tools fail, as the 3D electrode configuration can capture the complex current flow patterns in anisotropic formations and deviated geometries.
2Measurement precision
If a three-dimensional array laterolog tool is used, then the measurement precision of formation resistivity is improved, but the device complexity increases
Solution Approach 1:
The 3D array laterolog tool is segmented into multiple electrode arrays arranged in distinct planes along the longitudinal axis. Each plane contains electrodes spaced both axially and azimuthally, creating a modular structure. This segmentation allows the complex 3D measurement function to be achieved through coordinated operation of simpler, repeating electrode units, making the overall complex device more manageable and manufacturable.
3Ease of operation
If conventional two-dimensional array laterolog measurements are taken, then the ease of operation is maintained, but the reliability of resistivity data in high resistivity formations deteriorates
Solution Approach 1:
The patent employs a three-dimensional electrode configuration with multiple planes of electrodes spaced axially and azimuthally. This 3D arrangement enables the tool to accurately measure formation resistivity in high resistivity formations by capturing current flow in multiple directions, overcoming the limitations of 2D tools that assume planar current flow. The enhanced geometric coverage improves data reliability while maintaining operational simplicity through automated multi-plane measurements.
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 3D array laterolog tool enhances the accuracy of resistivity measurements, improves the precision of formation resistivity determination, and reduces the shoulder effect, enabling more reliable data for drilling operations in complex well geometries.
Implementation Method 1
An array laterolog tool is a current based tool in which a current is generated from the tool and resistivity is determined from measured voltages based on Ohm's law
Data Source
AI summary
Various embodiments include apparatus and methods to make resistivity measurements in a borehole using tool having an array of electrodes operable to provide focused currents and measure corresponding voltages to determine resistivity. Tools can be configured with a main electrode having a number of spaced apart electrodes within the main electrode such that the spaced apart electrodes are arranged azimuthally with respect to an axis of the tool. Generation of current from the spaced apart electrodes and control of current from additional electrodes on each side of the main electrode can provide for focused measurements. Additional apparatus, systems, and methods are disclosed.