Downhole Resistivity Measurement Device With Insulated Electrical Interface
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Solution Overview
Problem
Existing downhole resistivity measurement devices face signal perturbations due to coaxial cables, which can compromise the accuracy of resistivity measurements in harsh wellbore conditions.
Innovation Solution
A device with a watertight body and electrically insulated electrodes, featuring an electrical connecting module with insulating materials between contacting elements, projecting from the body to form an electrical interface, minimizing signal perturbations and maintaining atmospheric pressure for the data processing module.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a coaxial cable is used to transfer electrical signals from electrodes to the data processing module, then the electrical connection is established, but signal perturbations occur that compromise measurement accuracy
Solution Approach 1:
The patent extracts the harmful coaxial cable from the signal transfer path and replaces it with a direct electrical connection through the electrical connecting module. The contacting elements establish direct electrical contact with the electrodes without intermediate cable structures that generate perturbations, thereby eliminating the source of measurement inaccuracy while maintaining reliable electrical connection.
Solution Approach 2:
The electrical connecting module serves as an intermediary structure between the electrodes and the data processing module. It provides a controlled electrical interface with contacting elements that transmit signals without the harmful effects of coaxial cables. The insulating material within the module acts as a mediator to maintain electrical isolation where needed while allowing controlled signal transmission.
2Object-affected harmful factors
If the data processing module is positioned inside the tool in an atmospheric chamber, then protection from harsh wellbore conditions is achieved, but the electrical signals must be transferred through coaxial cables which generate perturbations
Solution Approach 1:
The patent segments the device into distinct functional zones: the electrodes at the proximal end for signal generation, the electrical connecting module in the intermediate zone for controlled signal transfer, and the data processing module in the protected distal zone. This segmentation allows each component to perform its function optimally while minimizing interference between zones, eliminating the need for coaxial cables in the signal path.
Solution Approach 2:
The harmful coaxial cable is extracted from the signal transfer path by implementing direct electrical contact through the electrical connecting module. This extraction eliminates the source of signal perturbations while maintaining the protected environment for the data processing module, resolving the contradiction between protection and signal accuracy.
3Measurement precision
If electrodes are positioned on the external surface of the tool body, then contact with drilling fluid is achieved for accurate measurement, but the electrical connecting module must be designed to minimize signal perturbations
Solution Approach 1:
The electrical connecting module applies local quality by providing different electrical characteristics at different locations. The contacting elements are positioned and configured to match the electrode geometries, with insulating material strategically placed to maintain isolation where needed. This localized optimization minimizes signal perturbations while maintaining the simplicity of the overall device structure.
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 solution ensures accurate resistivity measurements by reducing signal interference and protecting the data processing module from harsh conditions, while maintaining a watertight seal to prevent fluid invasion.
Implementation Method 1
with interposition of an electrically insulating material between the first and second contacting element
Implementation Method 2
a watertight body... overmolding a second body part on the first body part and the electrodes so that the first and second body parts form a watertight body
Data Source
AI summary
The disclosure relates to a device for measuring resistivity to be mounted on a downhole tool and comprising:a watertight body,a first electrode and a second electrode electrically insulated from the first electrode and surrounding the first electrode, arranged in the body at a proximal end of the device,an electrical connecting module arranged in the body and comprising a first contacting element electrically coupled to the first electrode and a second contacting element electrically coupled to the second electrode, surrounding the first contacting element, with interposition of an electrically insulating material between the first and second contacting element;wherein the electrical connecting module projects from the body at a distal end of the device so as to form an electrical interface.