Tilted Antenna EM Impulse Dip Angle Determination
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional Logging-While-Drilling (LWD) tools using electromagnetic (EM) waves struggle to effectively measure anisotropy and dip angle around and ahead of the drilling tool due to the need for multiple transmitters and receivers, which increases tool size and implementation complexity.
Innovation Solution
A directional resistivity tool (DRT) with a tilted transmitter and receiver uses EM impulses to derive transient responses, allowing for anisotropy and dip angle determination using a single transmitter and receiver, reducing tool size and complexity while improving measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If three mutually orthogonal transmitters and three mutually orthogonal receivers are used to measure formation around and ahead of the tool and dip angle, then measurement capability is improved, but device complexity and tool size increase
Solution Approach 1:
The patent combines multiple measurement functions into a single transmitter-receiver pair. By using a tilted transmitter configuration and processing EM impulse responses at multiple frequencies, the system integrates the capabilities of multiple orthogonal transmitters and receivers into one compact unit, reducing device complexity while maintaining formation measurement capability
Solution Approach 2:
The single transmitter-receiver system is designed to perform multiple functions: measuring formation resistivity around the tool, measuring formation ahead of the tool, and determining dip angle. This multi-functional approach replaces the need for separate specialized transmitters and receivers for each measurement type
2Measurement precision
If three mutually orthogonal transmitters and three mutually orthogonal receivers are used, then dip angle measurement capability is improved, but tool size increases
Solution Approach 1:
The patent merges dip angle measurement functionality into the standard EM impulse measurement system. By analyzing the response of a tilted transmitter configuration, the system extracts dip angle information without requiring separate dedicated dip meter hardware, thereby reducing tool size while maintaining measurement capability
3Device complexity
If conventional EM waves are used for mapping underground formation, then tool design is simplified, but depth of investigation around the tool is limited
Solution Approach 1:
The patent employs periodic EM impulse excitation at multiple frequencies. By shutting off a constant transmitter current to generate EM impulses and analyzing responses at different frequencies, the system achieves extended depth of investigation while maintaining relatively simple tool design, as the extended reach is accomplished through signal processing rather than hardware 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
Enables precise measurement of anisotropy and dip angle with a smaller tool size, improved signal reception, and reduced noise, facilitating better well placement in drilling operations.
Implementation Method 1
A Logging-While-Drilling (LWD) tool is typically used to map an underground formation both around and ahead of the tool. The depth of investigation is generally limited around the tool if using a conventional electromagnetic (EM) wave. The use of an EM impulse generated by near-instantaneously shutting off a constant transmitter current makes it possible to foresee changes in the underground formation
Data Source
AI summary
Transient responses of a tri-axial resistivity tool corresponding to an electromagnetic (EM) impulse are derived. A transient response of a directional resistivity tool (DRT) corresponding to the EM impulse is derived based on the transient responses of the tri-axial resistivity tool. A theoretical late time transient response of the DRT is derived based on the transient response of the DRT. The late time transient response of the DRT is measured. An anisotropy, a horizontal conductivity, and a dip angle are determined based on the measured late time transient response and the theoretical late time transient response.