Tilted Transmitter-Receiver Pair for Formation Parameter Determination
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Solution Overview
Problem
Conventional electromagnetic resistivity tools require multiple transmitter-receiver pairs to determine specific electromagnetic coupling components, which is inefficient, and they struggle to accurately measure formation parameters in planar geometries with parallel boundaries.
Innovation Solution
A method using a single tilted transmitter-receiver pair that rotates to measure electromagnetic signals, allowing for the determination of formation parameters by computing symmetrized and anti-symmetrized responses, thereby obtaining the necessary electromagnetic coupling components without the need for multiple pairs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple transmitter-receiver pairs are used to determine electromagnetic coupling components, then measurement accuracy is improved, but device complexity and efficiency deteriorate
Solution Approach 1:
A single transmitter-receiver pair is designed to perform multiple measurement functions by utilizing different orientation combinations. The transmitter and receiver can be oriented in various configurations (both tilted, one tilted one axial, both axial) to determine different electromagnetic coupling components (Vxz, Vzx, Vxx, Vyy, Vzz), making the single pair universal for multiple measurement purposes rather than requiring dedicated pairs for each component.
Solution Approach 2:
The system employs dynamic orientation adjustment where the transmitter and receiver orientations are varied during measurement operations. By changing the tilt angles and relative orientations of the transmitter and receiver, the same physical pair can measure different coupling components, transforming a static single-function device into a dynamic multi-function measurement system.
2Loss of information
If multiple transmitter-receiver pairs are used to determine electromagnetic coupling components, then measurement completeness is improved, but productivity deteriorates
Solution Approach 1:
The single transmitter-receiver pair is configured to obtain all necessary electromagnetic coupling components (Vxz, Vzx, Vxx, Vyy, Vzz) through different orientation measurements, ensuring complete information acquisition without requiring multiple pairs. This universal design maintains measurement completeness while improving productivity by reducing the number of physical components and measurement setups required.
Solution Approach 2:
Multiple measurement functions that would traditionally require separate transmitter-receiver pairs are merged into a single pair through strategic orientation variations. By combining multiple measurement capabilities in one physical unit, the system achieves complete electromagnetic coupling component determination while streamlining the measurement process and improving operational efficiency.
3Device complexity
If conventional axial transmitter-receiver configurations are used, then device simplicity is maintained, but measurement capability for directional parameters deteriorates
Solution Approach 1:
The system introduces asymmetric tilt angles for the transmitter and receiver relative to the axial direction. Rather than using symmetric axial configurations, the transmitter and receiver are tilted at different angles, creating an asymmetric geometry that enables sensitivity to directional formation parameters. This asymmetric configuration allows the simple single-pair device to acquire directional information and resistivity anisotropy that would be inaccessible with purely axial orientations.
Solution Approach 2:
The measurement capability is enhanced by changing the geometric parameters of the transmitter and receiver orientations. By varying the tilt angles from the axial position and adjusting the relative orientations, the system transforms a simple axial configuration into a versatile measurement system capable of determining directional parameters and formation anisotropy without significantly increasing device 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 enables accurate determination of formation parameters, including resistivity and bed boundary distances, with improved efficiency and precision, particularly in high-angle and horizontal wells.
Implementation Method 1
EM induction tools measure the resistivity of the formation by measuring the voltage induced in a receiver by currents flowing in the formation in response to an EM signal emitted by a transmitter
Implementation Method 2
The EM signal from the transmitter is transmitted into the surrounding formation, which induces a fluctuating current or 'eddy current' in the formation near the transmitter
Data Source
AI summary
A method and a downhole tool determine one or more parameters of a formation traversed by a borehole where at least a portion of the formation has substantially parallel boundaries. A tool is disposed in the borehole that includes a transmitter having a dipole moment at an angle θT with respect to a longitudinal axis of the tool, a receiver having a dipole moment at an angle θR with respect to the longitudinal axis of the tool and a rotational position indicator. The transmitter-receiver pair transmits an electromagnetic signal while rotating the tool, receives the electromagnetic signal to produce a measured signal, and determine(s) the formation parameters for the portion of the formation having substantially parallel boundaries based on the measured signal.