Induction Logging Circuitry Using Imaginary Voltage Components
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Solution Overview
Problem
Induction logging tools face challenges in accurately measuring formation parameters, especially near bed boundaries, due to the dominance of direct signals and phase measurement errors, which lead to unsuitable results and errors, as most algorithms ignore the imaginary components of the signal.
Innovation Solution
An induction logging system that includes a plurality of transmitter and receiver coils, with circuitry to separate real and imaginary components of the measured voltages, using the imaginary components to determine formation parameters, which are 90 degrees out of phase with the current on the transmitter coils.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the real part of the voltage is used for measurement, then the measurement is less sensitive to direct signal interference, but the measurement accuracy deteriorates near bed boundaries due to horn effects
Solution Approach 1:
The patent converts the harmful direct signal that causes phase measurement errors into a beneficial resource by using the imaginary component, which is uniquely sensitive to formation properties near bed boundaries. The direct signal's phase information, previously discarded as error, becomes the key to accurate measurement in challenging geological conditions.
Solution Approach 2:
The patent changes the measurement parameter from the real part of voltage to the imaginary part of voltage. This parameter transformation allows the system to exploit the different sensitivity characteristics of the imaginary component, which maintains accuracy near bed boundaries where the real component fails due to horn effects.
2Measurement precision
If the imaginary component of the signal is used, then the measurement accuracy near bed boundaries is improved, but the measurement is more sensitive to direct signal interference and phase errors
Solution Approach 1:
The patent converts the harmful direct signal that causes phase measurement errors into a beneficial resource by using the imaginary component, which is uniquely sensitive to formation properties near bed boundaries. The direct signal's phase information, previously discarded as error, becomes the key to accurate measurement in challenging geological conditions.
3Object-affected harmful factors
If bucking coils are used to cancel direct signal, then the direct signal interference is reduced, but the system complexity increases
Solution Approach 1:
The patent extracts and utilizes only the imaginary component of the received signal, separating it from the real component. This extraction approach allows the system to benefit from the imaginary component's sensitivity to formation properties while avoiding the need for complex bucking coil systems to cancel the direct signal.
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 provides more accurate formation parameter measurements, particularly at or near bed boundaries, by utilizing the imaginary components of the measured voltages, reducing errors and artifacts associated with real component measurements.
Implementation Method 1
an induction signal transmitted by a plurality of transmitters into the formation
Implementation Method 2
a response signal from the formation received by a plurality of receivers
Data Source
AI summary
A system and method for determining formation parameters is provided. The system includes an induction logging tool having a plurality of transmitter coils. The induction logging tool further includes a plurality of receiver coils, each of the receiver coils being spaced apart from the transmitter coils by a predetermined distance and receiving a response signal from the formation. The system includes circuitry coupled to the induction logging tool, the circuitry determining voltages induced in the plurality of receiver coils by the response signal. The circuitry separates real or in-phase portions of the determined voltages from imaginary of ninety degrees out of phase portions of the determined voltages and determines formation parameters using imaginary portions of the measured voltages.