Wellbore Fluid Depth Logging via Correlated Acoustic Signals
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Solution Overview
Problem
Current methods for determining the fluid depth in wellbores are inefficient due to interference from multiple reflections, noise from extraction processes, and the need for manual, time-consuming measurements, which hinder precise and continuous monitoring of fluid levels in deep drilling operations.
Innovation Solution
A method and device that utilize a signal pattern with a predetermined, time-variable frequency spectrum emitted into the wellbore, allowing for the filtration and analysis of relevant reflections to accurately determine fluid depth, enabling continuous and automatic monitoring without interrupting extraction operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If acoustic measurements are used to determine fluid depth in deep wellbores, then measurement capability is enabled, but interference from multiple reflections and noise from extraction processes degrades measurement precision
Solution Approach 1:
The patent applies parameter changes by using a signal pattern with a predetermined, time-variable frequency spectrum instead of a simple acoustic pulse. The frequency spectrum is specifically designed to be distinguishable from noise and reflection interference patterns, allowing the fluid depth measurement to be made precisely despite the presence of harmful factors like multiple reflections and extraction process noise.
Solution Approach 2:
The patent introduces an intermediary approach by using a correlated signal pattern as a mediator between the transmitted acoustic signal and the received echo. The analysis unit correlates the received signal with the expected signal pattern to identify true reflections from the fluid depth, filtering out spurious reflections and noise, thereby achieving precise measurement despite interference.
2Measurement precision
If manual acoustic measurements are performed, then fluid depth can be determined, but the process is time-consuming and cannot be performed continuously during extraction operations
Solution Approach 1:
The patent implements self-service by using an automatic analysis unit that continuously processes the acoustic signals without requiring manual intervention. The system automatically correlates received signals with the expected signal pattern, identifies the fluid depth, and provides continuous monitoring during extraction operations, eliminating the time loss associated with manual measurements.
Solution Approach 2:
The patent achieves continuity of useful action by enabling automatic, continuous fluid depth measurement during ongoing extraction operations. The analysis unit continuously processes acoustic signals as they return from the wellbore, allowing real-time monitoring without interrupting the extraction process, thus eliminating the time loss inherent in manual measurement methods.
3Device complexity
If simple acoustic signals are used, then the device complexity is reduced, but the ability to filter noise and multiple reflections is insufficient
Solution Approach 1:
The patent applies parameter changes by transforming the simple acoustic signal into a signal pattern with a predetermined, time-variable frequency spectrum. This enriched signal structure provides inherent discrimination capabilities that allow the analysis unit to filter out noise and multiple reflections more effectively, achieving higher measurement precision without proportionally increasing device complexity.
Solution Approach 2:
The patent implements feedback by using the received acoustic signal as feedback to the analysis unit, which then correlates it with the expected signal pattern. This feedback mechanism allows the system to automatically identify and filter out noise and spurious reflections, improving signal discrimination capability while maintaining relatively simple device architecture.
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 allows for precise, continuous, and automatic determination of fluid depth, reducing interference from noise and multiple reflections, and enabling real-time optimization of extraction processes, while also monitoring potential equipment failures and anomalies.
Implementation Method 1
a vibration-emitting device (41) is provided, which generates signal patterns (42) with a predetermined, time-variable frequency spectrum and emits them into the wellbore
Implementation Method 2
the pressure waves generated by the event travel downward in the wellbore, in which the pressure waves traveling into the wellbore are reflected at least also at the fluid depth
Implementation Method 3
the pressure waves traveling into the wellbore are reflected at least also at the fluid depth, in which pressure waves traveling out of the wellbore to the ground surface are picked up there
Implementation Method 4
pressure waves traveling out of the wellbore to the ground surface are picked up there and the time of travel since the acoustic event is measured
Implementation Method 5
the signals originating from the wellbore and picked up at the ground surface are analyzed, in that vibration events that correlate with the emitted signal pattern are filtered out of the picked-up signals during the analysis
Data Source
AI summary
In a method for logging the location of a fluid depth in a wellbore, an acoustic event is allowed to take place in a specific manner at the ground surface. This acoustic event generates pressure waves. The pressure waves travel in the wellbore downward. The pressure waves traveling in the wellbore are reflected at least also at the fluid depth. At the ground surface, the pressure waves traveling there out of the wellbore are picked up and the time of travel since the acoustic event is measured. The picked-up and measured pressure waves are analyzed and, together with the associated time of travel, the location of the fluid depth is deduced. The acoustic event generates a signal pattern having a predetermined, time-variable frequency spectrum. The signal pattern is emitted as vibration event into the wellbore, travels downward, and is reflected. At the ground surface, the picked-up signals originating from the wellbore are analyzed. During the analysis, vibration events that do not correlate with the emitted signal pattern are filtered out. From the vibration events that are among the picked-up signals and correlate with the emitted signal pattern and from the time of travel since the radiation of the signal pattern, the location of the fluid depth is deduced.