Real-Time DAS VSP Noise Reduction and Survey Control
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Solution Overview
Problem
The signal quality of Distributed Acoustic Sensing (DAS) Vertical Seismic Profiling (VSP) data is degraded by environmental and survey parameters, leading to low Signal-to-Noise Ratio (SNR), which hinders real-time processing and control in subterranean operations.
Innovation Solution
Integration of real-time data stream processing to identify and remove common-mode, vertical, and residual noise events, and revive faded traces in DAS VSP datasets, using a system that includes a DAS data collection system with optical fibers and an information processing system for noise reduction and quality evaluation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If DAS VSP surveys are conducted using fiber optic-based Distributed Acoustic Sensing, then seismic data can be acquired along the wellbore, but the signal quality is degraded by environmental and survey parameters resulting in low Signal-to-Noise Ratio
Solution Approach 1:
The patent extracts and removes harmful noise components from the DAS VSP data through signal processing techniques. Specifically, it separates and eliminates environmental and survey parameter-induced noise from the seismic signal, thereby improving signal quality and SNR.
Solution Approach 2:
The patent converts the harmful effect of environmental and survey parameters into beneficial information by using real-time quality metrics to monitor and adapt the acquisition process. The noise sources are identified and their effects are transformed into quality indicators that guide survey optimization.
2Productivity
If real-time processing is implemented to improve SNR and determine optimal number of sweeps, then survey control is improved, but processing complexity and computational requirements increase
Solution Approach 1:
The patent performs preliminary real-time processing and quality assessment during the acquisition phase itself, rather than as a separate post-processing step. Quality metrics are calculated and used to determine the optimal number of sweeps before the survey is completed, preventing wasted acquisitions and improving overall efficiency.
Solution Approach 2:
The patent implements a feedback loop where real-time quality metrics are continuously monitored and used to adjust the acquisition process. The system automatically determines when sufficient data quality has been achieved and signals when to stop acquiring, creating an adaptive, self-regulating survey process.
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 improves the SNR of DAS VSP data, allowing for accurate predictions of desirable signal quality and providing improved survey control, enabling more efficient and accurate subterranean operations by dynamically determining the optimal number of sweeps required.
Implementation Method 1
Acoustic sensing based on DAS may use the Rayleigh backscatter property of a fiber's optical core and may spatially detect disturbances that are distributed along a length of fiber positioned within a wellbore.
Data Source
AI summary
A system for processing DAS VSP surveys in real-time is provided. The system includes a DAS data collection system coupled to at least one optical fiber at least partially positioned within a wellbore and configured to repeatedly activate a seismic source of energy. The system further includes an information processing system connected to the DAS data collection system. A seismic dataset is received from the DAS data collection system. The seismic dataset includes a plurality of seismic data records. Two or more of the plurality of seismic data records are combined into a stack. A quality metric indicative of a desired signal-to-noise ratio or incoherence of the stack is determined for each processed seismic dataset collected from a repeated source. Instructions are sent to the DAS data collection system to stop activating the seismic source, in response to determining that the quality metric has reached a predefined threshold.