Seismic While Drilling Signal Acquisition Using Combined Geophone Observation
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Solution Overview
Problem
Current seismic while drilling methods are hindered by low signal-to-noise ratios and inaccuracy due to near-surface noise, making it difficult to obtain effective seismic signals, especially for horizontal drilling where direct wave reflections from the drill bit are hard to detect.
Innovation Solution
A method involving multiple geophone observation techniques, including near-wellhead, survey line, and geophone concentric circle combined observations, to enhance signal quality and accuracy by optimizing seismic data acquisition and processing through signal comparison, noise suppression, and cross-correlation analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional grid observation or survey line method is used to receive seismic while drilling signal, then the observation system is simple and easy to operate, but the received signal is greatly affected by near-surface noise and the signal-to-noise ratio is low
Solution Approach 1:
The patent combines three different observation methods (near-wellhead observation, survey line observation, and geophone concentric circle observation) into a unified data acquisition system. This merging allows the system to leverage the advantages of each method while compensating for their individual weaknesses, particularly in suppressing near-surface noise and improving signal-to-noise ratio for direct wave detection
Solution Approach 2:
The patent divides the seismic observation into multiple segments using different observation methods for different purposes. The near-wellhead observation segment captures strong direct waves, the survey line segment provides regional coverage, and the geophone concentric circle segment enhances noise suppression. This segmentation allows optimized signal extraction from each segment
2Measurement precision
If near-surface noise suppression and conventional cross-correlation methods are used to extract direct wave signals, then the processing method is simple, but the extracted signals are inaccurate especially when drill bit source signal is getting weaker
Solution Approach 1:
The patent implements feedback mechanisms in signal processing by using the characteristics of direct waves from different observation methods to validate and refine the extracted signals. The system continuously adjusts processing parameters based on signal quality metrics and cross-validation between multiple observation datasets, improving accuracy iteratively
Solution Approach 2:
The patent applies composite processing techniques by combining multiple signal processing methods (noise suppression, cross-correlation, travel time calculation) in a integrated framework. This composite approach processes signals from different observation methods simultaneously, leveraging their complementary strengths to achieve higher accuracy in direct wave extraction
3Loss of information
If only earth surface observation is used for horizontal drilling, then the observation system is simple, but reflected waves of geological body in front of drill bit cannot reach ground surface and seismic signal prediction is difficult
Solution Approach 1:
The patent transitions from traditional two-dimensional earth surface observation to a three-dimensional observation system by incorporating near-wellhead geophones and geophone concentric circle arrangements. This dimensional expansion allows detection of seismic signals from multiple spatial perspectives, capturing reflected waves that would otherwise remain undetected in horizontal drilling scenarios
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 significantly improves data acquisition efficiency and suppresses noise, enabling the effective extraction of direct wave information and accurate travel time measurement of drill bit signals, enhancing seismic imaging capabilities.
Implementation Method 1
seismic waves generated by drill bit drilling can be observed more efficiently by using a drill bit source for earth surface observation; geophones are arranged on the earth surface for recording by using the rock breaking vibration of the drill bit as the source
Data Source
AI summary
The present disclosure discloses a method of obtaining a seismic while drilling signal. The method comprises the following steps: arranging geophones by using a first observation method to obtain a first seismic reference signal and a second seismic reference signal; arranging geophones by using a second observation method to obtain first seismic data; arranging geophones by using a third observation method to obtain second seismic data; comparing the first seismic reference signal with the second seismic reference signal to obtain a first output reference signal, and optimizing the first output signal to obtain a second output reference signal. The present disclosure obtains square matrix and near-wellhead seismic while drilling data through the combination of geophone square matrix combined observation, near-wellhead observation, and survey line observation, the data acquisition efficiency is relatively high, the signal-to-noise ratio is high, and thus, the problem of near-surface noise interference is effectively solved.