Distributed Acoustic Fiber Optic Cable Seismic While Drilling Hazard Assessment
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Solution Overview
Problem
Conventional Seismic While Drilling (SWD) systems face challenges in obtaining high signal-to-noise ratio (SNR) seismic data due to surface noise interference, limiting the accuracy of near-surface hazard detection and subsurface structure reconstruction during drilling operations.
Innovation Solution
The system employs distributed acoustic sensing using fiber-optic cables deployed in upholes to record seismic data at depths below surface complexities, enhancing SNR through cross-correlation and interferometric transformations, and utilizing a control station to interrogate the cables with laser beams for improved signal processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If surface geophones are used to record seismic waves in conventional SWD systems, then the system can detect subsurface signals, but surface noise from drilling operations obscures the desired signal and reduces signal-to-noise ratio
Solution Approach 1:
The patent extracts the recording function from the surface environment by deploying fiber optic cables in downholes, removing the receivers from the noisy surface zone where drilling operations occur. This physical separation eliminates surface noise interference while maintaining the ability to record subsurface seismic signals generated by the drill bit.
Solution Approach 2:
The fiber optic cable acts as an intermediary medium that transmits seismic signals from the subsurface drill bit source to the surface recording equipment. By placing the fiber optic cable in the downhole, it serves as a protected transmission path that isolates the signal path from surface noise sources while still capturing the desired seismic waves.
2Object-affected harmful factors
If recording stations are positioned at large offsets away from the well, then surface noise interference is reduced, but the obtained profiles are not sufficiently robust and contain insufficient useful information for characterizing near-surface hazards
Solution Approach 1:
The patent extracts the recording capability from the surface environment by deploying fiber optic cables in downholes at various depths. This allows recording stations to be effectively positioned at zero or small offsets from the wellbore without being subjected to surface noise, enabling robust near-surface hazard characterization while maintaining low noise levels.
3Measurement precision
If fiber optic cables are deployed at shallow depths, then near-surface hazard detection is improved, but surface noise interference increases
Solution Approach 1:
The fiber optic cable serves as a protected intermediary that allows the system to position recording sensors at shallow depths for improved near-surface hazard detection while the cable itself shields the recording elements from surface noise interference. The cable acts as a barrier that isolates the sensitive recording function from the noisy surface environment.
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 the reconstruction of robust velocity profiles and accurate subsurface imaging, enhancing drilling safety and efficiency by reducing noise interference and improving data quality.
Implementation Method 1
at least one distributed acoustic fiber optic cable deployed vertically in each uphole
Implementation Method 2
a control station for interrogating the at least one fiber optic cable using a laser beam
Data Source
AI summary
A system and method of obtaining a high SNR seismic while-drilling data and a robust velocity profile of a geological site having a main well and at least one uphole located in the vicinity of the main well, the seismic profile being obtained from seismic waves generated by a drilling device located at the main well. The method comprises deploying at least one distributed acoustic fiber optic cable vertically in the at least one uphole, at least a portion of the fiber optic cable being positioned at a depth exceeding a predetermined depth below the surface, receiving seismic data at recording station positioned on the at least one fiber optic cable at at least the predetermined depth, generating, at a processor a high SNR seismic while-drilling signal; yielding a reliable velocity profile from the seismic data received, and determining a presence of near surface hazards from the generated high SNR while drilling seismic data.