Borehole Seismic Tool Noise Sampling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional borehole seismic acquisition systems face limitations in accurately sampling seismic signals due to noise interference, particularly tube wave energy, which can lead to incomplete data coverage and tool retrieval issues, as they rely on mechanical clamping devices that are power-intensive and prone to jamming, limiting the number of measuring points and tool length.
Innovation Solution
A seismic acquisition tool with a cable up to several kilometers in length, equipped with sensors such as hydrophones, accelerometers, and rotational devices, spaced closely enough to sample both geophysical signals and noise without aliasing, allowing for unaliased data collection and subsequent noise removal through processing, eliminating the need for mechanical clamps and enabling longer, more efficient borehole surveys.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If mechanical clamping devices are used to isolate sensors and minimize noise, then noise attenuation is improved, but device complexity and power consumption increase
Solution Approach 1:
The patent removes the mechanical clamping devices from the system entirely. Instead of using complex mechanical structures to isolate sensors, the invention extracts this function and replaces it with a simplified sensor array that directly samples noise sources. The noise isolation function is achieved through signal processing rather than mechanical means, eliminating the harmful complexity of clamping mechanisms.
Solution Approach 2:
The patent replaces the mechanical clamping system with an electronic/signal processing system. Rather than using physical devices to mechanically isolate and attenuate noise, the invention uses closely spaced sensors to sample noise sources and applies signal processing techniques to remove noise from the seismic data. This substitution eliminates power consumption and mechanical failure modes.
2Measurement precision
If mechanical clamping devices are used to couple sensors to formation, then signal coupling is improved, but reliability decreases due to jamming risk
Solution Approach 1:
The patent extracts the coupling function from mechanical clamps and implements it through the sensor array geometry and signal processing. The sensors are positioned to naturally couple with formation vibrations, and the noise sampling capability is built into the array structure itself, eliminating the need for separate mechanical coupling devices that can jam.
Solution Approach 2:
The patent replaces mechanical coupling devices with a sensor array configuration that achieves coupling through proximity and geometric arrangement. The sensors are positioned close to the borehole wall to capture formation vibrations, and signal processing techniques maintain coupling quality without requiring mechanical clamps that can fail or jam.
3Productivity
If sensor spacing is increased to cover larger depth aperture, then productivity is improved, but measurement precision decreases due to insufficient noise sampling
Solution Approach 1:
The patent transitions from sparse sensor spacing to dense sensor spacing, adding a dimension of sampling density to the system. By placing sensors closely together along the borehole, the system can simultaneously cover large depth apertures and adequately sample noise sources at each location. This dimensional change in spacing density resolves the trade-off between coverage and precision.
Solution Approach 2:
The patent applies excessive sampling by placing sensors closer than the minimum spacing required for basic signal capture. This oversampling of noise sources provides redundant data that improves measurement precision while maintaining large depth aperture coverage. The excessive sensor density enables sophisticated noise removal through processing.
4Productivity
If complete tool is moved to different depth to cover larger aperture, then productivity is improved, but loss of time increases due to repeated experiments
Solution Approach 1:
The patent performs preliminary action by deploying a long sensor array that can capture the entire depth aperture in a single experiment. Rather than moving the tool between depths, the sensors are pre-positioned along the borehole to simultaneously record seismic responses at multiple depths, eliminating the need for repeated experiments and saving significant time.
Solution Approach 2:
The patent enables continuous useful action by having sensors distributed along the entire depth aperture record data simultaneously in a single continuous experiment. The long sensor array maintains continuous coverage from surface to target depth without interruption or repositioning, maximizing productivity and eliminating downtime associated with moving the tool between measurement locations.
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 ensures higher signal coherency and better noise attenuation, allowing for comprehensive borehole coverage in a single setting, overcoming the limitations of conventional systems by intentionally sampling noise and improving signal-to-noise ratios, while reducing the risk of tool jamming and enhancing survey efficiency.
Implementation Method 1
the downhole tool may include an array (or multi-level in depth) of individual acquisition nodes or shuttles housing at least one seismic sensor and associated acquisition electronics
Implementation Method 2
Both these tools are based on individual clamped units containing three-component geophones/accelerometers
Implementation Method 3
these shuttles can be designed to optimize their geophysical coupling response to the surrounding formation by mechanical, magnetic or hydraulic clamping devices
Implementation Method 4
these shuttles can be designed to optimize their geophysical coupling response to the surrounding formation by mechanical, magnetic or hydraulic clamping devices
Implementation Method 5
these shuttles can be designed to optimize their geophysical coupling response to the surrounding formation by mechanical, magnetic or hydraulic clamping devices
Implementation Method 6
Borehole seismic survey systems may involve sources located at the surface and receivers placed in the well
Data Source
AI summary
A tool is described for seismic data collection which may have sensors mounted along its entire length to sample both geophysical signal and noise including at least one of acoustic noise, system noise, and noise resulting from the interaction between the two. Systems and methods for acquiring borehole seismic data are also described. In contrast to conventional systems which attempt to avoid introducing noise into the collected data stream, the present systems include a sufficient type, number, and spacing of sensors to intentionally sample at least one source of noise. The methods include operating a borehole seismic acquisition system to sample both a target signal and at least one source of noise and using a processor with machine-readable instructions for separating the noise from the signal.