Streamer Resistivity Survey for Riverbed Analysis
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Solution Overview
Problem
Conventional electric resistivity surveys face challenges when applied to water-covered areas, as electrode position changes on the water surface affect measurements, leading to inaccurate analysis of underground structures, particularly in riverbeds, where drilling is time-consuming and other methods like GRP surveys have depth limitations and require complex setup.
Innovation Solution
A streamer electric resistivity survey system using a survey boat equipped with a streamer cable, multi-channel resistivity meter, RTK GPS, conductivity meter, and side scan sonar to measure electric resistivity and water conditions in real-time, allowing for precise positioning and data inversion to image underground structures below a riverbed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional electric resistivity survey is conducted on water surface, then survey coverage is expanded to water-covered areas, but measurement accuracy deteriorates due to electrode position changes on water
Solution Approach 1:
A streamer cable is introduced as an intermediary device to connect multiple electrodes in a fixed linear array. The cable maintains constant spacing between electrodes while allowing the entire array to be deployed on water surface, thus preserving both the adaptability to water-covered areas and the measurement accuracy through fixed electrode geometry
Solution Approach 2:
The system transitions from static land-based electrode positioning to dynamic water-based deployment while maintaining measurement integrity. The streamer cable allows the electrode array to be dynamically positioned on water surface and retrieved, with GPS tracking recording the exact position of each electrode during the survey, thus adapting to water environments without sacrificing measurement precision
2Measurement precision
If drilling method is used to check bedrock border, then measurement accuracy is improved, but survey time and cost increase significantly
Solution Approach 1:
The mechanical drilling system is replaced with an electrical resistivity survey system using streamer cables. Instead of physically drilling into the ground to observe bedrock borders, the system uses electrical current injection and potential difference measurement to image subsurface structures, thereby achieving comparable accuracy without the time-consuming and costly drilling operations
Solution Approach 2:
The streamer electric resistivity survey system provides a universal method that can survey both water-covered and land areas using the same equipment configuration. The system measures electrical properties to identify bedrock borders, sediment layers, and other subsurface features across diverse terrains, replacing the need for location-specific drilling operations
3Device complexity
If GRP survey is applied for shallow depth measurement, then equipment complexity is reduced, but investigation depth is limited by electric conductivity
Solution Approach 1:
The system changes the measurement parameters by using electrical resistivity instead of radar wave reflection. This parameter change allows penetration through conductive materials that block radar waves, enabling deeper investigation into riverbeds and lakebeds while maintaining relatively simple equipment configuration comparable to GRP surveys
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
Enables rapid and accurate analysis of sedimentary layer thickness and bedrock borders by measuring electric conductivity and water depth in real-time, reducing errors and improving survey efficiency compared to traditional methods.
Implementation Method 1
the electric resistivity survey is conducted in a way of flowing a certain current to a conductor and then calculating a potential difference between predetermined two points to calculate resistivity between two points
Implementation Method 2
a first RTK GPS (Real Time Kinematic Global Positioning System) loaded on the survey boat to measure a position of the survey boat in real time; and a second RTK GPS installed to a tail of the streamer cable to measure a position of the tail of the streamer cable in real time
Implementation Method 3
measuring electric conductivity of water in the river or lake as well as electric resistivity according to the change of electrode positions on the water
Implementation Method 4
a side scan sonar mounted to the lower portion of the survey boat to measure a water depth
Data Source
AI summary
A system for measuring electrical resistivity survey checks a border of bedrock or a thickness of a sedimentary layer in a riverbed of a river or lake within a short time. A method for analysis of an underground structure of a riverbed using the same is also provided. The system for streamer electric resistivity survey using a survey boat includes a streamer cable connected to the survey boat and having a plurality of electrodes attached thereto, a multi-channel resistivity meter loaded on the survey boat to measure electric resistivity from the plurality of electrodes, a first RTK GPS (Real Time Kinematic Global Positioning System) loaded on the survey boat to measure a position of the survey boat in real time, and a second RTK GPS installed to a tail of the streamer cable to measure a position of the tail in real time.