CSEM Receiver Noise Filtering via Water Intermediary
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Solution Overview
Problem
Existing CSEM and MT signal data collection techniques fail to effectively filter out in-frequency noise, particularly around 50-60 Hz, and surface-based measurements are hindered by noise from ferrous objects, leading to reduced resolution and depth of investigation.
Innovation Solution
The system employs multiple simultaneous channels of E and H field data acquisition with high-speed techniques, advanced noise filtering, and precise phase determination, up-converting differential signals, and using RF noise filtering to improve data resolution and depth, while synchronizing transmitter and receiver systems with low phase jitter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If physical isolation of receiving elements from noise sources is used, then noise from ferrous objects is reduced, but the depth of investigation and resolution are reduced
Solution Approach 1:
The patent introduces water as an intermediary medium between the receiving elements and the noise sources. By submerging the receiving elements in water, the system exploits the physical properties of water to filter out air wave noise while maintaining the ability to detect subsurface signals, thus resolving the contradiction between noise reduction and measurement precision
Solution Approach 2:
The patent changes the operating environment parameter from air to water for the receiving elements. This parameter change fundamentally alters the noise transmission characteristics, as water naturally filters out air wave noise in the 50-60 Hz range while preserving the electromagnetic signals from subsurface formations
2Object-affected harmful factors
If advanced noise filtering techniques are applied, then in-frequency noise is reduced, but the complexity of the data acquisition system increases
Solution Approach 1:
The patent replaces complex mechanical noise filtering systems with a simpler water-based physical filtering approach. Instead of using sophisticated active filtering equipment to remove in-frequency noise, the system simply submerges the receivers in water, which naturally attenuates the problematic 50-60 Hz noise frequencies while preserving the signal of interest
3Measurement precision
If multiple simultaneous channels of E and H field data are acquired, then resolution and depth of investigation are improved, but the amount of noise and interference increases
Solution Approach 1:
The patent uses water as a protective intermediary medium that simultaneously handles multiple noise sources. By submerging multiple receiving channels in water, the system maintains the ability to acquire multiple simultaneous E and H field data channels while water naturally filters out air wave noise for all channels, thus improving resolution without proportionally increasing noise
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 enhances the visualization of sub-surface formations by reducing noise, improving resolution, and allowing for deeper and more precise data interpretation in 2D, 3D, and 4D CSEM operations, with the ability to detect transient states during fluid or gas changes and fracturing operations.
Implementation Method 1
a transmitter system generates a periodic transmit waveform that propagates through a plurality of sub-surface formations. A receiver system detects the waveform
Implementation Method 2
a magnetometer card (MC) 240 for detecting ambient magnetic fields and generating nulling signals
Implementation Method 3
a nulling coil 487 for generating nulling signals to null local magnetic fields
Data Source
AI summary
Concurrently measuring, correlating, and processing magnetic and electric field data includes measuring base band signals, and then up-converting those band signals to a higher frequency for filtering, while at the same time preserving phase and amplitude information. All timed elements in the system are rigorously synchronized. The increased data set results in improved signal-to-noise ratio and information correlation.