ULF/ELF Electromagnetic Exploration for Deep Hydrocarbon Detection
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Solution Overview
Problem
Current geophysical exploration methods, such as seismic and magnetotelluric techniques, face challenges in accurately discriminating between water and hydrocarbon deposits due to limited depth penetration and sensitivity, especially in offshore environments, where the electrical properties of water and hydrocarbons differ significantly.
Innovation Solution
The use of ultra-low and extremely low-frequency (ULF/ELF) electromagnetic signals, generated by transmitters on land or at sea, to measure resistivity of rock formations, allowing for deeper penetration and improved resolution of hydrocarbon deposits through a 3D conductivity distribution determination using electromagnetic inversion techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If magnetotelluric methods are used for electromagnetic exploration, then regional field coverage is achieved, but sensitivity and resolution for thin horizontal resistive targets are very limited
Solution Approach 1:
The patent applies local quality by using multiple transmitter locations around the survey area rather than a single regional source. Each transmitter provides localized field coverage with optimized sensitivity for specific target zones, allowing thin horizontal resistive targets to be detected with high resolution while maintaining broad overall coverage through the network of transmitters
Solution Approach 2:
The patent segments the electromagnetic exploration system into multiple independent transmitter-receiver pairs distributed around the survey area. Each pair operates semi-independently to provide localized high-resolution measurements, and the combined data from all segments achieves both broad coverage and high sensitivity for thin horizontal targets
2Length of stationary object
If controlled source electromagnetic methods use large transmitter/receiver offsets to increase depth of investigation, then depth penetration is improved, but technological difficulties and cost increase
Solution Approach 1:
The patent transitions from traditional single-dimension offset adjustment to a multi-dimensional transmitter-receiver network configuration. By distributing multiple transmitters and receivers in a spatial array around the survey area, the system achieves deep investigation capability through geometric configuration rather than relying solely on large offsets, thereby reducing technological complexity
Solution Approach 2:
The patent creates a multi-functional transmitter-receiver network where each component can serve multiple measurement objectives. The same network configuration enables both deep investigation and high-resolution imaging of thin targets simultaneously, eliminating the need for separate specialized equipment for different depth requirements
3Length of stationary object
If controlled source electromagnetic methods use very powerful transmitters to increase depth of electromagnetic field penetration, then depth penetration is improved, but cost increases
Solution Approach 1:
The patent merges the functionality of multiple transmitters and receivers into a coordinated network system. By combining the signals and data from multiple lower-power transmitters, the system achieves the equivalent of a single high-power transmitter's penetration depth while using less total energy and reducing equipment cost
Solution Approach 2:
The patent uses multiple copies of transmitter-receiver pairs distributed around the survey area. Each copy provides localized measurement capability, and the combined effect of all copies achieves deep penetration and broad coverage without requiring any single transmitter to be extremely powerful, thereby reducing overall system cost
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 direct deposit imaging and quantitative evaluation of geoelectrical parameters, enhancing the ability to detect and characterize hydrocarbon deposits with improved depth penetration and sensitivity, overcoming the limitations of existing methods.
Implementation Method 1
generating an electromagnetic field with a frequency between about 0.01 Hz and about 30 Hz using a transmitter
Implementation Method 2
the corresponding electromagnetic transfer functions may be determined from the observed ULF/ELF signals by using the linear relationships between the different components of the electromagnetic fields
Implementation Method 3
A plurality of components of the electromagnetic field may be measured using a receiver to determine the electrical properties of the geological formations penetrated by the electromagnetic field
Data Source
AI summary
A method for measuring the resistivity of geologic formations is described. An electromagnetic field may be generated using at least one stationary long-range transmitter. The frequency of the electromagnetic field may be between and/or including the ULF/ELF range. At least one component of the electromagnetic field may be measured by land, marine, and/or airborne receiver. A conductivity distribution may be determined based on the at least one measured component. The determined conductivity distribution may be correlated with geological formations and/or hydrocarbon deposits.