CSEM Signal Ratio Processing for Environmental Perturbation Compensation
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Solution Overview
Problem
Controlled source electromagnetics (CSEM) measurements in oil and gas exploration are affected by environmental perturbations such as winds, tides, and waves, leading to inaccuracies in signal strength, timing, and orientation, which conventional methods struggle to compensate for effectively, especially in marine environments where GPS synchronization may fail under bad weather conditions.
Innovation Solution
A system using a ratio of measured signals from transmitters and receivers, processed to generate compensated signals that reduce or eliminate spurious effects, allowing for accurate determination of underground reservoir properties like depth, resistivity, and shape, independent of weather conditions and sensor variations, by employing a processing unit to control transmitter activation and receiver signal selection, and applying inversion operations based on forward models or libraries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If sensors are separated by large distances and disposed on different vessels or tow units, then the evaluation area of reservoirs can be expanded, but environmental effects such as winds, tides, and waves affect the relative orientation, signal strength, and signal timing
Solution Approach 1:
The system uses multiple sensors to measure environmental parameters (orientation, position, signal strength) and feeds this information back to the processing unit. The processing unit then compensates for these environmental effects on the CSEM signals, allowing large sensor separations while maintaining measurement accuracy through continuous environmental monitoring and correction.
Solution Approach 2:
The patent changes the measurement parameters by measuring not only the CSEM signals but also environmental parameters (orientation, position, signal strength) simultaneously. By measuring these additional parameters and using them to correct the CSEM measurements, the system maintains accuracy despite large sensor separations and environmental variations.
2Measurement precision
If GPS synchronization is used for sensor synchronization, then synchronization can be achieved, but GPS may not be operational under bad weather conditions
Solution Approach 1:
The patent introduces an intermediary synchronization method that uses acoustic signals or other non-GPS timing mechanisms as a mediator between sensors. This alternative synchronization pathway allows the system to maintain accurate timing and synchronization even when GPS is unavailable due to bad weather, ensuring continuous operational reliability.
3Measurement precision
If conventional calibration schemes are used for sensor synchronization, then synchronization can be achieved, but the calibration process is time-consuming
Solution Approach 1:
The system performs preliminary synchronization by continuously measuring environmental parameters and signal timing during operation. Rather than requiring time-consuming calibration procedures before deployment, the system establishes and maintains synchronization dynamically throughout the measurement process, eliminating idle calibration time while maintaining accuracy.
4Area of stationary object
If multiple sensors and evaluation points are used to evaluate large area reservoirs, then complete reservoir evaluation can be achieved, but the complexity of the system increases
Solution Approach 1:
The patent implements multi-functionality by using the same sensor platform to perform multiple functions: measuring CSEM signals for reservoir evaluation, simultaneously measuring environmental parameters (orientation, position, signal strength), and providing synchronization. This universal approach allows large area coverage with multiple sensors while reducing overall system complexity by consolidating measurement capabilities.
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
The solution provides more accurate and reliable measurements by compensating for environmental and sensor-related perturbations, enabling deeper and more precise sensing of underground reservoirs without the need for expensive electronics or collinear sensor placement, and operates effectively in large sensor arrays.
Implementation Method 1
a plurality of transmitters (105-T-1, 105-T-2 . . . 105-T-K . . . 105-T-L . . . 105-T-N) and a plurality of receivers (105-R-1, 105-R-2 . . . 105-R-I. . . 105-R-J. . . 105-R-M) are disposed with respect to one another
Implementation Method 2
each vessel and unit has a sensor capable of transmitting or receiving a signal
Data Source
AI summary
Various embodiments include apparatus and methods to operate with respect to environmental measurements. Apparatus and methods include a processing unit to generate a ratio from signals measured relating to an underground environment and to determine parameters of the underground environment based on the generated ratio.