Seismic Sweep Signal Harmonic Amplitude
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Solution Overview
Problem
Seismic exploration systems face limitations in maximizing the amplitude of seismic signals emitted by vibrators due to constraints on peak force, mass stroke, and oil flow rate, which restrict the effective imaging of subsurface geological structures.
Innovation Solution
Incorporating odd order harmonics into the seismic sweep signal, specifically tailored to the characteristics of the vibrator, to enhance the amplitude of the seismic signal without increasing required force, oil flow rate, or mass displacement, thereby optimizing the signal's amplitude and power within mechanical constraints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the amplitude of seismic signals is increased to improve subsurface imaging, then the imaging quality and signal power are improved, but the peak force, mass stroke, and oil flow rate constraints are exceeded
Solution Approach 1:
The patent applies parameter changes by modifying the frequency content of the seismic sweep signal to include odd order harmonics. This changes the signal parameters such that the same mechanical constraints (peak force, mass stroke, oil flow rate) produce higher effective signal amplitude and power for subsurface imaging, resolving the contradiction between signal strength and mechanical limitations.
2Power
If the amplitude of seismic signals is increased to improve subsurface imaging, then the imaging quality and signal power are improved, but the oil flow rate is exceeded
Solution Approach 1:
The patent modifies the signal frequency parameters to include odd order harmonics, which allows the hydraulic system to generate higher signal amplitude within the same oil flow rate constraints. The harmonic content changes how the hydraulic actuator translates fluid flow into mechanical vibration, improving power efficiency and signal strength without exceeding hydraulic capacity.
3Power
If the amplitude of seismic signals is increased to improve subsurface imaging, then the imaging quality and signal power are improved, but the mass stroke is exceeded
Solution Approach 1:
The patent changes the frequency domain parameters of the drive signal to incorporate odd order harmonics. This parameter modification allows the reaction mass to achieve higher vibration amplitudes and power output within the same physical stroke limits, as the harmonic content optimizes the energy transfer efficiency of the vibratory mechanism.
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 method effectively increases the amplitude and power of seismic signals, allowing for improved subsurface imaging without exceeding the mechanical limitations of the vibrator, thereby enhancing the accuracy and efficiency of seismic exploration.
Implementation Method 1
actuator 250 that applies a force between base plate 288 and reaction mass 284. Actuator 250 can be hydraulic and can consist of rod 280 and piston 282 inside reaction mass 284, in which case the force is generated by injecting into one of the piston chamber a pressurized fluid
Implementation Method 2
source 102 is operated so as to generate a seismic signal. This signal propagates firstly on the surface of the ground, in the form of surface waves 110, and secondly in the subsoil, in the form of transmitted body waves 112
Implementation Method 3
seismic waves generated artificially have been used for more than 50 years to perform imaging of geological layers. These reflected waves are received by seismic sensors, such as hydrophones, geophones or accelerometers, which convert the displacement or overpressure of the ground resulting from the propagation of the waves
Implementation Method 4
receivers 104 (e.g., geophones) for receiving a seismic signal and converting it into an electrical signal
Implementation Method 5
accelerometers, which convert the displacement or overpressure of the ground resulting from the propagation of the waves into an analog or digital, electrical or optical signal
Data Source
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AI summary
Sweep signals for vibrators used to generate seismic signals for seismic surveys are described. By selecting a certain amount of one or more odd order harmonic components to be included in the sweep signal, the amplitude of the seismic signal generated by the vibrator can be increased.