Seismic reflection full waveform inversion for reflected seismic data

A method for exploring under-ocean floor environments, the method comprising:

• generating a series of source signals by a seismic source configured to inject the source signals into an under-ocean floor explored structure;
• recording direct signals, reflected signals, and refracted signals corresponding to the source signals;
• solving a velocity model equation using a full waveform inversion function with respect to the set of direct signals, reflected signals and refracted signals to minimize a least square misfit function by splitting the full waveform inversion velocity model m into long wavelength components mo of the reflected signals, and short wavelength components δm of the reflected signals;
• updating the short wavelength components of the reflected signals, and the long wavelength components of the reflected signals using an iterative relaxation process;
• generating an iterative velocity model based on the solution to the velocity model equation that includes the iterated long wavelength components of the reflected signals and the iterated short wavelength components of the reflected signals;
• and
• determining location of a hydrocarbon reservoir in the under-ocean floor explored structure based on strong velocity or anisotropic parameter variations in the velocity model,
• wherein the iterative relaxation process includes updating the iterated long wavelength component mo while the short wavelength component δm is fixed.

A system for exploring under-ocean floor environments, the system comprising:

• a plurality of sources configured to generate a series of source signals and to inject the source signals into an under-ocean floor explored structure;
• a plurality of receivers configured to detect and record direct signals, reflected signals, and refracted signals corresponding to the source signals;
• a processor configured to solve a velocity model equation using a full waveform inversion function with respect to the direct signals, reflected signals and refracted signals to minimize a least square misfit function by relaxing a dependency on low frequency reflections in the full waveform inversion function, and to generate a velocity model based on the solution to the velocity model equation, and to determine location of a hydrocarbon reservoir in the under-ocean floor explored structure based on strong velocity or anisotropic parameter variations in the velocity model;
• and
• a display configured to display the velocity model,
• wherein the relaxing the dependency on the low frequency reflections includes splitting an initial velocity model m into a long wavelength component mo and a short wavelength component δm, and updating the long wavelength component mo while the short wavelength component δm is fixed.

A system for exploring under-ocean floor environments, the system comprising:

• a plurality of sources configured to generate a series of source signals and to inject the source signals into an under-ocean floor explored structure;
• a plurality of receivers configured to detect and record direct signals, reflected signals, and refracted signals corresponding to the source signals;
• a processor configured to
• solve a velocity model equation using a full waveform inversion function with respect to the direct signals, reflected signals and refracted signals to minimize a least square misfit function,
• split the full waveform inversion velocity model m into long wavelength components mo of the reflected signals, and short wavelength components δm of the reflected signals,
• update the short wavelength components of the reflected signals, and the long wavelength components of the reflected signals using an iterative relaxation process,
• generate an iterative velocity model based on the solution to the velocity model equation that includes the iterated long wavelength components of the reflected signals and the iterated short wavelength components of the reflected signals, and
• determine location of a hydrocarbon reservoir in the under-ocean floor explored structure based on strong velocity or anisotropic parameter variations in the velocity model;
• and
• a display configured to display the velocity model,
• wherein the iterative relaxation process includes updating the iterated long wavelength component mo while the short wavelength component δm is fixed.