Methods and systems that attenuate noise in seismic data

A system that attenuates noise in seismic data, the system comprising:

• a computer system comprising:
• one or more processors;
• one or more data-storage devices;
• and
• a computer-readable medium stored in one or more of data-storage devices and executed by the one or more processors,
• generating a sparse seismic-data matrix from the seismic data;
• transforming the sparse seismic-data matrix from a space-time domain to a transformation domain to generate a spectrum;
• determining a signal region of the spectrum;
• muting amplitudes in the signal region to generate a partial noise spectrum of the spectrum;
• iteratively determining a low-speed noise model based on the partial noise spectrum, the low-speed noise model includes noise that propagates at speeds less than the speed of sound in water and interpolated low-speed noise that represents noise affected by spatial aliasing and streamer irregularities;
• and
• subtracting the low-speed noise model from the sparse seismic-data matrix to generate noise-attenuated sparse seismic-data matrix.

A non-transitory computer-readable medium having machine-readable instructions encoded thereon for enabling one or more processors of a computer system to perform the operations of

• generating a sparse seismic-data matrix from seismic data;
• transforming the sparse seismic-data matrix from a space-time domain to a transformation domain to generate a spectrum;
• determining a signal region of the spectrum;
• muting amplitudes in the signal region to generate a partial noise spectrum of the spectrum;
• iteratively determining a low-speed noise model based on the partial noise spectrum, the low-speed noise model includes noise that propagates at speeds less than the speed of sound in water and interpolated low-speed noise that represents noise affected by spatial aliasing and streamer irregularities;
• and
• subtracting the low-speed noise model from the sparse seismic-data matrix to generate noise-attenuated sparse seismic-data matrix.

A method to attenuate noise, the method comprising:

• near-continuously recording seismic data;
• generating a sparse seismic-data matrix from the near-continuously recorded seismic data;
• transforming the sparse seismic-data matrix from a space-time domain to a transformation domain to generate a spectrum;
• determining a signal region of the spectrum;
• muting amplitudes in the signal region to generate a partial noise spectrum of the spectrum;
• iteratively determining a low-speed noise model based on the partial noise spectrum, the low-speed noise model includes noise that propagates at speeds less than the speed of sound in water and interpolated low-speed noise that represents noise affected by spatial aliasing and streamer irregularities;
• and
• subtracting the low-speed noise model from the sparse seismic-data matrix to generate noise-attenuated sparse seismic-data matrix.