Premigration deghosting of seismic data with a bootstrap technique
AssigneeCgg Services SAS
InventorsPing Wang, Can Peng
Life of this patent
Estimating the term…
Abstract
Methods and systems for optimized receiver-based ghost filter generation are described. The optimized ghost filter self-determines its parameters based on an iterative calculation of recorded data transformed from a time-space domain to a Tau-P domain. An initial ghost filter prediction is made based on generating mirror data from the recorded data and using a least squares technique during a premigration stage.
Claims18
A method, stored in a memory and executing on a processor, for generating a receiver-based ghost filter from recorded data, said method comprising:
- generating mirror data from said recorded data;
- transforming said recorded data and said mirror data from a time-space domain to a frequency-space domain;
- adding a phase coefficient to a mirror ghost filter so that the mirror ghost filter is time aligned with a ghost filter, wherein the transformed recorded data is expressed by multiplying initial primary receiver ghost-free data with the ghost filter and the transformed mirror data is expressed by multiplying the initial primary receiver ghost-free data with the mirror ghost filter;
- generating an initial ghost as a difference between the transformed recorded data and the initial primary receiver ghost-free data, wherein the initial primary receiver ghost-free data is calculated by jointly solving (i) a first equation that relates the transformed recorded data, the initial primary receiver ghost-free data and the ghost filter, and (ii) a second equation that relates the transformed mirror data, the initial primary receiver ghost-free data and the mirror ghost filter;
- generating said ghost filter by iterating through said transformed recorded data from which the initial primary receiver ghost-free data is subtracted and minimizing a sum of the initial primary receiver ghost-free data and the initial ghost multiplied by the phase coefficient to obtain a ghost delay time;
- calculating a final primary receiver ghost-free data associated with a current iteration based on the transformed recorded data and the ghost filter;
- and
- generating an image of a geophysical structure underground based on the final primary receiver ghost-free data.
A node for generating ghost-free receiver-based seismic data, said node comprising:
- recorded seismic data;
- one or more processors configured to execute computer instructions and a memory configured to store said computer instructions wherein said computer instructions further comprise:
- generating mirror data of said recorded data;
- transforming said recorded data and said mirror data from a space-time domain to a frequency-time domain and adding a phase coefficient to a mirror ghost filter so that the mirror ghost filter is time aligned with a ghost filter, wherein the transformed recorded data is expressed by multiplying initial primary receiver ghost-free data with the ghost filter and the transformed mirror data is expressed by multiplying the initial primary receiver ghost-free data with the mirror ghost filter;
- generating an initial ghost as a difference between the transformed recorded data and the initial primary receiver ghost-free data, wherein the initial primary receiver ghost-free data is calculated by jointly solving (i) a first equation that relates the transformed recorded data, the initial primary receiver ghost-free data and the ghost filter, and (ii) a second equation that relates the transformed mirror data, the initial primary receiver ghost-free data and the mirror ghost filter;
- applying said final ghost filter to said transformed recorded data and outputting final primary receiver ghost-free data associated with a current iteration;
- and
- generating an image of a geophysical structure underground based on the final primary receiver ghost-free seismic data.
Dependencies are inferred from the claim text.