Seismic data apparatus and methods
AssigneeShell Oil Company
InventorsDavid M Cook, Ran-Fun Chiu
Life of this patent
Estimating the term…
Abstract
Methods and apparatus are provided related to seismic sensor data. Seismic sensor signaling is digitally sampled in accordance with a local clock and without synchronization to standardized time. Timestamp data is used to synthesize data correspondent to an artificial stimulus waveform. Cross-correlation of the synthesized data with the seismic sensor data yields a correlation result. The correlation result can be scaled to an original starting time for the seismic data sampling. The scaled correlation result can be stored in computer-accessible media and subject to further processing or interpretation.
Claims9
A method performed using one or more computers, comprising:
- analyzing one or more timestamps to determine a data sampling frequency and an offset time;
- synthesizing pilot sweep data according to the data sampling frequency, the synthesized pilot sweep data characterized by one or more parameters of an artificial seismic stimulus waveform;
- and
- cross-correlating seismic sensor data with the synthesized pilot sweep data to derive a correlation result.
A system, comprising:
- a source configured to provide seismic stimuli as respective frequency-modulated energy sweeps;
- one or more field sensors configured to store seismic data corresponding to incident energy originating from the source, each field sensor also configured to store timestamps each including a local time value from an onboard clock and a standardized time value received from a remote source;
- and
- one or more computers configured to derive a cross-correlation result using the seismic data and the timestamps;
- the one or more computers further configured to:
- calculate a sample frequency using the timestamps;
- synthesize sweep data consistent with sample frequency, the synthesized sweep data formatted to emulate a seismic stimulus waveform used by the source;
- and
- cross-correlate the synthesized sweep data with the seismic data so as to derive the cross-correlation result.
A storage media including a computer-readable program code configured to cause one or more processors to:
- analyze one or more timestamps to determine an original starting time for a data set;
- calculate a sample frequency using the one or more timestamps;
- synthesize sweep data according to the sample frequency, the synthesized sweep data correspondent to an artificial seismic stimulus waveform;
- and
- cross-correlate the data set with the synthesized sweep data to derive a correlation result.
Dependencies are inferred from the claim text.