# US 8,787,112 B2 · Seismic data apparatus and methods

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- Number: US 8,787,112 B2
- Document ID: US8787112B2
- Status: Granted
- Kind: B2
- Application number: 12/958,158
- Filed: 2010-12-01
- Published: 2012-06-07
- Granted: 2014-07-22
- Earliest claimed: 2010-12-01
- Assignees: Shell Oil Company
- Applicants: David M Cook; Ran-Fun Chiu
- Inventors: David M Cook; Ran-Fun Chiu
- Web page: https://patentgrep.com/patent/US8787112B2

## CPC

- G01V 1/375: {Correlating received seismic signals with the emitted source signal}
- G01V: GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS (means for indicating the location of accidentally buried, e.g. snow-buried, persons A63B29/02)

## 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.

## Claims

### Claim 1

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.

### Claim 2 (depends on 1)

The method according to claim 1 further comprising recording the correlation result to a computer-accessible storage media.

### Claim 3 (depends on 1)

The method according to claim 1, the one or more timestamps each including a local clock time value and a standardized time value.

### Claim 4 (depends on 3)

The method according to claim 3, each local clock time value provided by an onboard clock of a seismic sensor device, each standardized time value provided by a remote time source to a seismic sensor device by way of wireless communication.

### Claim 5 (depends on 1)

The method according to claim 1 further comprising scaling the correlation result to an original starting time using the offset time to derive a scaled correlation result.

### Claim 6 (depends on 1)

The method according to claim 1 further comprising acquiring at least some of the seismic data and at least some of the timestamps from a seismic sensor device.

### Claim 7

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.

### Claim 8 (depends on 7)

The system according to claim 7, each field sensor further configured to:
store the seismic data at regular intervals in accordance with the onboard clock; and
store the timestamps asynchronous with the storing of the seismic data.

### Claim 9

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.