Methods and systems for using known source events in seismic data processing

Patent metadata

Field	Value
Publication number	US-10345463-B2
Application number	US-201514594846-A
Country	US
Kind code	B2
Filing date	Jan 12, 2015
Priority date	Feb 21, 2014
Publication date	Jul 9, 2019
Grant date	Jul 9, 2019

Abstract

Embodiments of using known source locations in seismic data processing are disclosed. In one embodiment, a method of locating a seismic event includes receiving location information for a plurality of known source events proximate the seismic event, and determining an estimated location of the seismic event using a relative locator constrained by the location information for the plurality of known source events.

First claim

What is claimed is:

1. A method, comprising:
activating one or more perforation shots, each perforation shot resulting in one or more seismic events;
receiving a picked arrival time corresponding to a seismic event of the one or more seismic events;
deriving a calculated travel time for a proposed location corresponding to the seismic event from a velocity model;
determining a relative location for each of a plurality of known source events associated with the one or more perforation shots with respect to a respective seismic event;
selecting a subset of known source events from the plurality of known source events based at least in part on the determined relative locations for each of the plurality of known source events;
receiving a plurality of picked arrival times and a plurality of calculated travel times corresponding to the subset of known source events;
determining an estimated location of the seismic event based at least in part on reducing a difference between:
relative differences between the picked arrival time corresponding to the seismic event and the plurality of picked arrival times corresponding to the subset of known source events; and
relative differences between the calculated travel time corresponding to the proposed location of the seismic event and the plurality of calculated travel times corresponding to the subset of known source events; and

adjusting a location of one or more subsequent perforation shots based at least in part on the determined estimated location.

2. The method of claim 1 , wherein each respective one of the plurality of known source events is a seismic source event with a respective known location.

3. The method of claim 2 , further comprising determining each of the plurality of calculated travel times corresponding to each of the subset of known source events based on the respective known location of each respective known source event and the velocity model.

4. The method of claim 2 , wherein the known location for each of the plurality of known source events is determined based on a position of a perforation source within a wellbore.

5. The method of claim 4 , wherein the position of the perforation source within the wellbore is determined from a wireline.

6. The method of claim 2 , wherein the respective known location of each respective one of the plurality of known source events includes a three-dimensional subsurface position and an origin time, and the three-dimensional subsurface position and origin time are known to within a specified accuracy.

7. The method of claim 1 , wherein at least some of the plurality of known source events are perforation shots in a wellbore casing.

8. The method of claim 1 , wherein the plurality of known source events comprises three or more perforation shots.

9. The method of claim 1 , wherein reducing the difference comprises iteratively updating the proposed location corresponding to the seismic event.

10. The method of claim 9 , wherein the proposed location corresponding to the seismic event is iteratively updated until a change between successive iterations of said difference is less than a predetermined threshold.

11. The method of claim 9 , wherein the proposed location corresponding to the seismic event is iteratively updated until said difference is reduced to below a predetermined threshold.

12. The method of claim 1 , wherein the picked arrival time corresponding to the seismic event at the sensor location is received in near-real time, and the estimated location of the seismic event is determined in near-real time.

13. The method of claim 12 , wherein the picked arrival time is one of a plurality of picked arrival times and the seismic event is one of a plurality of seismic events, and the estimated location of the one of the plurality of seismic events is determined without reference to the picked arrival times for others of the plurality of seismic events.

14. A method, comprising:
activating one or more perforation shots, each perforation shot resulting in one or more seismic events;
determining a relative location for each of a plurality of known source events associated with the one or more perforation shots with respect to a respective seismic event;
selecting a subset of known source events from the plurality of known source events based at least in part on the determined relative locations for each of the plurality of known source events; and
determining an estimated location of a seismic event using a relative locator constrained by location information for the subset of known source events based at least in part on reducing a difference between:
relative differences between the picked arrival time corresponding to the seismic event and the plurality of picked arrival times corresponding to the subset of known source events; and
relative differences between the calculated travel time corresponding to the proposed location of the seismic event and the plurality of calculated travel times corresponding to the subset of known source events; and

adjusting a location of one or more subsequent perforation shots based at least in part on the determined estimated location.

15. The method of claim 14 , wherein the relative locator is a double difference locator.

16. The method of claim 14 , further comprising clustering the seismic event together with the subset of known source events for use by the relative locator.

17. The method of claim 14 , wherein the estimated location of the seismic event includes an estimated origin time and an estimated three-dimensional subsurface position.

18. The method of claim 14 , wherein the plurality of known source events comprises a first set of known source events associated with a first stage of perforating a hydraulic fracturing well and a second set of known source events associated with a second stage of perforating a hydraulic fracturing well.

19. The method of claim 18 , further comprising determining the estimated location of the seismic event by interpolating between the first and second sets of known source events.

20. A method of visualizing a seismic event, comprising:
receiving a plurality of picked arrival times corresponding to a respective plurality of known source events;
determining a relative location for each of the plurality of known source events with respect to a respective seismic event;
selecting a subset of known source events from the plurality of known source events based at least in part on the determined relative locations for each of the plurality of known source events;
deriving a plurality of calculated travel times corresponding to the subset of known source events from an initial velocity model, wherein the plurality of calculated travel times are calculated with reference to a slowness field of the initial velocity model, and the initial velocity model is updated by iteratively adjusting the slowness field to reduce a difference between (a) relative differences between the plurality of picked arrival times and (b) the relative differences between the plurality of calculated travel times;
updating the initial velocity model based on relative differences between the plurality of picked arrival times and relative differences between the plurality of calculated travel times;
displaying the seismic event based at least in part on the updated initial velocity model.

21. The method of claim 20 , wherein at least some of the plurality of known source events are perforation shots in a wellbore casing, whose three-dimen

Assignees

• Ion Geophysical Corp

Inventors

• Kahn Daniel S
• Leveille Jacques P

Classifications

• G01V2210/65

  Source localisation, e.g. faults, hypocenters or reservoirs · CPC title

• G01V1/288 Primary

  Event detection in seismic signals, e.g. microseismics (G01V1/36 takes precedence) · CPC title

• G01V1/282 Primary

  Application of seismic models, synthetic seismograms · CPC title

• G01V1/40

  specially adapted for well-logging · CPC title

• G06F17/10

  Complex mathematical operations {(function generation by table look-up G06F1/03; evaluation of elementary functions by calculation G06F7/544)} · CPC title