US 9,772,413 B2Granted

Simultaneous sourcing during both seismic acquisition and seismic inversion

AssigneeExxonMobil Upstream Research Company

InventorsChristine E. Krohn, Partha S. Routh

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Abstract

Method for acquiring, at reduced acquisition cost, seismic data using simultaneous, field-encoded sources in the field (702), and then constructing pseudo source-records (703) that better meet the requirements for using additional simultaneous computer-encoded sourcing for computer simulations or forward modeling (706) as part of (707) iterative FWI (Full Wavefield Inversion) or RTM (Reverse Time Migration), with additional reduction in computational costs. By better meeting the requirements of simultaneous sourcing for FWI or RTM (701), artifacts and crosstalk are reduced in the output. The method can be used for marine streamer acquisition and other non-fixed spread geometries to acquire both positive and negative offsets and to mitigate the “missing data” problem for simultaneous-source FWI. It can also be used for land data to overcome issues with moving spreads and long continuous records.

Claims22

Dependent claims

method for inferring a subsurface model of velocity or other physical property, comprising:

obtaining seismic data acquired in a survey by advancing a front source and a trailing rear source along a source line with a non-fixed spread of receivers, and activating each source at selected intervals along the source line, wherein every activation location for the rear source falls on a previous activation location for the front source, and wherein a selected field encoding is used for all source shots with the field encoding for the rear source always being the same as was previously applied to the front source at the same activation location, resulting in a series of shot records each simultaneously recording both sources but with each shot recorded by less than a full spread of receivers;
and
processing the shot records by steps comprising:
(i) constructing from the shot records a plurality of pseudo super-shot records, constructed such that each has data from a full spread of receivers;
(ii) encoding each pseudo super-shot record and stacking to form a simultaneous-source record of measured data;
(iii) using a computer to simulate the simultaneous-source record of measured data, using the same encoding used in (ii) and also the field encoding, and using an assumed subsurface model of velocity or other physical property;
(iv) comparing the simulated simultaneous-source record with the simultaneous-source record of measured data, determining from that an adjustment to the subsurface model of velocity or other physical property;
and making the adjustment to the subsurface model of velocity or other physical property to generate a final model;
and
(v) displaying, with a computer, an image generated from the final model that includes subsurface structures.

7 more elements

A method for conducting a seismic survey with a plurality of simultaneous sources and a non-fixed spread of receivers, and inferring a subsurface model of velocity or other physical property, comprising:

(a) activating two or more sources with a selected field encoding applied to each source at a location along a source line with a first partial spread of receivers;
(b) activating the two or more sources, or identical sources, duplicating the field encoding in (a), at the same location along the source line with a second partial spread of receivers, wherein the first partial spread and the second partial spread, when combined, make a full spread of receivers for the location along the source line;
(c) repeating (a) and (b) for one or more additional locations along the source line;
then processing records of seismic data recorded by the receivers from the activations in (a)-(c) with steps comprising:
(d) constructing from the shot records a plurality of pseudo super-shot records, constructed to be of the same duration and spatial extent, and such that each has data from a full spread of receiver locations;
(e) computer encoding each pseudo super-shot record and summing to form a single simultaneous-source record of measured data;
(f) using a computer and a subsurface model of velocity or other physical property, simulating with one forward modeling operation a simultaneous-source record of synthetic data to predict the simultaneous source record of measured data;
(g) comparing the simultaneous source record of measured data to the simulated simultaneous source record, determining a misfit, and using the misfit to adjust the subsurface model to generate a final model;
and
(v) displaying, with a computer, an image generated from the final model that includes subsurface structures.

7 more elements

A method for iterative inversion or imaging of seismic data comprising:

(a) obtaining one or more field records generated by two or more sources using a field encoding scheme, wherein detected returns from sources interfere in time and space;
(b) selecting one or more operations from a group consisting of windowing, time shifting, padding time or traces, appending, and summing, then constructing a plurality of pseudo super-source records, each with the same spatial extent and time duration;
(c) identifing sources that contribute to each pseudo super-source record along with their position, firing time and encoding function;
(d) computer encoding each pseudo super-source record and stacking them to form a single measured simultaneous-source record;
(e) using a subsurface model and a computer, simulating in one forward modeling operation a response of the sum of all contributing sources using a combination of the field and computer encoding schemes to make a single simulated simultaneous-source record that predicts the measured simultaneous-source record;
(f) comparing the measured and simulated simultaneous-source records over a selected region of interest, and using the comparison to update the subsurface model;
(g) repeating (e)-(f) at least once using the updated subsurface model until a final subsurface model is obtained;
and
(h) displaying, with a computer, an image generated from the final model that includes subsurface structures.

6 more elements

Dependencies are inferred from the claim text.

Facts

Application: 14/329,431Filed 11 Jul 2014 · us provisional application
Priority: 23 Aug 2013
Published: US 2015/0057938 A126 Feb 2015
Granted: 26 Sep 2017
Term ends: Not estimatedThe source records don’t support an estimate.

Classification17 codes

G01V 1/282
Processing seismic data, e.g. for interpretation or for event detection: application of seismic models, synthetic seismograms
G01V 1/003
Seismology; Seismic or acoustic prospecting or detecting: seismic data acquisition in general, e.g. survey design
G01V 1/005
Seismic data acquisition in general, e.g. survey design: with exploration systems emitting special signals, e.g. frequency swept signals, pulse…
G01V 1/247
Recording seismic data: digital recording of seismic data, e.g. in acquisition units or nodes