WO2012148816A2 - Acquisition simultanée de données sismiques classiques et à codage de phase - Google Patents

Acquisition simultanée de données sismiques classiques et à codage de phase Download PDF

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Publication number
WO2012148816A2
WO2012148816A2 PCT/US2012/034496 US2012034496W WO2012148816A2 WO 2012148816 A2 WO2012148816 A2 WO 2012148816A2 US 2012034496 W US2012034496 W US 2012034496W WO 2012148816 A2 WO2012148816 A2 WO 2012148816A2
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WO
WIPO (PCT)
Prior art keywords
survey
seismic
sweeps
crew
frequency
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/US2012/034496
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English (en)
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WO2012148816A3 (fr
Inventor
Peter M. Eick
Joel D. Brewer
Stephen K. Chiu
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ConocoPhillips Co
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ConocoPhillips Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by ConocoPhillips Co filed Critical ConocoPhillips Co
Priority to CA2833278A priority Critical patent/CA2833278C/fr
Priority to EP12720048.3A priority patent/EP2702432B1/fr
Publication of WO2012148816A2 publication Critical patent/WO2012148816A2/fr
Publication of WO2012148816A3 publication Critical patent/WO2012148816A3/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
    • G01V1/00—Seismology; Seismic or acoustic prospecting or detecting
    • G01V1/003—Seismic data acquisition in general, e.g. survey design
    • G01V1/005—Seismic data acquisition in general, e.g. survey design with exploration systems emitting special signals, e.g. frequency swept signals, pulse sequences or slip sweep arrangements

Definitions

  • This invention relates to seismic prospecting for hydrocarbon resources and especially to acquisition of seismic data using sweep-type seismic sources.
  • a crew In the process of acquiring seismic data, a crew is typically deployed across several square miles of a survey area positioning cables and seismic receivers while seismic sources move from predetermined point to predetermined point to deliver vibrational seismic energy into the earth.
  • the receivers capture the reflected signals that are recorded and subsequently processed to develop images of geologic structures under the surface.
  • phase encoded surveys are being conducted at the same time in close proximity, as long as the start times for each sweep are reasonably separated and the phase encoding of each crew is optimally tuned, each may generally proceed without time sharing.
  • a conventional seismic survey crew receives the phase encoded sweeps as significant noise and, heretofore, have not been able to proceed when another crew is in the area.
  • the invention more particularly includes a process for conducting two adjacent seismic surveys in close proximity and concurrently where each survey utilizes multiple sweep type seismic vibrators and where one survey is conducted with the seismic vibrators using sweeps of about twice the length of time or longer as the sweeps of the seismic vibrators of the other survey.
  • one survey is shaking one shot point at a time while the other shakes multiple shot points concurrently.
  • the sweeps may begin at first frequency and end at a second frequency and progress from the first to the second wherein the first frequency of one survey is at least five percent different than the first frequency of the other survey.
  • the second frequency of one survey may be at least five percent different than the second frequency of the other survey.
  • one survey may utilize an upsweep while the other utilizes a downsweep.
  • Figure 1 is perspective view of a first seismic crew acquiring data in a conventional manner
  • Figure 2 is a perspective view of a second seismic crew acquiring data in a phase encoded manner; and
  • Figure 3 is a diagram illustrating hypothetical sweeps of the two survey teams shown in Figures 1 and 2 to point out how the sweeps may be distinguished and thus, where the two crews may continue to gather seismic data without interfering with one another.
  • FIG. 1 An example of a conventional seismic survey crew is shown in Figure 1, where a team 10 of four sweep vibes 11, 12, 13, and 14 are arrayed around a shot point A and a plurality of receivers 18 are set to record the signals arriving back to the surface after reflecting off of subsurface structures.
  • All the energy put into the ground by the team 10 are seen as from the single point and may be essentially summed to be equivalent to one very big vibe.
  • the team 10 will move together from shot point to shot point until every shot point in the survey has been shaken.
  • the source points may be arranged in a variety of arrays depending on the paradigms of the designing geophysicist.
  • phase encoded seismic survey team 20 is shown with four vibes 21, 22, 23 and 24 each setting on shot points J, K L and M while a plurality of receivers are set to record the signals arriving back to the surface.
  • the data recorded at each receiver 28 includes the energy from each of the shot points J, K, L, and M.
  • four shot points are surveyed at the same time and the phase encoding of each source provides for subsequent separation of the data so that interpretations of the subsurface geology may be made based on data from each shot point to each receiver point.
  • the goal of phase encoded seismic surveying is to create the same data set as acquired by a conventional seismic survey team, but in significantly less time.
  • phase encoded seismic survey team with four vibes on one shot point will essentially put four times the energy into the ground in a set period of time as one vibe.
  • the vibes spend more time delivering energy into the ground at each shot point as the vibe.
  • a phase encoded seismic survey team with 4 vibes will deliver at least four sweeps of distinctly longer length in time than a conventional survey team will deliver.
  • a conventional survey were to have four vibes provide a common set of four sweeps of 10 seconds each for each shot point, a phase encoded seismic survey team would have each vibe deliver at least four 20 second sweeps or 80 total seconds of energy.
  • the conventional seismic crew will be contaminating the phase encoded survey, but the energy from the conventional vibes is typically easier to identify, especially once there are many sweeps. Moreover, with successive sweeps and the total energy of the sweeps delivered over a longer time leads mathematically to stacking out of the errant data and retention of sufficient useful data.
  • the inventive process comprises cooperation from the adjacent crews and some tailoring of the sweeps to be used.
  • a sweep is characterized by a starting frequency and ending frequency, and a sweep duration. The moment a sweep starts is also helpful information to separate sweeps.
  • Most sweeps are upsweeps, but using down sweeps for one crew while the other uses upsweeps with further characterize the sweeps for distinction in the data record for both crews.
  • the phase encoded crew will conduct four sweeps 2a, 2b, 2c and 2d of 16 seconds starting at 9 hertz to 65 hertz while the conventional crew will conduct two sweeps la andlb of 8 seconds in length starting at 4 hertz and ending at 72 hertz.
  • the sweeps will overlap in at most two places, labeled "X" and "Y", and for only a brief moment in time.
  • the data will be suspect, but it is unlikely that both X and Y will be at the same frequency.
  • the data from the sweep lb will provide the gap filling data.
  • the sweep la will provide the data for the overlap frequency Y.
  • each crew will require time to move the vibes from point to point. It is expected that a lot of seismic data for each crew will be gathered while the other is moving its vibes.
  • phase encoded survey One aspect that should be noted is that with the phase encoded system, the vibes will spend more time on each shot point and will therefore not be able to move to as many shot points in a single day as a conventional survey. However, each vibe in a phase encoded survey provides the energy, by itself, for each shot point. Thus, when the vibes move in a phase encoded survey, four shot points are completed versus a single shot point in a conventional survey. Thus, it should be easily seen that a phase encoded survey is a much more productive and ultimately time efficient survey.

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  • Engineering & Computer Science (AREA)
  • Remote Sensing (AREA)
  • Physics & Mathematics (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Acoustics & Sound (AREA)
  • Environmental & Geological Engineering (AREA)
  • Geology (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Geophysics (AREA)
  • Geophysics And Detection Of Objects (AREA)

Abstract

La présente invention concerne un procédé qui permet à deux équipes sismiques de travailler à proximité l'une de l'autre, ce qui impliquerait autrement un partage du temps coûteux avec une équipe disposant d'un système d'acquisition sismique classique et une équipe disposant d'un système d'acquisition sismique à codage de phase. Généralement, chaque système d'enregistrement reçoit de l'autre système, l'énergie sismique d'un ensemble de données qui ne sont pas très utiles. La présente invention envisage une certaine collaboration entre les équipes dans laquelle chaque équipe ajuste ses balayages pour comprendre une plage de temps différente de sorte que l'énergie des sources de l'autre équipe soit repérable dans l'ensemble de données et facilement éliminée de ce dernier. Les différences peuvent être renforcées plus encore lorsque les deux équipes utilisent leurs balayages de sorte que chaque équipe ait une fréquence de démarrage différente et une fréquence de fin visiblement différente.
PCT/US2012/034496 2011-04-29 2012-04-20 Acquisition simultanée de données sismiques classiques et à codage de phase Ceased WO2012148816A2 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
CA2833278A CA2833278C (fr) 2011-04-29 2012-04-20 Acquisition simultanee de donnees sismiques conventionnelles et codees en phase
EP12720048.3A EP2702432B1 (fr) 2011-04-29 2012-04-20 Acquisition simultanée de données sismiques classiques et à codage de phase

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US201161480777P 2011-04-29 2011-04-29
US61/480,777 2011-04-29
US59235612A 2012-04-20 2012-04-20
US12/592,356 2012-04-20

Publications (2)

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WO2012148816A2 true WO2012148816A2 (fr) 2012-11-01
WO2012148816A3 WO2012148816A3 (fr) 2013-06-13

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CA (1) CA2833278C (fr)
WO (1) WO2012148816A2 (fr)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3885225A (en) 1972-07-21 1975-05-20 Seiscom Delta Inc Broad line seismic profiling
US4715020A (en) 1986-10-29 1987-12-22 Western Atlas International, Inc. Simultaneous performance of multiple seismic vibratory surveys
GB2306219A (en) 1995-10-12 1997-04-30 Nigel Allister Anstey 3-D seismic survey using multiple sources simultaneously
US20060164916A1 (en) 2003-08-11 2006-07-27 Krohn Christine E Method for continuous sweepting and separtion of multiple seismic vibrators

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4686654A (en) * 1986-07-31 1987-08-11 Western Geophysical Company Of America Method for generating orthogonal sweep signals
US8559270B2 (en) * 2008-08-15 2013-10-15 Bp Corporation North America Inc. Method for separating independent simultaneous sources

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3885225A (en) 1972-07-21 1975-05-20 Seiscom Delta Inc Broad line seismic profiling
US4715020A (en) 1986-10-29 1987-12-22 Western Atlas International, Inc. Simultaneous performance of multiple seismic vibratory surveys
GB2306219A (en) 1995-10-12 1997-04-30 Nigel Allister Anstey 3-D seismic survey using multiple sources simultaneously
US20060164916A1 (en) 2003-08-11 2006-07-27 Krohn Christine E Method for continuous sweepting and separtion of multiple seismic vibrators

Also Published As

Publication number Publication date
CA2833278A1 (fr) 2012-11-01
CA2833278C (fr) 2019-06-18
WO2012148816A3 (fr) 2013-06-13

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