BR112019011678B1 - SURVEY SYSTEM AND MANUFACTURING METHOD OF A GEOPHYSICAL DATA PRODUCT - Google Patents

Abstract

SURVEY SYSTEM AND MANUFACTURING METHOD OF A GEOPHYSICAL DATA PRODUCT. The present invention relates to the configuration of a marine seismic survey. In some embodiments, one vessel (210) may be coupled to one or more seismic sources (220) and one or more seismic floating cables (250), and a second vessel (230) may be coupled to one or more seismic sources of Remote removal (240). Close range sources (220) can be configured to be actuated according to a range of firing points; the remote offset sources (240) can be configured to actuate over a longer range of firing points. In some embodiments, the longest shotpoint range may be a multiple of the close-off source shotpoint range. The determination of the first and second firing point intervals may be based, at least in part, on, for example, the wave frequencies of the remote offset sources, the requirements of a full wave inversion process, or the various configuration parameters of seismic surveys.

Description

BACKGROUND DESCRIPTION OF THE RELATED TECHNIQUE

[001] Marine seismic surveying is a technique for investigating geological features beneath bodies of water. Various vessel configurations, seismic instruments and seismic sources can be useful for different applications. The requirements of different applications for seismic data can influence the design of the seismic survey. The actuation of additional seismic sources beyond what is necessary can increase costs, have an environmental impact or other undesirable effects.

BRIEF DESCRIPTION OF THE DRAWINGS

[002] Figure 1 is a diagram illustrating a system for conducting marine seismic surveys, according to some embodiments.

[003] Figure 2 is a diagram illustrating an arrangement for conducting a Simultaneous Long Distance (SLO) marine seismic survey, in accordance with some embodiments.

[004] Figure 3 is a diagram illustrating a range of firing points for conducting a marine SLO seismic survey, in accordance with some embodiments.

[005] Figure 4 is a diagram illustrating a relationship between the frequency and the distance of traces, according to some embodiments.

[006] Figure 5 is a diagram illustrating an arrangement for conducting a Simultaneous Long Distance (SLO) marine seismic survey, in accordance with some embodiments.

[007] Figure 6 is a diagram illustrating a range of shotpoints for conducting a marine SLO seismic survey with a range of shotpoints of longer remote offsets, in accordance with some embodiments.

[008] Figure 7 is a flowchart illustrating a method for conducting marine seismic surveys, according to some embodiments.

[009] Figure 8 is a flowchart illustrating a method for conducting a marine SLO seismic survey with a range of longer remote shooting points, in accordance with some embodiments.

[0010] Figure 9 is a diagram illustrating an arrangement for conducting a Wide Azimuth (WAZ) marine seismic survey, in accordance with some embodiments.

[0011] Figure 10 is a diagram illustrating a shotpoint range for conducting a marine WAZ seismic survey with a shotpoint range of longer remote offsets, in accordance with some embodiments.

[0012] Figure 11 is a flowchart illustrating a method for conducting a WAZ marine seismic survey with a range of longer remote offset shooting points, in accordance with some embodiments.

[0013] Figure 12 is a diagram illustrating an arrangement for conducting a marine seismic survey using multiple groups of floating cables, in accordance with some embodiments.

[0014] Figure 13 is a diagram illustrating a range of shotpoints for conducting a marine seismic survey, in accordance with the arrangement of Figure 12 with a range of shotpoints of longer remote spacings, in accordance with some embodiments.

[0015] Figure 14 is a flowchart illustrating a method for conducting a marine seismic survey, in accordance with the arrangement of Figure 12 with a range of shooting points of longer remote offsets, in accordance with some embodiments.

[0016] Figure 15 is a flow chart illustrating a method for conducting marine seismic surveys, in accordance with some embodiments.

[0017] Figure 16 is a block diagram illustrating a computational system, according to some embodiments.

[0018] Although the invention is susceptible to various modifications and alternative forms, its specific embodiments are shown by way of example in the drawings and are described in detail in the present specification. It should be understood, however, that the drawings and their detailed description are not intended to limit the invention to the particular form described, but rather, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and the scope of the present invention, including the appended claims. Particular aspects, structures or features may be combined in any suitable manner consistent with this description.

[0019] It is to be understood that the terminology used in the present specification is for the purpose of describing particular embodiments only, and is not intended to be limiting. As used in this specification, the singular forms "a", "an", "the" and "the" include both singular and plural referent forms, unless the content clearly indicates otherwise. Furthermore, the words "may" and "be able to" are used throughout this patent application in a permissive sense (i.e., having the potential to, be able to), not in an obligatory sense (i.e., must ). The term "include" and its derivatives mean "including, but not limited to".

[0020] Within this description, different entities (which may variously be referred to as "units", "circuits", other components, etc.) may be described or claimed to be "configured" to perform one or more tasks or operations. This formulation - [entity] configured to [perform one or more tasks] - is used to refer to structure (that is, something physical, such as an electronic circuit). More specifically, this formulation is used to indicate that the structure is arranged to perform one or more tasks during operation. A structure can be said to be "configured to" perform some task, even if the structure is not currently being operated. A "mobile device configured to generate a hash value" is intended to cover, for example, a mobile device that performs this function during operation, even if the device in question is not currently being used (for example, when its battery is not connected to it). Thus, an entity described or referred to as "configured to" perform some task refers to something physical, such as a device, circuit, memory storing executable program instructions to implement the task, etc. This term is not used in this specification to refer to anything intangible.

[0021] The term "configured to" is not intended to mean "configurable to". An unprogrammed mobile computing device, for example, would not be considered to be "configured to" perform some specific function, although it might be "configurable to" perform that function. After proper programming, the mobile computing device can then be configured to perform this function.

[0022] The indication in the appended claims that a structure is "configured to" perform one or more tasks is specifically intended not to invoke 35 U.S.C. § 112(f) for that element of the claim. Consequently, none of the claims in this patent application, as filed, are intended to be construed as having "meansplus-function" elements. In the event that the claimant wishes to invoke section 112(f) during proceedings, it must indicate the elements of claims using the construction "means to" [performing a function].

[0023] As used in this specification, the term "based on" is used to describe one or more factors that affect a determination. This term does not exclude the possibility that additional factors may affect the determination. That is, a determination can be based only on specific factors or based on specific factors as well as other non-specific factors. Consider the term "determine A based on B". The term specifies that B is a factor used to determine A, or that affects the determination of A. This term does not exclude that the determination of A may also be based on some other factor, such as C. This term is also intended to cover an embodiment in which A is determined based only on B. As used in the present specification, the term "based on" is synonymous with the term "based at least in part on".

[0024] As used in this specification, the term "coupled to" may indicate one or more connections between elements, and a coupling may include intermediate elements. That is, two elements can be indirectly coupled by virtue of intermediate elements. On the other hand, in the absence of intermediate elements, two elements can be said to be "directly coupled" to each other.

DETAILED DESCRIPTION

[0025] Driving a camera can be a difficult and expensive operation. The actuation of more seismic sources than necessary can increase costs, environmental impact or other undesirable effects. In some settings, a survey may generate data that is unnecessary or at least useless relative to the cost of obtaining the data. For example, very large offset data may be discarded due to problems with image quality or relatively little enhancement to the image. As another example, the Complete Wave Inversion (FWI) process, discussed below, can be conducted using only lower frequencies, which can dispense with spatial sampling, which is as dense as the rest of the dataset. Consequently, in some embodiments of marine seismic surveys, seismic sources, which are located at relatively remote distances, are not actuated as often as sources at relatively close distances. Several survey configurations can be implemented this way, including Simultaneous Long Offset (SLO), Wide Azimuth (WAZ), and multiple floating cable assemblies, all of which are discussed in turn below.

[0026] Turning now to Figure 1, a diagram of one embodiment of an arrangement for conducting a marine geophysical survey using a towed subsea buoyant cable assembly. In the embodiment shown, the tug vessel 100 is towing a set of submerged, floating cables 104. Each submerged floating cable can include multiple seismic sensors. The types of sensors that can be implemented on a given floating cable include (but are not limited to) hydrophones and geophones. Furthermore, a given floating cable may include more than one type of sensor (for example, a combination of hydrophones and geophones). Various operational considerations can make certain depths of towing buoyant cables advantageous. In some embodiments, single sensor buoyant cables 104 can be towed to depths between about 4 meters and 30 meters. In some embodiments, dual sensor buoyant cables can be towed to depths between about 15 and 30 meters.

[0027] The tug ship 100 can also tow multiple fountains 102 via towing cables 103. In some embodiments, the fountains 102 can be towed by another vessel or by other vessels (not shown). Sources 102 may include various seismic sources such as marine vibrators, air guns, etc. In some embodiments, the sources 102 can transmit sound waves into the water, the echoes of which can be detected by the seismic sensors of the floating cables 104. The sensors and receivers of the floating cables 104 can be coupled (e.g., electrically, wirelessly, etc. ) to electronic equipment on board the tug vessel 100, which can be used to record or analyze geophysical data, such as received echoes or detected signals. By using the arrangement shown in Figure 1, marine seismic surveys can be conducted. Among the uses of information obtained from these surveys may be the identification of geological formations indicative of oil and/or natural gas deposits.

[0028] Figure 2 illustrates an embodiment of a system configured to conduct a seismic survey. In the illustrated embodiment, a Simultaneous Long Offset (SLO) configuration is illustrated: the buoyant cable ship 210 tows at least two near offset sources 220 and a set of seismic buoyant cables 250, while the source ship 230 tows at least two remote offset sources 240. (In other embodiments, a single remote offset source 240 may be used, or multiple different source vessels 230 may be employed). In the illustrated embodiment, the fountain ship 230 is located ahead of the floating cable ship 210 in the tilting direction. The axes in Figure 2 illustrate the in-line direction as the y-direction and the perpendicular direction as the x-direction. The distance between ships 210 and 230 can be varied depending on the configuration of the survey system; non-limiting examples of the distance between the 210 and 230 ships include 4, 6 and 8 kilometers, although in principle the range is not limited.

[0029] In some embodiments, at least one near spacing source and at least one seismic floating cable are attached to the same vessel. In other embodiments, closer spacing sources can be attached to the vessel. In yet other embodiments, the seismic buoyant cables 250 can be attached to a vessel separate from the close range sources.

[0030] Figure 3 illustrates an embodiment of a Fire Point Interval (SPI) model corresponding to the system configured in SLO in Figure 2. In the illustrated embodiment, the sources act according to the SPI model: the distance sources remote act according to model 320 and close range sources act according to 310. Shooting points number from 1 to 4 each of SPI models 310 and 320, where similar numbers between models 310 and 320 indicate the position of sources at a point in ordinary time. For example, shooting point 1 in the close range model 310 and shooting point 1 in the far distance model 320 occur at approximately the same time. For purposes of this invention, simultaneous actuation of sources includes actuation of sources within a period of time such that the energy, generated by detonation of the sources, coincides with a degree to which coincident energy decomposition can be performed. Furthermore, in some embodiments, the actuations of the sources may be synchronized such that the remote and near offset data are partially coincident or completely separated in time, rather than substantially simultaneous.

[0031] In the illustrated embodiment, both close offset sources are alternately actuated and both remote offset sources are also alternately actuated. For example, the first close offset source 240 is actuated at firing points 1 and 3, and the second is actuated at firing points 2 and 4, in the illustrated embodiment. Similarly, in the illustrated embodiment, both near spacing sources 220 are respectively actuated alternately: the first source is actuated at points 1, 3, etc., while the second source is actuated at points 2, 4, etc. . The relative location of the stars in Figure 3 illustrates the physical location of the sources in this embodiment at the time of actuation. The axes in Figure 3 illustrate the in-line direction as the y-direction and the perpendicular direction as the x-direction. In the illustrated embodiment, the remote offset source ship 240 moves in the same direction and speed as the ship 210, so that the distance between the firing points, with the same number, is the same for the firing point range models. near and remote distances. For example, the distance between the near distance point 1 and the remote distance point 1 is equal to the distance between the near distance point 4 and the remote distance point 4, in the illustrated embodiment. In other embodiments, there may be additional sources, which may be actuated according to a different model; for example, there may be three sources, which are actuated sequentially, or there may be a single source, which is actuated at each point, or there may be other actuation models corresponding to the various configurations of sources. In some embodiments, ships 210 and 230 may not have the same number of sources.

[0032] In some embodiments, the advantages of acting seismic sources at each point of the remote remote source model 320 may not outweigh the disadvantages. Disadvantages of acting beyond what is necessary include higher costs (for example, a larger vessel may be needed to support greater average power from the sources), environmental impact, more seismic noise, or other undesirable effects. In some seismic surveys, the benefits of having one source at each shooting point may be small; for example, seismic surveys, which implement the Full Wave Inversion (FWI) technique, may not benefit from as many remote-offset source actuations as near-offset source actuations.

[0033] FWI is a data processing technique, which can be used to process data collected by a seismic survey. FWI can include simulation of seismic sources and wave propagation by a model of the area being surveyed. The model can be iteratively updated according to a loss function that compares simulated seismic measurements with real seismic measurements. In some embodiments, the complexity of calculating wave propagation limits the amount of frequencies, which are useful for FWI. In some embodiments, limiting the frequencies used can increase the calculation speed or the accuracy with which the iterative update process converges. In seismic survey embodiments where FWI is a desired technique, it can be advantageous to collect only those frequencies that are most useful. Desired frequencies can be lower frequencies, for example below 25 Hz, below 15 Hz, below 10 Hz, below 8 Hz, etc.

[0034] Figure 4 is a diagram illustrating an example of a relationship between the Nyquist frequency of seismic signals and the distance between the measured seismic traces. In the illustrated embodiment, the relationship shown in the graph by the triangular dots corresponds to a wave velocity of 1600 m/s and a dip of 30 degrees. In some embodiments, increasing the frequency requirements of a measurement implies a non-linear decrease in the distance of traces. In some embodiments, the distance of the traces corresponds to the distance between measurement devices (eg, hydrophones, geophones, etc.) on a seismic floating cable and/or the distance between source actuations.

[0035] In some embodiments, the determination of various SPIs is based, at least partially, on the frequencies of waves from remote spacing sources. In some embodiments (as a non-limiting example, Full Wave Inversion (FWI) or other seismic survey configurations), only certain frequencies may be required, as discussed above the FWI. In embodiments such as those, Figure 4 can illustrate the distance of traces that can provide adequate data. As a non-limiting example, SLO for FWI may require frequencies up to 10 Hz; the corresponding trace distance may be 75m for the particular conditions in the illustrated embodiment. Another example might be conventional SLO, which may require frequencies up to 32 Hz; the corresponding trace distance may be 25 m for the particular conditions in the illustrated embodiment.

[0036] Returning to Figure 5, another embodiment of a system, configured to conduct a seismic survey, is shown. In the illustrated embodiment, an SLO configuration, similar to that of Figure 2, is illustrated. While the embodiments illustrated in Figures 2 and 5 are similar, other embodiments of either system may differ, for example, the distance between ships 510 and 530 may be closer or further apart than the distance in Figure 2, the number or the configuration of sources 520 or 540 may be different, or other parameters for configuring a seismic survey may be different. Similar to the previous figures, the axes of Figures 5 and 6 illustrate the in-line direction as the y-direction and the perpendicular direction as the x-direction.

[0037] The illustrated embodiment of Figure 6 illustrates an SPI model corresponding to the survey system of Figure 5. The embodiment is, however, different from the SPI model of Figure 3. Similar to Figure 3, remote offset sources 540 can be actuated in accordance with remote offset sources template 620, while near offset sources 520 can be actuated in accordance with near offset sources template 610. The firing points are numbered 1 through 8 for each one of the SPI models 610 and 620, where similar numbers between models 610 and 620 indicate the position of the sources at a common point in time. As discussed below, in the illustrated embodiment, a source may not be actuated at certain firing points. However, if multiple sources are actuated at a given trigger point, those actuations can be actuated substantially simultaneously (e.g., 610 trigger point 1 and 620 trigger point 1 can be simultaneous, trigger point 2 of 610 and the firing point of 620 can be simultaneous, etc.). In some embodiments, a close-off source is actuated substantially simultaneously with a remote-off source.

[0038] In the illustrated embodiment, the remote removal model 620 illustrates some shooting points that do not correspond to an actuation. In the illustrated embodiment, the trigger points 2, 3, 5, 6 and 8, of the remote pull-off source template 620, indicate that a remote pull-off source is not to be actuated, while the same numbers of trigger points, for the close-off source model 610, indicate that a close-off source should be actuated. In some embodiments, close-off sources may be actuated on all firing points, or may be actuated on some firing points and not actuated on others. The illustrated embodiment shows a remote retreat source being detonated at every third fire point, every fourth fire point, alternating between two and three idle fire points, etc.).

[0039] In some embodiments, the range of the shooting points of one set of sources is an integer multiple of another set of sources, so that the first set of sources (e.g., remote offset sources) are actuated less frequently than the second set of sources (for example, the close spacing sources). Furthermore, in some cases, the shooting point ranges of the two sets of sources can be aligned with each other, so that when one of the remote offset sources is actuated, this is not done simultaneously with one of the sources. close distance. As a non-limiting example, remote remoteness sources can be configured to actuate within a range that is substantially three times the range of close range sources' shooting points, similar to the embodiment illustrated in Figure 6. In other embodiments, the sources of remote removal can be actuated in other multiples; for an example, not intended to be limiting, the remote offset source may be actuated within a range, which is 4, 5, 6, etc. times the range of nearby firing points. In some embodiments, the sources, which are configured in this way, can be actuated substantially simultaneously. However, it is not necessary for the shooting point range of one font set to be an integer multiple of another font set.

[0040] The reduced performance of the remote offset sources model 620 can provide sufficient data regarding the low frequencies of seismic sources to perform an FWI analysis. As discussed in relation to Figure 4, low frequency sources may not require actuations as often as high frequency sources. Additionally, higher frequencies can be attenuated at remote offsets, limiting the usefulness of remote offset sources for high frequency applications. Benefits associated with less actuations (e.g., lower cost, lower environmental impact, lower seismic noise, etc., as discussed above) can be promoted by the 620 remote remote sources model.

[0041] Figure 7 is a flowchart illustrating a method for performing a marine seismic survey, in accordance with some embodiments. The method shown in Figure 7 can be used in conjunction with any of the computational systems, devices, elements or components described in this specification, among other devices. In various embodiments, some of the elements of the method may be performed concurrently, in a different order than shown, or may be omitted. Other elements of the method can also be executed if desired.

[0042] At 710 in the illustrated embodiment, the one or more near-distance seismic sources are actuated in a marine seismic survey according to a first range of shot points. In some embodiments, the seismic sources include multiple sets of air guns; the separate sets of pneumatic guns can be fired sequentially, so that a specific firing point range can be maintained, in some embodiments. One or more sources of close spacing can include a pneumatic gun or a marine vibrator, in some embodiments. In some embodiments, seismic sources can be configured to emit a large portion of the seismic energy at a frequency below 10 Hz.

[0043] An interval of shooting points can be defined in terms of the time between successive actuations of a seismic source or it can be defined in terms of the distance between successive actuations of a seismic source. Examples of shooting point ranges, not intended to be limiting, include ranges as short as 6.25 m and ranging up to 50 m. In other embodiments, the firing point ranges may fall outside this range.

[0044] At 720 in the illustrated embodiment, one or more remote offset sources are actuated in a marine seismic survey, according to a second range of shot points. In some embodiments, the second shotpoint interval is of greater distance or time than the first shotpoint interval. In some embodiments, the one or more remote offset sources are located at a greater distance from the seismic buoyant cables than the one or more close offset sources. Remote remote sources can be attached to a separate vessel than floating cables or close remote sources. In some embodiments, one or more of the remote deterrent sources can include a pneumatic gun or a marine vibrator. In some embodiments, there may be fewer remote offset sources than close offset sources.

[0045] At 730 in the illustrated embodiment, seismic data responsive to the actuation of near and remote offset sources are collected. In some embodiments, the seismic buoyant cables are configured to receive seismic data responsive to actuation from at least one near-distance seismic source or at least one far-distance seismic source. As discussed in more detail below, a logging system can be set up to generate a stored record of seismic data. Seismic data can include seismic traces or other data, which are collected when seismic sources are being actuated. In some embodiments, performance responsive data from near remote sources may be collected at the same time as performance responsive data from remote remote sources. Data responsive to near and far away sources may be received by the sensors within coincident time periods, in such a way as to allow separation of data from respective sources, in some embodiments. For example, separation or disambiguation of multiple sources detonated simultaneously can occur during post-acquisition data processing.

[0046] Compared to the previous figure, Figure 8 is a flowchart illustrating a more detailed method for performing a marine seismic survey, according to some embodiments. The method shown in Figure 8 can be used in conjunction with any of the computational systems, devices, elements or components described in this specification, among other devices. In various embodiments, some of the method elements shown may be performed concurrently, in a different order than shown, or may be omitted. Other elements of the method can also be executed if desired.

[0047] At 810 in the illustrated embodiment, a marine seismic survey is set up. Configuration of the survey system may include selecting and configuring multiple vessels, configuring seismic sources and coupling them to vessels, configuring seismic buoyant cables and coupling them to at least one vessel, configuring buoyant cables to receive data, or any other operations suitable to prepare a survey system for survey activity.

[0048] At 820 in the illustrated embodiment, a remote offset SPI is selected. In some embodiments, the SPIs may be dependent on one or more performance requirements of a Full Wave Inversion (FWI) process, as discussed above. In some embodiments, selecting the SPI includes selecting a multiple of the near offset source SPI, selecting particular remote offset points to avoid actuation, or determining a distance between consecutive shot points. FWI process performance requirements may include the amount of data collected at specific frequencies, the total amount of data collected, the noise level in the data collected, or other parameters from a seismic survey that may affect the data obtained.

[0049] At 830 in the illustrated embodiment, seismic buoys and seismic sources are towed in the vicinity of a geological feature. Towing may include pulling buoyant cables and fountains across a vessel in the water. Geological features may include underground deposits of minerals, oil or gas, salt domes, or any other items capable of being imaged using seismic techniques.

[0050] At 840 in the illustrated embodiment, the near-distance seismic sources are actuated according to an SPI. In some embodiments, there may be two or more closely spaced seismic sources, and these sources may be actuated alternately.

[0051] At 850 in the illustrated embodiment, the remote offset seismic sources are actuated in accordance with an SPI. In some embodiments, there may be two or more closely spaced seismic sources, and these sources may be actuated alternately. In the illustrated embodiment the SPI of the remote offset sources is greater than the SPI of the close offset sources. As described above, in some embodiments, the SPI of the remote offset sources may be a multiple of the SPI of the close offset sources.

[0052] At 860 in the illustrated embodiment, data responsive to the action of seismic sources are collected and recorded. For example, pressure sensors and/or particle motion sensors (eg hydrophones and/or geophones), attached to the floating cable, can collect seismic data from each firing point, and this data can be recorded by a recording system, which is coupled to hydrophones or geophones. In some embodiments, the recording system can be a generic computer system or a computer system specifically configured to record seismic data.

[0053] Figure 9 illustrates one embodiment of a system configured to conduct a seismic survey. Similar to Figures 3 and 5, Figure 9 illustrates a vessel assembly 910, 920 and 930, a source assembly 940, 950 and 960, and a seismic floating cable assembly 970. In the illustrated embodiment, these components are configured in a Wide Azimuth (WAZ) array, which can facilitate seismic data collection in the presence of obstructions (eg, salt domes), which are difficult to image with other survey geometries. In this embodiment, there may be two fountain ships: a vessel 930, coupled to the remote spacing sources 960, and a vessel 920, coupled to the intermediate spacing sources 950. As with the previous figures, the axes of Figure 9 illustrate the in-line direction as the y direction and the perpendicular direction as the x direction. In some embodiments, all of the ships may be located on one side (e.g., port or starboard) of the buoyant cable ship 910, in the perpendicular direction, although it is possible for the source ships to be located on different sides of the source ship. floating cables 910, in a WAZ survey. In some embodiments, the one or more intermediate offset sources 950 and the one or more remote offset sources 960 are located on the same side of the seismic buoyant cables in the perpendicular direction. The intermediate offset sources may be located farther from the seismic buoyant cables than the near offset sources 940 and closer to the seismic buoyant cables than the remote offset sources 960. In the illustrated embodiment, the close offset sources 940 and the seismic buoyant cables 970 are attached to the buoyant cable vessel 910.

[0054] Figure 10 illustrates an embodiment of an SPI configuration, which corresponds to the WAZ configuration illustrated in Figure 9. Figure 9, similarly to Figure 6, illustrates a set of firing points arranged in space, where the number for each firing point corresponds to a source's position at a point in time when a source can be triggered. As with the previous figures, the axes in Figure 10 illustrate the in-line direction as the y-direction and the perpendicular direction as the x-direction.

[0055] Figure 10 includes a model of detonation of intermediate distance sources 1020. In some embodiments, the intermediate distance sources can be configured to be actuated according to the same SPI as the close distance sources, or the sources of remote offset, or they can be configured to be actuated according to an SPI that is not the same as any of the near and remote offset source SPIs.

[0056] In the illustrated embodiment, the detonation model of remote remote sources 1010 includes the firing points at which no actuation is indicated: the firing points 2, 3, 5, 6 and 8. The illustrated embodiment shows the detonation of the far-off sources at an SPI, which is three times larger than the near- and far-off SPIs; although, this is not intended to be a limiting example, and other configurations, as previously discussed, can be used.

[0057] Figure 11 is a flowchart illustrating a method for performing a marine seismic survey, in accordance with some embodiments. The method shown in Figure 11 can be used in conjunction with any of the computational systems, devices, elements or components described in this specification, among other devices. In various embodiments, some of the method elements shown may be performed concurrently, in a different order than shown, or may be omitted. Other elements of the method can also be executed if desired.

[0058] The method illustrated in Figure 11 includes several elements, which are substantially similar to the elements of Figure 8. In the illustrated embodiment, elements 1110, 1120 and 1130 can be implemented similarly as elements 810, 820 and 830 of Figure 8, respectively, and will not be discussed further in this case. Element 1170 can be implemented similarly as element 860 of Figure 8. The differences between the methods of Figures 8 and 11 will be discussed below; it should be noted that, in other embodiments, the method of Figure 11 can be implemented with more, less or different elements and need not employ elements that are similar to those of Figure 8.

[0059] At 1140 in the illustrated embodiment of Figure 11, an intermediate spacing source ship and a remote spacing source ship are arranged in the perpendicular direction. In some embodiments, the intermediate clearance source ship may be closer to the seismic buoyant cable than the remote clearance ship and further away from the seismic buoyant cable assembly than the near clearance source ship. In some embodiments, the near clearance sources ship can tow both the near clearance sources and the seismic buoyant cable assembly.

[0060] At 1150 in the illustrated embodiment of Figure 11, one or more near spacing sources and one or more intermediate spacing sources are actuated according to a range of firing points. In the illustrated embodiment, the SPIs for the near and intermediate offset sources are the same. In some embodiments, the near offset sources and the intermediate offset sources are actuated according to the same range of firing points. In other embodiments, the near and intermediate offset sources may be actuated according to different ranges, or the intermediate offset sources may not be actuated at the firing points. In some embodiments, the intermediate clearance sources are actuated substantially simultaneously with the near clearance sources; although, in other embodiments, they may not be.

[0061] Step 1160 is similar to element 850 of Figure 8, although, in the illustrated embodiment of Figure 11, the SPI of the remote offset source may have a relationship with the SPI of the intermediate offset source, as well as that of the source close distance. In some embodiments, the remote offset source may have an SPI greater than that of both the near and intermediate offset sources, or may have an SPI greater than that of the near offset source and a lower SPI than that of the near offset source. of intermediate spacing, or it may have a higher SPI than the near spacing source and the same SPI as the intermediate spacing source, etc.

[0062] Figure 12 illustrates another embodiment of a system configured to conduct a seismic survey. Similar to Figures 3, 5 and 9, Figure 12 illustrates a set of ships 1210, 1230 and 1250, a set of sources 1220, 1240 and 1260, and sets of floating seismic cables 1270 and 1280. above, the axes in Figure 12 illustrate the in-line direction as the y-direction and the perpendicular direction as the x-direction. In the illustrated embodiment, these components are configured in a floating multiple cable array arrangement, which like the WAZ arrangement, can improve survey quality for some types of subsurface conditions. In this embodiment, there may be three source ships: a ship 1250 coupled to the remote remote sources 1260, a ship 1210 coupled to the close remote sources 1220, and a ship 1230 coupled to the close remote sources 1240. In the illustrated embodiment, both ships with close spacings can tow seismic buoyant cable assemblies 1270 and 1280, and can be positioned so that ship 1230 is perpendicular to ship 1210; additionally, remote source ship 1250 can be positioned ahead of both ships 1210 and 1230 in the in-line direction and approximately midway between ships 1210 and 1230 in the perpendicular direction. In some embodiments, one or more additional close spacing sources (not shown) can be arranged between ships 1210 and 1230.

[0063] In some embodiments, ship 1250 is located substantially equally apart from ships 1201 and 1230. However, ship 1250 may be disposed in any suitable position, ranging from, for example, directly in front of ship 1210 to directly in front of ship 1230. In some embodiments, the seismic buoyant cables include at least two groups of buoyant cables, which are respectively attached to at least two seismic buoyant cable ships. In some embodiments, at least two near spacing sources 1220 and 1240 are coupled to at least two ships 1210 and 1230, respectively, and at least one remote spacing source 1260 is located substantially equally distant from ships 1210 and 1230.

[0064] In some embodiments, such as the survey configurations discussed above, the close-off sources 1220 and 1240 may contain more or less seismic sources than in the illustrated embodiment, and the seismic floating cable assemblies 1270 and 1280 may be comprised of more or less seismic floating cables than in the illustrated embodiments. In some embodiments, there may be other ships, which may be attached to other sources or floating cables. In some embodiments, the remote source ship 1250 can be positioned, as non-limiting examples, closer to the ship 1210, closer to the ship 1230, farther in the perpendicular direction than the ship 1230, etc.

[0065] Figure 13 illustrates an embodiment of an SPI, which corresponds to the configuration of a group of multiple floating cables illustrated in Figure 12. Figure 13, similarly to Figures 10 and 6, illustrates a set of firing points arranged in space, where the number for each firing point indicates a position of a source at a point in time when the source can be actuated; the axes in Figure 13 illustrate the in-line direction as the y-direction and the perpendicular direction as the x-direction.

[0066] Figure 13 includes two close-off sources detonation models 1310 and 1320. In the illustrated embodiment, the close-off sources 1220 and 1240 can be configured to be actuated according to the same SPI, which can result in the model 1310 being the same as model 1320. In some embodiments, sources 1220 and 1240 can be configured to be actuated according to an SPI that is not the same, for example, model 1310 can be different from model 1320.

[0067] In the illustrated embodiment, the remote remote source detonation model 1330 includes the firing points at which no source actuation is indicated: the firing points 2, 3, 5, 6 and 8. The illustrated embodiment shows the detonation from remote remote sources at an SPI that is three times greater than the near and intermediate distance SPIs; however, this is not intended to be a limiting example, and other configurations, as previously discussed, can be used.

[0068] Figure 14 is a flowchart illustrating a method for performing a marine seismic survey, according to some embodiments. The method shown in Figure 14 can be used in conjunction with any of the computational systems, devices, elements or components described in this specification, among other devices. In various embodiments, some of the method elements shown may be performed concurrently, in a different order than shown, or may be omitted. Other elements of the method can also be executed if desired.

[0069] The method illustrated in Figure 14 includes several elements, which are substantially similar to the elements of Figure 8. In the illustrated embodiment, elements 1420 and 1430 can be implemented similarly as elements 820 and 830 of Figure 8, respectively, and not will be discussed further in this case. Element 1480 can be implemented similarly as element 860 of Figure 8. The differences between the methods of Figures 14 and 8 will be discussed below; it should be noted that, in other embodiments, the method of Figure 11 can be implemented with more, less or different elements and need not employ elements that are similar to those of Figure 8.

[0070] At 1410 in the illustrated embodiment of Figure 14, a marine seismic survey system, which includes two seismic sources, three or more ships and two or more sets of seismic floating cables, is illustrated. Step 1410 illustrates a system similar to element 810 of Figure 8; although in 1410 specifically included 3 or more ships and 2 or more sets of floating cables. In some embodiments, the method illustrated in Figure 14 can describe a process with a set of multiple floating cables similar to that illustrated in Figures 12 and 13.

[0071] In the element 1440 in the illustrated embodiment of Figure 14, the second group of floating cables can be arranged in the perpendicular direction of the first set of floating cables. In some embodiments, the second set of buoyant cables may be disposed on the port side or the starboard side of the first set of buoyant cables. The floating cable assemblies can have, in some embodiments, different numbers of floating cables, different lengths of floating cables, different sensors of the floating cables, etc.

[0072] In the element 1450 in the illustrated embodiment, a remote offset source ship is disposed ahead of the two seismic floating cable ships in the in-line direction and midway between the two seismic floating cable ships in the perpendicular direction. In some embodiments, the remote offset source ship may be closer to one floating cable ship or the other in the perpendicular direction, or the source ship may be located further away in the port or starboard direction than any of the source ships. floating cables.

[0073] At 1460 in the illustrated embodiment, one or more close-off seismic sources associated with all floating cable assemblies are actuated according to a range of shot points. In some embodiments, the sources associated with all floating cables are actuated according to the same SPI; in other embodiments, the font sets may be actuated according to different SPIs. In some embodiments, there are seismic sources attached to all ships towing the floating cable assemblies.

[0074] At 1470 in the illustrated embodiment, one or more remote offset seismic sources are actuated according to a larger firing point range. This element may be similar to 850 of Figure 8, although, the remote offset source may have a relationship to any of the close offset sources, in some embodiments. In some embodiments, the SPI of the remote offset source is greater than any of the SPIs of the near offset sources. In some embodiments, the near spacing sources can have different SPIs, and the remote spacing source can have, for example, a greater SPI than one or the other, or both of the near spacing sources.

[0075] Figure 15 is a flowchart illustrating a method for performing a marine seismic survey, in accordance with some embodiments. More particularly, as described in more detail below, Figure 15 relates to the generation of a geophysical data product, based on survey data. The method shown in Figure 15 can be used in conjunction with any of the computational systems, devices, elements or components described in this specification, among other devices. In various embodiments, some of the method elements shown may be performed concurrently, in a different order than shown, or may be omitted. Other elements of the method can also be executed if desired.

[0076] In some embodiments, the collected survey data may be represented in a "geophysical data product". A geophysical data product may comprise a non-transient, computer-readable medium having geophysical data stored on the medium, including, for example, raw floating cable data, processed floating cable data, two- or three-dimensional maps based on floating cable data , or other suitable representations. Some non-limiting examples of computer-readable media could include hard drives, CDs, DVDs, flash memory, hard copies, etc. In some embodiments, raw analog data from the floating cables can be stored in the geophysical data product. In other cases, the data may first be digitized and/or conditioned before being stored in the geophysical data product. In most other cases, the data may be fully processed into a two- or three-dimensional map of the various geophysical structures, before being stored in the geophysical data product. The geophysical data product may be manufactured during the course of a survey (for example, by equipment on a ship) and then, in some cases, transferred to another location for geophysical analysis, although analysis of the geophysical data product may occur later with the collection of survey data.

[0077] In the 1510 illustrated embodiment, one or more near-distance seismic sources are actuated in a marine seismic survey according to a blast model. Realizations of seismic sources and configurations of seismic surveys were previously discussed; further reference can be found in the discussion of 710 in Figure 7. A blast model can indicate, among other things, the manner or order in which seismic sources are acted upon. In some embodiments, the detonation pattern can be described similarly to an interval of firing points. In some embodiments, the blast pattern may include a time or distance between actuations, and may vary from actuation to actuation.

[0078] In some embodiments, two or more close spacing sources are actuated alternately. In embodiments with two closely spaced sources, these may include the actuation of the first source, then the actuation of the second source, then the actuation of the first source again, etc. In some embodiments, more than two closely spaced sources may be actuated in an alternating manner by actuating all the sources in a sequence, or alternating actuation in another pattern or randomly. Multiple close-off sources can also be actuated simultaneously instead of, or in addition to, alternately.

[0079] At 1520 in the illustrated embodiment, one or more sources of remote detonation are actuated in a marine seismic survey, according to a less frequent detonation model. In some embodiments, the remote offset sources are located at a greater distance from the seismic buoyant cables than the close offset sources. Remote remote sources can be attached to a vessel separate from floating cables or close to close remote sources. In some embodiments, a less frequent detonation pattern may correspond to a greater range of firing points; for example, actuation of a source less frequently may imply a greater distance or time between actuations.

[0080] In some embodiments, two or more remote offset seismic sources are actuated alternately. The alternating actuation of the remote remoteness seismic sources can be done in a similar way to that described above for the near distance sources. In some embodiments, the detonation pattern for close range sources detonate substantially three times as often as the knock pattern for remote range sources.

[0081] At 1530 in the illustrated embodiment, geophysical data, responsive to the actuation of one or more close-off sources and one or more remote-off sources, are collected. Geophysical data can include seismic traces or other data, which are collected during a seismic survey. In some embodiments, the geophysical data includes seismic data, such as data recorded by pressure and/or particle motion sensors. In some embodiments, performance-responsive data from close-off sources may be collected at the same time as performance-responsive data from remote-off sources. Data responsive to near and far away sources may be indistinguishable or may be collected in such a way as to separate the data from the respective sensors, in some embodiments.

[0082] At 1540 in the illustrated embodiment, the geophysical data is stored on a tangible computer-readable medium, thereby completing the manufacture of a geophysical data product. As mentioned above, non-limiting examples of the medium may include: a magnetic hard disk drive, computer memory, non-volatile memory, a DVD, a tape drive, a cassette disk, optical media, a combination of the media previously mentioned, etc.

[0083] Referring now to Figure 16, a block diagram illustrating one embodiment of a computational system 1600 is shown. The illustrated processing elements may be used to implement all or part of a marine seismic survey system or a data logging system, in some embodiments. While Figure 16 illustrates an exemplary organization of a computing device, many variations are possible and envisaged, and the illustrated configuration is specifically intended to be non-limiting. In the illustrated embodiment, computer system 1600 includes interconnect 1610, processor 1620, input/output (I/O) bridge 1650, storage device 1652, geophysical data 1654, cache memory controller 1645, memory cache 1646, code 1648 and graphic display unit 1660.

[0084] Interconnect 1610 can include various devices configured to facilitate communication between the various elements of computer system 1600. In some embodiments, portions of interconnect 1610 can be configured to implement several different communication protocols. In other embodiments, interconnect 1610 can implement a single communication protocol, and elements coupled to interconnect 1610 can internally convert from the single communication protocol to other communication protocols.

[0085] In the illustrated embodiment, processor 1620 includes bus interface unit (BIU) 1625, cache 1630, and cores 1635 and 1640, although many variations of the illustrated organization are possible. For example, other multiple processor cores can be employed. BIU 1625 may be configured to control communication between processor 1620 and other elements of computational system 1600. Processor cores, such as cores 1635 and 1640, may be configured to execute instructions of a particular instruction set architecture (ISA), which may include operating system instructions and user application instructions.

[0086] Cache memory controller 1645 can be configured to control data transfer between interconnect 1610 and one or more caches and/or memories, including cache memory 1646. For example, cache memory controller 1645 can be coupled to an L3 cache, which can be, in turn, coupled to a system memory. In other embodiments, cache memory controller 1645 can be directly coupled to a memory.

[0087] In the illustrated embodiment, cache memory 1646 stores code 1648. In some embodiments, code 1648 can be used to configure computer system 1600. In other embodiments, code 1648 can include instructions for processor 1620 to execute, such as instructions relating to the control of any of the systems or devices discussed above, such as operating survey equipment and/or collecting survey data. Code 1648 may include other information not described in this specification, including, but not limited to, data, settings for other components of computer system 1600, or instructions to be executed by computer system 1600.

[0088] Graphic display unit 1600 may include one or more processor and/or one or more graphics processing units (GPUs). Compared to processor 1620, graphics display unit 1660 can be specifically configured to perform graphics-related processing operations to present information to a monitor. In some embodiments, unit 1660 may be omitted; its operations may alternatively be performed by, or integrated within, a processor 1620.

[0089] The 1650 I/O Bridge can include various elements configured to implement: universal serial bus (USB) communications, security, audio, and/or low-power steady state functionality, for example. The 1650 I/O Bridge may also include interfaces, such as, for example, Pulse Width Modulation (PWM), General Purpose Input/Output (GPIO), Serial Peripheral Interface (SPI), and/or a inter-integrated circuit (I2C). Various types of peripherals and devices may be coupled to device 1600 via I/O bridge 1650. In the illustrated embodiment, I/O bridge 1650 is coupled to storage device 1652.

[0090] In some embodiments, storage device 1652 may be a hard disk drive or a solid state drive. Storage device 1652 can be a tape drive, a magnetic drive, a removable media drive, etc. in some embodiments. In the illustrated embodiment, storage device 1652 includes geophysical data 1654. In some embodiments, storage device 1652, with geophysical data 1654 stored therein, corresponds to the geophysical data product discussed above.

[0091] While specific embodiments have been described above, those embodiments are not intended to limit the scope of the present description, wherein only a single embodiment is described with respect to a particular aspect. Examples of aspects provided in the description are intended to be illustrative rather than restrictive, unless otherwise indicated. The above description is intended to cover those alternatives, modifications and equivalents, which will be apparent to those skilled in the art having the benefit of such description.

[0092] The scope of this specification includes any aspect or combination of aspects described in this specification (explicitly or by implication), or any generalization thereof, whether or not it mitigates any or all of the issues addressed in this specification. Consequently, new claims may be formulated during the course of this patent application (or a patent application claiming priority for it) for any of these combinations of aspects. In particular, with reference to the appended claims, aspects of the dependent claims may be combined with those of the independent claims, and aspects of the respective independent claims may be combined in any suitable manner and not merely in the specific combinations enumerated in the appended claims.

Claims (20)

1. Method, characterized in that it comprises: towing, from one or more tugboats (100) during a portion of a marine seismic survey carried out by a survey system, a set of multiple seismic sources at the respective source distances from a plurality of seismic floating cables (550, 970, 1270, 1280); wherein the multiple seismic source set includes a set of one or more close spacing seismic sources (520, 940, 1220, 1240) that includes all sources in the survey system whose source spacings are less than a first source spacing boundary during the marine seismic survey portion; wherein the multiple seismic source set further includes a set of one or more remote offset seismic sources (540, 960, 1260) that includes all sources in the survey system whose source offsets lie between the first boundary source offset and a second major boundary source offset during the marine seismic survey portion; the set of close range seismic sources (520, 940, 1220, 1240) actuate during the marine seismic survey portion, in accordance with a first shot point interval, where the first shot point interval is an interval of close-off shot points measured in distance or time between actuations of any source in the set of one or more close-off seismic sources (520, 940, 1220, 1240); actuate the remote offset seismic source array (540, 960, 1260) during the marine seismic survey portion in accordance with a second shot point interval, wherein the second shot point interval is a shot point interval remote offset measured in distance or time between actuations of any member of the remote offset seismic source set, where the second shot point interval is greater in distance than the first shot point interval,; and collect, by means of the various floating seismic cables (550, 970, 1270, 1280), the seismic data responsive to the action of one or more seismic sources of close distance (520, 940, 1220, 1240) and of one or more sources Remote Seismic Surveys (540, 960, 1260). 2. Method, according to claim 1, characterized by the fact that: acting on the set of near-distance seismic sources (520, 940, 1220, 1240) comprises alternately acting on each of the two near-distance seismic sources; actuating the set of remote offset seismic sources (540, 960, 1260) comprises alternately actuating each of the two remote offset seismic sources; and the second shotpoint range is substantially three times the first shotpoint range. 3. Method, according to claim 1, characterized by the fact that the determination of the first and second intervals of shooting points is based, at least in part, on wave frequencies of the remote seismic sources. 4. Method according to claim 1, characterized in that the set of remote removal sources (540, 960, 1260) includes sources that are configured to emit seismic energy, in which a large part of the seismic energy is emitted at a frequency below 25 Hz. 5. Method, according to claim 1, characterized by the fact that the second interval of shooting points is an integer multiple of the first interval of shooting points, so that, when the set of seismic sources of remote removal ( 540, 960, 1260) is actuated, the remote offset seismic source array is actuated substantially simultaneously with the near offset seismic source array (520, 940, 1220, 1240). 6. Method, according to claim 1, characterized in that: the various seismic floating cables (550, 970, 1270, 1280) include at least two sets (1270, 1280), which are, respectively, coupled to at least least two seismic floating cable ships (1210, 1230). 7. Method, according to claim 1, characterized in that the set of multiple seismic sources includes a set of one or more intermediate distance seismic sources (950) that includes all sources in the survey system whose distance of sources is greater than the remoteness of any source in the set of one or more near-distance seismic sources (520, 940, 1220, 1240) and less than the remoteness of any source in the set of one or more remote-distance sources (540 , 960, 1260) during the marine seismic survey portion; the method further comprising: actuating the set of intermediate spacing sources (950) in accordance with a third range of firing points. 8. Method, according to claim 7, characterized in that the set of seismic sources of intermediate distance (950) and the set of seismic sources of remote distance (540, 960, 1260) are located on the same side of the seismic floating cables in a perpendicular direction. 9. Method, according to claim 1, characterized in that at least one of the one or more near-distance seismic sources (520, 940, 1220, 1240) or at least one of the one or more remote-distance seismic sources (540, 960, 1260) includes or include a pneumatic gun. 10. Method, according to claim 1, characterized in that at least one of the set of near-distance seismic sources (520, 940, 1220, 1240) or at least one of the set of remote-distance seismic sources (540 , 960, 1260) includes or includes a marine vibrator. 11. Method, according to claim 1, characterized by the fact that there are fewer seismic sources of remote distance (540, 960, 1260) than seismic sources of close distance (520, 940, 1220, 1240). 12. Method, according to claim 1, characterized in that it further comprises selecting the first and second intervals of shooting points, depending on one or more performance requirements of a complete wave inversion process. 13. Survey system, characterized in that it comprises: several floating seismic cables (550, 970, 1270, 1280); a multiple seismic source set includes: a set of one or more close spacing seismic sources (520, 940, 1220, 1240); a set of one or more remote offset seismic sources (540, 960, 1260); the survey equipment configured to: tow, from one or more tugboats (100) during a portion of a marine seismic survey performed by a survey system, the array of multiple seismic sources at respective source spacings of the plurality of seismic buoyant cables (550, 970, 1270, 1280); wherein the set of one or more near-offset seismic sources (520, 940, 1220, 1240) includes all sources in the survey system whose source offsets are less than a first boundary source offset during the marine seismic survey portion ; wherein the set of one or more remote offset seismic sources (540, 960, 1260) includes all sources in the survey system whose source offsets lie between the first limit source offset and a second major limit source offset during the survey. portion of the marine seismic survey; at least one of the set of one or more near-distance seismic sources (520, 940, 1220, 1240) act according to a first point-fire interval, wherein the first point-fire interval is a point-fire interval close-off shot measured in distance or time between actuations of any source in the set of one or more close-off seismic sources (520, 940, 1220, 1240); at least one of a set of one or more remote offset seismic sources (540, 960, 1260) in accordance with a second shot point interval, wherein the second shot point interval is a shot point interval of remote offset measured in distance or time between actuations from any source in the set of one or more remote offset seismic sources (540, 960, 1260), where the second range of shot points is greater in time or distance than the first point-of-fire interval, where the second point-of-fire interval is an integer multiple of the first point-of-fire interval, and where the actuation of at least one source in the set of one or more remote offset seismic sources ( 540, 960, 1260) is configured to occur substantially simultaneously with at least one source in the array of one or more close spacing seismic sources (520, 940, 1220, 1240); in which the various floating seismic cables (550, 970, 1270, 1280) are configured to receive seismic data, responsive to the performance of the set of one or more seismic sources of close distance (520, 940, 1220, 1240) and the set of one or more remote offset seismic sources (540, 960, 1260) during the marine seismic survey portion; and a recording system (1600) configured to generate a stored record of the seismic data. 14. System according to claim 13, characterized in that the determination of the first and second intervals of shooting points is based, at least in part, on wave frequencies of the set of one or more sources of remote distance. 15. System, according to claim 13, characterized in that the seismic floating cables (550, 970, 1270, 1280) include two or more sets (1270, 1280), which are respectively coupled to two or more ships ( 1210, 1230). 16. System, according to claim 15, characterized in that the set of one or more seismic sources of close distance (520, 940, 1220, 1240) includes two or more seismic sources, coupled, respectively, to two or more ships, and wherein the set of one or more remote seismic sources (540, 960, 1260) includes a source that is located substantially equally distant from the two or more ships. 17. System, according to claim 13, characterized in that it further comprises a set of one or more intermediate distance seismic sources (950), in which the lifting equipment is further configured to tow the set of one or more intermediate offset seismic sources (950) during the marine seismic survey portion, wherein the intermediate offset seismic source set (950) includes all sources in the survey system whose source offsets are greater than the offset of any sources in the set of one or more near-distance seismic sources (520, 940, 1220, 1240) and less than the remoteness of any sources in the set of one or more remote sources (540, 960, 1260) during the survey portion marine seismic, and wherein the set of one or more intermediate spacing seismic sources (950) is configured to act according to a third firing point interval. 18. System according to claim 13, characterized in that the set of one or more seismic sources of close distance (520, 940, 1220, 1240) and at least one of several floating seismic cables (550, 970 , 1270, 1280) are coupled to the same vessel. 19. Method of manufacturing a geophysical data product, characterized in that it comprises: towing, from one or more tugboats (100) during a portion of a marine seismic survey performed by a survey system, a set of multiple sources seismic at respective source spacings of a plurality of floating seismic cables (550, 970, 1270, 1280); actuate one or more members of a set of near-distance seismic sources (520, 940, 1220, 1240) in the marine seismic survey, according to a first blast model during a portion of the marine seismic survey, in which the set of sources close offset (520, 940, 1220, 1240) includes all sources of the survey system whose source offset is less than a first source offset during the marine seismic survey portion; one or more members of the remote remote seismic source set (540, 960, 1260) actuate in accordance with a second blast pattern during the portion of a marine seismic survey in which the remote remote source set (540, 960, 1260) includes all sources of the survey system whose source offsets lie between the first boundary source offset and a second major boundary source offset during that portion of the marine seismic survey, where under the second blast model, the remote offset seismic source set (540, 960, 1260) are detonated less frequently than the remote remote seismic source set (520, 940, 1220, 1240); collect, by means of the various floating seismic cables, the geophysical data responsive to the performance of one or more members of the set of near-distance seismic sources (520, 940, 1220, 1240) and of one or more members of the set of seismic sources of remote offset (540, 960, 1260) during the marine seismic survey portion; and storing the geophysical data on a tangible, computer-readable medium (1652), thereby completing the manufacture of the geophysical data product. 20. Method, according to claim 19, characterized by the fact that: acting on one or more members of the set of close distance seismic sources (520, 940, 1220, 1240) comprises alternately acting on each of the two seismic sources of close clearance; actuating the one or more member of the remote offset seismic source assembly (540, 960, 1260) comprises alternately actuating each of the two remote offset seismic sources; and the first detonation model detonates substantially three times as often as the second detonation model.