Patent Description:
A seismic data acquisition system can acquire seismic data relating to subsurface features, such as lithological formations or fluid layers that may indicate the presence of hydrocarbons, minerals or other elements. An acoustic signal can penetrate the surface of the earth. The acoustic signal can reflect or refract off of subsurface lithological formations. The reflected or refracted acoustic signals can be acquired, analyzed, and interpreted to indicate physical characteristics of, for example, the lithological formations such as the presence of hydrocarbons.

The present disclosure is directed to systems and methods of near surface imaging and hazard detection with increased receiver spacing as described in claims <NUM> and <NUM>, respectively. Systems and methods of the present disclosure can use a near field array. The systems and methods of the present disclosure can use a hydrophone located above an array of sources to collect data that can be used to characterize the source, as well as collect data that can be used to generate an image of the subsurface.

Seismic surveys may not be able to capture sufficient data or generate images for certain locations without introducing additional receivers into the array. Having excessive receivers in an array can increase resource utilization, such as increase fuel usage if the receivers are being towed in a streamer configuration, or increase resources associated with deploying receivers on the ocean bottom. Further, utilizing excessive resources can increase the need for receiver storage on a vessel, cable length, battering charging stations, data retrieval off of receivers for the survey, or data processing.

Systems and methods of the present technical solution can facilitate the generation of images using fewer receivers or receivers spaced further apart. Systems and methods of the present technical solution can facilitate the generation of images of certain locations using hydrophones positioned or configured in an array. For example, by generating images from data collected by a hydrophone located above an acoustic source that collects data regarding both the acoustic shot and reflections from the acoustic shot, the present technical solution can generate images for locations between receivers, which allows for a greater receiver spacing in an array, which can result in fewer receivers being used in an array, while also providing an image for a location that may not otherwise be imaged. Thus, the present technical solution can both facilitate the generation of images of locations not previously imaged while reducing the number of receivers in an array by increasing the receiver spacing.

At least one aspect is directed to a system of seismic hazard detection with receiver spacing according to claim <NUM>.

At least one aspect is directed to a method of seismic hazard detection with receiver spacing according to claim <NUM>.

The present disclosure is directed to systems and methods of near surface imaging and hazard detection with increased receiver spacing. The systems and methods of the present disclosure can provide shallow images that can include or indicate shallow hazards. The systems and methods of the present disclosure can use a near field array. The systems and methods of the present disclosure can use one or more hydrophones located above, below, beside or otherwise situated in close proximity (e.g., within <NUM> meter, <NUM> meters, <NUM> meters, <NUM> meters or <NUM> meters) of an array of sources to collect data that can be used to characterize the source, as well as collect data that can be used to generate an image of the subsurface.

For example, an array of source guns can include one or more hydrophones located approximately <NUM> meter (e.g., plus or minus <NUM>%) above, below or beside one or more source guns. The hydrophone can be used to characterize the source gun when the source gun fires, effectively recording a boom that can be analyzed to characterize the source. The hydrophone can also record higher quality data, and generate a recording of a longer duration (e.g., <NUM> milliseconds as compared to <NUM> to <NUM> seconds). Along with recording the acoustic shot, or boom, the hydrophone can also record reflection data. This reflection data can correspond to acoustic waves of the acoustic shot that travel through the aqueous medium and into the earth via the ocean bottom, and are then reflected by a subsurface lithologic formation or hydrocarbons back towards a receiver. The receiver can refer to or include a seismic data acquisition node, geophone, or hydrophone.

However, seismic surveys may not be able to capture sufficient data or generate images for certain locations without introducing additional receivers into the array. Having excessive receivers in an array can increase resource utilization, such as increase fuel usage if the receivers are being towed in a streamer configuration, or increase resources associated with deploying receivers on the ocean bottom. Further, utilizing excessive resources can increase the need for receiver storage on a vessel, cable length, battering charging stations, data retrieval off of receivers for the survey, or data processing.

Systems and methods of the present technical solution can facilitate the generation of images using fewer receivers. Systems and methods of the present technical solution can facilitate the generation of images of certain locations using hydrophones positioned or configured in an array. For example, by generating images from data collected by a hydrophone located above an acoustic source that collects data regarding both the acoustic shot and reflections from the acoustic shot, the present technical solution can generate images for locations between receivers, which allows for a greater receiver spacing in an array, which can result in fewer receivers being used in an array, while also providing an image for a location that may not otherwise be imaged. Thus, the present technical solution can both facilitate the generation of images of locations not previously imaged while reducing the number of receivers in an array by increasing the receiver spacing.

Further, the systems and methods of the present technical solution allow for the collection of near field data used to produce images of the near field. Images of the near field can be used for near surface or sub-surface hazard detection. The present technical solution allows for near surface or sub-surface hazard detection without increasing the number of receivers in the array or reducing the spacing of receivers in the array. Rather, the systems and methods of the present technical solution can facilitate near surface or sub-surface hazard detection using fewer receiver nodes, which is faster, safer, and reduces resource consumption. To do so, the present technical solution can utilize the hydrophone located above the acoustic sources that collect data regarding the acoustic shot for the purpose of characterize the acoustic shot to also reflection data corresponding to the acoustic shot. The present technical solution can generate an image from the data collected by the hydrophone located above the acoustic source, where the data includes both the acoustic signals from the acoustic shot, as well as acoustic signals corresponding to reflections of the acoustic shot that are reflected via the seabed. In some case, the present technical solution can filter this collected data to remove or filter out the data corresponding to the acoustic shot, identify the reflections, and then generate an image of the reflections. The image of the reflections can indicate near surface or sub-surface hazards, such as gas pockets located within <NUM> meters, <NUM> meters, <NUM> meters, <NUM> meters, <NUM> meters, <NUM> meters, <NUM> meters, <NUM>,<NUM> meters or more below the ocean bottom. By identifying these hazards, a safer location for drilling can be selected that may avoid such hazards.

<FIG> illustrates a system to perform a seismic imaging in accordance with an implementation. The system <NUM> can include a data processing system <NUM>. The data processing system <NUM> can include one or more processors, memory, logic arrays, or other components or functionality depicted in <FIG>. The data processing system <NUM> can include or execute on one or more servers. The data processing system <NUM> can include one or more servers in a server farm, or distributed computing infrastructure, such as one or more servers forming a cloud computing infrastructure. The data processing system <NUM> can include at least one logic device such as a computing device <NUM> having one or more processors 610a-n. The data processing system <NUM> can be located on a vessel <NUM>. A component of the data processing system <NUM> can be located on the vessel <NUM>, and a second component of the data processing system <NUM> can be located remotely.

The data processing system <NUM> can include, interface or otherwise communicate with at least one interface. The data processing system <NUM> can include, interface or otherwise communicate with at least one database <NUM>. The data processing system <NUM> can include, interface or otherwise communicate with at least one source controller <NUM>. The data processing system <NUM> can include, interface with or otherwise communicate with data retrieval component <NUM>. The data processing system <NUM> can include, interface with or otherwise communicate with at least one image generation component <NUM>. The data processing system <NUM> can include, interface with or otherwise communicate with at least one filtering component <NUM>.

The source controller <NUM>, data retrieval component <NUM>, image generation component <NUM>, or filtering component <NUM> can each include at least one processing unit or other logic device such as programmable logic array engine, or module configured to communicate with the database repository or database <NUM>. The source controller <NUM>, data retrieval component <NUM>, image generation component <NUM>, or filtering component <NUM> can be separate components, a single component, or part of the data processing system <NUM>. The system <NUM> and its components, such as data processing system <NUM>, can include hardware elements, such as one or more processors, logic devices, or circuits.

The data processing system <NUM> can communicate with one or more computing devices <NUM>, the vessel <NUM>, or component of the seismic survey via network <NUM>. The network <NUM> can include computer networks such as the Internet, local, wide, metro, or other area networks, intranets, satellite networks, and other communication networks such as voice or data mobile telephone networks. The network <NUM> can be used to access information resources such as seismic data, parameters, functions, thresholds, or other data that can be used to identify or detect hazards in the near field and display images corresponding to the seismic survey or hazards via one or more computing devices <NUM>, such as a laptop, desktop, tablet, digital assistant device, smart phone, or portable computers. For example, via the network <NUM> a user of the computing device <NUM> can access information or data provided by the data processing system <NUM>. The computing device <NUM> can be located proximate to the data processing system <NUM>, or be located remote from the data processing system <NUM>. For example, the data processing system <NUM> or computing device <NUM> can be located on a vessel <NUM> or a vessel <NUM>.

The data processing system <NUM> can interact with or retrieve data from a seismic survey. The system <NUM> can include components in a marine seismic survey environment <NUM>. The seismic survey can be a marine based seismic survey, such as a deep sea or ocean bottom survey. For example, a vessel <NUM> can be on a surface of water <NUM>. The vessel <NUM> can tow or deploy components used to perform the seismic survey. The components can include one or more hydrophones 116a-b, one or more shot sources 118a-f, and one or more sensor devices <NUM>.

In the marine seismic environment <NUM>, the vessel <NUM> can deploy or two one or more strings of sources 114a-b. For example, the vessel <NUM> can deploy or two a first string 114a and a second string 114b. The first string 114a can refer to or include one or more sources 118a, 118b and 118c. The first string 114a can also include a hydrophone 116a. The second string 114b can include one or more shot sources 118d, 118e, and 118f. The second string 114b can include a hydrophone 116b. The second string 114b can be located opposite the first string 114a. For example, the first string 114a can run parallel to the second string 114b. The first string 114a can be separated from the second string 114b by a distance <NUM>, such as <NUM> meters, <NUM> meters, <NUM> meters, <NUM> meters, <NUM> meters, <NUM> meters, <NUM> meters or some other distance that facilitates performing a seismic survey in a marine environment.

There can be one or more strings of air guns (e.g., <NUM> strings, <NUM> strings, <NUM> strings or more). Each string can include more than one air gun or source located on the string (e.g., <NUM>, <NUM>, <NUM><NUM>, <NUM>, <NUM>, <NUM> or more). This collection of air guns on a single string can be referred to as an "array" of guns. The vessel can tow and use, for example, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> or more strings (depending on towing ability and width of the vessel <NUM>). When a source is fired, one or more strings of guns can be fired. All air guns on a string can fired, or individual air guns on a single string can be fired in close temporal proximity and in a pre-determined pattern. A shot can refer to a gun or string of guns being fired. The acoustic shot can be from one gun or more than one gun, on one or more strings. A source array can be a collection (<NUM> or more guns) that are fired in close temporal proximity (e.g., within <NUM> second or <NUM> seconds, or simultaneously) to each other. The source guns can be single guns or a gun cluster. A gun cluster can be a grouping of two or more guns very close to each other, typically <NUM> meter. A gun cluster may have a single near field hydrophone. In an illustrative example, the vessel <NUM> can tow <NUM> strings of guns, where each string includes <NUM> air guns. A near field hydrophone can be mounted near each of the guns. Thus, the vessel <NUM> can two <NUM> near field hydrophones.

The data processing system <NUM> can include a source controller <NUM> designed, constructed or operational to facilitate generating a shot from an acoustic source. The source controller <NUM> can coordinate firing of shots by the acoustic source. The source controller <NUM> can maintain timestamps corresponding to shots fired by acoustic sources 118a-f. The source controller <NUM> can control which acoustic source is fired, generate a pattern for firing acoustic sources, use a flip flop pattern, a dither pattern for multiple shots, or use other timing function.

The acoustic sources 118a-f can be separated from one another in the array. The array can refer to the array formed from two or more strings 116a-b. For example, the array can be defined by the strings 116a and 116b. The distance between acoustic sources 118a and 118b in the first string 114a can be distance <NUM>, such as such as <NUM> meters, <NUM> meters, <NUM> meters, <NUM> meters, <NUM> meters, <NUM> meters, <NUM> meters or some other distance that facilitates performing a seismic survey in a marine environment. The acoustic sources in the second string 114b can also be separated by distance <NUM>.

The hydrophone 116a can be located above the shot sources 118a-c. In some cases, the first string 114a can include one or more hydrophones 116a. For example, each shot source 118a-c can have a corresponding hydrophone 116a located above the shot sources 118a-c. The hydrophone 116a can be located directly above a shot source 118a (e.g., along a vertical axis that is perpendicular to the water surface <NUM> and that passes through the hydrophone 116a and shot source 118a). The hydrophone 116a can be located above a shot source 118a but not directly above, such as off to a side. The hydrophone 116a can be located within a distance <NUM> above the shot source 118a, or a distance in a vertical z-axis. The distance <NUM> can be within <NUM> meter, <NUM> meters, <NUM> meters, or more. The hydrophone 116a can be located approximately within <NUM> meter above the shot source 118a (e.g., plus or minor <NUM>% or <NUM>% or <NUM>%). The hydrophone 116a can be located approximately within <NUM> meters above the shot source 118a (e.g., plus or minor <NUM>% or <NUM>% or <NUM>%).

The hydrophones 116a-b can be configured to detect or collect signals, information or data corresponding to shots fired, triggered or otherwise provided by the source 118a. The hydrophone can acquire trace data responsive to acoustic signals propagated from the acoustic source. Thus, a seismic survey may be performed by providing a source signal, such as an acoustic or vibrational signal. Reflected signals from the seabed <NUM> and underlying structures (e.g., <NUM>, <NUM>, or <NUM>) are recorded by one or more sensor devices <NUM> or hydrophones 116a-b on. The source signal or "shot" can be provided by a second marine vessel <NUM>, such as a gun boat. In some cases, the source signal can be provided by the first marine vessel <NUM>. The data processing system <NUM> can use the recorded data to generate an image, graph, plotted data, or perform other analysis.

Hydrophones 116a-b can be configured to measure a pressure wavefield that is transferred from a liquid to a solid, such as from an aqueous medium into the hydrophone pressure sensor. As compared to the solid-to-solid interface associated with the geophone, the pressure wavefield can undergo less attenuation or change at the liquid to solid interface where this motion due to the pressure wavefield is transferred into the hydrophone. Further, liquid sea water can be relatively consistent across the area of a survey as compared to the geology of the seabed, so there may be minimal differences in hydrophone attenuation across a survey. The hydrophone 116a-b can acquire hydrophone trace data responsive to the acoustic signal propagated by the acoustic source 118a-f. The hydrophone 116a-b can include one or more components of the sensor device <NUM>, such as a power source, battery, memory, processor, controller, ports, etc..

The acoustic source 118a can fire or generate acoustic signals (e.g., acoustic signals <NUM>, <NUM>, <NUM>, or <NUM>). The acoustic signal <NUM> can propagate through the aqueous medium towards hydrophone 116a, and be recorded by hydrophone 116a. The acoustic signal <NUM> can propagate through the aqueous medium towards hydrophone 116b, and be recorded by hydrophone 116b. The acoustic signal <NUM> can propagate through the aqueous medium towards the seabed <NUM>, traverse the seabed and reflect off of a subsurface formation <NUM>, and reflect back via acoustic signal <NUM> towards hydrophone 116b, and be collected or recorded by hydrophone 116b.

For example, the acoustic source 118a can generate an acoustic shot, and the first hydrophone 116a can record an acoustic signal from the acoustic shot. Recording an acoustic shot by a first hydrophone 116a can refer to or include recording an acoustic signal <NUM> from the acoustic shot generated by the acoustic source 118a. Recording the acoustic shot by a second hydrophone 116b can refer to or include recording an acoustic signal <NUM> from the same acoustic shot generated by the acoustic source 118a. The second hydrophone 116b can also record acoustic reflections corresponding to the acoustic shot. Recording acoustic reflections can refer to or include recording acoustic signal <NUM> that is a reflection from a subsea <NUM> formation, such as <NUM>, where the reflection corresponds to an acoustic signal <NUM> corresponding to the same acoustic shot generated by the acoustic source 118a that generated acoustic signals <NUM> and <NUM>.

In some cases, the hydrophone 116a may also record the acoustic reflections. The hydrophone 116b can record both the acoustic signal <NUM> from the acoustic shot, as well as acoustic reflections <NUM>. The hydrophone 116b can have a dynamic range or sensitivity or resolution sufficient to record both the acoustic shot acoustic signal <NUM>, and the reflection acoustic signal <NUM>. The hydrophone 116a-b can generate a recording having a duration of <NUM> to <NUM> seconds, or more. The duration of the recording can allow for the recordation of acoustic signals corresponding to the original acoustic shot (e.g., acoustic signal <NUM>) as well as reflection acoustic signals <NUM>. In some cases, there may be numerous acoustic reflection signals recorded by the hydrophone 116b, such as reflections off of subsea formations <NUM>, <NUM> or <NUM>, as well as multiple reflection acoustic signals that may reflect off of the water surface <NUM> and be detected by the hydrophone 116b from the water surface <NUM>.

The data processing system <NUM> can include an data retrieval component <NUM> (or interface component) designed, configured, constructed, or operational to receive seismic data obtained via acoustic signals generated by at least one acoustic source and reflected from at least one subsurface lithologic formation. The data retrieval component <NUM> can receive seismic data corresponding to the acoustic shot and the acoustic reflections recorded by the second hydrophone. For example, a source device 118a-f (such as an acoustic source device <NUM> depicted in <FIG>) can generate an acoustic wave or signal that reflects from at least one subsurface lithologic formation beneath the seabed <NUM>, and is sensed or detected by seismic sensor devices <NUM>. The data retrieval component <NUM> can receive the seismic data via a wired or wireless communication, such as a direct wired link or through a wireless network or low energy wireless protocol. The data retrieval component <NUM> can include a hardware interface, software interface, wired interface, or wireless interface. The data retrieval component <NUM> can facilitate translating or formatting data from one format to another format. For example, the data retrieval component <NUM> can include an application programming interface that includes definitions for communicating between various components, such as software components. The data retrieval component <NUM> can communicate with one or more components of the data processing system <NUM>, network <NUM>, or computing device <NUM>.

The data processing system <NUM> can receive the seismic data as ensembles of common-source or common-receiver data. The seismic data can include ensembles or sets of common-source or common-receive data.

By receiving data from the hydrophone 116b that includes both the acoustic shot information (e.g., acoustic signal <NUM>) and acoustic reflection information (e.g., acoustic signal <NUM>), the system <NUM> allows for more efficient performance of the seismic survey since the same hydrophone 116b can be used to both characterize the acoustic shots, as well as generate images of the subsea <NUM> features. The hydrophone 116b can generate images of locations of the subsea <NUM> without a sensor device <NUM> located at that location or configured to generate an image for that location, thereby allowing for a greater spacing between seismic sensor devices <NUM>. For example, the spacing <NUM> between seismic sensor devices <NUM> can be greater than a spacing that may be used to generate a satisfactory image of a location at the nearfield subsea <NUM>, such as location <NUM>, but the present technical solution allows for image generation at a location corresponding to the formation <NUM>, thereby providing a technical improvement since sensor devices <NUM> can be spaced apart by a distance <NUM> and still allowing for the overall system <NUM> to generate an image of a location corresponding to formation <NUM>, which may not otherwise have been possible at a spacing of <NUM> without a hydrophone 116b configured to collect acoustic signals <NUM> and a filtering component <NUM> to remove the acoustic shot signal <NUM>.

The data processing system <NUM> can include a filtering component <NUM> designed, constructed and operational to filter the seismic data to remove the acoustic shot from the seismic data. The data processing system <NUM> can filter the seismic data to remove the acoustic shot because the image generation component <NUM> may not be able or configured to generate a suitable image that includes the acoustic signals corresponding to the acoustic shot. For example, the filtering component <NUM> can remove acoustic signals <NUM> from the seismic data, while keeping the acoustic signals <NUM> that correspond to reflections from the subsea <NUM> features. The acoustic signals <NUM> from the acoustic shot can generate excessive noise or artifacts in any image. The acoustic signals <NUM> from the acoustic shot may have a high amplitude relative to the acoustic reflections <NUM>, thereby potentially masking or hiding the acoustic signals <NUM> in the image. Thus, the filtering component <NUM> can remove the acoustic signals <NUM> corresponding to the acoustic shot in order to facilitate generation of an improved image by the image generation component <NUM> that identifies or indicates subsea features <NUM> such as the formation <NUM> to allow for nearfield hazard detection.

The filtering component <NUM> can use one or more techniques, rules, policies or functions to filter out the acoustic shot acoustic signal <NUM> prior to forwarding the seismic data to the image generation component <NUM>. The filtering component <NUM> can use timestamps to remove the acoustic shot acoustic signal <NUM>. The filtering component <NUM> can obtain timestamps for the acoustic shots from the source controller <NUM>. The filtering component <NUM> can obtain timestamps from or via the source controller <NUM> for when shots were fired, and then determine which set of samples to remove from the seismic data. For example, the filter component <NUM> can remove all samples before a timestamp, or within a range of timestamps.

The filtering component <NUM> can filter out data based on an amplitude threshold. The filtering component <NUM> can use a predetermined amplitude threshold or a dynamic amplitude threshold. The filtering component <NUM> can remove samples having an amplitude greater than what a highest expected amplitude might be from a reflection acoustic signal <NUM>. The filtering component <NUM> can remove samples having an amplitude greater than what a highest expected amplitude might be from a reflection acoustic signal <NUM>, plus an amplitude offset. The filtering component <NUM> can use a dynamic amplitude threshold to remove samples that are within a certain percentage or number of dB from a highest amplitude.

The filtering component <NUM> can remove samples based on a frequency filter, such as a low pass filter, bandpass filter or high pass filter. The filtering component <NUM> can set the frequency ranges or thresholds based on frequencies expected to correspond to acoustic signal shots <NUM> as compared to acoustic reflection <NUM>.

The data processing system <NUM> can include an image generation component <NUM> designed, constructed or operational to generate an image. The image generation component <NUM> can generate the image from seismic data that includes both the acoustic reflections <NUM>, and the acoustic signal <NUM> from the acoustic shot. For example, the image generation component <NUM> can receive the seismic data from the data retrieval component <NUM> that includes the seismic data collected by a hydrophone located above a source that was in standby and opposite a source that fired, and then generate an image that includes the acoustic shot (e.g., signal <NUM>) as well as the reflections (e.g., <NUM>).

In some cases, the image generation component <NUM> can generate the image from seismic data that includes the acoustic reflections <NUM>, but not the acoustic signal <NUM> from the acoustic shot. In some cases, the image generation component <NUM> can process the seismic data to generate the image, such as forward propagate or backward propagate the traces, applying binning function, transforms, or otherwise manipulate or process the data to generate an image. In some cases, the data processing system <NUM> can propagate the seismic data through the subsurface model to generate the image.

The data processing system <NUM> can generate, based on the acoustic reflections absent the acoustic shot, an image of a portion of earth between receiver stations. For example, the portion of the earth <NUM> can be between sensor devices <NUM>. The data processing system can generate an image of the portion of earth <NUM> between receiver stations <NUM> where the portion of the earth is within <NUM> meters of an ocean bottom. For example, the subsea portion <NUM> can be less than <NUM> meters from the water/surface boundary <NUM> that corresponds to the ocean bottom. The data processing system can identify, or provide an image that indicates or from which can be identified, a gas-pocket, such as gas-pocket <NUM>.

For example, <FIG> shows an illustration <NUM> of an image generated using one or more components of system <NUM> depicted in <FIG>. The image illustrates the acoustic signal reflections. The image <NUM> includes trace data. Each trace is single stacked shot into a near field array. The trace spacing can be the shot interval, such as <NUM> meters, <NUM> meters, <NUM> meters, for example, the trace spacing in the display <NUM> can be <NUM> meters.

At <NUM>, the display shows water bottom reflections. At <NUM>, the display shows subsurface structures. The subsurface structures at <NUM> can be near the ocean bottom (e.g., within <NUM> meters, <NUM> meters, <NUM> meters, <NUM> meters, <NUM> meters, or <NUM> meters). At <NUM>, the display shows subsurface reflections. At <NUM>, the display shows water bottom multiple reflections. Thus, using the techniques of the present technical solution, the system can generate near surface imaging and hazard detection. The receivers (e.g., geophones) may be spaced further apart without detracting from collecting the data used to generate this image because the data used can be recorded by the near field hydrophone array instead of the geophone or ocean bottom nodes or other streamers. Thus, by using the near field hydrophones that are mounted proximate to the gun sources, the data processing system can generate a display indicating the near surface features, which can include hazards such as a gas pocket or other subsurface features.

<FIG> depicts an array used in a system of seismic hazard detection with increased receiver spacing in accordance with an implementation. The system <NUM> can depict two acoustic sources (e.g., 118c and 118f) that alternate firing as the vessel <NUM> travels through water in a direction over time. The label "X" can refer to the active source at that moment in time, and the label "O" can refer to the passive source at that moment in time. <FIG> depicts the progression of the two sources 118c and 118f over time windows T1, T2, T3, and T4 of a seismic survey. The seismic survey can include greater time windows or fewer time windows. The time window can have a duration, such as <NUM> seconds, <NUM> seconds, <NUM> seconds, <NUM> seconds, <NUM> seconds, <NUM> seconds, <NUM> minutes, <NUM> minutes or more. In the first time window T1, acoustic source 118c can be the active source, and acoustic source 118f can be the passive source. As the vessel travels through the water, the shot sequence can progress to time window T2, where the acoustic source 118c can be switch to be the passive source, and the acoustic source 118f can switch to be the active source. As the vessel travels through the water, the shot sequence can progress to time window T3, where the acoustic source 118c can be alternate back to be the active source, and the acoustic source 118f can alternate back to be the passive source. As the vessel travels through the water, the shot sequence can progress to time window T4, where the acoustic source 118c can be switch to be the passive source, and the acoustic source 118f can switch to be the active source.

The system <NUM> can trigger the shots using a flip flop dual source mode. For example, the source controller <NUM> can instruct the acoustic sources 118c and 118f to fire using a flip flop dual source mode. The indication of "X" on the acoustic source 118c can indicate an active source. And the indication "O" on the acoustic source 118f can indicate the inactive or other source. Active sources can fire shots, while inactive sources may not fire shots. In the flip flop dual source mode configuration, a source 118c on a first string can fire, while the corresponding source 118f on the opposite string can be in standby, passive mode, or not fire. Thus, the source controller <NUM> can cause the first string of acoustic sources can be configured to trigger a shot on alternating acoustic sources of the first string of acoustic sources, and the second string of acoustic sources configured to trigger a shot on alternating acoustic sources of the second string that are opposite acoustic sources on the first string of acoustic sources that are in standby.

The hydrophone located above the source that is not firing (e.g., source 118f) can collect data that can be used to generate images of the earth. The hydrophone located above the other source (or the source that is not firing) can be hydrophone 116b. The hydrophone located above the source that fires a shot (e.g., source 118c) can be a hydrophone 116a. The hydrophone 116a may collect data regarding the acoustic shot. The hydrophone 116a can collect data about the acoustic source that can be used to identify a characteristic of the source from the acoustic shot recorded by the first hydrophone 116a. The second hydrophone 116b can collect data about the acoustic shot that can also be used to identify a characteristic of the source from the acoustic shot recorded by the second hydrophone 116b. Thus, the second hydrophone 116b can collect seismic data that is both indicative of the acoustic shot as well as subsea features. Characteristics of the acoustic shot can include timing, pattern, number of acoustic shots, amplitude of acoustic shot, frequency, or pressure. Both hydrophones 116a and 116b can record data on every shot, regardless of whether the corresponding source is active or passive.

<FIG> depicts an array used in a system of seismic hazard detection with increased receiver spacing in accordance with an implementation. The system <NUM> can depict multiple acoustic sources on each string of acoustic sources, where the strings alternate firing as the vessel <NUM> travels through water in a direction over time. For example, the first string 114a can include <NUM> acoustic sources 118c, 118b, 118a, and <NUM>. The second string 114b can include <NUM> acoustic sources 118f, 118e, 118d, <NUM>. A near field hydrophone can be mounted proximate to each source on each string. For example, hydrophone 116a can be mound within a predetermined distance (e.g., within <NUM> meter, within <NUM> meters, within <NUM> meters) from acoustic source 118c; hydrophone 116c can be mound within a predetermined distance from acoustic source 118b; hydrophone 116d can be mound within a predetermined distance from acoustic source 118a; and hydrophone 116e can be mound within a predetermined distance from acoustic source <NUM>. The second string 114b can also include multiple sources and multiple hydrophones. For example, hydrophone 116b can be mounted near source 118f; hydrophone 116f can be mounted near source 118e; hydrophone <NUM> can be mounted near source 118d; and hydrophone <NUM> can be mounted near source <NUM>.

If there are multiple sources on each string of sources, then all the sources on the string can be active, while all the sources on the opposite string can be passive. For example, each source 118c, 118b, 118a and <NUM> on the first string 114a can fire or be active during a first time window; and each source 118f, 118e, 118d, and <NUM> on the second string 114b can be passive or in standby during the first time window. In a second time window, all the active sources on the string 114a can flip to being passive sources, and all the passive sources on the string 114b can flip to being active sources.

If there are multiple sources on a string, then the data processing system can generate multiple image lines for each source fired. As the vessel travels through water over time, the seismic survey shot sequence can progress and the sources on the first string can alternate from being active to being passive, while the sources on the second string can alternate from being passive to being active. The sources on a string of sources can be separated from one another by at least <NUM> meters. Any acoustic source on the first string of acoustic sources can be separated from any acoustic source on a second string of sources by at least a distance <NUM>, such as <NUM> meters. Also, if there are multiple sources on a string, there can be multiple hydrophones associated with the string. Each source can have a corresponding hydrophone positioned or located proximate to the source (e.g., within <NUM> meter, <NUM> meters, <NUM> meters, <NUM> meters or <NUM> meters). Each source can have multiple (e.g., <NUM>, <NUM>, <NUM> or more) hydrophones positioned or located proximate to the source. The one or more hydrophones can be positioned underwater above, below, or on a side of the source.

The acoustic sources in the first string of acoustic sources can be separated by at least <NUM> meters from one another, <NUM> meters, <NUM> meters, <NUM> meters or more. The acoustic sources in the second string of acoustic sources can be separated by at least <NUM> meters from one another, <NUM> meters, <NUM> meters, <NUM> meters or more. The first string of acoustic sources can separated from the second string of acoustic sources by at least <NUM> meters, <NUM> meters, <NUM> meters or more.

As an example, the system <NUM> depicted in <FIG> can include <NUM> source gun 118c on a string. When source gun 118c fires a shot, the near field hydrophone ("NFH") 116a near gun 118c can measure and record both i) a direct arrival - from the gun 118c to the NFH 116a; and ii) a reflected arrival - from the gun 118c to the reflector below (e.g., the ocean bottom) and back to the NFH 116a. The reflected arrival can be used to create an image line, so this example would create one image lines.

Further, the system <NUM> can include two guns 118c and 118f on different strings 114a and 114b, and each gun 118c and 118f can have a NFH (e.g., 116a and 116f) mounted proximate to the gun. In a first time window T1 when gun 118c fires a shot, the NFH 116a can measure and record both a direct and a reflected arrival; the NFH 116b can measure and record both i) a direct arrival - from the gun 118c to NFH 118f and, ii) a reflected arrival - from the gun 118c to the reflected mid-point between the gun and the NFH 116b.

In a second time window T2 when 118f fires a shot, NFH 116b can measure and record both a direct and a reflected arrival; and NFH 116a can measure and record both a direct arrival - from the gun 118f to NFH 116a and a reflected arrival - from the gun 118f to the reflected mid-point between the gun 118f and the NFH 116a. Each of these measures of reflected arrivals can be used to create an image line, so this example can create three image lines (118c to 116a, midpoint between 118c and 116b (and 116a and 118f if the midpoints are different), and 118f to 116b).

The example system <NUM> depicted in <FIG> includes three strings 114a, 114b and 114c towed by vessel <NUM>. Each string can include a source gun <NUM> (e.g., source gun 118a). Each string can include a near field hydrophone <NUM> (e.g., 116a) near the source gun or within a predetermine distance from the source gun (e.g., within <NUM> meter or <NUM> meters).

For example, there can be a first source gun 218a on a first string 114a; a second source gun 218b on a second string 114b; and a third source gun 218c on a third string 114c. Each source gun can have a corresponding NFH. For example, NFH 216a corresponds to gun 218a on the first string 114a, NFH 216b corresponds to gun 218b on the second string 114b, and NFH 216c corresponds to gun 218c on the third string 114c.

In time window T1, when source gun 218a fires a shot, then:.

In time window T2, when source gun 218b fires a shot, then:.

In time window T3, when source gun 218c fires a shot, then:.

When <NUM> gun (e.g., 218a) fires into <NUM> receivers (e.g., 216a, 216b and 216c), the data processing system can create <NUM> reflected images (e.g., a to a, a to b, a to c). When the next gun, which is evenly spaced, is fired then the data processing system can create <NUM> reflected images from each shot (e.g., <NUM> x <NUM> = <NUM>), but even spacing can create multiple measures at the same line spacing, so there is not a unique image line for each reflected image. There are <NUM> unique "reflection locations" for these <NUM> shots because some locations are measured more than once by different shots, such as the mid-point a to b is the same as for b to a; the mid-point for b to c is the same as for c to b; the mid-point for a to c is the same as for c to a and this is the same as the reflection point for b to b. The data processing system can then produce the following image lines: directly underneath each source/NFH, and at the mid-point between each source/NFH.

Each of these reflected measures can be used to create an image line, so this example can create <NUM> different image lines. If the sources <NUM> are evenly spaced, the number of image lines created can be determined using the following equation: 2n-<NUM>, where n = the number of sources. For example, if there are <NUM> sources, then the number of image lines created from this technique = <NUM> x <NUM> - <NUM> = <NUM>.

If, however, there are <NUM> strings and they are NOT evenly spaced apart from one another, then the number of image lines the data processing system can create is greater. Because the un-even spacing eliminates the multiple measures at the same line spacing location, un-even spacing produces more image lines than even spacing. The number of image lines created by un-even spacing of the source/NFH is equal to the sum of the number of sources. For example, with <NUM> sources, the number of image lines = <NUM> + <NUM> + <NUM> = <NUM> image lines. If there were <NUM> sources, for example, then the data processing system can create <NUM> image lines.

Thus, by removing the direct arrival data (and the bubble cause by the shot), the data processing system can process the reflection data to produce sub-surface images. This technique can be used with ocean bottom nodes or streamers. The systems and methods of the present technical solution can provide streamer configurations the ability to generate zero offset traces (and/or near-zero offset traces) from the A to A / B to B / C to C traces.

Thus, the present technical solution and technical improvement can provide more imaging data at no additional field cost or field time because the data processing system can remove the direct arrival data and process the reflected data recorded and stored in the near field hydrophone data. The data processing system, by separating this data from the bubble/direct arrival, can generate images from the data. In effect, you are extracting the data that has always been there to derive more reflection data for sub-surface imaging.

<FIG> is a method of seismic hazard detection with increased receiver spacing. The method <NUM> can be performed by one or more system or component depicted in <FIG> or <FIG>, <FIG> or <FIG>. For example, a data processing system, source controller <NUM>, data retrieval component <NUM>, filtering component <NUM> or image generation component <NUM> can perform one or more function or process of method <NUM>. At ACT <NUM>, the method <NUM> includes providing a string of sources. The method <NUM> can include providing a first string of acoustic sources and a second string of acoustic sources. The strings of acoustic sources can be towed by a marine vessel. The strings of acoustic sources can be located under water. The acoustic sources can be located mid-water. Each string of acoustic sources can include one or more acoustic sources, such as <NUM>, <NUM>, <NUM>, <NUM> or more acoustic sources. The method <NUM> can include providing one or more strings of acoustic sources.

At ACT <NUM>, the method <NUM> includes providing a hydrophone underwater and above a string of acoustic sources. A first hydrophone can be located above a first string of acoustic sources, and a second hydrophone can be located above a second string of acoustic sources. The hydrophone can be towed by the vessel. The hydrophone can be located <NUM> meter above the acoustic source. The hydrophone can be underwater. The hydrophone can be in mid-water. A hydrophone can be provided and located approximately <NUM> meter (e.g., plus or minus <NUM>%) above each acoustic source in the string.

At ACT <NUM>, the method <NUM> includes recording acoustic signals. The first hydrophone can record an acoustic shot generated from a source on the first string of acoustic sources. A second hydrophone can record the acoustic shot and acoustic reflections corresponding to the acoustic shot. The first hydrophone may also record the reflections.

At ACT <NUM>, the method <NUM> includes receiving seismic data. A data processing system can receive seismic data corresponding to the acoustic shot and the acoustic reflections recorded by the second hydrophone. At ACT <NUM>, the method <NUM> includes generating an image. The method can include generating the image from the acoustic reflections and the acoustic shot. The data processing system can generate the image for display via a display device.

<FIG> is an isometric schematic view of an example of a seismic operation in deep water facilitated by a first marine vessel <NUM>. <FIG> is a non-limiting illustrative example of a marine environment in which the systems and methods of the present disclosure can perform a seismic survey to collect seismic data and generate images.

By way of example, <FIG> illustrates a first vessel <NUM> positioned on a surface <NUM> of a water column <NUM> and includes a deck <NUM> which supports operational equipment. At least a portion of the deck <NUM> includes space for a plurality of sensor device racks <NUM> where seismic sensor devices (e.g., first device <NUM>) are stored. The sensor device racks <NUM> may also include data retrieval devices or sensor recharging devices.

The deck <NUM> also includes one or more cranes 25A, 25B attached thereto to facilitate transfer of at least a portion of the operational equipment, such as an ROV (e.g., second device <NUM>) or seismic sensor devices, from the deck <NUM> to the water column <NUM>. For example, a crane 25A coupled to the deck <NUM> is configured to lower and raise an ROV 35A, which transfers and positions one or more sensor devices <NUM> on a seabed <NUM>. The seabed <NUM> can include a lakebed <NUM>, ocean floor <NUM>, or earth <NUM>. The ROV 35A is coupled to the first vessel <NUM> by a tether 46A and an umbilical cable 44A that provides power, communications, and control to the ROV 35A. A tether management system (TMS) 50A is also coupled between the umbilical cable 44A and the tether 46A. The TMS 50A may be utilized as an intermediary, subsurface platform from which to operate the ROV 35A. For most ROV 35A operations at or near the seabed <NUM>, the TMS 50A can be positioned approximately <NUM> feet above seabed <NUM> and can pay out tether 46A as needed for ROV 35A to move freely above seabed <NUM> in order to position and transfer seismic sensor devices <NUM> thereon.

A crane 25B may be coupled (e.g., via a latch, anchor, nuts and bolts, screw, suction cup, magnet, or other fastener) to a stem of the first vessel <NUM>, or other locations on the first vessel <NUM>. Each of the cranes 25A, 25B may be any lifting device or launch and recovery system (LARS) adapted to operate in a marine environment. The crane 25B can be coupled to a seismic sensor transfer device <NUM> by a cable <NUM>. The transfer device <NUM> may be a drone, a skid structure, a basket, or any device capable of housing one or more sensor devices <NUM> therein. The transfer device <NUM> may be a structure configured as a magazine adapted to house and transport one or more sensor devices <NUM>. The transfer device <NUM> may include an on-board power supply, a motor or gearbox, or a propulsion system <NUM>. The transfer device <NUM> can be configured as a sensor device storage rack for transfer of sensor devices <NUM> from the first vessel <NUM> to the ROV 35A, and from the ROV 35A to the first vessel <NUM>. The transfer device <NUM> may include an on-board power supply, a motor or gearbox, or a propulsion system <NUM>. Alternatively, the transfer device <NUM> may not include any integral power devices or not require any external or internal power source. The cable <NUM> can provide power or control to the transfer device <NUM>. Alternatively, the cable <NUM> may be an umbilical, a tether, a cord, a wire, a rope, and the like, that is configured solely for support of the transfer device <NUM>.

The ROV 35A can include a seismic sensor device storage compartment <NUM> that is configured to store one or more seismic sensor devices <NUM> (e.g., first devices <NUM>) therein for a deployment or retrieval operation. The storage compartment <NUM> may include a magazine, a rack, or a container configured to store the seismic sensor devices. The storage compartment <NUM> may also include a conveyor, such as a movable platform having the seismic sensor devices thereon, such as a carousel or linear platform configured to support and move the seismic sensor devices <NUM> therein. The seismic sensor devices <NUM> can be deployed on the seabed <NUM> and retrieved therefrom by operation of the movable platform. The ROV 35A may be positioned at a predetermined location above or on the seabed <NUM> and seismic sensor devices <NUM> are rolled, conveyed, or otherwise moved out of the storage compartment <NUM> at the predetermined location. The seismic sensor devices <NUM> can be deployed and retrieved from the storage compartment <NUM> by a robotic device <NUM>, such as a robotic arm, an end effector or a manipulator, disposed on the ROV 35A.

The seismic sensor device <NUM> may be referred to as seismic data acquisition unit <NUM> or node <NUM> or first device <NUM>. The seismic data acquisition unit <NUM> can record seismic data. The seismic data acquisition unit <NUM> may include one or more of at least one geophone, at least one hydrophone, at least one power source (e.g., a battery, external solar panel), at least one clock, at least one tilt meter, at least one environmental sensor, at least one seismic data recorder, at least global positioning system sensor, at least one wireless or wired transmitter, at least one wireless or wired receiver, at least one wireless or wired transceiver, or at least one processor. The seismic sensor device <NUM> may be a self-contained unit such that all electronic connections are within the unit, or one or more components can be external to the seismic sensor device <NUM>. During recording, the seismic sensor device <NUM> may operate in a self-contained manner such that the node does not require external communication or control. The seismic sensor device <NUM> may include several geophones and hydrophones configured to detect acoustic waves that are reflected by subsurface lithological formation or hydrocarbon deposits. The seismic sensor device <NUM> may further include one or more geophones that are configured to vibrate the seismic sensor device <NUM> or a portion of the seismic sensor device <NUM> in order to detect a degree of coupling between a surface of the seismic sensor device <NUM> and a ground surface. One or more component of the seismic sensor device <NUM> may attach to a gimbaled platform having multiple degrees of freedom. For example, the clock may be attached to the gimbaled platform to minimize the effects of gravity on the clock.

For example, in a deployment operation, a first plurality of seismic sensor devices, comprising one or more sensor devices <NUM>, may be loaded into the storage compartment <NUM> while on the first vessel <NUM> in a pre-loading operation. The ROV 35A, having the storage compartment coupled thereto, is then lowered to a subsurface position in the water column <NUM>. The ROV 35A utilizes commands from personnel on the first vessel <NUM> to operate along a course to transfer the first plurality of seismic sensor devices <NUM> from the storage compartment <NUM> and deploy the individual sensor devices <NUM> at selected locations on the seabed <NUM>. Once the storage compartment <NUM> is depleted of the first plurality of seismic sensor devices <NUM>, the transfer device <NUM> is used to ferry a second plurality of seismic sensor devices <NUM> as a payload from first vessel <NUM> to the ROV 35A.

The transfer system <NUM> may be preloaded with a second plurality of seismic sensor devices <NUM> while on or adjacent the first vessel <NUM>. When a suitable number of seismic sensor devices <NUM> are loaded onto the transfer device <NUM>, the transfer device <NUM> may be lowered by crane 25B to a selected depth in the water column <NUM>. The ROV 35A and transfer device <NUM> are mated at a subsurface location to allow transfer of the second plurality of seismic sensor devices <NUM> from the transfer device <NUM> to the storage compartment <NUM>. When the transfer device <NUM> and ROV 35A are mated, the second plurality of seismic sensor devices <NUM> contained in the transfer device <NUM> are transferred to the storage compartment <NUM> of the ROV 35A. Once the storage compartment <NUM> is reloaded, the ROV 35A and transfer device <NUM> are detached or unmated and seismic sensor device placement by ROV 35A may resume. Reloading of the storage compartment <NUM> can be provided while the first vessel <NUM> is in motion. If the transfer device <NUM> is empty after transfer of the second plurality of seismic sensor devices <NUM>, the transfer device <NUM> may be raised by the crane 25B to the vessel <NUM> where a reloading operation replenishes the transfer device <NUM> with a third plurality of seismic sensor devices <NUM>. The transfer device <NUM> may then be lowered to a selected depth when the storage compartment <NUM> is reloaded. This process may repeat as until a desired number of seismic sensor devices <NUM> have been deployed.

Using the transfer device <NUM> to reload the ROV 35A at a subsurface location reduces the time required to place the seismic sensor devices <NUM> on the seabed <NUM>, or "planting" time, as the ROV 35A is not raised and lowered to the surface <NUM> for seismic sensor device reloading. The ROV 35A can synchronize a clock of the node <NUM> at the time of planting. Further, mechanical stresses placed on equipment utilized to lift and lower the ROV 35A are minimized as the ROV 35A may be operated below the surface <NUM> for longer periods. The reduced lifting and lowering of the ROV 35A may be particularly advantageous in foul weather or rough sea conditions. Thus, the lifetime of equipment may be enhanced as the ROV 35A and related equipment are not raised above surface <NUM>, which may cause the ROV 35A and related equipment to be damaged, or pose a risk of injury to the vessel personnel.

Likewise, in a retrieval operation, the ROV 35A can utilize commands from personnel on the first vessel <NUM> to retrieve each seismic sensor device <NUM> that was previously placed on seabed <NUM>, or collect data from the seismic sensor device <NUM> without retrieving the device <NUM>. The ROV 35A can adjust the clock of the device <NUM> while collecting the seismic data. The retrieved seismic sensor devices <NUM> are placed into the storage compartment <NUM> of the ROV 35A. In some implementations, the ROV 35A may be sequentially positioned adjacent each seismic sensor device <NUM> on the seabed <NUM> and the seismic sensor devices <NUM> are rolled, conveyed, or otherwise moved from the seabed <NUM> to the storage compartment <NUM>. The seismic sensor devices <NUM> can be retrieved from the seabed <NUM> by a robotic device <NUM> disposed on the ROV 35A.

Once the storage compartment <NUM> is full or contains a pre-determined number of seismic sensor devices <NUM>, the transfer device <NUM> is lowered to a position below the surface <NUM> and mated with the ROV 35A. The transfer device <NUM> may be lowered by crane 25B to a selected depth in the water column <NUM>, and the ROV 35A and transfer device <NUM> are mated at a subsurface location. Once mated, the retrieved seismic sensor devices <NUM> contained in the storage compartment <NUM> are transferred to the transfer device <NUM>. Once the storage compartment <NUM> is depleted of retrieved sensor devices, the ROV 35A and transfer device <NUM> are detached and sensor device retrieval by ROV 35A may resume. Thus, the transfer device <NUM> is used to ferry the retrieved seismic sensor devices <NUM> as a payload to the first vessel <NUM>, allowing the ROV 35A to continue collection of the seismic sensor devices <NUM> from the seabed <NUM>. In this manner, sensor device retrieval time is significantly reduced as the ROV 35A is not raised and lowered for sensor device unloading. Further, safety issues and mechanical stresses placed on equipment related to the ROV 35A are minimized as the ROV 35A may be subsurface for longer periods.

For example, the first vessel <NUM> can travel in a first direction <NUM>, such as in the +X direction, which may be a compass heading or other linear or predetermined direction. The first direction <NUM> may also account for or include drift caused by wave action, current(s) or wind speed and direction. The plurality of seismic sensor devices <NUM> can be placed on the seabed <NUM> in selected locations, such as a plurality of rows Rn in the X direction (R1 and R2 are shown) or columns Cn in the Y direction (C1-Cn are shown), wherein n equals an integer. The rows Rn and columns Cn can define a grid or array, wherein each row Rn (e.g., R1 - R2) comprises a receiver line in the width of a sensor array (X direction) or each column Cn comprises a receiver line in a length of the sensor array (Y direction). The distance between adjacent sensor devices <NUM> in the rows is shown as distance LR and the distance between adjacent sensor devices <NUM> in the columns is shown as distance LC. While a substantially square pattern is shown, other patterns may be formed on the seabed <NUM>. Other patterns include non-linear receiver lines or non-square patterns. The pattern(s) may be pre-determined or result from other factors, such as topography of the seabed <NUM>. The distances LR and LC can be substantially equal and may include dimensions between about <NUM> meters to about <NUM> meters, or greater. The distance between adjacent seismic sensor devices <NUM> may be predetermined or result from topography of the seabed <NUM> as described above.

The first vessel <NUM> is operated at a speed, such as an allowable or safe speed for operation of the first vessel <NUM> and any equipment being towed by the first vessel <NUM>. The speed may take into account any weather conditions, such as wind speed and wave action, as well as currents in the water column <NUM>. The speed of the vessel may also be determined by any operations equipment that is suspended by, attached to, or otherwise being towed by the first vessel <NUM>. For example, the speed can be limited by the drag coefficients of components of the ROV 35A, such as the TMS 50A and umbilical cable 44A, as well as any weather conditions or currents in the water column <NUM>. As the components of the ROV 35A are subject to drag that is dependent on the depth of the components in the water column <NUM>, the first vessel speed may operate in a range of less than about <NUM> knot. In examples where two receiver lines (rows R1 and R2) are being laid, the first vessel includes a first speed of between about <NUM> knots and about <NUM> knots. In some implementations, the first speed includes an average speed of between about <NUM> knots, which includes intermittent speeds of less than <NUM> knots and speeds greater than about <NUM> knot, depending on weather conditions, such as wave action, wind speeds, or currents in the water column <NUM>.

During a seismic survey, one receiver line, such as row R1 may be deployed. When the single receiver line is completed a second vessel <NUM> can be used to provide a source signal. In some cases, the first vessel or other device can provide the source signal. The second vessel <NUM> is provided with a source device or acoustic source device <NUM>, which may be a device capable of producing acoustical signals or vibrational signals suitable for obtaining the survey data. The source signal propagates to the seabed <NUM> and a portion of the signal is reflected back to the seismic sensor devices <NUM>. The second vessel <NUM> may be required to make multiple passes, for example at least four passes, per a single receiver line (row R1 in this example). During the time the second vessel <NUM> is making the passes, the first vessel <NUM> continues deployment of a second receiver line. However, the time involved in making the passes by the second vessel <NUM> is much shorter than the deployment time of the second receiver line. This causes a lag time in the seismic survey as the second vessel <NUM> sits idle while the first vessel <NUM> is completing the second receiver line.

The first vessel <NUM> can use one ROV 35A to lay sensor devices to form a first set of two receiver lines (rows R1 and R2) in any number of columns, which may produce a length of each receiver line of up to and including several miles. The two receiver lines (rows R1 and R2) can be substantially (e.g., within +/-<NUM> degrees) parallel. When a single directional pass of the first vessel <NUM> is completed and the first set (rows R1, R2) of seismic sensor devices <NUM> are laid to a predetermined length, the second vessel <NUM>, provided with the source device <NUM>, is utilized to provide the source signal. The second vessel <NUM> can make eight or more passes along the two receiver lines to complete the seismic survey of the two rows R1 and R2.

While the second vessel <NUM> is shooting along the two rows R1 and R2, the first vessel <NUM> may turn <NUM> degrees and travel in the X direction in order to lay seismic sensor devices <NUM> in another two rows adjacent the rows R1 and R2, thereby forming a second set of two receiver lines. The second vessel <NUM> may then make another series of passes along the second set of receiver lines while the first vessel <NUM> turns <NUM> degrees to travel in the +X direction to lay another set of receiver lines. The process may repeat until a specified area of the seabed <NUM> has been surveyed. Thus, the idle time of the second vessel <NUM> is minimized as the deployment time for laying receiver lines is cut approximately in half by deploying two rows in one pass of the vessel <NUM>.

Although only two rows R1 and R2 are shown, the sensor device <NUM> layout is not limited to this configuration as the ROV 35A may be adapted to layout more than two rows of sensor devices in a single directional tow. For example, the ROV 35A may be controlled to layout between three and six rows of sensor devices <NUM>, or an even greater number of rows in a single directional tow. The width of a "one pass" run of the first vessel <NUM> to layout the width of the sensor array can be limited by the length of the tether 46A or the spacing (distance LR) between sensor devices <NUM>.

<FIG> depicts a block diagram of an architecture for a computing system employed to implement various elements of the system depicted in <FIG>, to perform the method depicted in <FIG>, or generate the image depicted in <FIG>. <FIG> is a block diagram of a data processing system including a computer system <NUM> in accordance with an embodiment. The computer system can include or execute a coherency filter component. The data processing system, computer system or computing device <NUM> can be used to implement one or more component configured to filter, translate, transform, generate, analyze, or otherwise process the data or signals depicted in <FIG>. The computing system <NUM> includes a bus <NUM> or other communication component for communicating information and a processor 610a-n or processing circuit coupled to the bus <NUM> for processing information. The computing system <NUM> can also include one or more processors <NUM> or processing circuits coupled to the bus for processing information. The computing system <NUM> also includes main memory <NUM>, such as a random access memory (RAM) or other dynamic storage device, coupled to the bus <NUM> for storing information, and instructions to be executed by the processor <NUM>. Main memory <NUM> can also be used for storing seismic data, time gating function data, temporal windows, images, reports, executable code, temporary variables, or other intermediate information during execution of instructions by the processor <NUM>. The computing system <NUM> may further include a read only memory (ROM) <NUM> or other static storage device coupled to the bus <NUM> for storing static information and instructions for the processor <NUM>. A storage device <NUM>, such as a solid state device, magnetic disk or optical disk, is coupled to the bus <NUM> for persistently storing information and instructions.

The computing system <NUM> may be coupled via the bus <NUM> to a display <NUM> or display device, such as a liquid crystal display, or active matrix display, for displaying information to a user. An input device <NUM>, such as a keyboard including alphanumeric and other keys, may be coupled to the bus <NUM> for communicating information and command selections to the processor <NUM>. The input device <NUM> can include a touch screen display <NUM>. The input device <NUM> can also include a cursor control, such as a mouse, a trackball, or cursor direction keys, for communicating direction information and command selections to the processor <NUM> and for controlling cursor movement on the display <NUM>.

In some embodiments, hard-wired circuitry may be used in place of or in combination with software instructions to effect illustrative implementations. Thus, embodiments are not limited to any specific combination of hardware circuitry and software.

Although an example computing system has been described in FIG. <NUM>, embodiments of the subject matter and the functional operations described in this specification can be implemented in other types of digital electronic circuitry, or in computer software, firmware, or hardware, including the structures disclosed in this specification and their structural equivalents, or in combinations of one or more of them.

The subject matter described in this specification can be implemented as one or more computer programs, e.g., one or more circuits of computer program instructions, encoded on one or more computer storage media for execution by, or to control the operation of, data processing apparatus. Alternatively or in addition, the program instructions can be encoded on an artificially generated propagated signal, e.g., a machine-generated electrical, optical, or electromagnetic signal that is generated to encode information for transmission to suitable receiver apparatus for execution by a data processing apparatus. Moreover, while a computer storage medium is not a propagated signal, a computer storage medium can be a source or destination of computer program instructions encoded in an artificially generated propagated signal. The computer storage medium can also be, or be included in, one or more separate components or media (e.g., multiple CDs, disks, or other storage devices).

The operations described in this specification can be performed by a data processing apparatus on data stored on one or more computer-readable storage devices or received from other sources. The term "data processing apparatus" or "computing device" encompasses various apparatuses, devices, and machines for processing data, including by way of example a programmable processor, a computer, a system on a chip, or multiple ones, or combinations of the foregoing.

A computer program (also known as a program, software, software application, script, or code) can be written in any form of programming language, including compiled or interpreted languages, declarative or procedural languages, and it can be deployed in any form, including as a stand-alone program or as a circuit, component, subroutine, object, or other unit suitable for use in a computing environment. A program can be stored in a portion of a file that holds other programs or data (e.g., one or more scripts stored in a markup language document), in a single file dedicated to the program in question, or in multiple coordinated files (e.g., files that store one or more circuits, subprograms, or portions of code).

Processors suitable for the execution of a computer program include, by way of example, microprocessors, and any one or more processors of a digital computer. A processor can receive instructions and data from a read only memory or a random access memory or both. The elements of a computer are a processor for performing actions in accordance with instructions and one or more memory devices for storing instructions and data. A computer can include, or be operatively coupled to receive data from or transfer data to, or both, one or more mass storage devices for storing data, e.g., magnetic, magneto optical disks, or optical disks. A computer need not have such devices. Moreover, a computer can be embedded in another device, e.g., a personal digital assistant (PDA), a Global Positioning System (GPS) receiver, or a portable storage device (e.g., a universal serial bus (USB) flash drive), to name just a few. Devices suitable for storing computer program instructions and data include all forms of non-volatile memory, media and memory devices, including by way of example semiconductor memory devices, e.g., EPROM, EEPROM, and flash memory devices; magnetic disks, e.g., internal hard disks or removable disks; magneto optical disks; and CD ROM and DVD-ROM disks.

To provide for interaction with a user, implementations of the subject matter described in this specification can be implemented on a computer having a display device, e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor, for displaying information to the user and a keyboard and a pointing device, e.g., a mouse or a trackball, by which the user can provide input to the computer.

The implementations described herein can be implemented in any of numerous ways including, for example, using hardware, software or a combination thereof. When implemented in software, the software code can be executed on any suitable processor or collection of processors, whether provided in a single computer or distributed among multiple computers.

Such computers may be interconnected by one or more networks in any suitable form, including a local area network or a wide area network, such as an enterprise network, and intelligent network (IN) or the Internet. Such networks may be based on any suitable technology and may operate according to any suitable protocol and may include wireless networks, wired networks or fiber optic networks.

A computer employed to implement at least a portion of the functionality described herein may comprise a memory, one or more processing units (also referred to herein simply as "processors"), one or more communication interfaces, one or more display units, and one or more user input devices. The memory may comprise any computer-readable media, and may store computer instructions (also referred to herein as "processor-executable instructions") for implementing the various functionalities described herein. The processing unit(s) may be used to execute the instructions. The communication interface(s) may be coupled to a wired or wireless network, bus, or other communication means and may therefore allow the computer to transmit communications to or receive communications from other devices. The display unit(s) may be provided, for example, to allow a user to view various information in connection with execution of the instructions. The user input device(s) may be provided, for example, to allow the user to make manual adjustments, make selections, enter data or various other information, or interact in any of a variety of manners with the processor during execution of the instructions.

The various methods or processes outlined herein may be coded as software that is executable on one or more processors that employ any one of a variety of operating systems or platforms. Additionally, such software may be written using any of a number of suitable programming languages or programming or scripting tools, and also may be compiled as executable machine language code or intermediate code that is executed on a framework or virtual machine.

In this respect, various inventive concepts may be embodied as a computer readable storage medium (or multiple computer readable storage media) (e.g., a computer memory, one or more floppy discs, compact discs, optical discs, magnetic tapes, flash memories, circuit configurations in Field Programmable Gate Arrays or other semiconductor devices, or other non-transitory medium or tangible computer storage medium) encoded with one or more programs that, when executed on one or more computers or other processors, perform methods that implement the various embodiments of the solution discussed above. The computer readable medium or media can be transportable, such that the program or programs stored thereon can be loaded onto one or more different computers or other processors to implement various aspects of the present solution as discussed above.

The terms "program" or "software" are used herein to refer to any type of computer code or set of computer-executable instructions that can be employed to program a computer or other processor to implement various aspects of embodiments as discussed above. One or more computer programs that when executed perform methods of the present solution need not reside on a single computer or processor, but may be distributed in a modular fashion amongst a number of different computers or processors to implement various aspects of the present solution.

Program modules can include routines, programs, objects, components, data structures, or other components that perform particular tasks or implement particular abstract data types. The functionality of the program modules can be combined or distributed as desired in various embodiments.

Any references to implementations or elements or acts of the systems and methods herein referred to in the singular can include implementations including a plurality of these elements, and any references in plural to any implementation or element or act herein can include implementations including only a single element.

Any implementation disclosed herein may be combined with any other implementation, and references to "an implementation," "some implementations," "an alternate implementation," "various implementations," "one implementation" or the like are not necessarily mutually exclusive and are intended to indicate that a particular feature, structure, or characteristic described in connection with the implementation may be included in at least one implementation. Such terms as used herein are not necessarily all referring to the same implementation. Any implementation may be combined with any other implementation, inclusively or exclusively, in any manner consistent with the aspects and implementations disclosed herein.

References to "or" may be construed as inclusive so that any terms described using "or" may indicate any of a single, more than one, and all of the described terms. References to at least one of a conjunctive list of terms may be construed as an inclusive OR to indicate any of a single, more than one, and all of the described terms. For example, a reference to "at least one of 'A' and 'B'" can include only 'A', only 'B', as well as both 'A' and 'B'. Elements other than 'A' and 'B' can also be included.

Claim 1:
A system for collection of near field data used to produce images of the near field to be used for seismic hazard detection with receiver spacing, characterized by:
a first string (114a) of one or more acoustic sources (118a, 118b, 118c) and a second string (114b) of one or more acoustic sources (118d, 118e, 118f) opposite the first string (114a);
the first string (114a) of acoustic sources configured to trigger a shot on alternating acoustic sources of the first string (114a) of acoustic sources (118a, 118b, 118c); and
the second string (114b) of acoustic sources configured to trigger a shot on alternating acoustic sources of the second string that are opposite acoustic sources on the first string (114a) of acoustic sources (118a, 118b, 118c) that are in standby;
a first one or more hydrophones (<NUM>16a) mounted within a predetermined distance of the first string (114a) of one or more acoustic sources (118a, 118b, 118c);
a second one or more hydrophones (116b) mounted within the predetermined distance of the second string (114b) of one or more acoustic sources (118d, 118e, 118f);
the first one or more hydrophones (116a) located above at least one source on the first string (114a) of acoustic sources (118a, 118b, 118c); or
the second one or more hydrophones (116b) located above at least one source on the second string (114b) of acoustic sources (118d, 118e, 118f);
the first one or more hydrophones (116a) configured to record an acoustic shot generated from a source on the first string (114a) of one or more acoustic sources (118a, 118b, 118c);
the second one or more hydrophones (116b) configured to record the acoustic shot and acoustic reflections corresponding to the acoustic shot;
a third hydrophone located below the first string (114a) of acoustic sources (118a, 118b, 118c);
and a fourth hydrophone located below the second string (114b) of acoustic sources (118d, 118e, 118f) and;
a data processing system (<NUM>) comprising one or more processors and memory to:
receive seismic data corresponding to the acoustic shot and the acoustic reflections recorded by the second one or more hydrophones (116b); and
generate an image from the acoustic shot and the acoustic reflections with the seismic data recorded by the second one or more hydrophones (116b) mounted within the predetermined distance from the second string (114b) of one or more acoustic sources (118d, 118e, 118f).