Abstract: Methods, apparatuses, and systems are disclosed for datuming multi-component seismic data. In one example of such a method, a plurality of seismic traces are accessed, the plurality of seismic traces including data representative of amplitude and spatial gradient samples of a seismic wavefield at a plurality of recording locations in a medium. Using a computer-based processing unit, a wavefield propagation from the plurality of recording locations through a medium is initialized, using the amplitude and spatial gradient samples of the seismic wavefield. Seismic traces are generated that correspond to the propagated wavefield at defined locations within the medium.

Abstract: A method for verifying the accuracy of a wave velocity model. The method may include generating an extended image using the wave velocity model, operating on the extended image using an annihilator, where the extended images represent a geophysical field, and determining if the extended image obeys at least one physical characteristic. In the event that the extended image does not obey at least one physical characteristic the method may include recreating or altering the wave velocity model accordingly.

Abstract: An underwater seismic system for reducing noise due to ghost reflections or motion through the water from seismic signals. The system includes two motion sensors. One sensor has a first response and is sensitive to platform-motion-induced noise as well as to acoustic waves. The other sensor has a different construction that isolates it from the acoustic waves so that its response is mainly to motion noise. The outputs of the two sensor responses are combined to remove the effects of motion noise. When further combined with a hydrophone signal, noise due to ghost reflections is reduced.

Abstract: Methods, apparatuses, and systems are disclosed that reduce seismic noise. In one embodiment, a method of processing seismic data includes accessing seismic data representative of a plurality of seismic input traces acquired by one or more seismic sensors. The method also includes stacking the plurality of seismic input traces into a stacked trace. The method also includes generating, utilizing at least one processor unit, a function of similarity between at least two of the plurality of seismic input traces. The method also includes scaling at least one of the seismic input traces or the stacked trace with the function of similarity.

Abstract: A skeg mounts from the stern of a towing vessel and extends below the waterline. A channel in the skeg protects cables for steamers and a source of a seismic system deployed from the vessel. Tow points on the skeg lie below the water's surface and connect to towlines to support the steamers and source. A floatation device supports the source and tows below the water's surface to avoid ice floes. The streamers can have vehicles deployed thereon for controlling a position on the streamer. To facilitate locating the streamers, these vehicles on the streamers can be brought to the surface when clear of ice floes so that GPS readings can be obtained and communicated to a control system. After obtaining readings, the vehicles can be floated back under the surface. Deploying, using, and retrieving the system accounts for ice at the surface in icy regions. In addition, handling the seismic record can account for noise generated by ice impact events.

Abstract: A skeg mounts from the stern of a towing vessel and extends below the waterline. A channel in the skeg protects cables for steamers and a source of a seismic system deployed from the vessel. Tow points on the skeg lie below the water's surface and connect to towlines to support the steamers and source. A floatation device supports the source and tows below the water's surface to avoid ice floes. The streamers can have vehicles deployed thereon for controlling a position on the streamer. To facilitate locating the streamers, these vehicles on the streamers can be brought to the surface when clear of ice floes so that GPS readings can be obtained and communicated to a control system. After obtaining readings, the vehicles can be floated back under the surface. Deploying, using, and retrieving the system accounts for ice at the surface in icy regions. In addition, handling the seismic record can account for noise generated by ice impact events.

Abstract: A marine threat monitoring and defense system and method protects a target vessel in icy or other marine regions. The system uses communications, user interfaces, and data sources to identify marine obstacles (e.g., icebergs, ice floes, pack ice, etc.) near a target vessel performing set operations (e.g., a stationed structure performing drilling or production operations or a seismic survey vessel performing exploration operations with a planned route). The system monitors positions of these identified marine obstacles over time relative to the target vessel and predicts any potential threats. When a threat is predicted, the system plans deployment of support vessels, beacons, and the like to respond to the threat. For example, the system can direct a support vessel to divert the path or break up ice threatening the target vessel.

Abstract: Methods and apparatuses are disclosed that assist in correlating subsequent geophysical surveys. In some embodiments, geophysical data may be generated including a first set of data from a monitor survey that is matched with a second set of data from a baseline survey. An attribute value may be generated for each datum in the first set of data, and the generated attribute value may be associated with the datum from the first set of data and at least one of a plurality of bins. In some embodiments, the at tribute values may be based upon the geometric closeness of sources and receivers in the baseline and monitor surveys.

Abstract: Methods and apparatuses are disclosed that assist in correlating subsequent geophysical surveys. In some embodiments, geophysical data may be generated including a first set of data from a monitor survey that is matched with a second set of data from a baseline survey. An attribute value may be generated for each datum in the first set of data and each attribute value generated may be stored with its corresponding datum. Then, the first set of data may be processed based on the stored attribute values. In some embodiments, the attribute values may be based upon the geometric closeness of sources and receivers in the baseline and monitor surveys.

Abstract: A marine threat monitoring and defense system and method protects a target vessel in icy or other marine regions. The system uses communications, user interfaces, and data sources to identify marine obstacles (e.g., icebergs, ice floes, pack ice, etc.) near a target vessel performing set operations (e.g., a stationed structure performing drilling or production operations or a seismic survey vessel performing exploration operations with a planned route). The system monitors positions of these identified marine obstacles over time relative to the target vessel and predicts any potential threats. When a threat is predicted, the system plans deployment of support vessels, beacons, and the like to respond to the threat. For example, the system can direct a support vessel to divert the path or break up ice threatening the target vessel.

Abstract: Methods, apparatuses, and systems are disclosed for forming a transducer. The transducer may include a bottom plate formed from a first sheet of material, a top plate formed from a second sheet of material, and a middle portion. The middle portion includes a mid-upper element formed from a third sheet of material, the mid-upper element having a mid-upper frame, a mid-upper mass, and a plurality of mid-upper attachment members coupling the mid-upper mass to the mid-upper frame. The middle portion also may include a central element formed from a fourth sheet of material, the central element having a central frame and a central mass.

Abstract: Methods and apparatuses are disclosed that assist in sensing underwater signals in connection with geophysical surveys. One embodiment relates to a transducer including a cantilever coupled to a base. The cantilever may include a beam and a first coupling surface angularly oriented from the beam, and the base may include a second coupling surface angularly oriented from the beam and substantially parallel to the first coupling surface of the cantilever. The transducer may further include a sensing material coupled between the first coupling surface of the cantilever and the second coupling surface of the base.

Abstract: A skeg mounts from the stern of a towing vessel and extends below the waterline. A channel in the skeg protects cables for steamers and a source of a seismic system deployed from the vessel. Tow points on the skeg lie below the water's surface and connect to towlines to support the steamers and source. A floatation device supports the source and tows below the water's surface to avoid ice floes. The streamers can have vehicles deployed thereon for controlling a position on the streamer. To facilitate locating the streamers, these vehicles on the streamers can be brought to the surface when clear of ice floes so that GPS readings can be obtained and communicated to a control system. After obtaining readings, the vehicles can be floated back under the surface. Deploying, using, and retrieving the system accounts for ice at the surface in icy regions. In addition, handling the seismic record can account for noise generated by ice impact events.

Abstract: Seismic acquisition systems are disclosed that allow contemporaneous seismic sources to be separated from a composite signal comprising two or more constituent seismic sources. In some embodiments, a representation of the composite signal may be developed that includes a noise contribution of undesired signals present in the composite signal. Additionally, an operator, referred to herein as an “annihilator”, may be developed such that it may be conditioned and inverted to minimize undesired noise contributions in the composite signal. This inversion may assist in recovering the constituent seismic sources from the composite signal. Furthermore, in some embodiments, the accuracy with which the constituent source measurements are approximated may be increased by implementing them as random sweeps having a conventional length.

Abstract: A method and system for controlling the shape and separation of an arrangement of streamers towed behind a survey vessel. Each streamer is steered laterally by lateral steering devices positioned along its length at specific nodes. Each streamer is driven by its lateral steering devices to achieve a specified separation from a neighboring streamer. One of these actual streamers, used as a reference by the other actual streamers, is steered to achieve a specified separation from an imaginary, or ghost, streamer virtually towed with the actual streamers.

Abstract: Methods, apparatuses, and systems are disclosed for processing seismic data. In some embodiments, a set of vectorial measurements and a set of corresponding scalar measurements of a seismic wavefield may be obtained at a seismic receiver. An angle of incidence of the seismic wavefield at a first instance of time may be determined by calculating an incidence vector of the seismic wavefield at the seismic receiver at the first instance of time, with the incidence vector derived from a measure of correlation of at least one of the vectorial measurements. A component of a vectorial measurement may be corrected with the determined angle of incidence of the seismic wavefield at the first instance of time, and the corrected component may be combined with a scalar measurement that corresponds to the first instance of time.

Abstract: A skeg mounts from the stern of a towing vessel and extends below the waterline. A channel in the skeg protects cables for steamers and a source (e.g., air gun array) of a seismic system deployed from the vessel. Tow points on the skeg lie below the water's surface and connect to towlines to support the steamers and the source. A floatation device supports the source and tows below the water's surface to avoid ice floes or other issues encountered at the water's surface. The floatation device has a depth controlled float and one or more adjustable buoyancy floats. The controlled float has its buoyancy controlled with pressurized gas used for the air gun source and actively controls the depth of air gun source in the water. Each of the adjustable float connects in line with the controlled float with flexible connections. Each adjustable float has its buoyancy preconfigured to counterbalance the weight in water of the air gun or portion of the source that the float supports.

Abstract: Apparatus and method for retrieving instrumented marine cables. The cable-handling apparatus comprises carriers that capture and pull on rigid elements in or on a marine cable to retrieve the cable hand-over-hand onto a deployment vessel. The carriers are spaced apart along an endless path on spacings matching the spacings of the rigid elements in the cable. A take-up mechanism allows manual adjustment of the relative spacings of the carriers to account for tolerances in the spacings of the rigid elements on the cable.

Abstract: A rope-tension system for a marine seismic cable comprising a series of sensor nodes connected between flexible cable sections connected to other sensor nodes and flexible sections by armored cable segments. The flexible sections, which are housed in flexible protective covers, have a pair of ropes as stress members. The two ropes are pivotably pinned at both ends to termination units at the opposite ends of the flexible sections. The two ropes extend through a ring positioned between the two termination units. The pivots at the rope ends form linkages with the ropes that allow the ropes to adjust their positions as the flexible section engages a curved surface during retrieval. The ring presents bearing surfaces with a large radius of curvature to the ropes to avoid sharp bending loads.

Abstract: A seismic streamer system and associated methods for estimating the shape of a laterally steered seismic streamer. The streamer is divided into a series of contiguous streamer segments by lateral-steering devices. Heading sensors positioned in forward and aft portions of each segment produce heading readings. Each segment is modeled as having a linear shape in the forward portion and a curved shape in the aft portion. The shape of the segment is estimated according to the model from the heading readings on the segment.