Seismic data are obtained by recording simultaneously in seismic streamer, acquired by activating approximately simultaneously two or more seismic sources towed at two positions in the vicinity of seismic streamers. A residual is updated iteratively for an inversion solution for the activations of the two or more seismic sources. The iterative updating of the residuals utilizes a sequence of overlapping temporal windows containing reflection events and utilizes normal moveout corrections based on largest reflection events in each temporal window. A final updated residual is added to a final updated model result.

A seabed object detection system is provided. The system can include a receiver array including streamers. The system can include a plurality of receivers coupled with the streamers. The system can include a receiver array cross-cable to couple with the first streamer and to couple with the second streamer. The receiver array cross-cable can be disposed at a first depth of a body of water. The system can include a first diverter and a second diverter coupled with the receiver array cross-cable. The system can include a source array including a first source and a second source. The source array can be coplanar to the receiver array. The system can include a source array cross-cable to couple with the first source and to couple with the second source, the source array cross-cable disposed at a second depth of the body of water.

A method for a marine seismic survey can include towing streamers that are spaced apart in a cross-line direction by a streamer separation (L) and towing seismic source elements that are spaced apart in the cross-line direction by a source separation based on an integer (k), an inverse of a quantity of the seismic source elements (1/S), and the streamer separation as represented by (k+1/S)L. The seismic source elements can be actuated and seismic signals can be detected at each of a plurality of receivers on the streamers.

An inline source can be used for a marine survey. For example, a marine survey vessel can tow source units in line. The source units can be actuated near-continuously to cause a respective signal emitted by each of the source units to be uncorrelated with signals emitted by other of the source units.

A method for correcting for distortions in a seismic acoustic wavefield produced by a seismic vibrator that is immersed in a fluid, the method comprising: applying a pilot signal to the vibrator such that an acoustic wavefield travels outwards from the interface between the vibrator outer surface and the fluid: using a sensor located within the fluid so as to be sensitive to a property of the wavefield in the fluid to monitor the property of the wavefield as a function of time: and using the measured property to determine a change in wet volume of a component of the vibrator as a function of time V(t) or derivatives of V(t), and using the determined wet volume V(t) or its derivatives to correct for distortions in the seismic data produced by the vibrator.

Systems and computer readable media are described that actuate at least one marine seismic source according to a constrained sequence. The sequence exhibits an actuation time or distance interval between each actuation. The actuation time or distance interval corresponds to the sum of a nominal time or distance and a respective dither time or dither distance for each actuation. The sequence is constrained such that differences between consecutive dither times or dither distances remain within a threshold dither difference. Constraining the sequence according to the threshold dither difference enables increased bottom speeds for the source (i.e., increased speeds of the source relative to the seafloor), while still maintaining at least a minimum actuation time or distance interval for the source, taking into account both the nominal time or distance and the respective dither times or dither differences.

A seismic source using tuned pulse sources to form an ultra-low frequency (ULF) cluster intended for use in generating seismic energy impulses for marine seismic exploration and more specifically to improved performance by increasing low frequency output to within a range of 1 Hz to 3 Hz to provide greater penetration of the seismic signal through complex overburden such as salt or basalt.

The present invention relates to the field of marine towing operations for marine seismic survey systems and seismic data gathering. More specifically, the present invention relates to seismic sources and receiver sensor cables, streamers, floats etc., that have means for adjusting and keeping a desired position in an array during a tow behind a vessel. The apparatus comprises a pulley apparatus, being a kind of miming block (1), connected with and supporting marine equipment (3, 3′). The miming block (1) is configured to attach to the deflected lead wire or tow wire (2, 9). It has means for traveling along the wire (2, 9).

An acoustic array has a frame and multimode transducers positioned along the frame. The multimode transducers are cylindrical and divided into circumferential transducer segments. The transducer segments each have a common ground electrode and an electrode associated with the segment. An elastomeric bushing is between each multimode transducer and the frame. Electrical leads are joined to the electrodes. A proximate plug is provided at one end of the frame, and a distal plug is provided at the other. A connector is positioned in the proximate plug and joined to the electrical leads. An elastomeric hose surrounds the frame and is sealed to the proximate plug and the distal plug. The interior volume is filled with a dielectric fluid.

A method and apparatus for marine surveying. A system includes: a standard-volume source element; a large-volume source element comprising an airgun having a volume greater than 1200 cubic inches; and a long-offset survey streamer. A method includes: towing a standard-volume source element; and towing a large-volume source element; activating the large-volume source element at large shotpoint intervals; and activating the standard-volume source element at standard shotpoint intervals, wherein the large shotpoint intervals are at least twice as long as the standard shotpoint intervals. A method includes: obtaining geophysical data for a subterranean formation; and processing the geophysical data to produce an image of the subterranean formation. A method includes: obtaining a firing plan for a plurality of seismic sources, wherein: a first seismic source of the plurality comprises a large-volume source element, and a second seismic source of the plurality consists of standard-volume source elements.