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.

A system can include a source and a front float coupled to the source. The front float can include a winch configured to adjust a position of the source. The front float can include a control unit configured to control functions associated with the front float. Lead-ins can be coupled to the front float and the source and configured to accommodate transfer of electrical energy between the front float and the source.

Presented are methods and systems for collecting marine seismic data. The collected seismic data can be low frequency (e.g., less than 10 Hz) or it can be a full seismic bandwidth (1-200 Hz) depending on if the low frequency tuned sources and tuned receivers are combined with conventional sources and receivers. The low frequency sources can be towed or they can be autonomous and positioned in the survey area by tether, drifting or self-propelled. The tuned low frequency receivers are towed at a depth greater than conventional receivers and the sources can be fired independently or simultaneously.

A method for seismic surveying comprises deploying a plurality of seismic receivers proximate an area of subsurface to be surveyed. At least one seismic energy source moves in a path that circumscribes a center, wherein positions of the plurality of seismic receivers remain fixed. At least one of a distance between the path and the center changes monotonically as seismic energy source traverses the path, or the center moves in a selected direction as the seismic energy source traverses the path. The source is actuated at selected times as the at least one seismic energy source traverses the path, such that a spacing between positions of the source along the source path and transverse to the source path varies between successive actuations of the source. Seismic energy is detected at the plurality of seismic receivers resulting from actuating the at least one seismic energy source.

A seismic measurement system and a method of obtaining seismic measurements are described. The seismic measurement system includes a cable and a plurality of sensors disposed at a first interval along the cable. The plurality of sensors receives reflections resulting from a seismic source and each of the plurality of sensors receives the reflection corresponding with a particular subsurface location. The system also includes a controller to turn on a first set of the plurality of sensors and turn off a second set of the plurality of sensors based on an area of interest.

A marine seismic source includes source elements configured to emit waves having different frequencies while the source elements are towed at different predetermined depths, respectively. The predetermined depths are calculated such that water-surface reflections of the waves generated by a source element among the source elements interfere constructively with the waves generated by the source element and propagating toward an explored structure under the seafloor. The waves combine to yield a spike-like signature of the source.

Disclosed are control systems for marine vibrators. An example method may comprise recording a signal at a seismic sensor; running an iterative learning control characterization for a marine vibrator on the signal from the seismic sensor; measuring movement of an outer shell of the marine vibrator using a motion sensor to obtain a motion sensor signal; and controlling the marine vibrator using the motion sensor signal as a reference signal.

A method is provided for managing a master vessel change in a multi-vessel seismic system. The system includes a master vessel M and at least one slave vessel. The method includes, during at least a part of a multi-vessel operation: selecting a new master vessel M′ among the at least one slave vessel, triggered by at least one predetermined event; and transmitting, to the at least one slave vessel, at least one piece of information related to a master vessel change from the master vessel M, called old master vessel, to the new master vessel M′.

An unmanned vessel system can include a hull system configured to provide buoyancy, one or more seismic sources configured to generate seismic energy, and a deployment apparatus configured to deploy the seismic sources from the hull system to a water body or water column. A control system can be configured to operate the deployment apparatus, in order to deploy the one or more seismic sources so that the seismic energy propagates through the water column. A compressed air source can be provided on board the unmanned vessel system, with a source line configured to provide compressed air to the seismic sources.

Embodiments herein describe a seismic source that includes a reservoir configured to hold compressed gas, a first firing head coupled to the reservoir where the first firing head configured to generate seismic energy by releasing a first portion of the compressed air from the reservoir to form a first gas bubble in a seismic medium, and a second firing head coupled to the reservoir where the second firing head configured to generate seismic energy by releasing a second portion of the compressed gas from the reservoir to form a second gas bubble in the seismic medium. Moreover, at least one first fill line is coupled directly to the reservoir.