Abstract: A first portion of electric potentials generated by a first detector and a second detector of a hydrophone can be isolated, wherein the first portion is indicative of particle motion. A second portion of the electric potentials generated by the first detector and the second detector of the hydrophone can be isolated, wherein the second portion is indicative of pressure.

Abstract: A system can include a first array of hydrophones and a second array of hydrophones. Each of the hydrophones can include a first detector and a second detector. A sensitivity of the first detector can be matched with a sensitivity of the second detector and a combined sensitivity of the first array of hydrophones can be matched with a combined sensitivity of the second array of hydrophones.

Abstract: Disclosed are dipole sources and associated methods. An example system may include a dipole source a first marine seismic vibrator and a second marine seismic vibrator. The first marine seismic vibrator may include two or more sound radiating surfaces. The second marine seismic vibrator may also include two or more sound radiating surfaces. A relative position of the second marine seismic vibrator to the first marine seismic vibrator may be fixed. The first marine seismic vibrator may be positioned above the second marine seismic vibrator in a towing configuration. The system may further include a control system operable to control the dipole source such that the first marine seismic vibrator is operating substantially 180° out of phase with the second marine seismic vibrator.

Abstract: Embodiments relate to the restriction of gas flow in a piston-type marine vibrator to compensate for air-spring effects. An embodiment provides marine vibrator comprising: a containment housing; a piston plate; a fixture coupled to the containment housing; a mechanical spring element coupled to the piston plate and to the fixture; a driver coupled to the piston plate and to the fixture; and a variable gas flow restrictor disposed in an interior volume of the marine vibrator, wherein the marine vibrator has a resonance frequency selectable based at least in part on the variable gas flow restrictor.

Abstract: Disclosed are devices and methods for marine geophysical surveying. An example device may comprise a shell, a base plate, wherein the base plate is coupled to the shell, a driver disposed within the shell, an inner spring element disposed within the shell, wherein the inner spring element is coupled to the driver, wherein outer ends of the inner spring element are coupled to outer ends of the inner spring element at spring element junctions, an outer spring element disposed within the shell, wherein outer ends of the outer spring element are coupled to the spring element junctions, and a back mass disposed on the outer spring element.

Abstract: Embodiments relate to marine seismic vibrators for use in seismic surveying and associated methods of use. An embodiment provides a marine seismic vibrator comprising: a shell having a spring constant selected to provide a first resonance frequency within an operational frequency range of about 1 Hz and about 300 Hz; a driver disposed within the shell and having a first end and a second end; and a spring element coupled to the shell between the first end and the second end of the driver, wherein the spring element has a second mode of oscillation that provides a second resonance frequency within the operational frequency range.

Abstract: 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.

Abstract: Techniques are disclosed relating to geophysical surveying. In various embodiments, a computer system may access seismic data for a geological formation, where the seismic data is recorded, using one or more sensors, during a seismic survey in which a first vibratory source was driven using a first digital code for at least a first time interval. The first digital code, in some embodiments, may include a first plurality of subsections corresponding to portions of the first time interval. In some embodiments, the computer system may image a first location of the geological formation using a correlation of only a first sub-section of the first plurality of sub-sections with the seismic data. Further, in some embodiments, the computer system may image a second location of the geological formation using a correlation of two or more of the first plurality of sub-sections with the seismic data.

Abstract: Techniques are disclosed relating to geophysical surveying. In various embodiments, a marine survey vessel may tow a plurality of streamers that each include a plurality of seismic sensors. Further, the survey vessel may tow a plurality of vibratory sources. In various embodiments, a first sweep may be performed, using one or more of the plurality of vibratory sources, for a first time interval. Further, in various embodiments, disclosed techniques may include recording, during the first time interval using the plurality of seismic sensors, seismic data on a tangible, computer-readable medium, thereby creating a geophysical data product.

Abstract: A disclosed data acquisition system includes one or more streamers having multiple spaced apart sensor units. At least one sensor unit includes at least one digital sensor employing a quantized feedback loop to produce a digital output signal. A data recording system collects and stores data from the sensor units. The quantized feedback loop may be adapted to exert a quantized force on the sensing element. A described method for acquiring data includes deploying at least one streamer having multiple spaced apart sensor units, where at least a portion of the sensor units include a digital sensor employing a quantized feedback loop to produce a digital output signal. A stimulus event is triggered. Data is received from the sensor units and stored.

Abstract: Techniques are disclosed relating to sensors configured to measure acceleration and pressure. In various embodiments, an apparatus includes a first hydrophone sensor having a first piezoelectric material and a first housing structure and a second hydrophone sensor having a second piezoelectric material and a second housing structure. In some embodiments, the apparatus includes a first pair of wires configured to provide a first differential voltage and a second pair of wires configured to provide a second differential voltage. The first pair of wires may be coupled to the first hydrophone sensor and the second pair of wires may be coupled to the second hydrophone sensor. In various embodiments, the apparatus is configured to determine, based on the first and second differential voltages, a pressure and an acceleration experienced by the first and second hydrophone sensors.

Abstract: Geophysical sensor cables. At least some of the example embodiments are sensor cable sections including hydrophone groups defined along a geophysical sensor cable section, the hydrophone group may include: a substrate of flexible material having electrical traces thereon, the substrate within the internal volume or embedded within the outer jacket, and the substrate having has a length measured parallel to the longitudinal axis; and a plurality of hydrophones mechanically coupled to the substrate. The substrate may have a variety of shapes, including one or more strips, helix, double helix, and cylindrical.

Abstract: Techniques are disclosed relating to geophysical surveying. In some embodiments, a marine survey vessel tows multiple sensor streamers including a group of four innermost streamers in a cross-line direction relative to a centerline of tow. In some embodiments, the vessel tows two or more vibratory sources between two outermost streamers in the first group, in a cross-line direction. In some embodiments, the two or more sources are simultaneously operated using different codes that are uncorrelated to at least a threshold degree. Various disclosed narrow-tow techniques may allow increased streamer separation without reducing cross-line bin size and/or reduce cross-line bin size for a given streamer separation, relative to conventional techniques.

Abstract: Techniques are disclosed relating to calibrating sensors configured to measure both pressure and acceleration. In various embodiments, a system detects a first voltage produce by a first piezoelectric material in a hydrophone when the hydrophone is exposed to an acceleration and detects a second voltage produced by a second piezoelectric material in the hydrophone when the hydrophone is exposed to the acceleration. The system, in some embodiments, compares the first voltage and the second voltage. Based on the comparing of the first and second voltages, in some embodiments, the system determines a resistance for a variable resistor coupled to one of the first and second piezoelectric materials.

Abstract: A disclosed seismic survey system includes one or more streamer(s) each having multiple spaced apart sensor units, and a data recording and control system. Each sensor unit receives a command from the data recording and control system, and operates in an enabled state or a disabled state dependent upon the command. The data recording and control system collects and stores data from enabled sensor units. The sensor units produce data when in the enabled state, and dissipate significantly less electrical power in the disabled state. A described sensor unit includes one or more sensor(s), an analog-to-digital converter, and a control unit that enables or disables the analog-to-digital converter dependent upon the command. A disclosed method for acquiring seismic survey data includes issuing an enable or disable command to each of multiple spaced apart sensor units, and receiving and storing data from those sensor units that are enabled.

Abstract: Geophysical surveys in marine environments. At least some of the illustrative embodiments are methods including: attaching a first sensor module to a sensor cable having an outer jacket, the first sensor module electrically isolated from an electrical conductor disposed within the outer jacket of the sensor cable; attaching a second sensor module to the sensor cable, the second sensor module electrically isolated from an electrical conductor disposed within the outer jacket of the sensor cable; placing the sensor cable and the sensor modules onto a sea floor; communicating with the sensor modules by way of the electrical conductor disposed within the outer jacket; collecting geophysical data by the first and second sensor modules while the sensor cable is on the sea floor; and downloading to a computer system geophysical data from the first and second sensor modules.

Abstract: A disclosed seismic survey system includes one or more streamer(s) each having multiple spaced apart sensor units, and a data recording and control system. Each sensor unit receives a command from the data recording and control system, and operates in an enabled state or a disabled state dependent upon the command. The data recording and control system collects and stores data from enabled sensor units. The sensor units produce data when in the enabled state, and dissipate significantly less electrical power in the disabled state. A described sensor unit includes one or more sensor(s), an analog-to-digital converter, and a control unit that enables or disables the analog-to-digital converter dependent upon the command. A disclosed method for acquiring seismic survey data includes issuing an enable or disable command to each of multiple spaced apart sensor units, and receiving and storing data from those sensor units that are enabled.

Abstract: A method for geophysical source steering including towing a first geophysical source through a body of water; and adjusting a first steering parameter of the first geophysical source while towing the first geophysical source. An apparatus for geophysical source steering including a first marine vibrator source having a first housing structure; a first vibrational surface functionally coupled to the first housing structure such that at least a portion of the first vibrational surface can vibrate relative to the first housing structure; and first steering control equipment.

Abstract: Embodiments related to addition of a variable mass load to the shell of a marine vibrator to compensate for air spring effects. An embodiment provides a marine vibrator, comprising: an outer shell; a driver disposed at least partially within the outer shell and coupled thereto; and a mass load coupled to an exterior surface of the outer shell; wherein the marine vibrator has a resonance frequency selectable based at least in part on the mass load.

Abstract: Embodiments may be directed to marine vibrators and associated methods that use appropriately selected composite code sequences. A method of seismic surveying may comprise operating a plurality of marine vibrators. At least one of the marine vibrators may repeatedly cycle through a plurality of composite code sequences that are unique to the at least one of the marine vibrators, wherein two or more of the marine vibrators operate contemporaneously for at least one output interval. The method may further comprise detecting seismic energy with one or more seismic sensors after the seismic energy has interacted with subsurface formations, wherein the seismic energy was emitted from the marine vibrators, wherein the detecting occurs while operating the plurality of marine vibrators.