Hydrodynamic depressor for marine sensor streamer arrays

{
  "publication_number": "US2011103179A1",
  "country": "US",
  "kind": "A1",
  "title": "Hydrodynamic depressor for marine sensor streamer arrays",
  "abstract": "A hydrodynamic foil system for a sensor streamer array includes at least two tow ropes each coupled at one end to a survey vessel and at the other end to a paravane. the paravanes configured to provide lateral outward force as the vessel and paravanes are moved through a body of water. A spreader cable is coupled to each of the paravanes. A plurality of laterally spaced apart sensor streamers coupled at forward ends thereof to the spreader cable. A plurality of foils is disposed on the spreader cables. The foils configured to provide hydrodynamic lift in a vertical direction as the spreader cables are moved through the water.",
  "claims": [
    "1. A hydrodynamic foil system for a sensor streamer array, comprising: at least two tow ropes each coupled at one end to a survey vessel and at the other end to a paravane, the paravanes configured to provide lateral outward force as the vessel and paravanes are moved through a body of water; a spreader cable coupled to each of the paravanes; a plurality of laterally spaced apart sensor streamers coupled at forward ends thereof to one of the spreader cables; and a plurality of foils disposed on the spreader cables, the foils configured to provide hydrodynamic lift in a vertical direction as the spreader cables are moved through the water. 2. The system of claim 1 wherein the vertical direction is downward. 3. The system of claim 1 wherein the foils are each configured to freely rotate about the spreader cable. 4. The system of claim 1 wherein sensors on the sensor streamers comprise seismic sensors. 5. The system of claim 1 wherein the spreader cables are interconnected between the paravanes. 6. A method for operating a geophysical data acquisition system, comprising: towing at least two tow ropes from a seismic survey vessel in a body of water, a distal end of each tow rope having a paravane coupled thereto; maintaining a lateral separation between the paravanes using a spreader cable coupled to each paravane; coupling a forward end of a plurality of sensor streamers at laterally spaced apart positions to each of the spreader cables; and applying a selected vertical force to the spreader cables along their length to move the spreader cables to a selected depth in the body of water. 7. The method of claim 6 wherein the vertical force is applied by a plurality of foils coupled to the spreader cables 8. The method of claim 6 wherein the vertical force is in a downward direction. 9. The method of claim 6 further comprising detecting seismic signals using the streamers."
  ],
  "description_excerpt": "Not applicable.\n\nNot applicable.\n\n1. Field of the Invention\n\nThe invention relates generally to the field of marine geophysical surveying. More particularly, the invention relates to devices for controlling depth of the forward end of sensor streamers.\n\n2. Background Art\n\nMarine geophysical surveying includes seismic surveying systems. Seismic survey systems are used to acquire seismic data from Earth formations below the bottom of a body of water, such as a lake or the ocean. Marine seismic surveying systems typically include a seismic vessel having onboard navigation, seismic energy source control, and data recording equipment. The seismic vessel is typically configured to tow one or more streamers through the water. At selected times, the seismic energy source control equipment causes one or more seismic energy sources (which may be towed in the water by the seismic vessel or by another vessel) to actuate. Signals produced by various sensors on the one or more streamers are ultimately conducted to the recording equipment, where a record with respect to time is made of the signals produced by each sensor (or groups of such sensors). The recorded signals are later interpreted to infer the structure and composition of the Earth formations below the bottom of the body of water.\n\nThe one or more streamers are in the most general sense long cables that have seismic sensors disposed at spaced apart positions along the length of the cables. A typical streamer can extend behind the seismic vessel for several kilometers.",
  "cpc": [
    "G01V 1/3826",
    "G01V 1/3808"
  ],
  "ipc": [
    "G01V 1/38"
  ],
  "assignees": [
    "PGS Geophysical AS"
  ],
  "inventors": [
    "Erling Vageskar",
    "Kenneth Karlsen"
  ],
  "filing_date": "2009-11-03",
  "publication_date": "2011-05-05",
  "priority_date": "2009-11-03",
  "application_number": "US-59012309-A",
  "family_id": "43597713",
  "cited_by_count": 32,
  "citations": [
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  ]
}