Method and device intended for seismic exploration of an underwater subsurface zone using seismic receivers coupled with the water bottom

• US 6,625,083 B2
• Filed: 12/14/2001
• Issued: 09/23/2003
• Est. Priority Date: 12/15/2000
• Status: Expired due to Fees

• Current Assignee: Institut Francais Du Petrole
• Original Assignee: Institut Francais Du Petrole
• Inventors: Vandenbroucke, Eric
• Primary Examiner(s): Moskowitz, Nelson
• Application Number:
  US10/014,403
• Publication Number:
  US 20020110048A1
• Time in Patent Office: 648 Days
• Field of Search: 367/6, 367/15, 367/16, 181/110, 181/112
• US Class Current: 367/15
• CPC Class Codes: G01V 1/16 Receiving elements for seismic signals; Arrangements or adaptations of receiving elements
• CPC Class Codes: G01V 1/3852 to the seabed
• CPC Class Codes: Y02A 90/30 Assessment of water resources

Abstract

A method and device for seismic exploration of an underwater subsurface zone using seismic receivers coupled with the bottom of the water mass. Acquisition units (1) comprising a spire (2) where seismic receivers (4) are arranged, a measuring compartment (5) for acquisition and storage of the data received by the receivers, as well as removable and selective floating devices (7) are used. The acquisition units (1) are launched and, under the effect of gravity, they attach to the bottom and couple the receivers with the underlying formations. The respective positions thereof are first detected, seismic acquisition operations are carried out using an underwater source so as to collect seismic data on the formation, then the floating devices (7) are actuated so as to bring all or part of acquisition units (1) back up to the surface or a data collection device (vehicle or passive collection unit) is lowered to the neighbourhood of the various units.

Claims

1. A system for seismic exploration of an underwater subsurface formation comprising:

a displaceable collecting assembly which moves under water and is deployed under water to collect seismic data and includes a recording unit;

at least one seismic signal acquisition unit for operation on a bottom of a water body comprising at least seismic receiver including a data acquisition module for collecting seismic signals sensed by the at least one seismic receiver which couples the at least one seismic receiver to the formation;

an acoustic ranging assembly which communicates with the at least one seismic signal acquisition unit and provides a reference for obtaining a position of the at least one seismic signal acquisition unit when operating on the bottom of the water body; and

a data transmission link which transmits seismic data collected by the at least one acquisition unit to the recording unit while the displaceable collecting unit is under water to collect seismic data.

3. A system as claimed in claim 1, wherein:

the acoustic ranging assembly includes an acoustic baseline with surface buoys provided with acoustic transponders and satellite positioning units to provide positions of the buoys.

5. A system as claimed in claim 1, wherein:

the acoustic ranging assembly includes an acoustic transponder associated with the at least one surface buoy provided with a satellite positioning unit to provide a position of the buoy for forming an acoustic baseline.

7. A system as claimed in claim 1, wherein:

the data transmission link includes a first transmission set in the at least one acquisition unit for transmission of the collected seismic data and the displaceable collecting assembly includes a vehicle provided with a second transmission set for communicating with the first transmission set.

9. A system as claimed in claim 1, wherein:

the data link comprises a first transmission set in the at least one acquisition unit for transmission of the collected seismic data and the displaceable collecting assembly includes a body including a data collection device and a second transmission set for communicating with the first transmission set and which is placed underwater at a distance from each acquisition unit during transmission of the seismic data to the displaceable collecting assembly.

10. A system as claimed in claim 1, wherein:

the data link comprises a first transmission set in the at least one acquisition unit for transmission of the collected seismic data and the displaceable collecting assembly includes a body including a data collection device and a second transmission set for communicating with the first transmission set during which is placed underwater a distance from each acquisition unit during transmission of the seismic data to the displaceable collecting assembly.

11. A system as claimed in claim 7, wherein:

the first transmission set and the second transmission set includes one of acoustic or optical transmission modules.

12. A system as claimed in claim 9, wherein:

the first transmission set and the second transmission set includes one of acoustic or optical transmission modules.

2. A system for seismic exploration of an underwater subsurface formation comprising:

a displaceable collecting assembly which moves under water and is deployed under water to collect data and includes a recording unit;

at least one seismic signal acquisition unit including a spire associated with housing containing at least one seismic receiver which collects seismic signals sensed by the at least one seismic receiver, the spire leading the acquisition unit downwards solely under an effect of gravity to the bottom of the water body and driving the spire therein to couple the at least one acquisition unit with the subsurface formation;

an acoustic transponder associated with the at least one acquisition unit;

an acoustic ranging assembly which communicates with the at least one seismic signal acquisition unit and provides a reference for obtaining a position of each acquisition unit on the bottom of the water body; and

a data link which transmits seismic data between the at least one acquisition unit and the recording unit which records the data when the displaceable collecting assembly is deployed under water to collect data.

4. A system as claimed in claim 2, wherein:

the acoustic ranging assembly includes an acoustic baseline with surface buoys provided with acoustic transponders and satellite positioning units to provide positions of the buoys.

6. A system as claimed in claim 2, wherein:

the acoustic ranging assembly includes an acoustic transponder associated with the at least one surface buoy provided with a satellite positioning unit to provide a position of the vehicle for forming an acoustic baseline.

8. A system as claimed in claim 2, wherein:

the data transmission link includes a first transmission set in the at least one acquisition unit for transmission of the collected seismic data and the displaceable collecting assembly includes a vehicle provided with a second transmission set for communicating with the first transmission set.

13. A method of seismic exploration of an underwater subsurface formation, comprising:

installing at a bottom of a water body at least one seismic signal acquisition unit including at least one seismic receiver including a data acquisition module for collecting seismic signals sensed by the at least one seismic receiver and an acoustic transponder coupling the at least one seismic receiver to the formation;

determining a position of each acquisition unit installed at the bottom of the water body with respect to an acoustic ranging assembly which communicates with the at least one seismic signal acquisition unit and provides a reference for obtaining a position of the at least one seismic acquisition unit which is obtained with a satellite positioning system;

carrying out seismic operations with transmission of seismic waves by an underwater seismic source to the subsurface formation and receiving waves with the at least one receiver reflected by discontinuities of the subsurface formation in response to the transmission of seismic waves to the subsurface formation and collecting seismic data with the data acquisition module of the at least one acquisition unit; and

recovering at the surface of the water body the seismic data collected by the at least one acquisition unit using a recording unit associated with a displaceable collecting assembly which moves under the water and is deployed under the water to collect seismic data while an acoustic or optical transmission link transmits seismic data collected by the at least one acquisition unit to the recording unit which records the seismic data.

14. A method as claimed in claim 13, comprising:

driving with a spire, associated with each of the at least one acquisition unit, each of the at least one acquisition unit under a sole effect of gravity into the bottom of the water body to couple the at least one seismic receiver with the subsurface formation.