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

• US 20020110048A1
• Filed: 12/14/2001
• Published: 08/15/2002
• Est. Priority Date: 12/15/2000
• Status: Active Grant

• Current Assignee: Institut Francais Du Petrole
• Original Assignee: Institut Francais Du Petrole
• Inventors: Vandenbroucke, Eric
• Granted Patent: US 6,625,083 B2
• Time in Patent Office: Days
• US Class Current: 367/24
• 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 neighborhood of the various units.

Claims

1. ) A device intended for seismic exploration of an underwater subsurface formation immersed in a water body, comprising at least one seismic signal acquisition unit including a part provided with a housing for at least one seismic receiver and a data collection module which collects data corresponding to seismic signals received by the at least one receiver, wherein each acquisition unit comprises a body which drives the acquisition unit downwards under an effect of gravity to the bottom of the water body to adhere to the bottom to couple the at least one seismic receiver with the subsurface formation, the device also comprising an acoustic ranging set used as a reference for positioning each acquisition unit at the bottom and an acoustic or optical transmitter which transmits data between each acquisition unit and data receiver associated with a displaceable collecting assembly.

2. ) A device as claimed in claim 1, wherein the set comprises an acoustic transponder associated with each acquisition unit, the acoustic ranging set comprising a baseline acoustic positioning device associated with a vehicle provided with satellite positioning system.

3. ) A device as claimed in claim 2, wherein the set comprises an acoustic transponder associated with each acquisition unit, the acoustic ranging set comprising acoustic transponders associated with at least one surface buoys provided with satellite positioning device, which forms an acoustic baseline.

4. ) A device as claimed in claim 1, wherein the transmitter comprises a first transmission set in each acquisition unit which transmits the acquired seismic data, the displaceable collecting assembly including a vehicle provided with a second transmission set suited to communicate with the first transmission set.

5. ) A device as claimed in claim 1, wherein the transmitter comprises a first transmission set in each acquisition unit which transmits the acquired seismic data, the displaceable collecting assembly including a body including a data collection device and a second transmission set suited to communicate with the first transmission set, the body being brought underwater to a certain distance from each acquisition unit to permit transmission of data thereto.

6. ) A device as claimed in claim 1, comprises a removable float associated with each acquisition unit which, on command from a surface installation, brings to the surface at least a part of each acquisition unit.

7. ) A seismic exploration method, comprising:

installing the device as defined in claim 1; and

carrying out seismic exploration operations with emission of waves by an underwater seismic source, receiving, by the at least one seismic receiver of each acquisition unit, waves reflected by discontinuities of the underwater subsurface formation in response to the waves, collection of the data received by the at least one receiver of each acquisition unit and transmission of the acquired data to a surface installation.

9. ) Application of the method as claimed in claim 7 to marine seismic prospecting.

10. ) Application of the method as claimed in claim 7 to repetitive marine seismic prospecting in a subsurface formation under development.

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

installing at the bottom of the water body at least one seismic signal acquisition unit comprising a body provided with a housing for at least one seismic receiver and a control and data collecting assembly which collects seismic signals received by each seismic receiver, the body of each acquisition unit driving each acquisition unit downwards under the effect of gravity to the bottom of the water body to adhere the acquisition unit to the bottom to couple the at least one seismic receiver with the subsurface formation;

determining a position of each acquisition unit installed at the bottom with respect to a an acoustic ranging set used as a reference provided with satellite positioning system;

carrying out seismic operations with emission of waves by an underwater seismic source, receiving waves reflected by discontinuities of the subsurface formation collecting data received by the receivers of each acquisition unit; and

recovering at the water surface seismic data acquired by each acquisition unit (1) using acoustic or optical transmitter which transmits control signals and data between each acquisition unit and receiver associated with a displaceable collecting assembly.