Deployment and Retrieval Method and Apparatus for Seismic Nodal Recording Systems

Abstract

A system and method for deploying seismic data acquisition equipment from a moving vessel. The system and method utilize movable pulley systems to manipulate a string of data acquisition equipment such that a technician may attach the seismic data acquisition equipment to a rope or cable during a period in which the rope or cable is stationary relative to the vessel. The system and method allow for equipment deployment at a relatively constant rate while the vessel maintains a relatively constant velocity. The system and method for deploying seismic data acquisition equipment allows for enhanced personnel safety and efficient equipment deployment.

Claims

1. A method for deploying seismic data collection equipment from a vessel into a body of water comprising: a. Providing a cable having a first end and a second end; b. Providing a cable dispensing and retrieving device at a location between the first and second ends of said cable; c. Providing a cable diverter mechanism at a location between said cable dispensing and retrieving device and the first end of said cable; d. Dispensing cable from said cable dispensing and retrieving device and deploying said cable into the body of water; e. Moving said cable diverter device for a time period T1 in a first direction that diverts a portion of said cable; f. Moving said cable diverter device for a second time period T2 in a second direction; g. Attaching one or more of said seismic data collection devices to the cable during said time period T2; and h. Repeating steps e. through g. until a desired number of seismic collection devices have been deployed.

2. The method of claim 1 wherein the cable diverter mechanism is a take-up pulley.

3. The method of claim 1 wherein the cable diverter mechanism is a spool.

4. The method of claim 1 wherein the cable dispensing and retrieving device is a reel.

5. The method of claim 1 wherein the cable dispensing and retrieving device is a squirter.

6. A method for deploying seismic data collection equipment from a vessel into a body of water comprising: a. Providing a cable having a first end and a second end; b. Providing a cable dispensing and retrieving device at a location between the first and second ends of said cable; c. Providing a first cable diverter mechanism at a location between said cable dispensing and retrieving device and the first end of said cable; d. Providing a second cable diverter mechanism at a location between said first cable diverter mechanism and the first end of said cable; e. Dispensing cable from said cable dispensing and retrieving device and deploying said cable into the body of water; f. Moving said first cable diverter device for a time period T1 in a first direction and simultaneously moving said second cable diverter mechanism for the time period T1 in a second direction; g. Moving said first cable diverter device for a time period T2 in the second direction, and simultaneously moving said second cable diverter mechanism in the first direction for the time period T2; h. Attaching one or more of said seismic data collection devices to said cable during the time period T2; i. Repeating steps f. through h. until a desired number of seismic collection devices have been deployed.

7. The method of claim 6 wherein at least one of said cable diverter mechanisms is a take-up pulley.

8. The method of claim 6 wherein at least one of said cable diverter mechanisms is a spool.

9. The method of claim 6 wherein the cable dispensing and retrieving device is a reel.

10. The method of claim 6 wherein the cable dispensing and retrieving device is a squirter.

11. A method of retrieving seismic data collection equipment from a body of water comprising: a. Providing a cable having a first end and a second end; b. Providing a cable dispensing and retrieving device at a location between the first and second ends of said cable; c. Providing a cable diverter mechanism at a location between said cable dispensing and retrieving device and the first end of said cable; d. Retrieving cable from the body of water with the cable dispensing and retrieving device; e. Moving said cable diverter device for a time period T1 in a first direction that diverts a portion of said cable; f. Moving said cable diverter device for a second time period T2 in a second direction; g. Removing one or more seismic data collection devices from the cable during said time period T2; and h. Repeating steps e. through g. until a desired number of seismic collection devices have been retrieved.

12. The method of claim 11 wherein the cable diverter mechanism is a take-up pulley.

13. The method of claim 11 wherein the cable diverter mechanism is a spool.

14. The method of claim 11 wherein the cable dispensing and retrieving device is a reel.

15. The method of claim 11 wherein the cable dispensing and retrieving device is a squirter.

16. A method of retrieving seismic data collection equipment from a body of water comprising: a. Providing a cable having a first end and a second end; b. Providing a cable dispensing and retrieving device at a location between the first and second ends of said cable; c. Providing a first cable diverter mechanism at a location between said cable dispensing and retrieving device and the first end of said cable; d. Providing a second cable diverter mechanism at a location between said first cable diverter mechanism and the first end of said cable; e. Retrieving the cable from the body of water with the cable dispensing and retrieving device; f. Moving said first cable diverter device for a time period T1 in a first direction and simultaneously moving said second cable diverter mechanism for the time period T1 in a second direction; g. Moving said first cable diverter device for a time period T2 in the second direction, and simultaneously moving said second cable diverter mechanism for a time period T2 in the first direction; h. Removing one or more seismic data collection devices from said cable during the time period T2; i. Repeating steps f. through h. until a desired number of seismic collection devices have been retrieved.

17. The method of claim 16 wherein at least one of said cable diverter mechanisms is a take-up pulley.

18. The method of claim 16 wherein at least one of said cable diverter mechanisms is a spool.

19. The method of claim 16 wherein the cable dispensing and retrieving device is a reel.

20. The method of claim 16 wherein the cable dispensing and retrieving device is a squirter.

21. A system for deploying and retrieving seismic data collection equipment to and from a vessel comprising: a. a cable having a first end and a second end; b. a cable dispensing and retrieving device at a location between the first end of said cable and the second end of said cable; c. a cable diverter mechanism at a location between said cable dispensing device and the first end of said cable.

22. The system of claim 21, wherein the cable diverter mechanism is a first cable diverter mechanism and further comprising: a. a second cable diverter mechanism located between said first cable diverter mechanism and the first end of said cable.

23. The system of claim 22 wherein at least one of said cable diverter mechanisms is a take-up pulley.

24. The system of claim 22 wherein at least one of said cable diverter mechanisms is a spool.

25. The system of claim 22 wherein the cable dispensing and retrieving device is a reel.

26. The system of claim 22 wherein the cable dispensing and retrieving device is a squirter.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] FIG. 1 is an example of a conveyor system with take-up pulley and a continuous belt;

[0016] FIG. 2 is an adaptation of the take-up pulley system of FIG. 1 for a reel dispensing a cable and the cable being deployed off the stern of a vessel;

[0017] FIG. 3 is an adaptation of FIG. 2 with the take-up pulley moving in a manner such as to slow the deployment of the cable off the stern of the vessel;

[0018] FIG. 4a is an example of an embodiment of the invention at the beginning of the deployment cycle;

[0019] FIG. 4b is an embodiment of FIG. 4a where the take-up pulley is moving in a manner with which the speed at which the cable is dispensed and the speed of the cable at the workstation are increased while the speed of deployment of the cable off the stern of the vessel remains constant;

[0020] FIG. 4c is an embodiment of FIG. 4a where the take-up pulley is moving in a manner with which the speed at which the cable is dispensed and the speed of the cable at the workstation become essentially zero while the speed of deployment of the cable off the stern of the vessel remains constant;

[0021] FIG. 5a is a second preferred embodiment of the invention at the beginning of the deployment cycle;

[0022] FIG. 5b is an embodiment of FIG. 5a where the first and second take-up pulleys are moving in a manner with which the speed at which the cable is dispensed and the speed at which the cable is deployed remain constant while the speed of the cable at the workstation increases;

[0023] FIG. 5c is an embodiment of FIG. 5a where the first and second take-up pulleys are moving in a manner with which the speed at which the cable is dispensed and the speed at which the cable is deployed remain constant while the speed of the cable at the workstation becomes essentially zero.

DETAILED DESCRIPTION OF THE INVENTION

[0024] One preferred embodiment of the current invention is shown in FIGS. 4a-4c. In these figures, there is a cable (4001) on a cable storage device (4002). In this embodiment the cable storage device (4002) is a reel. This embodiment also includes a work station (4003) where a technician (4004) can attach nodes to the cable (4001). This embodiment further includes 2 bend pulleys (4005 and 4006), a take-up pulley (4007) and a deployment ramp (4008) for node deployment. This embodiment operates through a repeated cycle of steps, each step accomplishing a specific purpose for the deployment of the nodal system. At the beginning of the cycle, shown in FIG. 4a, the take-up pulley (4007) is in a starting position (4101), the cable deployment reel (4002) is dispensing cable at a rate equal to the speed of the vessel (4102). The cable is traveling past the workstation (4003) at rate equal to the speed of the vessel (4103) and the cable is being deployed off the end of the ramp (4008) at a rate equal to the speed of the vessel (4104). As an example, the take-up pulley (4007) moves to the position shown in FIG. 4b (4201) at a rate of one half of the speed of the vessel (4202), the rate at which the reel dispenses cable is increased to a rate twice the speed of the vessel (4203), the cable is traveling past the workstation at a rate twice the speed of the vessel (4204) and the cable is being deployed off the end of the ramp at a rate equal to the speed of the vessel (4205). After a time T1, the take-up pulley moves back to the position shown in FIG. 4c (4301) at a rate of one half the speed of the vessel (4302), the reel stops dispensing cable (4303), the cable is stationary in front of the workstation (4304) and the cable is being deployed off the end of the ramp at a rate equal to the speed of the vessel (4305). The time period Ts, in which the cable is stationary in front of the workstation is equal to the length of time required to move the take-up pulley (4007) from the diverted position shown in FIG. 4b (4201) to the un-diverted position shown in FIG. 4c (4301). The time period Ts can be adjusted by changing the speed of the vessel V1, the distance the take-up pulley diverts the cable D1, or both and is described by the equation Ts=(2*D1)/V1. Scalars other than one half of the vessel speed for the rate at which the take-up pulley diverts the cable can be used and will provide different speeds at which the cable moves past the workstation. These scalars may be suitable for certain implementations of the invention. In FIG. 4a, the take-up pulley (4007) is returned to the initial starting position and conditions. This embodiment accomplishes the goal of providing a period of time where the cable is stationary with respect to the technician (4004) while he or she attaches the node and also maintaining a constant vessel speed and rate of node deployment.

[0025] A second embodiment of the current invention is shown in FIGS. 5a-5c. In these figures, there is a cable (5001) on a cable storage device (5002), a work station (5003), a technician (5004), 2 bend pulleys (5005 and 5006), a take-up pulley (5007), two additional bend pulleys (5008 and 5009), an additional take-up pulley (5010) and a deployment ramp (5011). This embodiment operates through a repeated cycle of steps, each step accomplishing a specific purpose for the deployment of the nodal system. At the beginning of the cycle, shown in FIG. 5a, take-up pulley (5007) is in a starting position (5101), take-up pulley (5010) is in a starting position (5102), the cable deployment reel (5002) is dispensing cable at a rate equal to the speed of the vessel (5103), the cable is traveling past the workstation (5104) at a rate equal to the speed of the vessel (5104) and the cable is being deployed off the end of the ramp (5105) at a rate equal to the speed of the vessel (5105). After a time, take-up pulley (5007) moves to the position shown in FIG. 5b (5201) at a rate of one half of the speed of the vessel (5202), take-up pulley (5010) moves to the position shown in FIG. 5b (5203) at a rate of one half of the speed of the vessel (5204), the rate at which the reel dispenses cable remains equal to the speed of the vessel (5205), the cable is traveling past the workstation at a rate of twice the speed of the vessel (5206) and the cable is being deployed off the end of the ramp at a rate equal to the speed of the vessel (5207).

[0026] After a time T1, take-up pulley (5007) moves back to the position shown in FIG. 5c (5301) at a rate of one half the speed of the vessel (5302). Take-up pulley (5010) moves back to the position shown in FIG. 5c (5303) at a rate of one half the speed of the vessel (5304), the rate at which the reel dispenses cable remains equal to the speed of the vessel (5305), the cable is stationary in front of the workstation (5306) and the cable is being deployed off the end of the ramp at a rate equal to the speed of the vessel (5307). The time period Ts, in which the cable is stationary in front of the workstation (5306) is equal to the length of time required to move the take-up pulley (5010) from the diverted position shown in FIG. 5b (5203) to the un-diverted position shown in FIG. 5c (5303). The time period Ts can be adjusted by changing the speed of the vessel V1, the distance the take-up pulley diverts the cable D1, or both and is described by the equation Ts=(2*D1)/V1. Scalars other than one half of the vessel speed for the rate at which the take-up pulley diverts the cable can be used and will provide different speeds at which the cable moves past the workstation. These scalars may be suitable for certain embodiments of the invention. In the embodiment of FIG. 5c, the take-up pulleys have returned to the initial starting position and conditions. In this embodiment of the current invention, the goal of providing a period of time where the cable is stationary for the technician to attach a node to the cable while maintaining a constant vessel speed and rate of deployment are all accomplished. In addition, this embodiment allows the cable reel to dispense cable at a constant rate.

[0027] The operation of the present invention may also be performed in the opposite direction. The reels disclosed in the embodiments disclosed herein can be used for either dispensing or retrieving cable. By reversing the direction of the relative motion of the cables and pulleys, the present invention can be used to retrieve a deployed cable with attached nodes while maintaining constant vessel speed, constant speed of cable recovery, constant take-up of cable on the reel, and a period of time during which the cable is stationary relative to a workstation, thereby allowing nodes to be safely removed from the cable by a technician.

[0028] It should be recognized that the descriptions and terminology used in the preceding discussion and in the following claims are intended to convey the concept of the current invention and not to limit the scope of what is claimed. While several embodiments of the present invention have been disclosed herein, it is to be understood that these embodiments are given by example only and not in a limiting sense. Those skilled in the art may make various modifications and additions to the preferred embodiments without departing from the spirit and scope of the present invention. For example, in the descriptions, the term cable can be understood to mean a steel cable, a rope, a chain or any other device that can be implemented in the same manner within the context of this disclosure. Accordingly, it is to be realized that the patent protection sought and to be afforded hereby shall be deemed to extend to the subject matter claimed and all equivalence thereof fairly within the scope of the invention.