Patent Application
20140153360
1. Technical Field
Embodiments of the subject matter disclosed herein generally relate to methods and systems and, more particularly, to mechanisms and techniques for improving and making more efficient a maintenance task associated with a head-buoy.
2. Discussion of the Background
Seismic data acquisition and processing generate a profile (image) of geophysical structures under seafloor or subsoil. While this profile does not provide an accurate location for oil and gas reservoirs, it suggests, to those trained in the field, the presence or absence of them. Thus, providing a high-resolution image of the structures under the seafloor/subsoil is an ongoing process.
To construct images of the subsoil (or subsurface), geologists or geophysicists conventionally use, for example, wave emitters (sources) placed on the surface. For the case of marine seismic surveys, the wave emitters are towed by a vessel at or under the surface of the water. Such emitters emit waves (e.g., acoustic waves) which propagate through the water (and subsoil for the land seismic) and which are reflected on the surfaces of the various layers thereof (reflectors). Waves reflected to the surface are recorded as a function of time by receivers (which are towed by the same vessel or another vessel for the marine seismic or lay on the ocean bottom). The signals received and recorded by the receivers are known as seismic traces. Based on the seismic traces, an image of the surveyed subsurface is generated.
When performing a marine seismic survey, the receivers are placed along a cable to form a streamer, and plural streamers are towed by a vessel. Such a marine seismic survey having a towing vessel 10 is shown in
An example of a front-end gear 30 is provided between the vessel 10 and the various streamers 12, and this gear is configured to achieve the desired positioning for the streamer heads.
For maintaining the streamers 12 substantially parallel relative to a reference plane (e.g., the water surface), as shown in
The head-buoy 40 is equipped with various equipment, e.g., acoustic equipment for detecting positions of neighboring streamers and global positioning system (GPS) equipment for determining an absolute position of the streamer. In order to power the equipment, electric power generated on the towing vessel may be transferred through an electric cable 52 to the head-float 40. The electric cable 52 and the cable 40A connect to the streamer 12 through a connection device 54.
From time to time, maintenance is required on the head-float because its equipment requires constant checks. Such maintenance may be performed while the head-buoy is deployed in the water, i.e., during a seismic survey. Such environment makes the working conditions difficult for the maintenance personnel due to, e.g., large waves, moving equipment, humid environment, etc. Also, the maintenance may be time-consuming because the environmental conditions are not appropriate.
Having the streamer spread deployed underwater and the seismic survey stopped for head-buoy maintenance is highly undesirable because the cost of the streamer spread is high. Thus, it would be desirable to provide systems and methods that avoid the afore-described problems and drawbacks, i.e., simplify and/or expedite the maintenance of the head-float.
According to one exemplary embodiment, there is a streamer head-float system connected to a head portion of a streamer or to a lead-in. The system includes: (A) a head-buoy configured to float in water and connected through a cable to the head portion of the streamer or to the lead-in, (B) a head-float configured to float in water, (C) a connector connecting the head-float to the head-buoy, and, (D) positioning equipment on the head-float and configured to determine a position of the streamer.
According to another exemplary embodiment, there is a head-float associated with a head portion of a streamer or a lead-in towed underwater. The head-float includes (A) a body configured to float in water, (B) a connector connecting the head-float to a head-buoy, and (C) positioning equipment attached to the head-float and configured to determine a position of the streamer or a position of a source. The head-float does not provide floatation to the streamer.
According to another exemplary embodiment, there is a method for performing a seismic survey. The method includes (A) towing a streamer, (B) connecting a head-buoy to a head portion of the streamer or to a lead-in, and (C) towing with the head-buoy a head-float configured to float in water. The method further includes determining a position of the streamer with positioning equipment attached to the head-float.
The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate one or more embodiments and, together with the description, explain these embodiments. In the drawings:
The following description of the exemplary embodiments refers to the accompanying drawings. The same reference numbers in different drawings identify the same or similar elements. The following detailed description does not limit the invention. Instead, the scope of the invention is defined by the appended claims. The following embodiments are discussed, for simplicity, with regard to the terminology and structure of a head-float that is connected to a head-buoy.
Reference throughout the specification to “one embodiment” or “an embodiment” means that a particular feature, structure or characteristic described in connection with an embodiment is included in at least one embodiment of the subject matter disclosed. Thus, the appearance of the phrases “in one embodiment” or “in an embodiment” in various places throughout the specification is not necessarily referring to the same embodiment. Further, the particular features, structures or characteristics may be combined in any suitable manner in one or more embodiments.
According to an exemplary embodiment, a head portion of a streamer is attached by a cable to a head-buoy for providing floatability. A head-float is detachably attached to the head-buoy. The head-float is not intended to provide floatability to the streamer. In one application, there is no direct connection between the head-float and the streamer. Various equipment (e.g., acoustic, GPS, etc.) that is traditionally on the head-buoy is now moved in the head-float. The head-buoy still provides floatability for the streamer. When maintenance of the equipment is necessary, because the equipment is now on the head-float and not on the head-buoy, the head-float may be disconnected from the head-buoy and replaced with a working head-float.
Thus, the maintenance operations are essentially moved from the sea to the vessel because the head-float may be towed to the vessel and there the maintenance may be performed while the seismic survey is not interrupted. Thus, the down-time of the seismic survey is reduced by using the novel embodiment. The reduced down-time may include the time for sending a boat with maintenance personnel to the head-float, disconnecting the head-float from the head-buoy, attaching a new head-float to the head-buoy, and retrieving the head-float on the vessel. However, the reduced down-time does not include the time necessary for replacing or fixing the equipment in the head-float.
The novel features are now discussed in more detail with regard to a few exemplary embodiments. According to an exemplary embodiment illustrated in
As illustrated in
In one exemplary embodiment illustrated in
Further, in another application, a control device 142 may be provided inside the head-buoy. The control device 142 may be configured to receive data from the streamer 104, through the cable 112, or wireless from the towing vessel 102, for controlling a depth position of the streamer. Thus, in this last exemplary embodiment, the head-buoy 110 is capable of adjusting a depth position of the streamer or lead-in independent of the presence or not of the head-float.
The head-float 120 has a body 121 that is configured to house one or more positioning devices for determining the position of the streamer relative to other streamers and/or its absolute position. Such positioning devices may include a GPS (or other similar device that uses the air as medium) system 150, which provides an absolute position relative to earth, and/or an acoustic system (or other systems for determining relative positions of other streamers and which uses the water as medium, a passive acoustic monitoring system) 152, which provides a relative position of the buoy to the streamers or a position of one streamer to another streamer. In one application, the GPS system 150 is provided on top of the head-float while the acoustic system 152 is provided on the bottom of the head-float. Although
For example, a battery 154 may be provided inside the head-float for powering the GPS and acoustic systems. Optionally, if the head-buoy 110 does not have an electric power source or cannot receive electrical power directly from the streamer, the battery 154 may provide electrical power to the actuator 112A through the connection 122. A controller 156 (e.g., a processor and/or a memory) may be provided for controlling/coordinating the GPS, acoustic systems, battery and other equipment on the head-float, e.g., for deciding when to recharge the battery. The battery 154 may be charged with a solar panel 158 provided on a top portion of the float, or a fuel cell 160, or with a generator (or hydro-generator) 162 that has a propeller 163 that is rotated when the head-float is towed by the vessel, or by a device that harvests the energy of the ocean waves, or by a combination of these devices. Therefore, for this exemplary embodiment, no power cable is necessary from the streamer to the head-buoy 110 and through the connection 122 to the head-float 120. Thus, for this configuration, the cable 112 does not include a cable to transmit power and/or data. Still for this embodiment, a data transmitting device 161 may be provided for exchanging data with the vessel. The data transmitting device 161 may be an acoustic modem or radio device that communicates with a corresponding device and a server or computing device of the vessel. The data transmitting device 161 may be used to communicate, in real time, with the vessel to share the positions of the streamers (absolute and relative positions acquired with GPS 150 and acoustic system 152). In this way, the streamers may be positioned as desired. In this regard, it is noted that a central control device on the vessel may instruct birds attached to the streamers to position the streamers based on the data collected by the GPS 150 and/or the acoustic system 152. In another application, a power/data cable may be connected between the streamer and the head-float.
The head-float 120 may also include one or more fins 164 for controlling the direction of the head-float. The fin may be connected to an actuator 166, for example, an electric motor, for adjusting an orientation of the fin. The fin may be disposed vertically or horizontally or to make a desired angle with the body of the head-float. Other equipment may be added to the head-float as would be recognized by those skilled in the art.
Returning to the connector 122, it is noted that there are various possibilities for connecting the head-buoy 110 to the head-float 120. For example, as illustrated in
In another exemplary embodiment illustrated in
The body 121 of the head-float may be made of a material that is resistant to humid and corrosive environments, for example, plastic, composite, aluminum, stainless steel, etc. The body may be made to have a cavity inside which all or part of the equipment may be provided. An access door may be provided to the cavity to access the equipment for maintenance and to protect it from water droplets.
Regarding the positioning of the streamer 104 according to the requirements of the seismic survey, it is shown in
It is noted that in one exemplary embodiment, only one head-float may be used to determine the absolute location of the streamers relative to the earth. However, with only one head-float, the entire streamer arrangement may turn around the head-float, thus, making the location of the streamer arrangement inaccurate. To prevent this situation, at least two head-floats equipped with the GPS system, local positioning system and the data communication system may be used as shown in
The head-float and the head-buoy may be used to perform a seismic survey as discussed next. According to an exemplary embodiment illustrated in
According to another exemplary embodiment illustrated in
The above embodiments have been discussed with regard to providing at least a head-float next to a head-buoy that is connected to a streamer. However, the novel embodiments are equally applicable to a head-buoy connected to a seismic source, as illustrated in
The system 200 in
The hydro-generator 162 and its novel features are now discussed with regard to
In another embodiment illustrated in
Further, the portion 404 may prevent debris and/or marine animals to get trapped between the body 401 of the head-float and the hydro-generator 162. In one application, the portion 404 is a simple rod. However, in another application, the portion 404 is a mesh. The protection grid 402 may have different shapes. One example shown in
In still another embodiment illustrated in
The movable grid 506 is configured to rotate relative to the stationary grid 504. Thus, the movable and stationary grids may have a cylindrical shape. One or more paddles 512 may be located on the movable grid 506 to generate the rotation motion under the water action. The movable grid 506 may be kept in place, next to the stationary grid 504 by various mechanisms, for example, each grid has a track that engages the other grid's track. More movable grids may be provided on the stationary grid to cover most of the stationary grid. However, the movable grids should be able to rotate without touching the hydro-generator.
In still another embodiment, the controller 156 may be configured to monitor the power generated by the hydro-generator and when this power falls below a predetermined threshold (which indicates that debris or other things are reducing the flow of water to the propeller), to instruct the attachment mechanism 304 or the motor 406 to rotate the protection grid for cleaning purposes.
In yet another exemplary embodiment illustrated in
The methods discussed above may be implemented in dedicated devices (e.g., dedicated networks or computers or cloud-computing networks, etc.) for being performed. A combination of software and hardware may be used to achieve the event-related transversal isotropic axis and/or an associated tilt model. A dedicated machine that can implement one or more of the above-discussed exemplary embodiments is now discussed with reference to
An exemplary computing arrangement 1600 suitable for performing the activities described in the exemplary embodiments may include server 1601. Such a server 1601 may include a central processor (CPU) 1602 coupled to a random access memory (RAM) 1604 and to a read-only memory (ROM) 1606. The ROM 1606 may also be other types of storage media to store programs, such as programmable ROM (PROM), erasable PROM (EPROM), etc. The processor 1602 may communicate with other internal and external components through input/output (I/O) circuitry 1608 and bussing 1610, to provide control signals and the like. The processor 1602 carries out a variety of functions as are known in the art, as dictated by software and/or firmware instructions.
The server 1601 may also include one or more data storage devices, including hard and floppy disk drives 1612, CD-ROM drives 1614, and other hardware capable of reading and/or storing information such as DVD, etc. In one embodiment, software for carrying out the above-discussed steps may be stored and distributed on a CD-ROM 1616, removable media 1618 or other form of media capable of portably storing information. These storage media may be inserted into, and read by, devices such as the CD-ROM drive 1614, the disk drive 1612, etc. The server 1601 may be coupled to a display 1620, which may be any type of known display or presentation screen, such as LCD, plasma displays, cathode ray tubes (CRT), etc. A user input interface 1622 is provided, including one or more user interface mechanisms such as a mouse, keyboard, microphone, touchpad, touch screen, voice-recognition system, etc.
The server 1601 may be coupled to other computing devices, such as the landline and/or wireless terminals and associated applications, via a network. The server may be part of a larger network configuration as in a global area network (GAN) such as the Internet 1628, which allows ultimate connection to the various landline and/or mobile client/watcher devices.
As also will be appreciated by one skilled in the art, the exemplary embodiments may be embodied in a wireless communication device, a computer network, as a method or in a computer program product. Accordingly, the exemplary embodiments may take the form of an entirely hardware embodiment or an embodiment combining hardware and software aspects. Further, the exemplary embodiments may take the form of a computer program product stored on a computer-readable storage medium having computer-readable instructions embodied in the medium. Any suitable computer-readable medium may be utilized including hard disks, CD-ROMs, digital versatile disc (DVD), optical storage devices, or magnetic storage devices such a floppy disk or magnetic tape. Other non-limiting examples of computer readable-media include flash-type memories or other known memories.
The disclosed exemplary embodiments provide a system and a method for reducing the down-time associated with equipment maintenance of a head-float. It should be understood that this description is not intended to limit the invention. On the contrary, the exemplary embodiments are intended to cover alternatives, modifications and equivalents, which are included in the spirit and scope of the invention as defined by the appended claims. Further, in the detailed description of the exemplary embodiments, numerous specific details are set forth in order to provide a comprehensive understanding of the claimed invention. However, one skilled in the art would understand that various embodiments may be practiced without such specific details.
Although the features and elements of the present exemplary embodiments are described in the embodiments in particular combinations, each feature or element can be used alone without the other features and elements of the embodiments or in various combinations with or without other features and elements disclosed herein.
This written description uses examples of the subject matter disclosed to enable any person skilled in the art to practice the same, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the subject matter is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 1261469 | Nov 2012 | FR | national |
