Ultrasonic Cleaning of Marine Geophysical Equipment
Various methods and apparatuses for facilitating cleaning of submerged geophysical equipment using sound waves transmitted at ultrasonic frequencies are disclosed. In some embodiments, one or more transducers may be configured to transmit sound at one or more ultrasonic frequencies. The sound at ultrasonic frequencies may be transmitted in the vicinity of submerged geophysical equipment, such as a sensor streamer towed behind a survey vessel. Obstructions (e.g., barnacle larvae) adhering to surfaces of the geophysical equipment may be loosened or removed altogether when ultrasonic transmissions occur within its vicinity. The transducers used to transmit the ultrasonic frequencies may be implemented in various ways, such as being attached to a remote operated vehicle, a cleaning unit, or as being an integral component of the geophysical equipment.
Marine seismic surveys utilize sound waves transmitted to the earth's crust and reflected back to recording sensors. The recording sensors may be hydrophones in one of a number of streamers that may be towed behind a survey boat. The survey boat may tow an array of multiple streamers in parallel. When towed behind the survey boat, the streamer may be submerged. A sound source may also be towed in the water behind the survey boat for transmitting the sound waves to be received by the hydrophones of the streamers. One common application of marine seismic surveying is oil and gas exploration in marine environments. More particularly, sound waves received during a marine seismic survey may be analyzed to locate hydrocarbon bearing geological structures, and thus determine where deposits of oil and natural gas may be located.
Periodically, cleaning operations may be conducted on streamers used in marine seismic surveys. Cleaning operations may be conducted by a crew on a workboat separate from the survey boat. To clean a particular one of the towed streamers, the workboat crew may lift the streamer out of the water, clean by hand, and lower the streamer back into the water. Since the streamers can have significant length, (e.g., 8 km), in some cases only a portion of the streamer is lifted out of the water. The workboat crew may progressively lift portions of a particular streamer out of the water until cleaning is complete. The workboat crew may then progress to the next streamer and repeat the process. The process may be subsequently repeated until all streamers have been cleaned. The process of cleaning using a workboat crew can be very time consuming, and in some cases, dangerous to the crew members that perform the work.
Other aspects of the disclosure will become apparent upon reading the following detailed description and upon reference to the accompanying drawings which are now described as follows.
While the embodiments disclosed herein are susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the drawings and description thereto are not intended to limit the disclosure to the particular forms disclosed; on the contrary, the disclosure is intended to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure as defined by the appended claims.
DETAILED DESCRIPTIONThis specification includes references to “one embodiment” or “an embodiment.” The appearances of the phrases “in one embodiment” or “in an embodiment” do not necessarily refer to the same embodiment. Particular features, structures, or characteristics may be combined in any suitable manner consistent with this disclosure.
The present disclosure is directed to method and apparatus embodiments in which ultrasonic frequencies are used to clean submerged geophysical equipment. The ultrasonic frequencies may be transmitted by any type of transducer or other device capable of generating sound waves at those frequencies. The transmission of the ultrasonic frequencies may be used to facilitate the cleaning of various obstructions from the geophysical equipment. Such obstructions may include (but are not limited to) barnacle larvae, barnacles, and ice. In various embodiments, the geophysical equipment may be a sensor streamer that may be towed behind a survey vessel, although other types of geophysical equipment may also be cleaned using ultrasonic frequencies. As used herein, the term “ultrasonic” refers to frequencies above the range of normal human hearing, at least including frequencies greater than 20 kHz.
In various embodiments, a cleaning apparatus may include one or more transducers configured to transmit sound at ultrasonic frequencies. In one embodiment, a number of transducers may be integrated into a sensor streamer. The transducers may be periodically activated, or activated responsive to a command by a user at a control input. In another embodiment, a cleaning apparatus may include a streamer cleaning unit that is attachable to a sensor streamer. In addition to brushes and other mechanisms for physically removing obstructions from a sensor streamer, the streamer cleaning unit may also include one or more transducers that may be activated during a cleaning operation. In yet another embodiment, a cleaning apparatus may include a remotely operated vehicle having transducers capable of transmitting sound at ultrasonic frequencies.
Various embodiments of a method for cleaning geophysical equipment may include transmitting ultrasonic frequencies in the vicinity of the geophysical equipment. As used herein, the terms “in the vicinity” and “in a vicinity” refers to a location sufficiently near to the geophysical equipment that the transmission of the ultrasonic frequencies may effectively remove or at least loosen some obstructions thereof or other undesired matter attached thereto. Since the power at which the ultrasonic frequencies are transmitted may vary, the terms “in the vicinity” and “in a vicinity” may also be variable based on the transmission power. In one exemplary embodiment, transmissions may be made from 20 centimeters at a transmission power of 10 watts or greater using directional transducers to transmit the ultrasonic frequencies in a directed manner. It is noted that this example is not intended to be limiting, and the transmission power may be varied from one embodiment to the next.
The transducers used in the cleaning operations discussed herein may transmit sound at one or more ultrasonic frequencies. In one embodiment, the ultrasonic frequency at which sound is transmitted may be a discrete frequency which has been determined to be effective for the desired cleaning operation. In another embodiment, sound may be transmitted at multiple, discrete ultrasonic frequencies, sequentially or concurrently. In still another embodiment, the transmission of sound at ultrasonic frequencies may be performed by sweeping across a range of frequencies (e.g., between 20 kHz and 100 kHz). Sweeping of frequencies may begin at a high frequency and descend to a low frequency, or may begin at a low frequency and increase to a high frequency.
Turning now to
Tow vessel 100 may also tow a number of sources 102 via tow cables 103. In some embodiments, sources 102 may be towed by another vessel (not shown). Sources 102 may include a variety of seismic sources, such as marine vibrators or air guns. Sources 102 may also include a variety of electromagnetic (EM) sources, such as antennas or magnetic coils. In some embodiments, sources 102 may transmit sound waves into the water, the echoes of which may be detected by the seismic sensors of the streamers 104. In some embodiments, sources 102 may transmit EM signals into the water, which may be detected by the EM receivers of the streamers 104. The sensors and receivers of streamers 104 may be electrically coupled to electronic equipment aboard tow vessel 100 that may be used to analyze geophysical data, such as received echoes or detected signals. Using the arrangement shown in
During the conduct of marine geophysical surveys, equipment may at times become obstructed. For example, the growth of barnacles and barnacle larvae on streamers may occur during the conduct of marine geophysical surveys, particularly in certain geographic locations. In colder geographic locations, ice may sometimes form on geophysical survey equipment such as the streamers discussed herein. When obstructions such as barnacles are attached to the streamers, the sensitivity of the sensors and receivers contained therein may be reduced. This in turn can adversely affect the data collected in the survey. Accordingly, cleaning of the streamers may be periodically performed in order to remove obstructions from the streamers 104 and thus to increase the effectiveness of a survey in progress.
In some embodiments, the cleaning of the streamers (and more generally, of geophysical equipment) may include transmission of sound at one or more ultrasonic frequencies. The sound may be transmitted toward the geophysical equipment undergoing the cleaning operations. Transmission of sound at one or more ultrasonic frequencies may be effective in loosening or removing various obstructions that may otherwise adhere to the geophysical equipment. Such obstructions that may be loosened or removed using sound transmitted at one or more ultrasonic frequencies may include, but are not limited to, barnacle larvae, barnacles, and ice. In cases where the obstructions are not completely removed, additional cleaning using brushes and/or other types of cleaning apparatuses may be utilized to complete the cleaning.
In addition to the sensors 111, sensor streamer 104 also includes a plurality of transducers 113. The transducers 113 in the embodiment shown may be configured to transmit sound at one or more ultrasonic frequencies. A control unit 120 coupled to sensor streamer 104 may be used to activate the transducers 113 in order to cause them to transmit sound responsive to a user input. Inputs from control unit 120 in some embodiments may determine the ultrasonic frequencies at which sound is transmitting. Sound may be transmitted at a single ultrasonic frequency, at a number of discrete ultrasonic frequencies (sequentially or concurrently), or by sweeping across a range of ultrasonic frequencies. Sound transmitted at one or more ultrasonic frequencies by transducers 113 may facilitate the cleaning of sensor streamer 104, and more particularly, for loosening or removing obstructions otherwise adhered thereto.
Streamer 104 in the embodiment shown also includes a streamer telemetry unit (STU) 116. STU 116 may be used to perform measurements based on raw data received from the sensors 111, and may also transmit measurement data to receiving equipment on tow vessel 100. STU 116 may be susceptible to attracting barnacles and barnacle larvae. Accordingly, one or more transducers 113 may be located in the vicinity of STU 116, if not within the unit itself.
Cleaning of survey equipment (e.g., streamers 104, sources 102, or tow cables 103) as discussed herein may, in some embodiments, be facilitated by the use of an ROV. Turning now to
In the embodiment shown, ROV 200 includes one or more transducers 211 that may be configured to transmit sound at ultrasonic frequencies. In conducting a cleaning operation, ROV 200 may be maneuvered into the vicinity of a streamer while transmitting sound from transducer(s) 211. As is discussed below, in one embodiment a cleaning method includes an ROV 200 causing a cleaning attachment to traverse the length of a streamer while sound is transmitted at ultrasonic frequencies by transducer(s) 211 as ROV 200 moves cleaning attachment to move along the streamer.
In some embodiments, ROV 200 may be used to facilitate cleaning of a streamer by attaching an SCU thereto, wherein the SCU includes transducers configured to transmit sound at ultrasonic frequencies.
SCU 205 in the embodiment shown includes a cleaning apparatus 213. More particularly, cleaning apparatus 213 may include one or more transducers from which sound may be transmitted at one or more ultrasonic frequencies. These transducers may be activated once SCU 205 is attached to the streamer 104.
In
In the example shown in
Turning now to
With the SCU attached to the ROV, the ROV may then be maneuvered into close proximity to the streamer to be cleaned (block 710). In one embodiment, the ROV may be maneuvered into a position near the end of the streamer closest to the tow boat. When in close enough proximity, the SCU may be attached to the streamer (block 715). The SCU may be released from the ROV after having been securely attached to the streamer (block 720).
After the ROV has released the SCU, cleaning of the streamer may commence. The SCU discussed in this embodiment is a self-propelled unit, and may traverse the length of the streamer while transmitting sound at ultrasonic frequencies from one or more transducers (block 725). After the SCU has reached the end of the streamer, it may be held in place by a stopper in order to prevent it from becoming unintentionally de-attached from the streamer. The ROV may be maneuvered into position for re-attachment of the SCU (block 730). After re-attachment to the ROV, the SCU may be removed from the streamer for retrieval or for cleaning of another streamer.
Upon attaching the cleaning apparatus to the streamer, the cleaning operation may commence. The ROV may propel the cleaning apparatus along the streamer, traversing its length (block 820). The ROV in one embodiment may include one or more transducers, and may thus transmit sound at one or more ultrasonic frequencies as it propels the cleaning tool along the streamer. Upon reaching the end of the streamer (or the end of the portion to be cleaned), the ROV may detach the cleaning tool from the streamer (block 825). The cleaning tool may then be returned to a chase vessel for retrieval, or the ROV may be maneuvered into position to clean another streamer.
Turning now to
Numerous variations and modifications will become apparent to those skilled in the art once the above disclosure is fully appreciated. It is intended that the following claims be interpreted to embrace all such variations and modifications.
Claims
1. A method comprising:
- towing geophysical equipment behind a survey vessel; and
- cleaning the geophysical equipment while the geophysical equipment is being towed, wherein said cleaning is performed at least in part by transmission of sound at an ultrasonic frequency.
2. The method as recited in claim 1, wherein the transmission of sound at the ultrasonic frequency is performed at least in part by a plurality of transducers internal to the geophysical equipment.
3. The method as recited in claim 1, wherein the transmission of sound at the ultrasonic frequency is performed at least in part by one or more transducers coupled to a remotely operated vehicle (ROV).
4. The method as recited in claim 3, wherein the geophysical equipment is a sensor streamer, and wherein the method further comprises:
- the ROV traversing the length of the sensor streamer; and
- transmitting sound at the ultrasonic frequency toward the sensor streamer during said traversing the length of the sensor streamer.
5. The method as recited in claim 1, wherein the geophysical equipment is a sensor streamer, and wherein the transmission of sound at the ultrasonic frequency is performed at least in part by one or more transducers coupled to a streamer-cleaning unit (SCU) that is attachable to the sensor streamer.
6. The method as recited in claim 5, further comprising:
- attaching the SCU to the a first end of the sensor streamer;
- the SCU traversing from the first end to a second end of the sensor streamer; and
- the SCU transmitting sound at the ultrasonic frequency during said traversing.
7. The method as recited in claim 1, wherein the transmission of sound at the ultrasonic frequency further includes transmitting sound at a plurality of ultrasonic frequencies, and wherein the transmitted sound is generated externally to the geophysical equipment and directed toward the geophysical equipment.
8. The method as recited in claim 7, wherein said transmitting sound at a plurality of ultrasonic frequencies comprises sweeping across a range of ultrasonic frequencies.
9. An apparatus comprising:
- a cleaning unit configured to clean one or more pieces of geophysical equipment, including by transmission of ultrasonic frequencies.
10. The apparatus as recited in claim 9, wherein the one or more pieces of geophysical equipment include a sensor streamer, and wherein the apparatus includes the cleaning unit and the sensor streamer.
11. The apparatus as recited in claim 9, wherein the one or more pieces of geophysical equipment is include a sensor streamer, and wherein the apparatus is a streamer cleaning unit (SCU) that includes one or more transducers configured to transmit sound at ultrasonic frequencies.
12. The apparatus as recited in claim 9, wherein the apparatus is located in a remotely operated vehicle (ROV), and wherein the ROV includes one or more transducers configured to transmit sound at ultrasonic frequencies.
13. The apparatus as recited in claim 9 wherein the one or more pieces of geophysical equipment include a sensor streamer, and wherein the cleaning unit comprises one or more transducers configured to transmit sound at ultrasonic frequencies, wherein the one or more transducers are integrated in the sensor streamer.
14. The apparatus as recited in claim 13, further comprising a control unit coupled to the sensor streamer, wherein the control unit is configured to activate the plurality of transducers responsive to a first input and further configured to deactivate the plurality of transducers responsive to a second input.
15. The apparatus as recited in claim 9, further comprising a control unit coupled to the cleaning unit, wherein the control unit control unit is configured to cause the cleaning unit to transmit sound by sweeping across a range of ultrasonic frequencies.
16. A method comprising:
- towing geophysical equipment in water behind a survey vessel; and
- transmitting sound at one or more ultrasonic frequencies in the water in a vicinity of the geophysical equipment.
17. The method as recited in claim 13, wherein said transmitting comprises one or more transducers on a remotely operated vehicle (ROV) transmitting sound at one or more ultrasonic frequencies.
18. The method as recited in claim 17, wherein the geophysical equipment includes a sensor streamer, and wherein the method further comprises the ROV traversing from a first end of the sensor streamer to a second end of the sensor streamer while transmitting sound at the one or more ultrasonic frequencies.
19. The method as recited in claim 16, wherein said transmitting comprises one or more transducers on a streamer cleaning unit (SCU) transmitting sound at one or more ultrasonic frequencies.
20. The method as recited in claim 19, wherein the geophysical equipment includes a sensor streamer, and wherein the method further comprises:
- attaching the SCU to a first end of the sensor streamer;
- initiating transmission of sound at one or more ultrasonic frequencies by the one or more transducers;
- the SCU traveling from the first end of the sensor streamer to a second end of the streamer while transmitting sound at one or more ultrasonic frequencies.
21. The method as recited in claim 16, further comprising a plurality of transducers internal to the geophysical equipment transmitting sound at one or more ultrasonic frequencies.
22. The method as recited in claim 16, wherein the transmitting sound includes sweeping across a range of ultrasonic frequencies.
23. The method as recited in claim 16, wherein the transmitting sound includes transmitting sound at a first ultrasonic frequency and at least one additional ultrasonic frequency.
Type: Application
Filed: Sep 27, 2012
Publication Date: Mar 27, 2014
Inventor: Michael Bo Erneland (Loddekopinge)
Application Number: 13/629,412
International Classification: B08B 3/12 (20060101);