A thruster driven barnacle cleaning device and Method for acoustic deployment and retrieval positioning
Publication Date: 2016-Mar-22
The IP.com Prior Art Database
The present application relates to the art of cleaning marine streamers and related equipment used for seismic and/or electromagnetic surveying from barnacles or other kind of marine growth. This invention describes how we can do positioning of streamers during deployment and retrieval using an acoustic ranging system.
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The present application relates to the art of cleaning marine streamers and related equipment used for seismic and/or electromagnetic surveying from barnacles or other kind of marine growth.
So-called streamers are used for marine seismic and/or electromagnetic surveying. These streamers compromise active sections with sensors such as one or more of the following: hydrophones, acceleration sensitive sensors and electrodes. In addition, the streamers comprise adapters and additional elements such as stretches, inserts, acoustic devices for positioning, depth-keeping and steering control devices (birds).
Marine streamers are subject to bio-growth and barnacles adhering to the outside of the streamer during its use in the marine environment. Barnacles on the streamer create undesired turbulences in the water around the streamer. These turbulences may manifest themselves as acoustic noise on hydrophones, vibration noise on accelerometers and electrical potential noise on electrodes. In addition, barnacles create additional drag and thereby increase the tension on the cable. Hence it is helpful to remove the bio-growth and barnacles from the marine streamer at those times when the generated noises exceed accepted noise levels and/or when the tension on the streamer cable exceeds a predefined limit.
Cleaning of seismic streamers relates to surfacing the streamer and from the workboat or seismic vessel manually cleaning the streamer cables either by washing machines, pressure cleaners or mechanical scraping the cable using a scrape or a rope.
A thruster driven barnacle cleaning device
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Images above are of streamer with barnacle (left) and a rope set up for cleaning a streamer
Some streamer cleaning devices operate on the streamer at an operational depth without surfacing the streamer. One such device is shown in US7145833, another description is found in US7409919. Those can be cumbersome, time consuming and limit production. It is therefore desired to have a device/process of which we can clean the streamer as the equipment is operational.
Another way of avoiding the marine growth on the streamer is by painting the streamer skin with anti-fouling paint such as CLEAR Signal (from Severn marine Technology , http://www.severnmarinetech.com/applications.html)). Others again claim nanomaterial or
other materials used in the skin of the streamer in order to avoid the attachment of the barnacles to the skin. Historical these processes have limited life and indeed a mechanical solution is needed.
As noted, efficient streamer cleaning is beneficial to maintaining a high productivity of the seismic operation. The present application is related to solutions to such including a mechanical device that is run on the streamer in order to remove barnacles and/or other marine growth.
According to embodiments, the present application relates to a device that has thrusters...