Abstract:
A skeg mounts from the stern of a towing vessel and extends below the waterline. A channel in the skeg protects cables for steamers and a source of a seismic system deployed from the vessel. Tow points on the skeg lie below the water's surface and connect to towlines to support the steamers and source. A floatation device supports the source and tows below the water's surface to avoid ice floes. The streamers can have vehicles deployed thereon for controlling a position on the streamer. To facilitate locating the streamers, these vehicles on the streamers can be brought to the surface when clear of ice floes so that GPS readings can be obtained and communicated to a control system. After obtaining readings, the vehicles can be floated back under the surface. Deploying, using, and retrieving the system accounts for ice at the surface in icy regions. In addition, handling the seismic record can account for noise generated by ice impact events.
Abstract:
A skeg mounts from the stern of a towing vessel and extends below the waterline. A channel in the skeg protects cables for steamers and a source of a seismic system deployed from the vessel. Tow points on the skeg lie below the water's surface and connect to towlines to support the steamers and source. A floatation device supports the source and tows below the water's surface to avoid ice floes. The streamers can have vehicles deployed thereon for controlling a position on the streamer. To facilitate locating the streamers, these vehicles on the streamers can be brought to the surface when clear of ice floes so that GPS readings can be obtained and communicated to a control system. After obtaining readings, the vehicles can be floated back under the surface. Deploying, using, and retrieving the system accounts for ice at the surface in icy regions. In addition, handling the seismic record can account for noise generated by ice impact events.
Abstract:
A skeg mounts from the stern of a towing vessel and extends below the waterline. A channel in the skeg protects cables for steamers and a source (e.g., air gun array) of a seismic system deployed from the vessel. Tow points on the skeg lie below the water's surface and connect to towlines to support the steamers and the source. A floatation device supports the source and tows below the water's surface to avoid ice floes or other issues encountered at the water's surface. The floatation device has a depth controlled float and one or more adjustable buoyancy floats. The controlled float has its buoyancy controlled with pressurized gas used for the air gun source and actively controls the depth of air gun source in the water. Each of the adjustable float connects in line with the controlled float with flexible connections. Each adjustable float has its buoyancy preconfigured to counterbalance the weight in water of the air gun or portion of the source that the float supports.
Abstract:
A marine seismic surveying apparatus for obstructed waters includes a deployed device and a buoy. The deployed device is disposed at an end of a streamer and is towed below a surface of water. The buoy extends from the end of the streamer to the water's surface. A coupling connects the buoy to the end of the streamer and is breakable due to tension from the buoy obstructed at the surface of the water. A receiver associated with the buoy obtains location information via the buoy at the water's surface. The deployed device can reckon its location with an inertial navigation system in place of location information obtained with the buoy's receiver. Also, the buoy can be deployed at the surface of the water, and more than one buoy can be available for deployment should one be lost.
Abstract:
A skeg mounts from the stern of a towing vessel and extends below the waterline. A channel in the skeg protects cables for steamers and a source of a seismic system deployed from the vessel. Tow points on the skeg lie below the water's surface and connect to towlines to support the steamers and source. A floatation device supports the source and tows below the water's surface to avoid ice floes. The streamers can have vehicles deployed thereon for controlling a position on the streamer. To facilitate locating the streamers, these vehicles on the streamers can be brought to the surface when clear of ice floes so that GPS readings can be obtained and communicated to a control system. After obtaining readings, the vehicles can be floated back under the surface. Deploying, using, and retrieving the system accounts for ice at the surface in icy regions. In addition, handling the seismic record can account for noise generated by ice impact events.
Abstract:
A marine seismic survey is performed in icy waters by initially planning a survey track traversing a survey area. The initial track is planned based on initial ice conditions in the survey area having the icy waters. After preparing the system, a seismic system is deployed into the water from a survey vessel at the survey area. This is typically done in an area relatively free of ice. At least one escort vessel escorts the survey vessel as it traverses the survey track and obtains seismic data. The survey vessel tows the seismic system under the surface of the icy water to avoid the ice. All the while, systems and operators monitor the survey area along the survey track for actual ice conditions. In this way, the escort vessel can handling the actual ice conditions along the survey track so the survey vessel does not need to halt.
Abstract:
A skeg mounts from the stern of a towing vessel and extends below the waterline. A channel in the skeg protects cables for steamers and a source of a seismic system deployed from the vessel. Tow points on the skeg lie below the water's surface and connect to towlines to support the steamers and source. A floatation device supports the source and tows below the water's surface to avoid ice floes. The streamers can have vehicles deployed thereon for controlling a position on the streamer. To facilitate locating the streamers, these vehicles on the streamers can be brought to the surface when clear of ice floes so that GPS readings can be obtained and communicated to a control system. After obtaining readings, the vehicles can be floated back under the surface. Deploying, using, and retrieving the system accounts for ice at the surface in icy regions. In addition, handling the seismic record can account for noise generated by ice impact events.
Abstract:
A skeg mounts from the stern of a towing vessel and extends below the waterline. A channel in the skeg protects cables for steamers and a source (e.g., air gun array) of a seismic system deployed from the vessel. Tow points on the skeg lie below the water's surface and connect to towlines to support the steamers and the source. A floatation device supports the source and tows below the water's surface to avoid ice floes or other issues encountered at the water's surface. The floatation device has a depth controlled float and one or more adjustable buoyancy floats. The controlled float has its buoyancy controlled with pressurized gas used for the air gun source and actively controls the depth of air gun source in the water. Each of the adjustable float connects in line with the controlled float with flexible connections. Each adjustable float has its buoyancy preconfigured to counterbalance the weight in water of the air gun or portion of the source that the float supports.