Seismic vessels are specialized ships which are used to carry out seismic surveys at sea. They use survey-induced seismic pulses to image subsurface formation. Read here to know more about the types of seismic operations carried out at the sea.
Considering the type of jobs these ships perform at sea, an extremely competent crew is required. In addition to the normal marine crew, seismic vessels also have an additional group of professionals called the seismic crew, who play a major part in the seismic operation.
The seismic team/crew, headed by the Party chief, consists of the following professionals:
- Processors (geophysicists)
- Gun technicians
Do note that these are the most common people present on board a seismic vessel; the number and type of people can vary, depending on the operation the vessel is engaged in and the company’s requirement.
Responsibilities of the Seismic Crew
To be a part of the seismic team, a person should have a strong technical background in electronics, computers and, of course, seismic tools, apart from the basic qualifications and experience required.
Party chief – is the head of the seismic crew. He oversees the overall seismic operation and plans the operation in consultation with the Master. As a company’s or clients representative he submits reports on daily basis regarding the seismic survey or any other matter concerning the operation.
Processors – are the geophysicists onboard. They monitors the survey operation closely, check the quality of data collected and approve the acquisitions to be retained and send ashore for further processing.
Observers – generally are technicians with good electrical and electronic knowledge. The do maintenance and troubleshooting of problems related to streamer cables, geo phones etc. They keep watch on the data being received from the geophones and also do the preliminary quality check. They also point out the error in real time and co-ordinate with processors to improve the quality and quantity of data acquired.
Navigators – are people who plan and monitor the tracks to be followed for acquiring data. These people also record the the data, which includes the co –ordinates and time of each firing point, estimate the firing time and keep watch on cable depth, and adjust birds accordingly. Navigators closely work with the bridge, plans on the route to be followed and advices on maneuvering the vessel. However, the ship’s master is the final decision maker, considering the safety of people on board, the environment and the ship.
The navigators and observers also work together in deploying cables and sorting out problems on streamer cables, hydrophones, birds, acoustic etc.
Gun technicians – they carry out the maintenance of water or air guns on board, deploys gun strings, keep watch on compressors and generators which are used for seismic operation.
The Marine crew
Just like any other vessel, a seismic vessel also needs to be operated and maintained, which is done by the mariners.The main departments includes – deck, engine and galley departments.
Sometimes during seismic operation, the total people on board can reach up to 50 to 60 and the saloon department therefore has an important role to play, not just for preparing food but also for maintaining high standard of hygiene and proper housekeeping.
In engine room, during acquisition, apart from regular watch keeping duties in the engine control room, the engineers also have to watch and maintain seismic compressors, the hydraulic power packs and other seismic related machinery systems. Taking in to account the number of machineries being operated while acquiring data, a proper housekeeping of the engine room is the duty of the the engine department in order to avoid oil spill or any other accident.
On deck ,the major responsibility of the master and deck officers is to adhere, implement and observe safe working practices on board. Although the people who work on board are well trained and experienced, care must be taken to avoid accidents, taking in to account the total number of person, working schedule and fatigue. Before the vessel sets it sails, all crew including the seismic crew should be familiar with every safety aspect of the ship and this should be recorded.
As a vessel restricted in her ability to maneuver (RAM), on deep sea seismic operation, navigation of Seismic vessel becomes easier. But often these operations are held at close proximity to shore and in area of dense traffic and thus extreme caution is required.
With high tech equipment, maintaining vessel on track lines becomes easier, but proper look out is also required to keep a watch on fishing activity, which can damage the seismic equipment, resulting in delay in acquisition.
Information on vessel traffic separation is provided with details of the co-ordinates of the boundaries of the survey area, CPA (closest point of approach ) to be maintained by other vessels, duration of survey etc. Navigators are regularly informed with the prevailing traffic weather and sea condition. Utmost care is also taken while making a seismic vessel turn, which is always larger as sharp turns can damage the streamers and make them part off.
With more than 40 people onboard seismic vessel, a number of high-tech machineries and operations close to shore, these vessels are vulnerable to extreme marine pollution. A high standard of pollution prevention policy is therefore maintained by the companies to avoid spill and other damage to maritime environment.
Over to you..
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The views and opinions of the authors expressed herein do not state or reflect those of the Marine Insight. Marine Insight has made every attempt to ensure the accuracy and reliability of the information provided in this article. However, we do not accept any responsibility or liability for the accuracy, content, completeness, legality, or reliability of the information contained in this article.