Cable & Pipelay Support Operations


Cable & Pipe Lay Operations

GSO personnel are very experienced in all aspects of cable & pipeline surveys. This ranges from pre-engineering, through pre-lay, as-laid and as-left surveys, with or without the use of ROV. Extended video reporting using the most advanced software possibilities are amongst GSO achievements, as well as mine-field investigation, clearance and confirmation surveys. Cable/pipe lay monitoring services are conducted on a routine basis, including construction activities as mattress laying, sleeper installations, inspections of existing structures etc. This normally includes work-class ROV operations. Although not primarily ROV orientated, GSO has all necessary in-house experience to supervise and incorporate ROV operations in its activities. This can includes but is not limited to: ROV mounted positioning, bathymetry, magnetometry and SBP for inspections and  burial assessment, etc.                   


Pre Engineering Surveys:- Pre-engineering surveys are in principle a combination of standard route survey and seabed investigation techniques. These surveys utilise sensors either towed from a vessel or installed on ROV/AUV. Pre-engineering surveys are very work intensive and subsequently need skilled personnel able to understand the client’s requirements. Our personnel are able to quickly extract the relevant information from the acquired data, ready for presentation to the client. GSO personnel have been involved with numerous such surveys in the role of data QC Geo or as the client’s representative on-board.


Pre Lay Surveys:- Pre-lay surveys are an essential part of any cable or pipelay operation, over the previous years, senior GSO personnel have been involved with some of the most ambitious and technically demanding projects around the world Including at the time the deepest pipeline laid (Bluestream) and more recently for the pipeline that will supply gas to the 2014 winter Olympic village. This project lasted for more than a year and GSO personnel were involved from the initial pre-engineering surveys through to the final submission of As-built documentation.

Lay Support Operations:- During lay support operations Touch Down Monitoring (TDM) and pipeline/cable inspection is performed with a ROV using visual techniques and acoustic sensors. GSO personnel can assist with video review, editing, the processing of pipeline data and the production of the daily field reports.




Trenching Support:- Pre and post trenching surveys can be performed with a combination of standard geophysical sensors such as MBES, SSS and SBP. The sensors can be mounted on a suitable ROV or deployed from a survey support vessel. The acquired geophysical data is processed to determine the condition of the trench, depth of burial of the pipeline or cable and finally the amount of back fill/cover of the object. GSO personnel are very experienced in the processing and interpretation of this type of data. On-board managers can quickly have the information they require to determine if remedial work is required, ensuring that the specifications for trenching are met.  

As-Laid/As-Built Surveys:- As-laid surveys are meant to establish the situation after engineering operations. GSO has extensive expertise in this kind of operations. We can make sure required targets are met during operations. GSO also performs independent investigations and post-engineering surveys. This includes checking the position of subsea installations, pipeline free-spans, burial depth, back-fill quantities etc.

Pipeline Inspections:- Over the past few years GSO personnel have been involved in regular pipeline inspection projects. Typical pipeline inspections include an acoustic (sidescan sonar and multibeam echosounder) survey and if needed an ROV inspection of the critical locations identified during the survey. Results can be provided in any required form such as alignment charts or files compatible with the client’s database.


Subsea Installation Suport:- Because GSO personnel have years of experience with cable & pipeline lay operations, they have also been involved with peripheral operations such as mattress and crossing support installations for cable & pipeline crossings, spool piece installations, pipeline and wellhead inspections etc.

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