A cable route Desktop Study (DTS) is a key part of the initial planning phase of a submarine cable system. For Hydrocarbon developments it often forms part of the FEED process.

A DTS should detail all the influences on cable route safety, solutions for the environment encountered as well as specifying the amounts of submarine cable and the plant required to build the system.

Driving the Sector

Working together with our peers to drive positive industry change is an integral part of the work that we do as a business. OceanIQ’s parent company, Global Marine Group, are long standing Executive Committee members of the International Cable Protection Committee (ICPC) and European Subsea Cable Association (ESCA), and members of the North American Submarine Cable Association (NASCA).

All our Desktop Studies comply with ICPC Recommendation No 9 “Minimum Technical Requirements for a Desk Top Study”.

A technical reference for the entire project and throughout the life of the cable system

• OceanIQ’s DTS will detail factors likely to influence all subsequent activities, from survey through to installation, and then throughout the system’s operations and maintenance lifecycle. Our team will:
• Visit potential landing sites to assess the engineering requirements, then meet with local representatives of relevant marine authorities and visit industry representatives and other entities whose actions may affect the integrity of the cable (e.g. fishing, shipping, planning and port authorities). We are continuing to complete projects around the world despite the current Covid-19 travel restrictions by utilising alternative solutions including local partners.
• Research bathymetry, seafloor and shallow seabed lithology, currents, weather, seismology, tides, permits, other seabed users, fishing, and shipping.
• Identify areas of potential difficulty for survey, installation and subsequent maintenance.
• Investigate and detail environmental and cultural factors relating to the cable route, highlighting relevant statutes and regulations of the various authoritative bodies.
• Identify possible sources of risk to the cable – and the extent of that risk for the cable system. This includes an analysis of faults on existing systems nearby from OceanIQ’s extensive database. This data can also be supplied in a standalone Fault Analysis report.
• Identify permits, licences and other regulatory requirements necessary to install the cable and for the cable to remain in situ along the proposed route.
• Recommend routes that do not conflict with existing subsea infrastructure.

Both during and after the cable route survey, our team is able to utilise the data collected along with the information gained during the Desktop Study, to optimise the cable route and create the essential engineering documents for the installation project.

We create comprehensive route position lists (RPLs) and straight line diagrams (SLDs) which detail the position and all aspects of the cable route such as the cable plant (branching units, repeaters, joints, beach manholes), cable lengths, armour types, transitions, slack, water depths, cable and pipeline crossing points, and maritime boundaries.

The RPL and SLD provide the definitive cable and plant quantities for manufacture, system integration and installation.

We ensure the route is designed in harmony with the planned installation methodology and burial tools, making sure that when the cable is installed the offshore teams have a route and cable engineered to produce a quality result.

Decades of professional route engineering solutions

Gulf 2 Africa (G2A) connecting Oman to Africa via a 1,450km repeater system

OceanIQ completed the route engineering with the information gathered from the marine survey and our Desktop Study, to successfully install the cable connecting Salalah, Bosaso, and Berbera.

BT Highlands and Islands, Scotland – route engineering for the 20 inter-island cables connecting the west coast and Orkney in Scotland

This project involved the engineering design for 40 shore ends and cable routing through some remote sites with challenging geological and tidal current conditions. OceanIQ also managed the route survey and burial assessments for these 20 cable routes.

Uninett system, Svalbard – route engineering for a two segment, 500km system connecting Longyearbyen to Ny-Ålesund in the Arctic Circle, the most northerly commercial cable system in the world.

This project involved overcoming the specific engineering challenges posed by icebergs and shore based ice.

Celtix Connect, Irish Sea

Route engineering for the cable connecting Dublin to Anglesey in Wales

Our knowledge of how to plan and engineer for the practical aspects of a shore end or a connection to an offshore platform, results in a better system for our customers.

OceanIQ’s route engineering team use the latest bespoke GIS software, both the internally developed GeoCable® and the industry leading MakaiPlan software.

OceanIQ’s cable fault database contains information on over 5,500 historical faults, approximately 95% of all faults worldwide which is a powerful resource for planning future cable systems.

Combine this with our intrinsic knowledge of cable installation and maintenance gained from being part of Global Marine Group, and we offer the very best intelligence for your projects.

The report uses anonymised fault data to characterise the risk environment for new cables based on actual faults on existing and out of service cables in that region.

This provides confidence at both a commercial and technical level that a new cable system has been designed with complete knowledge, from historical data, of the real risks it faces and that all possible steps have been taken to mitigate those risks.

Example report structure

Introduction

• Description of the area, the fault records found and the aim of the report.

Data Analysis

• Calculation of an expected fault rate for the region and the planned cable system.
• Fault rate for different kinds of cables (if applicable).
• Change in fault frequency and types over time.
• Presentation and discussion of the report findings, with easy-to-read summaries.

Conclusions

• Identification of the most likely causes of faults for a new cable in the region studied. If information on the expected protection measures is provided by the client then a high level commentary on the likely effectiveness of these measures and the resultant residual risk can be provided.

An unusually high fault rate is often due to unexpected environmental conditions or changes in the pattern of human activity over the cable.

In many cases these challenging environments will only have come to light after the installation of the cable.

With an unrivalled understanding of cable fault causes, OceanIQ’s Cable Protection Assessment (CPA) uses all of the information available about an in-service cable system to describe the potential root cause of faults and propose solutions for preventing them in the future.

Example Report Structure

Introduction

• Description of the cable system and aim of the report.

Data Analysis 

• A review of the key hazards and risks exposed to the cable and an analysis of all available data. This may include information from the original desk top study, survey data, installation and repair reports and OceanIQ worldwide cable fault database.

Remedial Options

• A discussion of various protection measures applicable to the cable including a summary of the advantages and disadvantages associated with each option.

Appendices

• Supporting documentation, data and detailed overview charts.