Meeting the Challenges of Deepwater Cable and Pipeline Burial

Abstract

Cables and pipelines are buried in deepwater to provide thermal insulation, on-bottom stability and physical protection. In the soft soils associated with deepwater regions cable ploughs and ROV based jet trenchers are the tools of choice.The Offshore Engineering Division of the Coflexip Stena Offshore (CSO) Group and Perry Slingsby Systems have contributed significantly to the development of deepwater cable and pipeline burial systems. Significant resources continue to be allocated to geotechnical research programmes to support product developments. This paper discusses the key technical issues with respect to deepwater cable and pipeline burial. The state-of-the-art of geotechnical engineering and research, and it's application to new burial product developments, is also presented.

Review of hydrate prevention methods for deepwater pipelines

“…However, their effectiveness is influenced by numerous factors. Such as, crucial task of complex working nature of wide multidisciplinary working structure to determine optimal protection and design consideration for selecting the insulation for optimal design, degradation of thermal performance of insulating material over time, complicated maintenance of the insulation in terms of repair and installation, seawater seasonal conditional changes, and pipeline burial capabilities are out weighted with existing stability and protection issues as water depth increases, and ice gauging phenomena in arctic regions (iceberg grounding causing large soil movements) [27][28]. Despite, recent innovations in insulating materials such as the novel Thermotite [29], with increased efficiency and effectiveness, the insulation costs still remains as a concern simply because the need of insulation for the entire length of pipeline.…”

Perspective Review on Subsea Jet Trenching Technology and Modeling

“…The ROV-based jet trenchers are often preferred to the other trenching methods in deep-sea soft soils regions, due to their excellent versatility and operability. In reality, except for some trenching tools such as cable ploughs and pipeline ploughs [28,29], conventional trenching devices are heavy and complex machines (with several moving units), which makes them difficult to be controlled in deep-water conditions [30].…”

Flotation of pipes and cables in consolidating backfill

“…This paper will discuss buried pipes throughout, but the findings are equally applicable to cables. In order to install the pipe, a trench must be created using either ploughs, jet trenchers, cutters or hybrid trenchers (Finch and Machin 2001). Jet trenching fluidises the soil beneath the pipeline, allowing the pipe or cable to settle into the seabed due to its self-weight and providing backfill once the fluidised sediments have reconsolidated.…”