We were involved in supporting our client’s bid for a sizeable sub-sea pipe installation project that was to take place in a difficult geographical area. This project called not only for our analysis expertise and jet trenching simulation experience but also drew upon our considerable experience of successful collaboration with a variety of experts.
Our client was creating a bid for a large sub-sea pipe installation project. The planned route passed through shipping lanes and areas with active trawling, meaning the pipe was required to be buried under stringent conditions and with extensive validation of the proposed burial methodology. The pipe was also to be buried at a greater depth than the client’s existing hardware was able to achieve, and, alongside the proposal, design and validation of modifications to a piece of jet trenching equipment were taking place.
We were asked to support the bid by validating the proposed design modification. The validation required an assessment of:
- the pipe burial depth,
- the depth of sand covering the pipe
- the amount of sand escaping the trench for different operational conditions.
We were approached due to our significant trenching simulation experience, gathered over multiple projects, and following many successful collaborations with the various disciplines involved in this project; geotechnical and soils experts, installation contractors, product specialist and the like.
We began by capturing the critical aspects that the customer needed to take away from the analysis using our proprietary analysis planning approach. This data was then used to scope the project and to ensure that the requirements could be met most cost-effectively. To facilitate this, we performed a series of test analyses evaluating the effectiveness of a range of analysis methodologies, before selecting the most appropriate to model this complicated system. We then progressed, using the method found to best capture the behaviour of the system, to undertake a multiphase, transient model of the jet trenching operation, configured in ANSYS CFX. The model included a representation of the sand erosion and deposition and modelled the jet trencher moving through the seabed. This model was solved, post-processed, and the results were compared to experimental and operational data. It was found to show good correlation in critical areas, and this was used to validate the effectiveness of the modelling approach. The model was then configured to represent a further range of operational conditions, and from the results, an assessment of the depth of lay, the depth of cover and the over-spill from the trench were all made. These critical parameters were supplied to the client in a technical report that accompanied their bid and underpinned the approach they had proposed.
- Reduced risk: assessing a validated model provided assurance to the bid.
- Enhanced performance: the evaluation of the performance of the jet trencher enabled the client to use the equipment more efficiently.
- By undertaking the analysis at the bid stage, our client was able to provide confidence in their proposed solution and hence gain a competitive advantage.