Noble Denton, the leading global offshore engineering and marine consulting firm, is funding a three-year research programme at the University of Cambridge, to consider effective modelling for ultra-deepwater mooring and riser developments in the oil and gas industry.

The move by the exploration and production sector towards ever-increasing water depths, often greater than 1,500m, creates significant difficulties for the integrated modelling of the floater, moorings and risers. 

In the case of computational models, the dynamics of the floater, moorings and risers are highly coupled, and complex mathematical equations are required to capture this behaviour, leading to excessive computation times. For physical model tests it is impossible to produce a scale model which accurately captures all aspects of the system, given the restricted water depth of testing tanks.

This research will consider methods of overcoming these difficulties. In the case of computational modelling, the project will consider the development of an efficient truncated model of the mooring lines and risers. BP is providing relevant industry expertise and guidance to the research programme.

With this approach, the dynamics of the upper section of each line will be modelled in detail, terminating in an approximate analytical model which aims to simulate the remainder of the line. 

With regard to physical modelling, two strategies will be considered. Firstly, the use of actuators to replicate the behaviour of the lower sections of the lines, using the type of model developed for the computational work. Secondly, the use of dynamic similitude to develop a passive shallow water line with the same vibrational characteristics as the full line.

The work on physical models will initially be conceptual, although the findings may lead to modelling in collaboration with a testing facility.

RV Ahilan, Noble Denton’s Assurance & Consulting Managing Director, said: “Professor Robin Langley from the University of Cambridge approached us with an opportunity to develop a research project that would be of interest to the energy industry.

“Along with BP, we have developed the outline of a project that has the potential to make fundamental advances in technology, permitting model testing of ultra-deepwater concepts with confidence.”

(Noble Denton)