Moorings and Anchors

The performance of the floating production system depends on more directly on the performance of the system of mooring lines and anchors rather than on the performance of a single line or anchor. To assess and study the component and system reliabilities for the mooring system, a 'theme' Spar and its mooring system is used for the reliability analysis. The results of this project may be used for the evaluation and possible improvement of the design codes for FPS mooring lines and anchors.

Full-scale polyester ropes were tested to determine the impact of damage on the strength of polyester rope used as mooring lines for deepwater structures. Polyester ropes from four manufacturers were tested (Bexco, Marlow, Whitehill, and CSL) to determine the impact of damage on the strength of polyester mooring lines.

Research pm the damage tolerance of Synthetic-Fiber Mooring ropes for use on MODU's. Analysis of controlled, damage-tolerance, static tension tests on elements and sub-rope components taken directly from representative polyester mooring rope products. This research laid a foundation into the behavior of ropes with damage including more sophisticated analytical modeling.

BP EXPLORATION, Upstream Technology Group has requested that Stress Engineering Services (SES), perform a set of tests and analyses to develop an interim criteria for replacing damaged polyester mooring rope. BP and SES recognize that the Offshore Technology Research Center (OTRC) is developing a more thorough, longer-term project on the same subject, funded in part by the Minerals Management Service (MMS). BP believes it will have Gulf of Mexico applications for polyester rope taut line mooring systems before a criterion is available.

The primary objective of this project was to characterize key types of polyester rope damage that might affect the performance of a deepwater taut line mooring system. Since recent experiences have shown that these polyester mooring lines are susceptible to damage during installation, it is important to identify how this damage is created when installing these polyester mooring lines.

The primary goal of this research project is to ensure the availability of a validated software tool that can be used to predict the response of polyester ropes under a variety of loading conditions. Such a tool is needed to interpret and extend test data and to develop design guidelines. Laboratory testing of large and full-scale ropes, while essential for gauging performance, is expensive and time consuming. Development of a reliable computer model has the potential to significantly reduce the costs and time needed for experimental testing.

Conduct model tests to measure the responses of a moor tanker-based FPSO in wave, wind, and current conditions typical of hurricanes and Loop currents in the Gulf of Mexico. The model test data was used to validate various analytical response models of FPSO's, including those developed in the earlier OTRC projects relating to Moored-Tanker-Based FPSO responses.

For the safety of an FPSO in survival conditions, it is important to accurately predict any extreme response and the maximum mooring tension during a storm. This study will examine a mooring/riser dynamic analysis program and compare its predictions with OTRC experiments.

The goal of this project is to establish a comprehensive research program on deep water anchors with applications to drilling and production operations. The work has three objectives;
1) Determine currently available, best practices for analysis and design of suction cassion anchors (SCAs) and vertically loaded anchors (VLAs), including drag embedment anchors (DEAs) and suction embedded plate anchors (SEPLAs);
2) Characterize deep water environments and site investigations strategies;

To evaluate the durability of fiber ropes used in deepwater development.