Denby Morrison

Deployment of Subsea Equipment in Ultradeep Water

This paper describes various options to deploy subsea equipment in ultra-deepwater. The methodology used to study the feasibility and cost of the various options is presented. The focus of this paper is the performance of the numerical tools compared with offshore observations. Both offshore measurements and wave tank data are emphasized in this paper in order to validate the numerical model. Two possible contributors to more benign offshore response compared with calculations are: (1) complex subsea package hydrodynamics, and (2) wire rope damping effects. Indications are that internal damping in the very long, and relatively complex, wire ropes used offshore, is a source of significant damping. This damping is helpful in mitigating resonance effects.Copyright

Heave Compensated Landing System - A Novel Tool for Subsea Intervention

This paper presents a new intervention system that allows the use of a low cost workboat to deploy and recover delicate payloads in subsea installations. Vessel motions are decoupled from the subsea package by a specific chain and buoy system. A prototype was built and successfully tested offshore in 3,000 ft of water during May 1996. The Heave Compensated Landing System (HCLS) concept, offshore testing program, test results, lessons learned, and future developments are discussed.

Advances in Designing for Riser Impacts Resulting From VIV

Well bay configurations often attempt to place risers as close as possible without incurring interference. Often avoiding interference is not possible, or resulting spacings are impractical and uneconomical. Alternatively, attempts have been made to quantify the results of impacts incurred by risers in service. Collision tests and numerical analyses have been conducted on pipe-on-pipe collisions to help establish such design guidelines. Collected test data have been scanned to establish the design algorithms for strength assessments and fatigue damage predictions of riser systems. This paper illustrates the methodologies and procedures to obtain the desired information from the test results.Copyright