Home
Services
April 2008
RiserTec Launch Website
Following months of research, development and testing, RiserTec proudly announce the launch of this, our new, enhanced website. The website has been designed to enhance the end users experience, educate and inform visitors on RiserTec services and Technology.
VIV Analysis Tools
RiserTec is an Independent Engineering Design Consultancy
VIV Calibration and Comparison
RiserTec experience includes extensive calibration work between 3rd Party software programs (e.g. SHEAR7 and the OrcaFlex Toolbox) as well as between design code predictions and Laboratory test and/or Field data. In addition several comparisons have been documented between the above software codes and simplified “hand” calculations based on the following design standards
- DNV-RP-C205, Section 9 (Vortex Induced Oscillations)
- DNV-RP-F105 (Free Spanning Pipeline)
- DNV-RP-204 (Riser Fatigue)
As a consequence a sound mix of technical understanding, combined with practical experience, is applied to all problems
RiserTec In-House Software
RiserTec’s in-house VIV assessment program RTVIV has been developed to undertake coupled in-line and cross-flow assessments of complex 3D structures. The program currently interfaces with several general purpose Finite Element Programs including ABAQUS, ASAS and RTFrame (RiserTec’s in-house 3D Frame analysis program). A conventional power-balance solution is used based on the normal modes obtained from the structural program. By including axial, bi-axial bending, shear and torsional 3D element forces in the modal data, fatigue assessments can be undertaken at all points around the pipe circumference, thus enabling combined IL and CF response situations to be handled in a systematic manner. This is important for many cases including complex flowline spool geometries and SCR catenary configurations. Hydrodynamic element sets can also be defined for different pipe sizes and/or strake details or to omit certain elements entirely from the VIV calculation (for example elements above MWL or below mudline).
Detailed Experience Profile
RiserTec has extensive experience with VIV analysis and associated hydrodynamic testing obtained over numerous Projects. Specific examples include:
- Planning, supervising and results evaluation of full scale strake hydrodynamic tests at Oceanic, Newfoundland for BP Sunbury.
- Back analysis and Shear7 calibration of NDP High mode VIV tests for BP.
- Planning, supervision and assessment of strake mechanical roller box testing at Heriot-Watt University for BP Atlantis Project.
- Benchmarking and calibration of Shear7 against Lake Seneca and Offshore Miami field data for Deepstar.
- VIV fatigue assessments of complex flowline jumper geometries for Technip Paris Dalia Project using Shear7 and RiserTec’s in-house program RTVIV.
- Detailed VIV back analysis for 22” drilling riser working in high currents offshore Brazil for BP Sunbury to assess effectiveness of fitted fairings.
- Independent verification of measured fatigue assessments based on Field data for BP drilling riser DDII in the Gulf of Mexico.
- Planning, supervision and assessment of results for hydrodynamic test program investigating strake systems designed for riserless rotating drill string for Geoprober Drilling, Aberdeen
- Riser Tower VIV assessments for the Chinook-Cascade development in the Gulf of Mexico for Petrobras America Inc.
- Development of detailed Methodology for coupled in-line and cross-flow VIV assessments for vertical and horizontal flowline jumper spools using ABAQUS interfaced with in-house program RTVIV for BP Sunbury.
- Detailed VIV assessment of in-line and cross-flow VIV of Olowi conductor platform using ASAS interfaced to RTVIV for Atkins Global.
- Detailed VIV assessments for pipe-lay in high current regions offshore South Africa for Aberdeen client.
In addition to the above VIV specific project, RiserTec has undertaken considerable analysis and design work where VIV assessment of the structure forms an important input to the overall design.
