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Technology
Assessment & Research (TA&R) Program
| Project Number |
510 |
| Date of Summary |
October 5, 2006 |
| Subject |
Seafloor Interaction with Steel Catenary Risers |
| Performing Activity |
Offshore Technology Research Center |
| Principal Investigator |
C.P. Aubeny, G. Biscontin, Jun Zhang, and J.D. Murff |
| Contracting Agency |
Minerals Management Service |
| Estimated Completion |
Completed September 2006 |
| Description |
This continued research will improve the current state of understanding
regarding the basic mechanisms affecting the seafloor stiffness within the
Steel Catenary Riser (SCR) touchdown zone, and develop a means for providing
quantitative estimates of seafloor stiffness and damping and their variation
over the life of the project for various soil and site conditions. The
geotechnical studies in this project will use finite element analyses to
develop load deformation relationships to describe soil-pipe interactions
for various conditions of soil properties, trench conditions, and
characteristics of riser motions. The hydrodynamic studies will investigate
riser-structure fluid interactions for various sea states, floating system
characteristics, and seafloor conditions. The parallel studies will be
coordinated throughout the project to ensure proper accounting of
interaction effects. |
| Progress |
Phase 1 of this project has provided an overall study framework and plan,
validation of FEM tools for use in this project, and an initial
identification and assessment of the important parameters for modeling SCRs
and developing boundary conditions in the touchdown area for use in
estimating the fatigue life of SCRs. Phase 2 developed a numerical model,
performed parametric studies, and identified conditions most influential on
the magnitude of bending stresses in the riser pipe. The parameters
evaluated included soil strength and stiffness, trench geometry, the effects
of trench collapse and infilling, strain rate effects, and non-linear
effects associated with a range of amplitudes and velocities of riser
motions. The range of riser motions near the touchdown zone were analyzed
using a numerical code accounting for the interaction among a floating
structure, its riser/mooring system and the seafloor.
The project's final report is currently under review by MMS and will be
posted upon project completion. Project
completed in September 2006. See the
following Final Report for additional information. |
| Report |
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AA
(35 pages) |
Seafloor Interaction with
Steel Catenary Risers, September
2006, Final Report by Charles
P. Aubeny, Giovanna Biscontin, & Jun Zhang,
Texas A&M University,
Offshore Technology Research Center,
Texas A&M University, 1200 Mariner
Drive, College Station, Texas and
Offshore Technology Research Center,
The University of Texas at Austin,
1 University Station C3700,
Austin, Texas. |
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