Interference Assessment between Top Tensioned Risers Using a Comprehensive Screening Approach Event: OMAE Date: June 2015 Author: S. Sundararaman, D. Saldana, S. Patel, B. Andrew, P. Padelopoulos - 2H, M. Karayaka, K. Raghavan, P. Hays - Chevron Interference between top tensioned risers (TTRs) is a key design challenge. Due to TTR tensioner stroke limits combined with large vessel offsets, the space out of wellheads is limited. Therefore, riser-to-riser contact is more likely to occur in extreme current conditions. Riser clearance between adjacent risers is evaluated accounting for the effects of wake, vortex-induced vibrations, current directionality (including variation through-depth), vessel offset, riser configuration, and drilling sequence. Accounting for all of these effects simultaneously and in detail when assessing TTR interference can be challenging. The typical TTR array interference approach consists of a combination of riser deflection shape matching and detailed wake assessment. In this paper, a revised TTR interference analysis approach is discussed, with the inclusion of an intermediate step involving screening for critical riser pairs using a simplified wake model assessment. Riser deflection shape matching ensures that the likelihood of clashing is minimized. The riser interference screening process avoids detailed wake modelling of non-critical riser pairs. The screening analysis method emphasizes avoidance of false positives (unrealistic riser clashing pairs) and false negatives (missing riser clashing pairs). It employs a simplified conservative wake model using a stratified downstream current profile to determine which riser pairs are critical and warrant detailed wake modelling. To illustrate the efficiency of the screening approach, results from this approach are compared to results from analysis with detailed wake modelling. An implementation of this approach is presented for riser joints with fairings and strakes. Nominal drag coefficients for these joints are obtained based on experimental testing and/or computational fluid dynamics simulations. Drag amplification of the upstream riser is obtained from vortex induced vibration (VIV) analysis and is also incorporated in the analysis. If you would like a copy of this technical paper register to download it (pop-up form). All technical papers Share this page Share on FacebookShare on LinkedinShare on Twitter Services Production & Export Riser Concept Engineering Steel Catenary Risers Top Tensioned Risers Hybrid Risers Flexible Pipes & Risers Corrosion Resistance and Composite Risers Subsea Jumper Spools Subsea Umbilicals Deep Sea Mining Integrity Engineering, Life Extension & Monitoring Riser Integrity & Life Extension Platform Well Integrity & Life Extension Subsea Wellhead System & Life Extension Machine Learning for Riser Engineering Riser System Digital Twin Drilling Riser Management Riser Monitoring System Engineering Riser Inspection, Maintenance & Repair Anomaly & Incident Engineering Subsea Engineering & Assessment Services Component Detailed Design Offshore Decommissioning Engineering Fracture Mechanics and Engineering Critical Assessment Installation Engineering Mechanical Connectors Offshore Renewable Energy Systems and Qualification Testing System Verification & CVA Well Plug & Abandonment Drilling, Completion & Workover Drilling Risers Subsea Completion & Workover Risers Subsea Wellheads & Conductors Offshore Platform Conductors Well Engineering and Casing Design Platform Design and Engineering Conductor Supported Wellhead Platforms & CoSMOS Monopile Wellhead Platforms Exploration to Early Production Systems Structural Engineering Services Riser Delivery Management & Systems Engineering Get the latest riser insights!Receive our riser news, published papers and blog posts in your inbox monthly.