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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.
RiserTec Projects
RiserTec is an Independent Engineering Design Consultancy
| Project | Client | RiserTec Scope | |
| Strake VIV Hydrodynamic Testing | BP, Sunbury | Planning and management of free and forced vibration VIV tests at Oceanic, Newfoundland. The test program included commercial CRP strakes with 5D and 16D pitch as well as 17.5D strakes from BP Thunder Horse Project. Involved with all aspects of the program from initial planning through to supervision of tests and extracting of hydrodynamic added mass and lift coefficients as required for input to VIV design programs. |  |
| Snorre Tie-back Riser FEED Study | RTI Energy Systems, Houston | Detailed analysis and design of future tie-back risers to be installed on the Snorre TLP for additional production, gas injection and water injection service. Due to existing topside restrictions, available tensions budgets were limited requiring low tension ratio designs to be investigated in detail. Performed detailed directional fatigue assessement and associated profile designs for both single-piece and double-piece lower stress joints. Produced all system and component drawings with associated weight estimates. Also undertook additional FEED extension study investigating several alternative riser dimensions as requested by Statoil. |  |
| Heidrun Workover Riser Slim-Line Drilling Operations | Statoil, Norway | Performed initial conceptual and final detailed engineering for slim-line drilling operations on existing Heidrun TLP workover riser system. The work considered both single and dual completion risers under through tubing drilling operations. As a consequence the planned operation is perfromed with the surface wellhead and tree in place requiring the use of a reduced length workover spool up to the drilling riser tensioner system. To reduce moments in the system, several stack-up configurations, including some with one or more flex-joints, were investigated. Detailed fatigue and strength assessments were then undertakena for the prefered arrangement. A detailed contact force study was also completed and the results used to assess expected wear rates in critical components. Also interfaced with RTI Energy Systems in Houston who were presponsible for component manufacture and procurement. |  |
| Shear7 Calibration | BP, Sunbury | Calibration of Shear7 against Norwegian Deepwater Program (NDP) High Mode Strake VIV Tests. The scope included review of NDP test arrangement and generation of models to extract natural frequencies and associated mode shapes. A program was then generated to extract all measured results from the Marintek database and automatically compare against detailed Shear7 calculations. To aid the comparisons, several bias and index functions were defined. A detailed methodology for undertaking the calibration was also developed and used to perform the initial work. It was noted that the measured results indicated several features that shear7 in its current form is unable to account for in detail. A verification study was also performed for the shear7 program using and independent in-house calculation. Finally several sets of Shear7 design parameters for project use under various strake cover conditions were derived for input in BP VIV Guidelines.. |  |
| Atlantis in-Field SCR Monitoring Requirements | BP Atlantis Project | Detailed risk review and assessment of requirements for riser monitoring on the Atlantis in-field SCRs. Performed detailed risk assessment and interfaced with several vendors with respect to available monitoring options. Recommended outline moitoring specifications for the in-field pipe-in-pipe production SCR. |  |
| FLAGS Hot Tap | Genesis, Aberdeen | Detailed FEED study for Hot-Tap on 36" FLAGS Gas pipeline in North Sea. The scope included review of different hot-tap methods, detailed Finite Element analysis including all phase of the operation from branch welding to removal of coupon, and assessment of stress level in the system. A non-linear FEA model was also developed for use against strain based design criteria. |  |
| Rosa Lirio Bundle Tow | SaiBOS, Paris | Detailed analysis and fatigue assessment for towing of the Rosa Lirio bundle tower system. Considered different weather directions and optimised towing configurations in terms of tensions, tow procedures, net buoyancy and speed. Final recommendations led to the adoption of the Surface Tow method being adopted for project use. |  |
| Strake Roller Box Tests | BP Atlantis Project | BP representative for strake roller box mechanical tests performed at Heriot-Watt University, Edinburgh. The scope of testing included various strake designs and materials under a range of roller loads. Produced summary report together with recommendations for design improvements for several of the strake configurations. |  |
| BAOBAB Project - Installation Analysis Manifolds and Suction Anchors | Technip | Carried out detailed assessment of the installation of the Manifolds and Suction Anchors for Baobab in up to 900m water depth. Results were bench-marked against actual crane measurements from offshore. Developed and assisted client in all aspects of procedures and analysis for installation. |  |
| Simian Sapphire Project - Span Assessment of Installed Sapphire Pipelines | Technip | On bottom roughness assessment for all Sapphire lines from 4in MEG Injection lines to 26in Export line. Automated assessment of spanning and through life pressure temperature cycling and VIV to DNV F101 and F105 codes using ABAQUS 2D/3D modelling of the seabed. Eventually analysed over 80Km of lines and umbilicals. Fracture assessment to BS7910 of Umbilical cores for as-installed condition and crack growth assessment. |  |
| Deepstar 7402 Empirical Benchmarking Study | Deepstar | RiserTec was a participant in this benchmarking study of the Lake Seneca test data against SHEAR7 for both 'open' and 'blind' test cases as part of the Deepstar JIP on riser VIV |  |
| Geoprober Drilling Riser System Design | Geoprober Aberdeen | Detailed back analysis of the 22" drilling riser working on the Algodoal well offshore Brasil in 750m of water. Due to strong currents in the region the drilling riser had been fitted with VIV suppression fairings and instrumented with a small number of accelerometers. Current profiles throughout the water column were also measured. RiserTec reviewed all data and performed a detailed back analysis of the measure riser response against Shear7 predictions. From this work the efficieny of the fairings was determined. |  |
| Algodoal Drilling Riser VIV Back Analysis | BP, Sunbury | Detailed back analysis of the 22" drilling riser working on the Algodoal well offshore Brasil in 750m of water. Due to strong currents in the region the drilling riser had been fitted with VIV suppression fairings and instrumented with a small number of accelerometers. Current profiles throughout the water column were also measured. RiserTec reviewed all data and performed a detailed back analysis of the measure riser response against Shear7 predictions. From this work the efficieny of the fairings was determined. |  |
| BP Drilling Riser DD2 Fatigue Verifications | BP America | Independent verifications of BPs RAE contractors fatigue assessemnts for the BP drilling riser DD2 in the Gulf of Mexico. The study scope includes an independent Modal analysis to determine riser response based on measured accelerometer data. Several different modal methods will be assessed and calibrated using a theorectical Orcaflex model of the riser. RiserTec's wave transfer function method for converting measured acceleration directly into currvature based on the wave equation solution for the riser will also be assessed. |  |
| Cascade & Chinook Riser Tower Bid Support | Petrobras America | RiserTec is undertaking an independent review and analysis of the Free Standing Hybrid Riser (FSHR) Towers for the Petrobras Cascade & Chinook Development. RiserTec is also providing support to Petrobras during the Riser bid evaluation phase. |  |
| Jotun Bend Stiffener Repair | Esso Norge A/S | Reanalysis of Riser with Inner Bend stiffener dropped out i.e. in Damaged Condition to identify the limits for operation. Development of ABAQUS contact models to predict the loads to be encountered during the push-in of the riser to assist repair contractor. Development of detailed models to identify stress in riser as result of new load paths. Development of Procedures for identifying Environmental Alarms for early shut-in of riser and procedure for start up after shut-in. The riser was safely operated for 1 year and then a full push in of the inner bend stiffener was carried out by Subsea7 using tools developed based on the Analysis loads in August 2006. |  |
| Simian Control Umbilical Fracture Assessment | Technip Aberdeen | RiserTec provided specialist Fracture Assessment on an Umbilical to establish that despite manufacturing issues the Umbilical was fit for purpose and adequately strong for the design life required. The 30kM Umbilical was shown by BS7910 and R6 assessment to have an adequate operational life based on a calculation of maximum initial defect size and through life loadings. The Umbilical was also successfully pressure cycled by Duco to substantiate the fatigue life claims established through detailed FEA and Fracture Assessment. RiserTec worked with GLO the certifying body Sandvik the material supplier, Technip, Duco and British Energy to produce a state-of-the-art fracture assessment to establish the long term fitness for purpose of the umbilical. |  |
| Gannet Bundle and TowHead Analysis | Shell Expro | RiserTec analysed the global bundle and local spool pipework as well as local material defects using detailed 3D FEA in order to understand the loadings and FOS for the operating conditions on remaining pipe wall thickness. The analyses were completed in ABAQUS using 3D and pipe-in-pipe modelling techniques and considered both limit state stress and strain based design approaches. |  |
