Riser ESDV leakage rate study

The purpose of this study was to conduct the annual tests on riser emergency shutdown valves (RESDV), in line with current legislation

Jee’s client has a presence in the North Sea and asked Jee to carry out tests on all RESDV to determine the time of closure and leakage rate when closed.  In 2008, one of these valves had been found to be approaching its’ currently specified maximum allowage leakage rate.

Jee conducted a study to determine the effect of seal degradation on leakage past the riser ESDV, accounting for energy losses in the system as the system passed the valve.

Key outputs were:

• Leakage rate of the valve when tested at MAOP, for varying levels of seal degradation (and hence gap between seal and ball valve interface)
• Assessment of an acceptable level of seal degradation whilst still maintaining the integrity of the RESDV, taking account of previous studies relating to the current maximum allowable leakage rate

• Re-assurance on the condition of the RESDV and whether remedial action was required, or if the allowable leakage rate could justifiably be increased
• Rapid turn-around of the study to enable prompt assessment of actions required

All case studies

• Trenching study for flexible pipeline subject to trawl gear interaction
• Wye piece verification
• Front-End Subsea Pipeline Conceptual Engineering Study
• Deep water pipelay capability spreadsheet
• Upheaval Buckling Analysis of a Flexible Pipeline
• Stability analysis of subsea gas pipelines using PRCI Level 2 stability analysis software
• Preparation of MathCAD sheets for pipeline stability analysis
• Goldeneye Third-Party Verification
• Overtrawling of large diameter pipeline trials JIP
• Recommended procedures and methods for design of subsea flanges
• Steady state FEA thermal analysis of a flexible pipeline in ANSYS
• Review of the Upheaval Buckling Analysis of a Pipe in Pipe System
• Investigation of data flow to foreign fishermen
• Pig impact at riser bends
• Analysis and tests of response of subsea equipment to acoustic vibrations
• Optimisation of fins on pipeline riser fairings using CFD
• Rock dump stability study
• Offshore support on pipeline inspection survey
• Pipeline design and installation procedure verification
• Study of fishing in the Gulf of Gabes
• Evaluation of the thermal properties of pipe sections and pipeline components
• Pipeline installation pull analysis
• Overtrawling capability of subsea protective structures
• Bundle towhead over-trawling – Scale model tests
• Thermal finite element analysis of a trenched umbilical
• Mattress placement study
• Pipeline stability assessment using PRCI Level 2 and Level 3 analysis tools
• Engineering critical assessment to BS 7910:2005
• Colombo harbour development
• Fishing interaction study
• Re-assessment of overtrawlability
• North Sea field development study
• Finite element analysis of mechanical connectors
• Flange leak investigation
• Spares and repairs
• Development of pipeline design sheets in MathCad
• Overtrawling of protection structures and umbilicals
• Riser ESDV leakage rate study
• Fatigue analysis of a riser in Orcaflex
• Support to BP Subsea and Pipelines Team
• Pipeline 4001 - Girth weld defect assessment
• Historical condition and lifetime prediction for Amethyst, Wollaston and Whittle
• Trawling risk assessment
• Assessment of pig run times
• Comparitive assessment of decommissioning options
• Assessment of current/ historical status of riser and bypass pipework
• Assessment of thermowell vibration fatigue due to vortex-induced vibration (VIV)
• Validation of water injection pipelines
• Defect assessment
• Unbilical stability assessment
• Technical authority and decommissioning support
• Major accident prevention document (MAPD) review and update
• General pipeline support
• Assessment of Pipeline Spares surrently held, future Spares and preservation requirements
• Creation of Technical Assessment summary sheets for North Sea pipelines
• Span and buckling assessment
• Overtrawlability trials of subsea structure
• Structural overtrawling trials
• Bend restrictor analysis
• Buoyancy module analysis
• FEA of an internally-lined pipe
• FEA of an internally-lined pipe Stage 2
• Fishing interaction
• Prediction of riser bend damage
• Pipeline decommissioning
• Fatigue analysis
• SNS decommission studies
• Riser ESDV leakage rate study
• Non-trenching study
• Span assessment and solution development
• Pipeline contingency plan
• Umbilical stability assessment
• Integrity under new flow conditions