Exploration • Drilling • Field Services
Build a model Only after the surge cases have been identified, can an accurate simulation model be built. Using a simulation tool like Flowmaster ensures all eventualities are considered. For instance both the Topsides and Subsea systems need to be incorporated to ensure confidence in any results obtained. It is critical that control systems (eg, minimum flow controllers), safety devices (eg, Topsides bursting discs), shutdown systems and elevation changes are included as they can have a significant impact on the results. For Subsea systems all the pipelines and wells should be included. Choke valves can be modelled to control the flow rate to each well and the injection wing or master valves slammed shut to create a surge event.
Simulation Simulating each potential surge case in detail is vital to reliable data for evaluation. It is especially important to determine the maximum allowable surge pressure that can be reached in each case. Some important considerations for running a surge study:
● Start with a well tuned steady state model that accurately reflects the normal operation
● Use a pipe model that accurately models pressure wave propagation
● Choose an analysis time step to effectively capture the effect of the transient event
● Run the simulation long enough to investigate the initial event as well as any secondary events that could be generated by system interactions
Evaluation
When surge analysis is carried out at an early stage in the design of a water injection facility, simulation software can be used to predict the maximum surge pressure and this can then be used to select system design pressure. When surge analysis is carried out
Enter 30 or ✔ at
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Doug Kolak is Process & Aerospace Product Engineer with Flowmaster Group, Towcester, Northants, UK.
www.flowmaster.com
Huisman’s oldest mast cranes lift Huisman’s largest mast crane T
he Happy Buccaneer sailed to Zhangzhou (Xiamen), China to load the newbuilding heavy lift mast crane
(HLMC) for the offshore installation vessel Borealis. The HLMC, with a capacity of 5000mton, was
constructed in four parts in the Huisman Equipment facility at Zhangzhou and brought alongside the Happy Buccaneer on trailers. The top mast (680mton) was loaded with the
two ship cranes in the lowerhold. The Slewing-section (1100mton) was positioned on the upperdeck with two cranes, skidded aft to the total aft end of the deck, to make space for the Jib (990mton) and the Mast-Base (1163mton). The jib had a total length of approx.
30
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on an existing system simulation, it can be used to investigate measures to mitigate surge (eg, extending valve closure time) to ensure that the system’s maximum allowable surge pressure is not breached. It is important that surge cases considered are realistic otherwise considerable expense may arise due to an overly-conservative design pressure on a new facility, or due to unnecessary modifications to an existing facility.
Mitigating Measures Based on the evaluation it is essential to identify mitigating measures that can counteract the effects of any surge problems. Tese measures should in all cases either eliminate surge pressure entirely or reduce it to within acceptable limits. Flowmaster allows users to simulate possible mitigating solutions such as installing additional pressure transmitters, programming in trips if certain pressure points are reached or exceeded, or staggering the closure of wells in the event of a shutdown. Termo-fluid system simulation tools allow engineers to design, optimise, validate and troubleshoot Oil and Gas system designs. Te wide range of solver capabilities and supplied loss and performance data enables users to build models and run simulations quicker and easier than ever before. Within the Oil and Gas industry, the need to
design safe, reliable and efficient systems across a range of applications is of paramount importance. Flowmaster provides system engineers with a powerful tool to investigate pressure surge, pressure drop, flow rate, temperature and system response times – removing the uncertainty from fluid flow systems. ●
first stage the jib was slewed over deck using 1 crane at one end and trailers at the other end. In stage two the jib was further lifted over deck to the portside of the ship using both cranes in tandem. After a successful loading operation, the Happy
Buccaneer set sail to Singapore, Sembawang shipyard, where the Asian Hercules II performed the installation on the hull of the Borealis. To upright the mast, the Happy Buccaneer assisted at the tailing lugs. ●
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97 metres. The loading operation contained two stages. In the
Big Lift Shipping BV is based in Amsterdam, The Netherlands.
www.bigliftshipping.com
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