32 EXPLORATION/DRILLING/FIELD SERVICES
Monitoring structures for safe and efficient operation
Sandy Thomas looks at two recent projects which have required load measurement, strain and stress measuring integrated with mooring and docking equipment.
T
wo recent projects have involved Strainstall in the design, manufacture and commissioning of force and strain measuring systems.
One project was an Integrated Marine Management System (IMMS) for the hull of the new Shenzi Tension Leg Platform, TLP, deployed in the Gulf of Mexico, by BHP Billiton. The EPC were MODEC Inc. Due to the occurrences and severity of hurricanes in the Gulf in recent years, the system needed to be robust and reliable, designed to withstand a 1000 year storm and have a 25-plus year life.
The system included:
o Tendon Compression Load Cells rated to 2500Kips (the largest ever supplied), to monitor tendon tensions installed in the tendon porches approx 120ft below the surface.
o MetOcean monitoring. o Ballast control including tank levels. o Load management. o Fire and gas detection o Motion and position monitoring. o Ventilation and HVAC monitoring.
All of these components were integrated into a fully
redundant PLC/HMI system. The system provides the operators with a full range of hull parameters including the tensions and bending in the tendons, draft, motion and inclination, tank levels, position, fire and gas status, ventilation and HVAC, environmental and oceanographic parameters to allow them to safely carry out oil production. Strainstall has also been awarded the contract to supply its Quick Release Hooks and Integrated BerthManager System for four new floating natural gas liquefaction units, (LNG Producers), with an option for a fifth, being constructed by Samsung Heavy Industries in Korea for FLEX LNG. These LNGPs will be the first dedicated offshore Liquefaction Units and will be used to develop stranded gas fields offshore. The LNGP is a self-propelled vessel that will be moored at the gas field and risers will bring natural gas aboard. The vessel is able to pre-treat and liquefy natural gas, store and offload LNG in an offshore location. The requirement for these LNGPs to be deployed for up to 25 years in remote waters, with minimal allowance for any downtime or dry docking, meant that all the equipment supplied needed to be proven, rugged, reliable and easily maintainable. The Strainstall scope of supply for each vessel is:
o GPS DockAlert vessel approach monitoring. o Quick Release Hooks. o Remote controlled hook release. o MoorAlert mooring load monitoring. o Local hook tension displays and alarms. o Hook release panels in the control room and on vessel deck.
o BerthManager integrated monitoring, display and logging.
Fig. 1. The new Shenzi TLP located in the Deepwater Gulf of Mexico. Oil production is due to start mid 2009.
LNG Carriers will come alongside the LNGP, moor side-by-side, and carry out ship-to-ship cargo transfer. The LNGC will approach the LNGP using the GPS
www.engineerlive.com ➠
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76