Mooring an Ocean Victory class MODU on a pre-laid mooring in 3,200 feet of water at Green Canyon 254
An Operator wanted to drill one or two additional delineation wells in 3,200 feet of water at Green Canyon 254. Because there were no MODUs capable of this water depth available to fit the Operator`s schedule, the Operator elected to increase the water depth capability of an existing Ocean Victory class MODU. The modification consisted of increasing the number of riser tensioners, installing longer BOP control hoses, guidelines and television cable, and using pre-laid moorings to enhance the mooring capability. This paper describes the pre-laid mooring procedures. Each pre-laid mooring leg consisted of one 10 metric ton anchor, 1,000 feet of ground wire, 2,500 feet of dip-zone chain and 3,000 feet of catenary wire. Prior to the arrival of the MODU, each leg also had 3,500 feet of 2 inch riser wire and a surface buoy. The moorings were laid using a single 6,140 brake-horsepower, anchor-handling, towing, supply vessel with a large A-frame at the stern. This same vessel was used to connect the chain from the MODU to the pre-laid moorings. Using pre-laid moorings to extend water depth capability gives the Operator greater flexibility in selecting MODUs for deep water drilling and can solve scheduling problems. The use of an A-frame and a ground wire adjacent to the anchor allowed use of a smaller vessel than would otherwise be required. The MODU can be moved to nearby deepwater locations without fully recovering the pre-laid moorings. This operation demonstrates that the water depth capability of an all chain MODU, normally capable of 2,000 feet of water, can be extended to over 3,000 feet by using wire inserts and pre-laid moorings.
- OSTI ID:
- 433985
- Report Number(s):
- CONF-960525-; TRN: IM9709%%419
- Resource Relation:
- Conference: 28. offshore technology conference, Houston, TX (United States), 6-9 May 1996; Other Information: PBD: 1996; Related Information: Is Part Of 28. annual offshore technology conference: Proceedings. Volume 4: Field drilling and development systems; PB: 942 p.
- Country of Publication:
- United States
- Language:
- English
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