Ursa Tension Leg Platform

The working interest owners acquired the leases in Lease Sales 72 (May 1983), 81 (April 1984) and 113 (March 1988). The discovery well was drilled in 1991 with Sonat's Discoverer Seven Seas drillship on MC Block 854 on behalf of Shell and BP. In addition to the discovery well, two delineation wells and two sidetrack wells were drilled.
 
Development Plans

Shell announced in July 1996 the partners' plans to develop Ursa utilizing a large tension leg platform to be installed on Block 809 in approximately 3,800 feet of water. It surpassed the world water depth record for a permanent drilling and production platform - Shell/Exxon/BP's Ram-Powell TLP - which was installed in 3,214 feet of water in May 1997.
  
Initial development plans call for as many as 14 producing wells from the TLP. 

TLP fabrication began in July 1996. Eleven of the wells were batch set and one of those wells was predrilled to total depth prior to installation of the TLP. Further development wells were drilled with a contract platform rig owned by Helmerich & Payne International Drilling Co. of Tulsa, Oklahoma.

TLP Engineering and Construction Details
A multi-company project team representing the Ursa partners was formed in September 1995 to evaluate and begin engineering design for the development systems for Ursa. Waldemar S. Nelson and Co. of New Orleans and W. H. Linder and Associates of Metairie, LA, were contracted to develop the detailed topsides design and Han-Padron Associates of Houston was contracted to develop the hull structural detailed design.
 
The total displacement of the TLP is 97,500 tons and total steel weight 63,300 tons. Completely assembled, the TLP is 4,285 feet high from seafloor to the crown block of the drilling rig. The TLP is designed to simultaneously withstand hurricane force waves and winds.
 
Hull
The hull is comprised of four circular steel columns, 85 feet in diameter, 177 feet high, and a ring pontoon 38 feet wide and 29 feet high, with a rectangular cross section. The hull weighs 28,600 tons. Belleli Offshore in Taranto, Italy, built the hull. Construction began in July 1996 and was completed in June 1998.
 
Deck
The deck is composed of six modules: wellbay, quarters, power, drilling and two (2) process. The deck modules are an open truss frame design, 300 feet x 300 feet by 50 feet high with a total steel weight of 12,500 tons.

The total topside weight is 22,400 tons, including all equipment and drilling rig. J. Ray McDermott International, Inc. in Morgan City, LA, built the modules in Amelia, LA. Construction began in July 1996 and was completed in July 1998.
 
Tendons
There are 16 tendons, 4 per corner, each with a diameter of 32 inches and a wall thickness of 1.5 inches. Each tendon is approximately 3,800 feet long. The total weight for the 16 tendons is 16,000 tons. The TLP foundation system is comprised of 16 piles, to which the tendons are attached by means of tendon receptacles. The piles are 96 inches in diameter and 440 feet long, weighing approximately 380 tons each. The TLP was installed by Heerema of Leiden, The Netherlands, utilizing the SSCV Balder.
 
Drilling and Production Topsides
There are 12 well slots, and the well layout on the seafloor is arranged in a rectangular pattern 100 feet x 60 feet.  The TLP supports a single modified API platform-type drilling rig (leased) equipped with a surface BOP and high pressure drilling riser.

The quarters module houses up to 180 people, and contains a control room and an emergency response center. The topsides were installed on the hull by Heerema off the island of Curacao in the Caribbean.
 
Pipelines
An 18-inch diameter oil pipeline and a 20-inch diameter natural gas pipeline transports production to the West Delta 143 platform. Both pipelines were installed as part of the Ursa development. From West Delta 143, the oil and gas are transported via existing pipelines to Clovelly and the Venice Gas Plant respectively.

Pipeline construction began in 1997 and was completed in 1998. The steel catenary risers at the TLP will be installed by J. Ray McDermott, Inc. of Houston, TX, using the Derrick Barge 50.