The increasing demand for subsea solutions for deepwater projects has brought with it the need for guidelineless technology for installation, intervention, completion and workover.

Kongsberg Offshore's hitherto successful Hinged-Over Subsea Template (Host) technology is facing its biggest challenge yet, as it is due to be put to the test on Elf's Girassol field offshore Angola due onstream later this year.
Girassol, which lies in 1,400m (4,565ft) of water, is a project at the leading edge of offshore technology in many ways, but particularly for its subsea innovations.
At the heart of the concept lies Kongsberg's deepwater version of its template system - the GLL Host 2500 - due to be delivered in September.
The company is to install and operate the guidelineless remote-controlled subsea production system for which it was awarded a US $220 million contract in 1998. The deal covers the delivery of wellheads, Xmas trees, manifolds, flowline connection systems and control and well intervention equipment. KOS will also provide assistance throughout the installation phase in conjunction with FMC, its parent company.
The Host system is not exactly a new technology, and has been successfully employed on a number of North Sea projects such as Statoil's Gullfaks field.
The philosophy behind it is one of total flexibility achieved by the use of standard interfaces combined with the use of modular building blocks, all of which is supported by a suite of dedicated tooling. The GLL Host is a modularized subsea field development system that can be installed from a drilling rig through a 5.5 by 6.8m moonpool. The various modules are lifted separately and assembled onboard the rig. The Host template is installed as one assembly. Wells can be drilled and completed either before or after installation of the manifold.
For an on-template solution, the Xmas trees are connected to the manifold by a tree-mounted inboard horizontally stroking connector. This allows the trees and the manifold to be installed and retrieved independently and in any order. Both the connector and the Xmas tree pipe flow loops have the flexibility to take the tolerance built up between the well and the connecting manifold hub.
The GLL Host can accommodate conventional and horizontal Xmas trees.
KOS pioneered the modular subsea production facilities concept with the Host being the system's central building block.
The company and its partners then embarked on a program to develop the ultra-deepwater version - the Host-2500 - which is rated to 2,500m.
The modular deepwater system is a total field development approach with the flexibility of handling template or satellite well completion scenarios associated with today's subsea completions.
The GLL-Host system will share many of the same components and capabilities as the shallow-water Host system, but certain elements will be reconfigured for guidelineless installation and re-entry operations. It also will be modified to meet the increased depth requirements.
The GLL-Host will employ the same hinged guide base concept used by Host that allows
the configuration to be changed at any point prior to drilling and setting the conductor
for that particular guide base.

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