Claxton Helps Ensure First oil from Tombua-Landana

Jan. 24, 2012 - PRLog -- Production facilities weighing 36,500 t are supported on a compliant tower weighing 56,400 t. This stands on a tower-base template of 3,000 t, which, in turn, rests on a leveling pile template. Under this, right on the seabed, there is a 12-slot predrilled template providing nine well and three docking slots designed, supplied and installed by Claxton.

Weighing just 30 t, the small but perfectly formed template provided the pattern for the first wells drilled before the giant platform was installed. It also determines the location of the platform and all 38 wells that will eventually be needed to complete the development.

The template was installed in two stages. It was initially lowered onto the seabed from an anchor-handling vessel. The Pride Venezuela semisubmersible drilling rig then picked up the template on drill pipe fitted with a Claxton supplied, overshot, double-J running tool and carefully located it over a single well already drilled in the seabed. It was then correctly oriented, landed and locked onto the well’s 30-in. wellhead housing. A further slot was then drilled through the template and a second 30-in. conductor installed, at which point the orientation of the template was effectively fixed.

In all, four wells were predrilled through the Claxton template (http://www.claxtonengineering.com/Products/Product/Drilli...), each furnished with a 30-in., low-pressure subsea wellhead and an 18¾-in., high-pressure wellhead on 20-in. casing. A docking pile was also installed through an outer, purpose-designed slot on the template before drilling was suspended and the rig was moved away.

Then after a pause, Claxton returned to carry out another pivotal task in the development of tying back two of the first four wells to the platform.  

The Tombua and Landana oilfields lie in Angola’s Block 14 in roughly 365 m of water. They are being developed by the Chevron subsidiary CABGOC. The fields’ combined production facilities are an integrated topsides structure supported by a 474-m-tall compliant tower. The platform is very similar in concept to the neighbouring Benguela Belize platform.

Claxton combines experienced project engineers, a fast-track design-analyse-build engineering service and huge inventory of rental tools to respond to the operating needs of its clients' well systems, structures and pipelines throughout the life of an asset, from pre-drilling through to decommissioning. Claxton has an enviable track record in providing both standard and non-standard drilling templates (http://www.claxtonengineering.com/Products/Templates-Stru...) and like many of their products, can be produced to tight timescales.

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Claxton, (http://www.claxtonengineering.com/) an Acteon company, is the leading supplier of engineering and services for shallow water, jackup depth markets.