Claudia.Martinez@anteagroup.com

STUDY, DESIGN AND CONSTRUCTION.

OF AN OIL PLATFORM IN A JUNGLE SWAMP. BELIZE, CENTRAL AMERICA

 

CHALLENGE:

In this occasion engineering faces a greater challenge, which is to build a platform of 1.5 hectares and a path of 8 km in a forest, marshland area and with the presence of gullies in Belize, Central America, highly protecting the environment and the project economics. The team of professionals and technicians who faced the challenge, found adverse conditions, because to access the site of the first drilling they should walk over 8 km through jungle with little intervention and in his last two kilometers through swamps with stagnant and putrid water. In addition, it presents a great development of vegetation, reason why the environmental authority has elevated its status of national park. The topography is quite flat and develops between dimensions of 0.0 and 20.5 meters.

The geology of the area of ​​interest is in rocks of Cretaceous age, consisting of a collation of sedimentary rocks, where there is presence of lenses of mudstone and powerful layers of limestone, marl and siltstone. The average stratigraphic distribution corresponds to a layer of organic material with thicknesses of up to 6 m, followed by a clay soil residual with a thickness of 1.5, underlain by sedimentary rocks of the limestone type, found up to 30 m of exploration. The limestone is affected by problems of karstification.

 

SOLUTION:

To identify and characterize the undersoil present in the selected area for the location and the access road, two geotechnical exploration campaigns were carried out with conventional equipment. As well as one campaign of 12 electrical scans in the area surrounding the cellar of the platform and a series of land inspections were performed to confirm the presence of caves in the limestone. The models were completed and the designs executed with the information collected in the field and from the geology offices of Belize and Guatemala.

 

RESULT:

The first 6 km of the access road were constructed in a conventional manner, with an embankment and then paved, but the final stretch, in the swamp area, was built with trench sheeting and rock fills in the base, landfill and paved cover in the surface.

The location area outside the oil rig area was built similar to the final stretch of the road, and the area of the oil rig was given an even more special treatment in consideration of the size of the loads to be exerted on the foundation - a dead weight of 3,000kN and a live load of 3,500kN – whereas the overall stability of the structure needs to be guaranteed. Where the differential slumps can affect the operation of the oil rig, it was necessary to implement a foundation system with a concrete plate supported by pre-excavated piles and supported by the relevant bedrock at a depth of 22 meters. Moreover, taking into account the conditions of the terrain, especially the presence of organic layers under the fills of the location and the presence of voids in the bedrock, the piles were designed with steel jackets to confine them, by which the buckling effects will be reduced in weakly zones.