Specification
The overall length and maximum allowable OD of buoyancy modules are defined by the riser joint length and the limiting dimensions of the drilling equipment (diverter housing and rotary table). Given riser and ancillary line diameters and orientations, stop collar, clamp band position and sizes together with the buoyancy requirement, we determine the elements volume and the composition of the composite syntactic foam necessary to yield the target buoyancy.
To achieve the riser performance characteristics, several depth ratings or types of buoyancy elements may be required. By working with the customer at all stages of the development process extremely accurate buoyancy ratings can be achieved. Typically, the client will require at least 96 to 98% efficiency from the buoyancy modules. The efficiency being the proportion of the riser string weight required to be supported by the upthrust provided by the modules.
As an aid to drilling operations and to ensure buoyancy modules are installed at the correct depths, we introduced the concept of color coding DRBMs. All of our buoyancy modules are clearly colour coded according to the chart below. Both ends of the modules are painted and matching colour identification label is attached to the side of each module.
| Depth range (feet) |
Depth range (metres) |
Colour Code |
| 0-1000 |
0-303 |
|
Grey |
| 1001-2000 |
304-607 |
|
Green |
| 2001-3000 |
608-914 |
|
Dark Blue |
| 3001-4000 |
915-1219 |
|
Yellow |
| 4001-5000 |
1220-1524 |
|
Orange |
| 5001-6000 |
1525-1829 |
|
Black |
| 6001-7000 |
1830-2134 |
|
Red |
| 7001-8000 |
2135-2438 |
|
Purple |
| 8001-9000 |
2439-2743 |
|
Brown |
| 9001-10000 |
2744-3048 |
|
Light Blue |