Above: A Mirage Double Drill Unit creating lift holes to aid the removal of a caisson.
With oil and gas decommissioning projects on the increase, knowing in advance how to choose the equipment best suited to each specific job will help you to plan and budget your project more effectively.
So which machines are suited to the wide variety of decommissioning tasks the typical project engineer is faced with?
Based upon the challenges our customers have faced, we’ve provided a quick overview matching the machines used in recent decommissioning projects with the most common decommissioning tasks.
Portable Band Saw
Portable Band Saw key features and uses
For cold cutting of surface or subsea components. The band saw is mainly used for severing tubular components, but can also be used for cutting bar stock, rails and beams.
Size guide: A range of different sized machines are available covering diameters from 9” up to 48”
Example items portable band saws can cut: Conductors, structural caissons, multiple grouted strings.
Manipulator Diamond Wire Saw
Manipulator Diamond Wire Saw Key features and uses
This item is smaller than other Mirage Diamond Wire Saws. The more lightweight, compact design is easily deployed and is compatible with 3-finger, 4-finger or parallel jaw manipulators.
Size guide: Outside diameters up to 12”
Example items the machine can cut: manipulator diamond wire saws are often used to cut pipelines, casings, mooring chains.
Diamond Wire Saw
Diamond Wire Saw Key features and uses
Ideal for cutting tubular components of dissimilar materials and capable resisting compressive forces, Diamond Wire Saws are primarily used for subsea use, but can also be used topside, however when done so this is not considered a ‘cold cutting’ method. Unlike the manipulator saw above, the machine is hydraulically clamped into position onto the item to be cut and is ideal for larger cutting jobs.
Size guide: A range of different sized machines are available covering external diameters from 6” to 84”
Example items subsea diamond wire saws can cut: subsea pipelines, multistring casings, piles, platform legs, wellheads, structural caissons.
Deepwater Diamond Wire Saw
Deepwater Diamond Wire Saw key features and uses
The Deepwater Diamond Wire Saw is very similar to those in the standard diamond wire saw range, but are equipped with two modular buoyancy modules for easier ROV use.
Size guide: A range of different sized machines are available to cut external diameters from 6” to 80”
Example items Diamond Wire Saws can cut: Same as for the standard range, but at a greater depth.
Double Drill Unit
Double Drill Unit Key features and uses
This Casing Double Pin Drill unit uses 2 cutters for creating two lifting pin holes in a single operation.
Size guide: The unit can be clamped on diameters from 16” to 36”
Example items the DDU can cut: single or multi string conductors and caissons.
Single Drill Unit
Single Drill Unit key features and uses
The single pin drill serves two functions; drilling the hole and pinning in one operation to capture the position of multiple strings. After drilling, the unit is removed from the job leaving the pin drill in situ.
Size guide: Can be clamped on diameters from 16” to 36”
Example items the SDU can cut: Ideal for multistring conductor applications when pinning multiple strings together is needed.
Single String Cutter
Single String Cutter key features and uses
This machine operates from inside the component to be cut.
Size guide: Internal diameters from 24” to 48”
Example items the cutter can be used on: This is a purpose designed solution for cutting single strings from the inside and below the mud line. More information can be found in this blog post.
Bolt Slitting Saw
Bolt Slitting Saw key features and uses
This machine cuts flange bolts quicker and more comfortably than when compared with a hand held reciprocating saw. The machine is strapped onto the flange joint with the cut being made between the two flange faces.
Size guide: The current machine is designed for cutting studs on flanges API 16 3/4” or API 13 5/8” Other sized machines can be made available on request.
Example items to cut: Seized flange bolts, for example when carrying out maintenance or decommissioning work.
Clamshell/Split Frame Cutter
Clamshell/split frame key features and uses
Although designed primarily for flange removal and weld prepping, the Split Frame Clan Shell Cutter can also be used for topside decommission tasks.
Size guide: Capable of cutting pipes and casing diameters from 2” to 48”
Example items to cut: Master valve casings, wellheads, pipes.
Choosing the right equipment for an unfamiliar project may seem daunting at first. Researching company websites its a great place start, but bear in mind that if you can’t find the ideal product it doesn’t mean it can’t be sourced. Many companies (including Mirage) can adapt existing machines for specialist use, or even design a bespoke product.
Find out more by downloading our decommissioning tools buyer’s guide or if you are ready to talk get in touch here.