The decommissioning of subsea oil and gas installations presents many difficult challenges, each needing to be overcome safely, within budget and without causing harm to the environment.
One example of these problems is the removal of piles or “strings,” which may have been used for structural purposes or as the drill string within a wellhead for transporting oil from beneath the seabed.
One product that makes this achievable is a “single string cutter.” This particular product is designed for cutting through cylindrical walls made from a single material.
This tool is capable of severing a single string of casing, conductor or pile using efficient cutting technology. Unlike other cutting machines such as band saws and diamond wire saws, a single string cutter is designed to fit inside the shaft needing to be severed. A cutter attached to a spindle cuts through the wall thick-ness and then follows a path around the diameter of the shaft, returning to the starting position to complete the cut.
Let’s take a look at the step-by-step process of using this machine:
First, the machine is lowered from above the surface until it is positioned at the required depth. It is then secured using integrated clamping jaws, and a mapping roller is rotated to verify the internal size/condition of the pile.
Next, the cutter’s spindle is rotated and radial out-feed is engaged. The out-feed hits the pre-set stop, which engages rotation for the cut path. Wedges are then deployed into the cut at pre-set intervals to eliminate any risk of the cutter being trapped.
Using the provided verification software, pressure readings show the status of operations. When rotation is complete, the clamping jaws are released and the machine is retrieved. The severed pile can then be lifted and removed.
For more information or advice on a machining project, visit www.miragemachines.com, call (281) 859-1234 or email sales@miragesubsea .com.