The best decommissioning strategy is the one that is safe, effective and efficient. Agility in the field has proven to be a catalyst for safe and effective decommissioning strategies offshore, and this agility has recently flourished with the breadth and depth of available subsea cutting equipment.
The situation can change at a moments notice offshore, and having the right tool for the right job is key. The depth to cut the piles below the seabed will depend upon the prevailing seabed conditions, local scouring, the condition of the piles or legs themselves, and currents.
These quickly changing conditions require the ability to adapt in the field and retain a fleet of machining equipment that excels in both dependability and versatility.
Having an arsenal of tools creates an ideal working environment for contractors to be sure they can handle any situation. Split frame cutters have recently increased their machining capabilities with the ability to adapt themselves with attachments to perform milling, sawing, and drilling capabilities. These plug and play attachments provide an environment where unexpected situations become controllable and practicable scenarios. Internal cutting equipment has lead to increased success in machining cuts where the external environment is not ideal for an external cut, or where time saving can be applied due to no longer necessitating external drilling or dredging around the mud line.
Articulating diamond wire saws have recently emerged in the subsea cutting world as a tool to increase the efficiency and effectiveness of low clearance cuts. These specific saws are ideal for cutting multi-string applications or heavy wall legs and cross members in the decommissioning industry, utilizing the existing diamond wire technology in a new way to perform cuts from a vertical orientation. This vertical stance means the saw can easily fit into cofferdams or excavations with minimal dredging, where other saws can’t fit or operate. The articulating design requires only two feet of clearance around casings, and the cut is made at the at the bottom of the saw so there is no need for extra dredging. The articulating diamond wire saws can easily fit into tight situations.
The compact and robust design creates an ideal cutting environment, reducing setup, installation, and removal time – saving operators and contractors time and money.
These unique articulating diamond wire saws are designed for below-the-mudline or low clearance cuts and include ROV compatibility allowing for deep-water cutting and maintenance. Many times an ROV is not even necessary as the guiding arms can be closed around a pipe and used as a guide to the location of the cut.
These efficiencies in time reduction and cut performance allow for the increased use of concurrent decommissioning practices, reducing the total time and capital associated with decommissioning projects. This also provides more scenarios to keep divers out of the water as much as possible and, in turn, out of harms way.
This abstract was written by Luke Wittenbraker for placement into offshore industry tradeshows and sharing portals. If you are interested in sharing this with your audience, feel free to contact the author.