T.D. Williamson (TDW) reported the successful development and field deployment of the Subsea 1200RC Tapping Machine, its new compact remote-controlled subsea hot tapping machine. The system, which is extremely lightweight, allows hot tapping to be carried out from the safety of a Diving Support Vessel (DSV) or platform, resulting in significant safety benefits and improvement in operational control.
Subsea hot tapping of pipelines is performed for a variety of reasons, including tie-ins, pipeline repair, insertion of instrumentation, facilitating chemical injection or providing access for temporary isolation tools. The full process – which involves installing the hot tap assembly, performing the tap and recovering the hot tap machine – has invariably necessitated diver assistance.
This has meant that the potential for subsea hot tapping was inevitably shaped by human factors, namely the limits of where divers can operate. Diver operations are limited to those taking place in a maximum of 300 meters (984 feet) of water depth, whereas a significant portion of existing subsea field infrastructure, as well as projected future developments, are in waters down to depths of 3,000 meters (9,842 feet). Furthermore, the ability of divers to operate effectively in shallow water can be affected by environmental factors, such as in wave breaking zones.