COSLProspector to run TVO wellhead system on Tui offshore New Zealand

Trendsetter Vulcan Offshore (TVO) will deploy its new wellhead fatigue mitigation system for Tamarind Resources in the Taranaki basin offshore New Zealand.


This is said to alleviate the impact of modern, large Blow Out Preventer system (BOPs) on legacy wellheads by arresting the motion of the BOP stack through four tethers, all anchored to the seafloor.


TVO CEO Jim Maher said. “This lighter and less expensive tethered BOP enables reliable operations on new exploration wells and simplifies re-entry and P&A on older wells.”


The system is said to reduce wellhead cyclic stresses substantially and enhance fatigue life.


Depending on the riser and wellhead configuration, fatigue life can be improved by 1,000 times the original unmitigated wellhead fatigue, the company claimed.


An added benefit is the increased limit to the rig watch circle, particularly in shallow water, where watch circles can be restrictive.


For the New Zealand programme, the technology will be combined with a wireless monitoring system based on Sonardyne’s Subsea Monitoring, Analysis and Reporting Technology (SMART) to reduce wellhead fatigue during the semi-sub COSLProspector’s upcoming drilling on the Tui oil field.


SMART is said to ensure that operations remain within fatigue safety limits by monitoring movement of the BOP and the bottom of the drilling riser, and providing in situ data processing to extract information such as minimum, maximum and standard deviations for accelerations and rotations in all axes.


According to Kevin Chell of TVO, the new design addresses the need to access wells where the wellhead was not designed to handle the loads and strain induced by modern, larger, and heavier BOPs.


“Using our tethering and monitoring system, operators are able to use their subsea infrastructure with confidence for longer, which means they can access more resources and extend the life of their fields economically.”


Source: Offshore Magazine