Record-breaker

DOF SUBSEA RECYCLES 99% OF DECOMMISSIONED OIL RIG

DOF Subsea claims nearly all of the materials making up the Buchan and Hannay oil fi eld projects were recycled or repurposed

DOF Subsea says it has decommissioned both the Buchan and Hannay oil and gas fi eld projects off the north coast of Scotland and achieved a 99% recycling and repurposing rate for all materials.

Operated by the Spanish/Chinese joint venture Repsol Sinopec, the offshore works were decommissioned in 74 days, says the company, which provided the engineering, preparation, removal and disposal (EPRD) services using its Skandi Skansen and Skandi Acergy vessels.

“The works saw the recovery of 135 concrete mattresses weighing approximately 800 tonnes, more than 12km of rigid pipelines, SSIV/PLEM structures, 15.5km of flexibles and umbilicals, spoolpieces, and around 1,500 grout bags and general debris,” DOF Subsea says.

“The material was shipped to Aberdeen Harbour’s Clipper Quay for dispersal, with 95% of the material being recycled and 4% being repurposed. Only 1% was sent to landfill as a last resort.”

Fifteen concrete mattresses were repurposed into aggregate for use in roads at the harbour, plastic sheaths from flexible risers and umbilicals were recycled by an approved supplier, and all metal was smelted.

“We are delighted with this outcome as part of one of our biggest subsea decommissioning projects in the North Sea to date,” said Luis Batalla, head of Decommissioning at Repsol Sinopec.

Repsol Sinopec has also announced that the Golden Eagle, Piper and Claymore field owners have executed new agreements reaffirming their commitment to export produced oil to the Orkney Islands’ Flotta Terminal until end of field life in the 2030s.

”This commitment to support the longevity of the terminal underpins a variety of growth opportunities in the wider area, including renewed drilling and several third party tie-backs. All field owners have recently completed successful drilling programmes to increase production volumes and are actively engaged with a number of third parties that are considering the use of the offshore facilities,” the JV said.

8 Decommissioned:

Repsol Sinopec’s Buchan and Hanny oil and gas project in the North Sea off Scotland

Subsea monitoring project fi rst

A subsea monitoring project has been completed using high-speed through-water wireless optical modems.

This is the first time that international subsea equipment rental and solutions company Ashtead Technology has used Hydromea’s LUMA high-speed throughwater wireless optical modems since signing a global rental partnership last year.

“When completing subsea installation projects, it is vital that the information provided is accurate, reliable and delivered in real-time. This reduces the risk of damage to the structure during installation and ensures it is installed within specification,” said Ross MacLeod, technical director, Ashtead Technology.

“We have been using LUMA modems on construction projects over the past three years and we have been very pleased with the functionality and ease of integration of the devices into our existing systems. The technology used within the LUMA modems is cutting edge and advances subsea data communication significantly whilst helping to reduce project complexity, risk and cost,” added Mr MacLeod.

This latest project saw Ashtead Technology provide its Autonomous Structure Monitoring Systems, which were each integrated with LUMA optical modems, to complete an underwater installation monitoring work scope for subsea and offshore wind contractor, Havfram, in the Norwegian North Sea.

Work scope included the provision of ten Autonomous Structure Monitoring Systems, two for each suction anchor template and an additional four Autonomous Structure Monitoring Systems, which were used to monitor the installation of a range of subsea structures. The Structure Monitoring Systems were configured for autonomous independent operation, communicating data to one of the installation ROVs. Ashtead Technology utilised LUMA optical modems to enhance the accuracy of the data collected, ensuring maximum performance of the system.

LUMA products are small, light, low power consuming subsea optical modems that provide high-speed and high-bandwidth wireless communication at depths of up to 6,000 metres with low latency, even in the murky waters of the North Sea. Ashtead Technology has rolled out the use of LUMA technology in all of its offshore energy global construction and O&M projects.