Delivery System sends VideoRay with Subsea Interchangeable Tooling to Inspect and Collect Interior Samples for of Large Storage Tanks Offshore
The problem facing Dong Energy in the North Sea is daunting. More than 500 platforms that have produced oil and gas for years are coming to the end of their productive lives. Many of these rival the size of the Eiffel Tower, and are located in deep and turbulent waters. When designed, constructed, and put into service, no thought was given to their removal – but international rules require that they be decommissioned and entirely removed. Estimates of decommissioning costs exceed one hundred billion dollars, and the technology and techniques for doing this safely and effectively are just now being developed.
One such problem facing Dong is inspecting the oil storage tank of the Siri platform, including environmental sampling and inspection inside the tank. The tank’s interior was never designed to be inspected, and access is very limited. The solution will be provided by Stinger Technology AS of Stavanger, Norway, a specialized systems integrator with tailored solutions to problems posed by working subsea in confined spaces. The challenge in this inspection was to get an ideal inspection tool that Stinger has had considerable experience with – the VideoRay Pro 4 – into exactly the right position to enter the tanks, and then to perform the necessary inspection and sampling without assistance from the surface while inside the tank.
To accomplish this, Stinger is developing the first-ever subsea tooling interchange system for a microROV, with several measurement tools and sampling tools to sample wax on the wall, sediments from the floor and emulsion from the oil-water interface. The VideoRay micro ROV collects water quality parameters, bathometric data from a scanning sonar and wax, sediment and emulsion samples from the oil/water layer. The bathometric data in combination with the ROV’s depth sensor is used to generate sediment volume measurements, which are critical for the decommissioning process.
VideoRay’s powerful and reliable Pro 4 series has been a mainstay of Stinger’s innovative environmental survey systems for years. Using an industry standard larger system such as the Falcon to deliver it was an easy choice, and MacArney’s deployment expertise – used successfully with other VideoRay systems recently, will ensure the success of this mission.
“It is always a pleasure working with VideoRay” said Bjarte Langeland, the CEO of Stinger. “I can count on VideoRay to help me customize and enhance their standard products for these extremely difficult projects from my demanding clients.”
PHOTO CREDIT: Stinger AS – This picture of the subsea system under development shows the current state of the project.Note the Tether Management System holds 125m of neutral Videoray tether, and the unique design assure constant tension when reeling in and out. Under the TMS a sampling toolbox holds the various tools for the Pro4, which will be picked up by the manipulator and interchanged during the mission without surfacing. The integration was carried out by Bjarte Langeland, Chief Executive Officer/ BSc/ Founder and his team at Stinger AS