Marine Technology Reporter Blogs - subsea

When Subsea 7 and SeeByte collaborated in engineering the AIV, the world’s first purpose built Autonomous Inspection Vehicle, they were looking for a new cost-effective asset for inspecting LoF (Life of Field) projects. The AIVs software was designed to dynamically control this unique hover-capable vehicle, which is already being used in Subsea 7 LoF projects for general visual inspection. It can also be used as an aid to field survey, integrity management and developments continue, looking at expanding its use to light intervention activities. One of the advantages of the AIV over other AUV’s is its capability to hover, maintaining station when necessary. It also has the ability to operate directly from a host facility such as an FPSO or rig as well as from infield support vessels.

As a world leader in construction and remote operations in deep waters, Petrobras has been developing new technologies and testing them with their partners in Brazil’s deepwater pre-salt fields for over a decade. Petrobras has historically opted for an incremental strategy to develop its technological capabilities to explore the Brazil’s offshore oil resources. As deepwater discoveries began to enter the production phase, Petrobras opted for using and FPSOs and wet x-mas trees. These discoveries of supergiant oil fields in the Brazilian pre-salt have offered Petrobras an opportunity for reviewing its technological path and it is becoming clear that the national operator has been increasingly inclined to move as much of the oil production systems to the seafloor as possible…

AS Connector was founded in Bergen, Norway in 2000 to provided dedicated services and equipment for deepwater pipeline inspection. In the last 13 years the company has built up a proven track record in pipeline IMR, through the use of innovative technology solutions. It has been doing extensive pipeline work with Petrobras in Brazil since 2002, including comprehensive deepwater pipeline repair systems, installation, supply of deepwater rider protection, correction of pipeline freespans, using in-house developed tools and equipment. One of their innovative equipment is a remote riser cleaning and inspection tool, the Riser Sovereign. This equipment was custom developed for Petrobras to clean and verify flex pipe integrity. The tool is self-propelled and operated similarly to a ROV.

As government agencies, research institutions, academia, and a range of industries look for new light-weight and low-cost solutions for subsea survey and inspection tasks, it becomes clear that new companies are entering the market with the goal of providing these specific services. At the same time the industry that manufactures the tools for these tasks, such as ROV’s, AUV’s and sensors and visualization software are also bringing in compact and affordable, yet powerful, products. Using the latest technology applied to inshore and offshore areas, these companies may soon be competing with established brands and in some case they offer services that few companies in the world can offer, creating their own niche.

Offshore Ocean Observatories, are composed of suites of surface and subsea instruments and sensors with long-term power supplies and permanent communications links that can feed data to scientific laboratories in real-time. Motivated by advances in computing, telecom, marine architecture and subsea sensor technology, researchers observe the oceans in real-time, for long periods of time, and sky around all the way to deepwater, including imaging and continuous sensor observation along the whole water column to the sea floor. Ocean observatories are designed to answer questions about how the seas and oceans work, their dynamics and peculiarities.

Riserless Light Well Intervention (RLWI) enables operators to increase the oil and gas recovery rate from subsea oil wells. It allows rapid well access by using smaller DP vessels instead of larger semisub drilling rigs or drillships. RLWI also enables subsea well intervention without having to use a drilling riser package connected to the subsea stack, which is topped by the blowout preventer system. Riserless intervention is a cost-saving alternative to drilling rigs, reducing mobilization time for life-of-well operations including wireline, logging, light perforating, zone isolation, plug setting and removal, and decommissioning. The technology is based on wireline well maintenance, where the cable is routed via a subsea lubricator system into the subsea well.

The Monterey Bay Aquarium Research Institute's (MBARI) Benthic Rover is a subsea lab which methodically charts deep-sea carbon cycles. To measure metabolic activity in the sediment, twin respirometry chambers isolate samples of seafloor for 3 days at a time. Agitators stir up the sediment while sensors record oxygen levels. Diagram: Ken Smith, MBARI. The rover also has two optical/acoustic scanners that detect active chlorophyll and animals like worms buried up to 4 inches in the sediment. These two pieces of information help to fine-tune the respirometry measurements and to determine how quickly sediment arrives. At the MARS site 891 m (nearly 3,000 feet) below the surface, it’s always dark and there are no plants making food.

Today, much emphasis is given to working with real-time production data, real-time pipeline monitoring, leak detection and equipment condition monitoring. ROV/ AUV operations are used to support all sorts of deepwater seafloor construction processes, allowing operators to continuously monitor their subsea systems and intervene when necessary. Basically all equipment being installed on the seafloor has real-time communication systems, which allow operators on the surface to monitor the equipment’s performance and even control much of the equipment from the surface. Equipment that can be monitored from the surface but which cannot be manipulated remotely…

According to Petrobras production engineers, secondary recovery is increasingly being implemented to improve oil recovery in the pre-salt carbonates, where reservoir rocks are usually oil wet, and this characteristic affects the performance of water injection. Another problem concerning water injection is related to rock-fluid interaction, which is more important and complex in carbonates. In order to assess the risks involved, as well as to define mitigation actions, rock-fluid interaction tests are being carried out in the reservoir rock and the salt cap rock. Alternative recovery methods are being implemented in the pre-salt reservoirs.

In any given subsea field there is a multitude of equipment, that need to be constantly monitored. Subsea Multi-Domain Condition Monitoring can be achieved by introducing additional hydrophones, specially designed for detecting sound from rotating machinery, subsea processing equipment, structural integrity, fluid flow rate variations among others. The latest high-end sensor systems ally acoustic condition monitoring with acoustic leak detection. This works in much the same way as surface-based acoustic emission monitoring and can be used to monitor rotating machinery to check speed tracking and resonant frequencies. It can also monitor rotational equipment in subsea plant such as bearing damage, unbalanced pumps, mechanical breakdown and reduced efficiency.

As more and more equipment is placed on the seafloor, especially in deep waters but also in shallow waters, concerns grow over potential hydrocarbon leaks from trees, manifolds, pumps, pipelines, flowlines, risers and valves. It’s no small challenge to have a reliable subsea leak detection system that can monitor the large array of subsea systems used in modern deepwater fields and on top of that there is the need to monitor the working condition of all this equipment and others, such as ESP’s and other pumps, which are rotating equipment. Acoustic emissions are the stress waves produced by the sudden internal stress redistribution of materials caused by changes in the internal structure.

During the recent Rio O&G 2014 Expo and Conference a range of new products for the O&G industry were launched. The size of the event, with over 1,000 companies present and tens of thousands of daily visitors made it a great medium for showing new products to the market. GE had its large booth constantly full and was probably the company, which had the largest number of new products on display. Naxys joined GE in September 2012 as a world-class sensors developer for the subsea sector. With its headquarter in Bergen, Norway, Naxys develops and supplies leak detection and condition monitoring sensors based on proprietary, passive acoustic hydrophone technology.

Compact remote methods of seabed geotechnical drilling, coring and sampling are being developed for deepwater operations and at the forefront of lightweight remote Geothechnical drilling are ROV systems combined to small drilling systems. Two companies, Forum Energy Technologies and Helix Energy Solutions, are leading the way in this technology. Forum Energy Technologies has been successfully employing its Rovdrill™ 3 system worldwide. This is Forum’s third generation Rovdrill system and it is where we will begin to look at the intricacies of these remote subsea coring and sampling systems. The advantages of taking the coring/sampling rig to the seabed are obvious, both from a technical and economic standpoint.

Remotely Operated Vehicles (ROVs) perform a wide range of tasks in a variety of underwater scenarios ranging from research to offshore oil industry support, military operations and S&R. Technological developments, have greatly enhanced their scope of operation including harsh environment operations, such as deepwater and Arctic ops. As oil operations went to deeper waters, so did ROVs, which became a key asset in subsea operations such as pre-salt development and has also been increasingly substituting divers below 300 meters, although saturation diving is very much alive and will also continue to be an important asset. The ROVs of the future will have increased intelligent autonomous behavior and will use logic driven circuitry for routine tasks like turning valves…

Ativatec is a Brazilian company specialized in subsea technology and robotics engineering. The company was born at the Genesis Incubator at the Catholic University of Rio de Janeiro (PUC-Rio) in 2005. Today, Ativatec offers subsea services for Petrobras at the Campos Basin. Ativatec has a very good track record in developing new subsea technologies in partnership with government research institutes and universities such as FINEP, FAPERJ, PUC-Rio and Petrobras. Prizes and recognition from Petrobras for the services and products developed for the National Operator along the last 9 years, has earned Ativatec a preferred partner status with Petrobras and the company is recognized as one of the main Brazilian subsea robotic companies in the market.

The C-Worker is an unmanned surface vehicle (USV) designed for offshore services in the O&G industry. The multi-role offshore USV is designed to conduct subsea positioning, surveying and environmental monitoring without the need of a ship on station or seabed anchoring. Autonomous Surface Vehicles Ltd (ASV Ltd) is a UK company and part of Global Fusion, a privately owned international marine services group based in Lafayette, Louisiana, USA. The small robust design incorporates an aluminum self-righting hull that makes the vehicle suitable for harsh ocean environments. At only 5.85 meters in length, a beam of 2.2 meters and a height of 4.75 meter with its mast extended, this USV is a much cheaper and compact option for some offshore jobs that today are done by much larger vessels.

The development of pipes that can withstand high pressure, heat and corrosion in deepwater locations such as offshore Brazil and the GoM and WA is continuous. For many years steel piping dominated the O&G industry but with pre-salt projects beyond 2,000 meters deep and corrosive enhanced oil recovery techniques widely being used in the industry, pipeline manufacturers have been looking for more flexible and robust materials. France's Technip, which is a world leader in pipe manufacture, uses layered steel with a stainless steel or plastic lining for main offshore pipes. However, British engineering company Magma Global and Dutch company Airborne are pioneering composite pipes made from a fusion of high-end fibers and plastics which are up to 90% lighter than steel pipes and do not corrode.

Bounded by the Atlantic Ocean on the east, Brazil has a coast that is 7,491 km (4,655 mi) long. Offshore, numerous islands and archipelagos form part of Brazilian territory, such as Fernando de Noronha, Rocas Atoll, Abrolhos, Saint Peter and Paul Rocks, and Trindade and Martim Vaz Islands. Yet Brazil has no Coast Guard, the coast being patrolled by the Brazilian Navy, which does not have a mandate to make arrests, but which does keep in check illegal fishing. Costal policing would theoretically be done by the Federal Police. However, the reality is that they do not have anything near enough assets to patrol such a large coast. In terms of environmental monitoring…

In the wake of the Subsea Vessel Brazil conference in Rio, Petrobras announced the approval to contract eight support vessels for its offshore activities. These are part of the 3rd Fleet OSV Renewal Plan (Prorefam). This is the 5th round and 4 vessels will be contracted from Bram Offshore, to be build at the Navship shipyard in the state of Santa Catarina, 3 from Starnav, with construction planned for the Detroit shipyard, also in Santa Catarina and 1 from Norskan, which will be built at the STX (Vard) shipyard in Niteroi, across the bridge from the city of Rio, where the Dof and Nordskan build all their Brazilian flagged ships. This is good news for the shipyards involved and for the OSV market in general, as the Brazilian offshore maritime market is heavily dependent on Petrobras orders.

Multiphase pump technology allows increased development of remote location, deepwater plays and for fields deemed uneconomical due to low flow pressure. With the ability to handle high gas volumes as well as potentially reducing the risk on the environment, multiphase pumps are being increasingly used for subsea and downhole applications. Selection of multiphase boosting options remains a bit subjective and is frequently influenced by the seller’s informationwhich may mask potential limitations of this emerging technology. Information on multiphase pumping tends to focus on a certain pump type for a specific field application, but does not provide more-generalized criteria for the selection of multiphase boosting solutions from among those available in the market.