DOSSIER

 

Operating shuttle tankers in Brazil


Demand for shuttle tankers is growing. However, their operational practices vary from region to region.

In an industry note, DNV GL took a closer look at Brazilian shuttle tanker operations, which has replaced the North Sea as the biggest single market. DNV GL recently invited the major players to a shuttle tanker workshop to share experiences and take a closer look at the market as well as new developments and technologies that can be adapted from other areas, such as the North Sea.

Jonas Mattos, Business Development Manager, DNV GL South America, explained the background: “These gatherings are important for us as we get all relevant stakeholders together to learn from best practices and discuss potential measures to further enhance the efficiency and safety of shuttle tanker operations. In a developing area as diverse as Brazil, where the field operators develop their own framework of operational regulations, making decisions that are normally left to authorities in other regions of the world, it is of utmost importance to get a better understanding of what is going on in the market.”

Catrine Vestereng, the class society’s Business Segment Director Tankers, talked of the emergence of shuttle tankers: “These ships are deployed to areas where subsea pipelines are not feasible, such as harsh climates, deepwater or remote locations. ‘Traditional’ shuttle tankers with bow loading and dynamic positioning initially started operating in the North Sea. They are now spreading to all corners of the globe, from Brazil, Russia and Canada to West Africa and various locations in Asia.

“While they feature varying technologies and safety levels, depending on weather conditions and traded volumes, they all benefit from the experience and technology developed for the North Sea,” she explained.

The shuttle tanker fleet has been growing steadily since the first ‘boom’ in the mid-1990s. There are currently 86 ships in service and 17 on order, which are expected to be delivered by 2021. Vessel sizes range from 35,000 to 170,000 dwt, with the majority in the 140,000 to 160,000 dwt category, a typical size for Brazilian waters.

Teekay Offshore and Knutsen NYK Offshore Tankers (KNOT) are the two biggest owners of shuttle tankers. Samsung Heavy Industries is the biggest builder, and DNV GL the leading class society with a share of 64% of the fleet in service and a newbuilding market share of 88%.


Brazil leads

With around 35 shuttle tankers in operation, Brazil is the largest deployment region and will remain so in the foreseeable future. According to Clarksons, there are at least 22 new oilfields under development in the probable or the discovery phase worldwide.

Brazilian oil companies have indicated that as many as 14 FPSOs will be installed by 2023. These will require a large number of shuttle tankers for offloading.

The biggest player in the Brazilian market is Petrobras, but other multi-national oil and gas companies are also present, including Equinor, Total, Chevron, Shell and ExxonMobil, Repsol and Galp.

Transpetro, a wholly owned subsidiary of Petrobras, illustrates the expanding Brazilian shuttle tanker market, having performed offloading operations since the mid-1970s, and specialised in offloading since 1996.

The company currently operates 14 shuttle tankers under timecharter for Petrobras, moving crude oil from FPSOs to terminals. The company is planning to upgrade its shuttle tanker fleet with new DP2 Suezmax vessels. Transpetro’s 2019–2023 strategic plan anticipates more Suezmax shuttle tankers being hired on a bareboat basis in the coming years.

AET is one of the newcomers in the shuttle tanker business in general and the Brazilian arena in particular, having placed several newbuilding orders lately, which will be chartered by Petrobras and Shell.

Bringing their experience from the North Sea, Teekay Offshore and KNOT Management Do Brasil are today among the main shuttle tanker operators in Brazil. They operate fleets of seven and 12 (plus two more in 2020) vessels, respectively.

 

New designs

Shuttle tanker designs have evolved considerably over the years, with the main focus on safe and environmentally friendly operations as well as manoeuvrability and positioning in rough weather, optimisation of loading procedures and systems, and reduction of emissions to sea and air.

New generation shuttle tankers entering the market today feature sophisticated bow loading and DP equipment. Some of the new shuttle tankers operating in the North Sea will use LNG technology. The Teekay E-Shuttle tanker types will operate on both LNG, as the primary fuel and a mixture of LNG and recovered volatile organic compounds (VOCs), as secondary fuel for dual-fuel engines.

Jose Elias, Teekay Brazil managing director, said: “LNG-powered shuttle tankers is a new concept. LNG is environmentally friendly and will become a trend in the future.” However, in the short term it will probably not be seen in Brazil, since local requirements are less stringent in the area than in the North Sea.

“Developments in the North Sea usually cascade to Brazil at a later time. Stricter emission regulations in the North Sea force shipowners to reduce emissions drastically. Furthermore, LNG bunkering stations are available there, enabling the use of those cutting-edge vessels in the North Sea,” Elias added.

IMO regulations applicable to shuttle tankers are more general and identical to those for crude oil tankers. In addition, IMO has developed guidelines for bow loading and vessels with DP systems.

Based on its decades of experience, DNV GL has developed rules to ensure a much higher safety standard than the non-mandatory IMO guidelines for DP, offshore loading and vapour recovery systems.

Most of the oil companies and operators therefore refer to class rules, especially those issued by DNV GL, as the standard for shuttle tanker design. For Brazil, Petrobras has its own specifications and guidelines, which are based on years of experience, as well as knowledge transferred from the North Sea.

A typical class notation for shuttle tankers and their high-risk operations is the Bow Loading notation. DNV GL’s rules for this cover the overall requirements for state-of-the-art offshore bow loading systems including fire safety, and requirements regarding telemetry and emergency shutdown (ESD) systems.

Today most shuttle tankers comply with DP redundancy as a minimum, which is similar to the IMO DP Class 2 requirements or higher. Local DP requirements, however, depend on industry practice in the respective region.

For example, in Brazil, IMO DP Class 2 is today’s minimum requirement, which corresponds to the DNV GL DPS(2) notation. In other parts of the world with harsher environmental conditions, eg in the North Sea and in UK and Canadian waters, DYNPOS(AUTR) has been established as the required minimum. DNV GL thought that this trend will continue, which means that DYNPOS(AUTR) may also become a requirement in Brazil.

The DP class notation spells out the required system redundancy, rather than the DP capability of the vessel, which depends on what the client needs and where operations take place, so naturally that decision is up to the Brazilian oil operators. For DYNPOS(AUTR), DNV GL requires the DP capability of a vessel to be documented.

A typical notation string for a modern shuttle tanker intended for operation in Brazil would be:

  • 1A Tanker for Oil ESP CSR E0 DPS(2) BOW LOADING F-M NAUT(OC) SPM TMON VCS(2) BIS BWM(T) COAT­PSPC(B,C) CLEAN RECYCLABLE LCS.

By comparison, a typical North Sea shuttle tanker operation might have the following notations:

  • 1A Tanker for Oil BIS BMON Bow loading Battery(Safety) BWM(T) CCO Clean(Design) COAT-PSPC(B, C) COMF(C-3, V-3) CSA(FLS2) CSR DYNPOS(AUTR) E0 ECA(SOX-A) ESP ESV(DP[HIL-IS]) F(A, M, C) Gas fuelled HELDK(S, H, CAA-N) HMON(A1, C, G1) LCS NAUT(AW) Plus Recyclable RP(2, 50%) SPM TMON(oil lubricated) VCS(2).

Offloading operations

Shuttle tanker operations in Brazil differ from North Sea in a number of ways: In the North Sea, and in Norway in particular, all offloading operations and consequently all DP activities are regulated by the Petroleum Safety Authority Norway (PSA) and DP systems are compulsory.

“In Brazil, operators have the choice between DP operations or the old way, like taut hawser offloading for example,” explained Lars Ole Hagland, KNOT Management Do Brasil general manager. Some oil operators in Brazil have already decided to operate with DP2 systems in all their fields, which means they also make all related decisions regarding DP operations.

“If an incident occurs involving a DP system on a shuttle tanker operating in Norway, it needs to be discussed with the authorities. In Brazil, no authorities need to be involved as long as there is no serious damage to the environment. In case of a severe incident ANP and Navy will be informed and need to decide on further investigations,” Hagland explained.

On the Brazilian continental shelf, DP operations involving FPSOs can either be performed with spread mooring, or using a turret without heading control. Unlike the North Sea, where FPSOs weathervane around an internal turret with the shuttle tanker following, most FPSOs in Brazil are spread-moored in a fixed position.

During loading, the shuttle tankers must therefore maintain a fixed position relative to the FPSO in the face of wind, waves and particular currents, which can be strong and variable in this part of the world. KNOT for example performs about 86% of its offshore connections with FPSOs in Brazil using spread mooring but only about 14% using a turret.

Since many shuttle tankers handle up to 50 loadings per year, discharging through ship­to-ship (STS) operations, they are hardly ever seen alongside a terminal. This harsh routine is stressful for both crews and operators, and it is difficult to allocate time for maintenance, DNV GL said


Operational challenges

Brazilian operational safety is improving steadily, mainly in response to Petrobras’ drive to develop appropriate guidelines. However, in the absence of a regulatory body or authority dictating requirements, some operational processes differ quite substantially from other parts of the world, ie the North Sea.

Considering KNOT’s 31 years of experience operating shuttle tankers, the workshop organisers in Rio de Janeiro asked KNOT’s management to share their operational experience and indicate potential areas that could benefit from revised processes.

One typical area, which may benefit from improvements is the standardisation of equipment on board FPSOs, for example, the introduction of standard requirements for a wireless Offloading Monitoring Telemetry System (OMTS), which includes an automatic remote shut-off feature for platform pumps to stop the flow of oil between the FPSO and the tanker.

These systems establish a ‘green line’ between the FPSO and the tanker’s bow loading system, which sends an ‘all clear’ signal for offloading after the monitoring circuit has verified that all valves and couplers on board the tanker are in correct position and that the mooring system and hose connections are properly secured.

This system has not been fully implemented as an additional safety measure in Brazil thus far but will be installed on more vessels over time.

Communication between FPSOs and shuttle tankers is one of the daily challenges in Brazil, not only because of the language barrier but also due to the fact that it is done via VHF radio. Installing telemetry and switching to UHF will improve communication and help prevent accidents.

Another focus area is emergency towing systems on the aft end of shuttle tankers. “It is important to test the equipment on board the shuttle tanker and tug and to train the crew properly. If these items are not documented, a finding during vetting is very likely to occur,” Hagland said. In Brazil training is not mandatory yet but some field operators have started requiring it for safer operations.

“The safety of shuttle tanker operations in Brazilian waters is everybody’s concern, and there is genuine interest in the industry to share operational experience to enhance operational safety and reduce downtime.

“The everyday challenge is to do what it takes at the right time. Nevertheless all the operators indicate their commitment to ‘safety first!’, which goes well with DNV GL’s objective ‘safeguarding life, environment and property at sea’,” Vestereng concluded.

 

 

 

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