final proposal helios jip

M A R I N P.O. Box 28

6700 AA Wageningen The Netherlands

T +31 317 493 911 F +31 317 493 245

E [email protected] I www.marin.nl

HELIOS Helicopter Operations for Offshore Ships

Final JIP Proposal

Version 6.0

November 2010

Proposal No. 22365-1-TM

November 2010

HELIOS Helicopter Operations for Offshore Ships

Final JIP Proposal


November 2010

1 BACKGROUND

Helicopter services have been used by the offshore industry for decades. Traditionally

the offshore production platforms were fixed. For drilling, installation and work-over large

and stable semi submersibles were deployed. Helicopter operations could be conducted

on such platforms, which are hardly affected by wave induced motions.

The current deepwater and marginal field developments and the available technology

have resulted in the use of floating production units such as FPSO’s, TLP’s and Spars

as well as moderately sized mono hull vessels for support services such as installation,

well intervention, seismic and survey work or other sub-sea activities. All these floating

units exhibit wave induced motions, which can be severe due to resonant roll (no-

heading control), swells or high seas.

As the activities of these vessels require permanent station keeping or tracking for

extended periods, logistics of crew, equipment and stores heavily depend on helicopter

transport. This implicates that helicopters have to approach, maintain position on deck

and depart from vessels exhibiting wave induced motions. Helicopters are also providing

emergency services in case of casualties and evacuations (e.g. hurricanes in the GoM).

If for some reason a helicopter cannot be operated the vessel has to rely on ship to ship

transits or has to stop its operation and go to shore. Therefore heli-operations are crucial

for the safety and economy of these offshore floaters and vessels.

In countries around the North Sea, Civil Aviation Authorities (CAA) and helicopter

operators have agreed on limits for safe operation of helicopters to floating offshore

vessels. In Norway, the helicopter operators (CHC and Norsk Helicopter) are operating

under a strict regime; for “small” vessels; helicopters are only allowed to land and

remain on deck if pitch and roll angles are less than 2o and the average heave rate of

the largest wave is less than 1m/s for the last 20 minutes. Since the introduction of this

regime, no major helicopter deck accidents have occurred offshore Norway. At the same

time it is noted that this restriction is limiting several offshore operations in terms of

logistics and planning. In the UK the landing limits currently in use are based on a

maximum heave value of 5m double amplitude but operators have argued for the

introduction of heave rate based limits such as the “Norwegian Method”. The criteria

currently in use are based on old empirical data and not supported by scientific work.


November 2010

Often helicopter services cannot be deployed and are delayed for several days to the

point that the vessel has to stop offshore operations and go into harbour herself for crew

changes and supplies.

In the coming decades offshore energy production will become more and more

dependent on helicopter operations. Not only will oil and gas production be more and

more based on floaters, these floaters will also be deployed in more remote harsh and

even arctic conditions (Snøvit, Shtokman). At the same time for offloading, installation,

early well-testing & workover relative small vessels will be used. For offshore wind

turbine parks access by helicopter will be essential for maintenance and inspection.

As mentioned, since the introduction of this regime in Norway no major helicopter

accidents have occurred. On the other hand the criteria used are lacking rational basis;

critical parameters such as helideck accelerations and cross-wind components are not

included in the regulations. Therefore the current criteria are not necessarily

conservative from a safety point of view. A workability analysis for an 80 m light well

intervention vessel operating offshore Norway, showed that the downtime for helicopter

operations in winter time assuming good visibility varied between 70 and 90%

depending on the relative wave direction. This is unacceptable for an economic

operation of this vessel as it requires the vessel to disconnect riser systems and go to

port herself on a regular basis.

In other parts of the world as well as on navy vessels, helicopters are operated safely

under much wider workability envelopes. E.g. in the Royal Netherlands Navy helicopters

are safely operated up to 20 degrees of roll motion. Military helicopters however are

guided by a flight intendant on deck and latched onto the helideck whereas civil

helicopters are standing on deck with a running rotor which makes them sensitive for

transverse accelerations and wind gusts. Moreover offshore production vessels normally

produce high temperature exhaust gases which may significantly reducing the heli-jet.


November 2010

As helicopter services form a critical link in offshore logistics and safety is top priority in

all offshore operations, there is a need for a better physical understanding on offshore

helicopter operations especially in relation to (small) ships to optimise these services. It

is noted that safety is and will be top priority in all operations of the oil and gas industry

of NW Europe.

In this respect the following questions are relevant:

1. What are the current regulations and operational limits for offshore helicopter

operations in NW Europe both in the civil industry (offshore) and in the defence

sector (navies)?

2. Can wider operational envelopes for helicopters be developed, maintained or

increased by the present high safety level?

3. Which are the dominant physical parameters involved in each of the phases of

helicopter operations (landing, parking and take-off)?

4. Can the 3-D turbulent windfield around the heli-deck including possible exhaust

gases be predicted by numerical models?

5. How can design of ships and heli-decks contribute to safety and workability of

helicopter operations?

6. Can a rational methodology toward the development and acceptance of operational

envelopes/criteria be developed?

7. Can the offshore vessels be categorised in terms of heli-platform motions and wind

conditions or should criteria be based on absolute Meteo and motion data?

8. Can advisory systems be (further) developed to assist the helicopter pilot?

9. Can the physical understanding be captured in numerical models i.e. a helicopter-

ship simulator for training of pilots and testing of systems?

In the UK, the CAA and WS Atkins have been working on several of the above issues to

replace existing operational criteria with new criteria that are based on the

understanding of helicopter stability on heli-decks. This work is supported with some

field data and has resulted in an operational envelope approach which is based on a

Motion Severity Index, a predictive measure of the maximum motions (MMS; Measure

for Motion Severity) in the next 10 minutes, and the Wind Severity Index, a predictive

measure of the wind speed.

The safe operational envelope is then defined as the area under a curve (the “limiting curve”, as shown below:


November 2010

This work has also identified the need for further investigations such as:

Wind field in particular the wind updraft around heli-decks of ships;

The dispersion of high temperature exhaust gases produces by ship engines, gas

turbines and flares.

Long term heli-deck motions (accelerations and inclinations) and statistics of MMS in

relation to vessel design and heli-deck location;

Landing operation and the use of heli-ship simulators;

Verification of the helicopter reaction forces ;

Extension of the operational envelopes for different helicopters;

Testing of newly developed operational criteria;

The present R&D proposal aims to investigate and resolve the issues presented taking

advantage of the insight and results of the work already performed in the UK and in

other sectors such as the defence industry. This proposal is the result of discussion with

UK CAA, NO-CAA and NL-CAA, Shell, Statoil, Petrobras, Kongsberg, Bayards, NLR

and Atkins. MARIN has been invited to organise this initiative, named HELIOS. The

work will be conducted as a Joint Industry Project with participation of oil companies,

vessel operators, helicopter operators, equipment suppliers, CAA’s and R&D

organisations. This participation ensures the required technical expertise, operational

experience and enables a common understanding and implementation of the results.

The partnership conducting the work in this JIP consists of MARIN, Atkins, NLR and

Kongsberg. The work will be conducted in close contact and full support by the aviation

authorities of UK, Norway and The Netherlands. UK-CAA has confirmed that results of

prior work by Atkins for the Helicopter Safety Committee will be made available to this

project.

MSI

safe

unsafe

WSI

β=-90°


November 2010

2 OBJECTIVES

The proposed study is aiming at resolving the issues mentioned in the previous section.

More specific this study should result in the following:

1. Report on current practice of helicopter operations on board offshore vessels

including the relevant CAA regulations and flight procedures of the helicopter

operators in the various countries and sectors;

2. Insight in the physics related to helicopter operations in relation to offshore ships

supported by scientific results from numerical, experimental and full scale tests;

3. Methodology for assessment of operational envelopes / workability criteria;

4. Recommendations for design of ships and heli-decks;

5. Recommendations for systems improving safety and workability;

6. Feasibility assessment of a helicopter-ship simulator for training and testing.


November 2010

3 SCOPE OF WORK

The tasks to be conducted in this pilot study are directly related to the required

deliverables:

1. Current Practice

Review of the existing practice and regulations in NW Europe and other areas. I.e. the

rules and regulations issued by the national aviation authorities, EASA, IVW and the

practice in offshore and navy in Norway, UK and Netherlands. This work includes

interviews with regulatory bodies and offshore helicopter operators in these countries.

2. Physical Understanding

Investigation into the physical parameters dominating the dynamic behaviour and safety

of helicopters when operating for offshore vessels. This includes the published results,

previous model tests and documented trials offshore. This task comprises heli landing,

helicopter stability on deck, wind field and heli-deck motions.

Helicopter landing

A helicopter approaching the vessel for landing is subject to the wind field around the

heli-deck. The local wind velocity and turbulence is strongly dependent on the wind-

climate, the vessel super structures and the location of the heli-deck . Another important

factor for the heli-pilot are motions of the helideck which basically are in 6 degrees of

freedom. In particular for high level bow mounted heli-decks these motions are

dominated by roll and pitch of the vessel. Landing on such heli-deck the pilot also

suffers from a lack of view on the vessel motions.

Helicopter stability

As helicopters on offshore vessels are normally not secured to the deck and keep their

rotors running with a minimum pitch setting, the stability of the helicopter with respect to

sliding and tipping is a main concern. Research has shown that the lift provided by the

rotor is a significant part of the weight and thus a destabilizing factor. This lift increases

with speed and rotor disc inclination as well as by updrafts.

Deck accelerations rather than the currently used static roll and pitch angles are the

crucial factors in this stability. The “Measure of Motion Severity” such as proposed in the

UK is defined as the ratio of the total accelerations in the horizontal directions and

normal to the deck. This “pendulum” angle thus includes the inertial accelerations which

are crucial for the stability. This concept will be evaluated in detail and existing heli-

stability model developed for Super puma and Sikorsky -76, will be refined and extended

for other types of helicopters.


November 2010

Wind field

To gain further insight in the wind field around heli-decks on board floaters and ships,

CFD modelling will be applied. The numerical analysis will provide data on the unsteady

wind conditions i.e. the mean wind velocity and turbulence fields including the wind

updraft which is important for helicopter stability.

On board offshore ships and FPSO’s exhaust gases produced by the ships engines, gas

turbines and flares are entering the wind field around the heli-deck. This a potential

hazard for helicopter operations as the thrust of the jet engine is strongly reduced by the

intake of high temperature exhaust gases.

For the evaluation of helicopter approach, landing and stability an accurate prediction of

the 3-D wind field around the heli-deck is essential. So-far such predictions have been

made by wind tunnel tests and numerical analysis. For numerical analysis normally

Reynolds Averaged Navier Stokes (RANS) CFD-codes are used. These codes however

only solve the station airy mean flow and the effect of all vortices (eddies) on the flow is

modelled by turbulence model. Besides the “steady RANS” also unsteady RANS or

URANS is used for many maritime applications.

For wind flow around complex objects however, which is characterised by very

strong turbulence (Reynolds numbers up to 106-107) and massive separation with a

wide turbulence spectrum, URANS should not be used. The reason is that URANS

is not a simulation of turbulence, but only of its statistics. In gas concentration RANS

models can easily give errors up to 300% and even 500% which is completely

unacceptable.

To obtain accurate simulations of the time-dependent flow over a heli-deck including the

actual simulation of vortices and gas concentrations, a new CFD model will be

developed. This model will be based on Large Eddy Simulation (LES) technique which

models only the eddies that are larger than the grid size. The effect of subgrid-scale

vortices will still simulated by a turbulence model.


November 2010

While the LES method itself is rather old, its application to atmospheric wind flow around

bluff bodies such as ships is new. The effect of LES compared with RANS is clearly

demonstrated by the adjacent figure (simulations by TU-E). Further details are given in

Appendix I.

Flow direction Flow direction

(a) RANS (b) LES

Flow directionFlow direction Flow directionFlow direction

(a) RANS (b) LES

The goal of the LES CFD simulations in HELIOS is to provide the distribution in time and

space of the relevant flow parameters to support helicopter operations. These flow

parameters are: mean wind speed, turbulence, pressure, temperature and exhaust gas

concentration. To this extent, this part of the HELIOS project consists of two research

components:

(1) Fundamental research: Optimising LES and/or hybrid LES/RANS for high-Reynolds number flow around ship configurations as a function of atmospheric boundary layer inflow conditions, geometric model representation, grid resolution, near-wall modelling and subgrid-scale modelling. Validation of simulations with these different parameters is performed by comparison of the simulation results with high-quality wind tunnel measurements. If necessary, new near-wall and/or subgrid-scale models will be developed and tested. The result is an extensive set of “Best Practice Guidelines” as a tool for future simulations. The fundamental research component provides the necessary basis for the success of the applied research component.

(2) Applied research: Application of CFD LES based on the developed Best Practice Guidelines for specific ship and helicopter deck configurations to provide insight in the wind conditions and to provide the boundary conditions for the other research tasks within the HELIOS project, including the Heli-Ship-Simulator.

The work on the LES CFD developments will be conducted by TU-Eindhoven in a

separately funded project. HELIOS JIP Supports this work with dedicated

windtunnel tests for verification and validation of the numerical model. The

results will be shared with the HELIOS Participants.

Heli-deck motions

The motions of the heli-deck are obviously the dominating factors for helicopter

operations offshore. The Measure for Motion Severity to be established for the

helicopter landing and stability on deck is strongly dependent on the ship size, loading

condition and stability as well as on the location of the heli-deck. From earlier research it

is known that the distribution of the MMS does not follow the commonly used Raleigh-

distribution for ship motions. For the prediction of the maximum values on the basis of a

limited period of motion records (typically 20 minutes), therefore the long term statistics

have to be investigated for various ship types and heli-deck locations and a reliable

extrapolation method has to be developed. The procedure will be checked by means of


November 2010

heli-deck motions recorded over a long period on board a offshore support vessel in

operation on the North Sea. Based on the new MMS prediction method a workability

analysis will be applied for various ship types and heli-deck locations.

3. Methodology for operational envelope

Derivation of a rational approach to establish operational criteria and workability

envelopes. This work will be based on the outcome of Task 1 and 2. The methodology

will include all phases of the helicopter operation i.e.: Approach of the vessel, Landing,

On deck stability and Departure.

Specifically use will be made of the existing procedures as issued by HCA for helicopter

approach, NLR for disturbed wind field approaches and SAIF (Ship Air Interface

Framework) in UK.

In particular the work conducted in the UK on helicopter stability and the proposal for

operational envelopes based on a Motion Severity Index and a Wind Severity Index

(The so-called MSI/WSI-limits) will be incorporated in this work. The UK-CAA has

confirmed to join Helios and to share results from their previous research. This forms a

solid basis for further work in HELIOS.


November 2010

4. Ship Design, Systems & Operations

Design of ship, heli-deck, systems and the actual operation of the vessel can contribute

significantly to the workability and safety of helicopter operations. For example one of

the major challenges for a heli-pilot is to land safely without any ship motion reference

when the heli-deck is mounted on the bow and the heli has to land nose forward. A

reference frame in front of the pilot can contribute is such situations. Also data

transmission between vessel and heli to provide info on Meteo, vessel motions and

relative speeds/distance could be an improvement. In this task potential improvements

will developed and evaluated.

5. Heli-Ship-Simulator

Recently a helicopter-ship simulator (Helicopter Pilot Station) for training of navy

operations has been developed by NLR. This simulator will be used for developing and

testing operating procedures and safety-critical systems for offshore vessels.

The simulator should resemble the governing parameters and behaviour of helicopter

and vessel including advisory systems such as heli-deck monitoring and pilot guidance.

6. Trials (Phase II)

In Phase II of the JIP full scale trials with helicopters approaching, landing, standing on

deck, and taking off from offshore vessel to verify and demonstrate the methodology

developed in Task 3 will be conducted. For these trials extensive instrumentation of

helicopter and heli-deck will be deployed. Results of earlier trials such as conducted in

the UK in recent years will be evaluated.


November 2010

The detailed plan for the Phase II trials will be drawn up after completion of Task 2 and

3. For these trials use will be made of helicopters and ships preferably operated by

participating companies. The trials will be conducted on airports, on an oscillating

platform (Test Pilot School Southampton) and on an offshore vessel.

7. Implementation & evaluation

Results of the above tasks will be evaluated and used to formulate:

Recommendations for design of vessels, heli-decks, systems and operations to

improve safety and economy of heli-operations;

Recommendations for the operational criteria for helicopter operations on offshore

vessels.


November 2010

4 ORGANISATION

The proposed work will be conducted on behalf of companies and organisations

participating in the HELIOS Joint Industry Project by the following partnership:

MARIN; Maritime Research Institute Netherlands;

Kongsberg; Control system integrators and suppliers, Norway;

NLR; National Aerospace Laboratory, Netherlands;

Atkins; Engineering company based in UK;

The JIP will be conducted as a joint Public-Private R&D project in which all stakeholders

are represented; in particular the following organisations:

Aviation authorities;

Oil companies;

Offshore contractors;

Vessel operators;

Helicopter operators;

Suppliers of relevant equipment.

The UK-CAA, No-CAA and NL-CAA have confirmed their support of this project and are

prepared to share results of their research work in this field with the HELIOS-JIP.

With these stakeholders directly involved in the project, the required expertise and

operational experience will be available for the project at the same time this group

enables the implementation of the findings in both the regulations and in the operations.

The work will be conducted in close co-operation with partners and participating

companies and the civil aviation authorities with input from the relevant helicopter

operators. MARIN will be the main contractor for this project and will subcontract the

relevant sub tasks.

Meetings will be held every 6 months and hosted by FPSO JIP Week or by one of the

participants.


November 2010

5 FINANCE The budget estimate for the above work is as follows:

Task Partner Cost in

Euro

1 Current Practice Marin/NLR 30,000.-

2

Physical Understanding

Helicopter landing

Helicopter stability

Wind tunnel tests for LES CFD valid.

Heli-deck motions & workability model

NLR

Atkins/Marin

NLR

Marin

50,000.-

42,000.-

50,000.-

57,000.-

3 Methodology for operational envelopes NLR/Marin/Atkins 120,000.-

4 Ship, design, systems & operation Marin/Kongsberg 41,000.-

5 Tests on Heli-Ship-Simulator NLR 36,000.-

6

Best Practice

Recommendations Rules & Regulations

Marin, NLR,

CAA’s 54,000.-

Subtotal Phase I 480,000.-

7 Trials (Phase II) Marin/NLR/Atkins 470,000.-

8 Implementation & Evaluation

Marin/Atkins/NLR/

CAAs/ 20,000.-

9 Management Marin 34,000.-

10 Contingency JIP 49,000.-

Total 1053,000.-

The work plan budgets for the each partner are as follows:

Contribution

[euro]

Budget Phase I

[euro]

Budget estimate

Phase II [euro]

Marin 70,000.- 243,000.- 150,000.-

NLR 70,000.- 220,000.- 150,000.-

Atkins 39,000.- 60,000.- 100,000.-

Kongsberg 39,000.- 30,000.- 100,000.-

Total 218,000.- 553,000.- 500,000.-

The HELIOS proposal is supported by the Dutch Agentschap NL Maritime

Innovation Program with a contribution of 240 keuro. This funding has already

been confirmed by MIP to MARIN in October 2010.


November 2010

Total

Contribution

Participation fee /year

[euro]

Oil companies 81,000.- 27,000.-

Marin & NLR 72,000.- 24,000.-

Authorities 12,000.- 4,000.-

Other Participants 39,000.- 13,000.-

Based on the confirmations of the CAA’s in UK, Norway and The Netherlands and the

interests of the involved oil companies, vessel operators, heli-operators and equipment

suppliers we expect the following contributions to meet the required budget estimate.

Contribution [euro]

AgentschapNL MIP 240,000.-

3 CAAs 36,000.-

3 Oil companies 243,000.-

8 other companies 312,000.-

Marin & NLR 144,000.-

Atkins & Kongsberg 78,000.-

Total 1,053,000.-


November 2010

6 DELIVERABLES

The following will be delivered to the client:

Report on current practice of helicopter operations on board ships including the

relevant regulations in the various countries and sectors;

Report explaining the physics related to helicopter operations on offshore ships;

Report on methodology for assessment of operational envelopes / workability

criteria;

Report on heli-deck motions, long term statistics of the Motion Severity Index and

workability analysis for various ships types and heli-deck locations.

Report on evaluation of vessel design, systems and operations contributions;

Report on helicopter-ship simulator testing;

Report with Recommended Practice;

o Vessel design, systems & operations

o Helicopter-vessel criteria

o Simulator training and testing

Report on Offshore heli trials;

Executive Summary of the HELIOS project.

7 TIME SCHEDULE & KICK-OFF MEETING

The HELIOS project will start in March 2011 and will be completed by December 2013.

The Kick-off meeting is scheduled on March 22, 2011 during the 26th FPSO JIP Week in

Monaco. To register for the meeting please visit www.fpsoforum.com.

http://www.fpsoforum.com/


November 2010

8 TERMS & CONDITIONS

This outline proposal should be regarded as preliminary JIP proposal. The proposal will

be updated after further discussion with partners and potential participants. Cost figures

given are only for budget estimate. Participation in the HELIOS JIP is confirmed by

signing the HELIOS JIP Participation Agreement with Marin.

Payment of the participation fee is equally distributed over the years 2011, 2012 and

2013.

9 CONTACT

For any further information please contact the undersigned.

Henk van den Boom Head Trials & Monitoring Phone +31 317493353 Fax +31 317 493208 E-mail [email protected]

final proposal helios jip

Documents

offshore operations

offshore vessels

helios helicopter operations

offshore norway

norsk helicopter

helicopter transport

offshore floaters

offshore industry