Belakang - FTSL - Institut Teknologi Bandung

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or.ganized by:

Oc ean Engineering Resear(h Group Faculty of Civil and Environmental En9ineering

Institut Teknolog.i Bandung

ISBN 978-979-96161-2�8

Organizing Partner:

Ministry of Transportation Republic of Indonesia

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The Second International Conference on Port Coastal, and Offshore Engineering

12" ^d lCPCOI

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ICPCD

ntE SECOND INTERNATIONAL CONFcRENCE ON PORT, COASTAL, AND OFFSHORE ENGINEERING

November 12-13, 2012 ITBCampus Bandung, Indonesia

1. Ocean Environmental and Coastal 7. Coastal Engineering Process Modeling 8. Tsunami and Mitigation 2. Material in Marine Environment 9. Ocean Renewable Energy 3. Offshore Engineering Technology 10. Floating Structure 4. Subsea Pipeline 11. Sea Defense Technology 5. Marine Geotechnics 12. Coastal Management 6. Port Engineering & Management

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Sitnultaneous Coupling Method: A New Approach in Wave Modeling ... 1

Recent Development of The Empirical Basis for Prediction of Vortex Induced Vibrations ... 2

Learning from Yi Sun-Sin Suspension Bridge and Other Modern Great Bridges for the Construction of the Sunda Strait Bridge ... 3

Near- and Far-Field Characteristics of The 2011 East Japan Tsunatni and Their Im pacts ... 4

Theoretical Wave Spectrum in Indonesia ... 5

Application Study of Finite Volume Model for Tsunami ... 6

Simulation of Waves with Highly Inaccurate Input ... 7

Tsunami Hazard Assessment and Mapping for the Southwest Coast of Sri Lanka ... 8

Mentawai Tsunami Wave Simulation Using Non-Orthogonal Curvilinear Coordinate Technique ... 9

Design & Installation Requirements for an Ultra Deepwater High Pressure Gas Pipe 1 in e . . . 1 0 Concept Selection of Lampung Floating Storage and Regasification Unit. ... 11

Santos Maleo Producer MOPU, In Situ Substructure Modification ... 12

Dented Member Modelling Using Finite Element Method for Push-Over Analysis of Offshore Platform ... 13

Subsea Pipeline Stress Analysis In Operating Condition Using Strain Based Design: A Finite Element Analysis Application ... 14

The Mapping Environmental Sensitivity Index to The Oil Spill in Coastal Areas of C i lac a p. . . 15

Cooling Water Recirculation Modeling of Cilacap Power Plant ... 16

Numerical Modeling of Cooling Water Recirculation ... 17

Application of Two Iterative Methods for Solving Syste1n of Linear Equations In a Tidally Generated Flow Model. ... 18

Oil Spill Modeling Study ofMontara WHP Blowout using Software MoTuM 19 Application of Large Scale 3D Non-Orthogonal Boundary Fitted Sediment Transport Model and Small Scale Approach for Offshore Structure in Cimanuk Delta North Java Sea ... 20

Design Optimization and Perfonnance Evaluation of a Floating Breakwater ... 21

Development of The BPPT-lock Breakwater Armour Unit ... 22

Physical Modelling of Tanjung Adikarta Fishery Port Breakwaters ... 23

Assessment of Navigation Channel Reliability of Tanjung Adikarta Port using Hydraulics Modeling ... 24

Pipe Coating and Concrete Mattress for Weighting Offshore Gas Pipes Using Nickel Slag as Concrete Aggregate ... 25

Reliability Assess1nent of Offshore Pipeline Subjected Corrosion ... 26

Retrofit of Corroded Offshore Platform by Grouting ... 27

Chloride Induced Corrosion of Concrete Cracked in Flexure ... 28

The Study on Hydrodynamic Perfonnances of IHL Mini-Sub1narine ... 29

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Prelhninary Study of the Flow Noise Measure1nent in the Cavitation Tunnel .. 30

The Sustainability of Wooden Ships in Indonesia ... 31

Application of Pile Driving Analyzer on Offshore Piles ... 32

Evaluation of Soil Liquefaction Potential in Mersing, Johor ... 33

Field and Model Studies of the Dynamics of Mud Shoreline Changes ... 34

Coastal Oceanographic Modelling Studies of Coastal Erosion Problem Along The Coast of Indramayu-Cirebon ... 3 5 Keywords : erosion, current, wave, sediment transpor, monsoon ... 35

Application of the Finite Volume Method to Cohesive Sedi1nent Bed Fluidisation due to Water Waves ... 36

Application of Finite Volume Cell Center Method with Wet and Dry Treatment in Hydrodynamic Flow Modeling ... 3 7 Sedimentation Process Study at Entrance Channel Study Case: Pulau Baai Port ... 3 8 Oil & Gas Project Delivery Incorporating The EPCIC and PSC Procurement Approach: The Malaysian Experience ... 3 9 Coastal Management Modeling Based on Equilibrium Shoreline Method ... 40

Videography Technology Utilization for Rip Current , Sandbar and Shoreline Position Identification to Safety Manage1nent of Coastal Tourism ... 41

The Contribution of Oceanographic Numerical Model In Supporting Integrated Coastal Management Around Komodo Island, Indonesia ... 42

Sediment Classification for Geotechnics Using Sonar Technology ... 43

Shnulation of the Single Hydrophone Source Localization Using Chirp Signal44 Application of Cascade Matrix Method on Reflection Coefficient Prediction of UnderwaterAcoustic for Inclined Seabed ... 45

Diver Detection Experi1nent Using Single Hydrophone ... 46

Coastal Ecosystem: Reducing or A1nplifying The Tsunami Impact,-...; A Lesson Learn from The Recent Events ... 4 7 Bukit Terbuka Hijau (Green Open Hills) as Green Solution of Urban Spatial Engineering in Tsunami-Prone Coastal City (Case Study: Cilacap Selatan District) ... 48

Building a Sustainable Local Community Preparedness Towards Tsuna1ni ... 49

Tsunami Disaster Mitigation Education for Kid's With Animation In Gambar To'ong ... 50

Investigation of Coastal Vegetation Characteristics and Field Experiment on Strength of Casuarina in Indonesia ... 51

Potential of Ocean Thermal Energy Conversion (OTEC) in Indonesia Seas ... 52

..

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Steering Committee :

1. Prof. Carl Larsen (NTNU, Norway)

2. Prof. Alan Blumberg (Steven Institute, USA)

3. Prof. Jun Sasaki (Yokohama National University, Japan) 4. Prof. Hitoshi Tanaka (Tohoku University, Japan)

5. Prof. Akira Mano (Tohoku University, Japan)

6. Prof. Fumihiko Imamura (Tohoku University, Japan)

7. Prof. Tai-Wen Hsu (National Cheng Kung University, ROC Taiwan) 8. Prof. Gregory Chiu (Asian Institute of Technology, Thailand)

9. Prof. Wirachman Wisnoe (UITM, Malaysia)

10. Prof. Hang Tuah Salim (Institut Teknologi Bandung, Indonesia) 11. Prof. Ricky Lukman Tawekal (Institut Teknologi Bandung, Indonesia) 12. Prof. Mukhtasor (National Energy Council, Indonesia)

13. Prof Priyo Suprobo (Institut Teknologi Sepuluh Nopember, Indonesia) 14. Dr. Bambang Susantono (Vice Minister of Transportation, Indonesia)

15. Ir. Sumaryanto Widayatin, MSCE (Deputy Minister of State Owned Enterprises for infrastructure and logistics, Indonesia)

16. Ir. Richard Lino (President Director of PELINDO II, Indonesia) 17. Ir. Wisnu Mustapha (BP Tangguh, Indonesia)

18. Dr. Erwandi (The Agency For the Assessment and Application Technology, Indonesia)

19. Dr. Muslim Muin (Institut Teknologi Bandung, Indonesia)

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Organizing Committee :

Advisory:

1. Dr. Muslim Muin (Head of Ocean Engineering Research Group, ITB) 2. Dr. Irsan S. Brodjonegoro (Head of Ocean Engineering Program, ITB) Conference Chair : Dr. Sri Murti Adiyastuti

Secretary : Dr. Paramashanti Bendahara : Dr. Nita Yuanita

Materi : Dr. Rildova

Kesekretariatan : Eko Charnius Ilman, MT dan Wida Marketing/Danus : Ahmad Mukhlis Firdaus, MT Prosiding/Makalah : Dr. Hendriyawan

Acara : Dr. Nita Yuanita

Publikasi dan Logisitik : Dr. Hendra Achiari Akomodasi dan Transportasi : Mahasiswa

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The Second International Conference on Port, Coastal, and Offshore Engineering (2nd ICPCO)

12-13 November 2012

1

ISBN: 978-979-96161-2-8

Oil Spill Modeling Study of Montara WHP Blowout using Software MoTuM

Muslim Muin ¹

1Ocean Engineering Institut Teknologi Bandung

TP Rakhmat 3^rd Floor Ganesha 10 Bandung 40132 Email: [email protected]

Abstract. The Blowout at the Montara Well Head Platform (WHP) had released significant amount oil to Timor Gap and adjacent area. The release of oil started on the 21^st August 2009 and stopped at November 2^nd 2009. The spatial extent of oil spill, fates, and exposure occurrence were simulated using software MoTuM.

The paper present the methodology and application of integrated three dimensional non-orthogonal boundary fitted ocean hydrodynamics and oil spill models in Geographic Information System (GIS). The ocean hydrodynamics model was calibrated and validated using available observation data. The spatial extents of the oil were compared with satellites image and flight observation.

The agreement between results of simulation and observation are excellent

Keywords: Oil Spill, Ocean Hydrodynamics, Non-Orthogonal Boundary Fitted, Geographic Information System, MoTuM, Model.

1 Introduction

Oil spill modeling was performed to simulate in the event of a release of oil due to an blowout at the Montara Well Head Platform (Latitude 12o 40’ 20.5”

South, Longitude 124^o 32’ 22.3” East). The area of study is presented in Figure 1. The water depth was approximately from 80 to 100 meters in Sahul Shelf and range from 2,000 to 3,500 meter in Timor Gap.

The paper presents the methology of modeling and results of simulation for Montara WHP Blowout. A lagrangian trajectory modeling system was implemented to simulate oil movement. The spillet were driven by simulated surface currents and wind. The hourly time varying current was obtained directly from three dimensional ocean hydrodynamics model. The path of simulated surface oil trajectories were compared to the satellite observations.

There is no re-initialized in the modeling effort to match the satellite images data.

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Figure 1 Area of Study, Timor Sea Australia - Indonesia.

The release of oil started on the 21^st August 2009 and continued leaking until 2rd November 2009, with a leak rate estimated at 400 barrels of Montara Crude oil per day (APASA, 2010). MoTuM calculated the spatial extent of the oil released the thickness of the surface oil and probability of oil exposure occurrence. The key success of the simulation is because the integration of three dimensional hydrodynamics model in simulation. Direct linkages to 3D hydrodynamic models are extremely important. The multi wind data was obtained from NOAA.

2 Software MoTuM Description

MoTuM was developed to meet the need for an extremely user friendly and verified modeling system to predict oil spill. MoTuM consists of three principal parts:

• 3D Ocean Hydrodynamics Model

• Oil Spill Model o Trajectory o Fates o Stochastic o Backtracking

• Geographic Information System (GIS)

The software was developed in Microsoft Windows System. The software is also designed to operate on low cost computers and user friendly. The

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Oil Spill Modeling Study of Montara WHP Blowout

using Software MoTuM 3

environmental data was stored in GIS Database. The wind forcing can be specified as constant or time varying for all computational domains. The model extrapolates the wind forcing for each computational cell if multi-wind data is available. The ocean hydrodynamics and oil spill model are coupled. Time varying ocean current as main driving force of oil dispersion was obtained directly from three dimensional ocean hydrodynamics non-orthogonal curvilinear technique or boundary fitted model (Muin, 1993; Muin and Spaulding, 1996-1997). The integration of ocean hydrodynamics model into oil spill model makes the software easier to use and more accurate. Therefore, it is important to calibrate the model for each area of application. Figure 2 show the scheme of MoTuM.

MoTuM is used by oil industry in Indonesia (Total Indonesie, Chevron, CNOOC, Exxons Mobile, Pertamina, BOB Jambi Merang, BOB Pertamina- Siak, EMP, Premier Oil, Citics-Seram, Conocco Phillip Indonesia, and BPTangguh). Software MoTuM has been adapted by Ministry of Environment Indonesia (MOE) and Upstream Oil and Gas Executive Agency (BPMigas) as primary response tool.

Figure 2 Software MoTuM Scheme

- Location & Time of Oil Spill - Quantity and Type of Oil Spill - Environmental Character.

- Map - Grid, Depth - Tidal Force Data - Wind Data - River Discharge Data - Physics Parameter - Time

- Hydrodynamic (Current & Water Elevation) - Fates (Percentage of Oil Spill) - Hydrodynamic

(Current & Water Elevation) - Fates (Percentage of Oil Spill) - Current Vector

- Oil Spill Trajectory - Oil Spill Thickness - Probability of Impacted Area - Probability of Oil Source - Current Vector - Oil Spill Trajectory - Oil Spill Thickness - Probability of Impacted Area - Probability of Oil Source

- Environmental Data - Link Video - Link Picture - Satelite Image - Environmental Data - Link Video - Link Picture - Satelite Image

Geographic Information System

(GIS)

3D Hydrodynamic Setup Model

3D Hydrodynamic Model Oil Spill Model (MoTuM) Model Setup

(MoTuM)

- Location & Time of Oil Spill - Quantity and Type of Oil Spill - Environmental Character.

- Map - Grid, Depth - Tidal Force Data - Wind Data - River Discharge Data - Physics Parameter - Time

- Hydrodynamic (Current & Water Elevation) - Fates (Percentage of Oil Spill) - Hydrodynamic

(Current & Water Elevation) - Fates (Percentage of Oil Spill) - Current Vector

- Oil Spill Trajectory - Oil Spill Thickness - Probability of Impacted Area - Probability of Oil Source - Current Vector - Oil Spill Trajectory - Oil Spill Thickness - Probability of Impacted Area - Probability of Oil Source

- Environmental Data - Link Video - Link Picture - Satelite Image - Environmental Data - Link Video - Link Picture - Satelite Image

Geographic Information System

(GIS)

3D Hydrodynamic Setup Model

3D Hydrodynamic Model Oil Spill Model (MoTuM) Model Setup

(MoTuM)

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3 Model Setup

The computational Non-Orthogonal Boundary Fitted Grid System is shown in Figure 3. It consists of 5850 water cell. Bathymetry was obtained from the US NOAA GEODAS.

Figure 3 Non-Orthogonal Boundary Fitted Grid System.

The time series of wind data in the computational domain is obtained from the US National Oceanic and Atmospheric Administration (NOAA). The version used in the study is NCEP Reanalysis 2, NOAA/NCDC blended daily in surface wind, provides global coverage with a horizontal resolution of 1°.

The global ocean current Indonesia Through Flow (ITF) is very important in the Timor Passage. Figures 4 show the observation data at depth 50 meter from surface in Longitude 122.9598^o E and Latitude 11.3683^o S. The data show that the surface water current along Timor Passage is very dynamics. The time varying of speed and direction of the surface current was caused by tidal and wind forcing. It can be seen that the surface water may flow to the Northern direction or to the Indonesia Coastline. Clearly, the tidal current cannot be ignored. At the surface the net flow or ITF along Timor Passage is about 0.35 m/s. The net or residual current of ITF is assumed as constant flow. The model input for ITF in the domain of Timor Passage is 7.6 Sv. The vertical Eddy

Montara WHP

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Viscosity in the ocean hydrodynamics model is tuned to match the net surface current 0.35 m/s at the observation station.

Figure 4 Ocean current observation data in E-W and N-S directions.

4 Model Calibration and Validation

The success of any model application depends on the credibility of the model predictions. This credibility is gained by careful comparison of model predictions with observations. The purpose of calibration is to select model coefficient to best match observation data. The following sections present the model calibration and validation

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Figure 5 Water elevation comparison between model and observations.

The bottom frictions in the main water body were tuned to match the water elevation data. It was found coefficient of bottom friction is 0.002. The comparison between the predicted and observed water elevations are presented in Figures 5. The agreement between the prediction and observations are excellent.

The results of ocean hydrodynamics model were also validated by comparing the Tracking Buoy Data collection by AMSA. The Buoy was deployed on 14^th October 2009 and latest position data on 22^nd October 2009. Figure 6 presents the comparison between tracking line of buoy data and model prediction. It can be seen that the agreement is very good. The ITF is simulated very well.

Darwin

-5 -4 -3 -2 -1 0 1 2 3 4 5

01/03/10 01/08/10 01/13/10 01/18/10 01/23/10 01/28/10

Date

Water Elevation (m)

BoM Australia Model

Kupang

-2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 2.0

01/02/10 01/07/10 01/12/10 01/17/10 01/22/10 01/27/10 02/01/10

Date

Water Elevation (m)

ORI Model

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Figure 6 The Comparison between Tracking Line of Buoy Data (AMSA, 2009) and MoTuM Prediction (blue line).

The comparison between the satellite image and model prediction are presented from Figures 7 to 10. The scale of oil thickness in the model prediction is based on experience at sea, the majority of the oil slick area shown in the satellite images are more than 100 microns (>0.1 mm). The oil thickness less than 50 microns cannot be observed by Satellites Image.

Figure 7 Comparison of the MODIS satellite images (right) with the model prediction (left) on the 03^rdSeptember 2009. Note: yellow polygons in the satellite image encircle identified visible oil patches and colored spots and blue polygon in the modeled image represent modeled oil patches.

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Figure 8 Comparison of the LAPAN satellite images (right) with the model prediction (left) on the 10^thSeptember 2009. Note: red polygons in the satellite image encircle identified visible oil patches and colored spots and blue polygon in the modeled image represent modeled oil patches

Figure 9 Comparison of the LAPAN satellite images (right) with the model prediction (left) on the 26^thSeptember 2009. Note: red polygons in the satellite image encircle identified visible oil patches and colored spots and blue polygon in the modeled image represent modeled oil patches.

Figure 10 Comparison of the MODIS (Terra) satellite images (left) with the model prediction (right) on the 21^stOctober 2009. Note: yellow polygons in the satellite image encircle identified visible oil patches and colored spots and blue polygon in the modeled image represent modeled oil patches.

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5 Results of Simulation

5.1 Oil Spill Trajectory and Thickness

The model indicates that the released oil started to enter Indonesia Coastal Water on August 30^th 2009 (Figure 11). The age of oil that had reached Indonesia Coastlines is mostly older than nine days. The color legends represent the age or the duration of each oil spillet which had been exposed in the surface water.

Figure 11 The Oil Spill Trajectory on 30^th August 2009.

From 6^th September to 26^th October 2009, the model indicated that the oil are exposed in the Indonesia Coastal Water. On 13^th October 2009, the oil was observed to be moving from its initial northerly position towards Australia as shown in Figure 10. However, the residual oil in offshore remains in Indonesia Coastal Water until 26^th October 2009.

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Figure 12 Oil Spill Thickness on 7^th September 2009.

It can be seen that the thickness of oil enter Indonesia Coastal Water and trapped along coastline exceed the minimum thickness threshold 0.1 m.

Therefore, the oil spill will impact the marine environment in that area.

The thickness of oil higher than 0.1 mm is shown in black colors which represent fresh oil. The thickness of oil had entered Indonesia Coastal Water are mostly less than 0.1 mm.

5.2 Mass Balance

Mass balance plots describe the fate of the oil as time-varying percentages of the total mass for the three primary phases: the offshore, stranded on shorelines, and mass evaporated into the atmosphere.

Figure 13 present the time series of evaporated oil. The model predicts that 8,000 barrels of 29,600 of released oil will be evaporated after 72 days.

The released oil started to reach Indonesia Coastline after 20 days of simulation.

The released oil movement change direction away from Indonesia’s coastal water after about 50 days of simulation. The results of simulation indicate that

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the total oil had been stranded in the Indonesia Coastal water is about 10,000 barrels.

Figure 13 Oil Mass Balance during Montara WHP Spill.

5.3 Oil Exposure Occurence

The stochastic model was run for 1776 hours. Surface oiling is defined as any oil having a thickness above the minimum thickness threshold, a value that protects aquatic biota from being smothered. This threshold is 0.1 μm, an order of magnitude below a minimum smothering thickness of 1 μm (French et al, 1999; NOAA, 1996). Thicknesses less than the 0.1 μm threshold are typically invisible to the eye (Koops, 1985).

Figure 14 Oil Relative percentage Oil Exposure Occurrence in Offshore.

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Figure 14 shows the results of simulation in relative percentage oil exposure occurrence of offshore region. It can be seen that the highest percentage of oil exposure occurs in the region of source released oil or Montara Well Platform.

However, the results of simulation indicate that the oil exposure in Indonesia Coastal Water can reach 35% or 622 hours, where the highest exposure is in Rote Island.

The modeling results also show that the risk of the released oil to Indonesia Coastline is higher than to Australia Coastline because the percentage of oil spill occurrence is higher in Indonesia Coastal Water.

6 Conclusion

Direct linkage of ocean hydrodynamics to oil spill model is the key success of oil spill simulation in Montara WHP Blowout. The ocean hydrodynamics model had been calibrated by comparing the results with available data (drogue experiments by AMSA and Bureau of Meteorological Australia). The comparisons are excellent. This indicated that the predicted flow pattern in Timor Passage regions is accurate.

The results of oil spill model had been validated by comparing the model prediction and observations data. The comparison between results of simulation and available data (satellite image) are excellent.

The strong surface water current along Timor Passage was also driven by dynamic local wind forcing which is seasonal. The observational data show that the net water current may flow to North direction. Under the condition of wind blow to Northern direction, the oil will move the oil to Indonesia Coastline.

The results of simulation show that the released oil from Montara WHP (Well Head Platform) has reached Indonesia Coastlines. Approximately 10,000 barrel released oils were stranded along the Indonesia Coastline.

The results of model prediction indicate that the percentage of oil exposure to Indonesia Coastline is higher than that of to Australia Coastline. Therefore, the impact of released oil to Indonesia Coastline is higher than to Australia Coastline.

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The simulation results indicate that the released oil had impacted 850 km Indonesia’s coastline and 172,000 km² coastal water areas.

7 Acknowledgement

The study was funded by Ministry of.Environment Indonesia.

8 References

[1] AMSA, Surveillance Flight Report, 2009.

[2] APASA, Montara Well Release Monitoring Study S7.1, 2010.

[3] French, D., H. Schuttenberg, and T. Isaji, Probabilities of oil exceeding thresholds of concern: examples from an evaluation for Florida Power and Light, In Proceedings of the 22nd Arctic and Marine Oil Spill Program (AMOP) Technical Seminar, 1999.

[4] Koops, W, The Oil Spill Slide Rule to Predict the Fate of an Oil Spill."

in: Proceedings of the 1985 International Oil Spill Conference (Prevention, Behavior, Control, Cleanup), February 25-28, 1985, Los Angeles, CA. Washington, DC: American Petroleum Institute, Publication 4385.647.

[5] Muin, M. & Spaulding, M., Three-Dimensional Boundary-fitted Circulation Model, J. Hydraulic Engineering, ASCE, 123(1), pp 2-11, 1997.

[6] Muin, M. & Spaulding, M., Application of Three-Dimensional Boundary- Fitted Circulation Model in Providence River, J. Hydraulic Engineering, ASCE, 123(1), pp 12-20, 1997.

[7] Muin, M. & Spaulding, M., Two-dimensional boundary-fitted circulation model in spherical coordinates, J. Hydraulic Engineering, ASCE, 122(1), pp 512-521, 1996.

[8] Muin, Muslim, A Three-Dimensional Boundary-Fitted Circulation Model in Spherical Coordinates, PhD dissertation, Department of Ocean Engineering, University of Rhode Island, 1993.

[9] NOAA, Aerial Observations of Oil at Sea, HAZMAT Report 96-7, 1996.

(Book with paper title and editor)