APPENDIX 9. Azeri Chirag Gunashi Phase III Drill Cuttings Modelling

Transcription

1 Azeri, Chirag & Gunashli Full Field Development Phase 3 Environmental & Socio-economic Impact Assessment Final Report APPENDIX 9 Azeri Chirag Gunashi Phase III Drill Cuttings Modelling ACG Phase 3 ESIA A9/1 October 2004

2 Azeri, Chirag & Gunashli Full Field Development Phase 3 Environmental & Socio-economic Impact Assessment Final Report This page is intentionally blank ACG Phase 3 ESIA A9/2 October 2004

3 Final Report TITLE Applied Science Associates, Aquitaine Maison Naba Castetbon FRANCE Tel: (0033) Fax: (0033) Applied science Associates, Inc 70 Dean Knauss Drive Narragansett USA Tel: (001) Fax: (001) Drill Cuttings Modelling Study In Support of the Azeri Chirag Gunashi Phase III EIA AUTHOR(S) Matthew Ward, P.E., Jill Rowe and Roddy Thomas CLIENT Robert Fitzsimmons URS Corporation Limited PROJECT NUMBER ASA February 2004

4 Table of Contents List of Figures... ii List of Tables...iii Introduction...1 Mud and Drill Cuttings Simulation Specifications...2 Description of Current Field...5 Mud and Drill Cuttings Dispersion Simulation Results...8 Combined Deposition Results...16 Summary...18 References...20 i

5 List of Figures Figure 1. Location of drilling platforms offshore Baku, Azerbaijan. 1 Figure 2. Caspian Sea hydrodynamic simulation computational grid. 5 Figure 3. Computational grid offshore Baku. 6 Figure 4. Current measurement data collection sites. 6 Figure 5. Characteristic hydrodynamic model output for the winter season. 7 Figure 6. Characteristic hydrodynamic model output for the summer season. 7 Figure 7. Stage I Predicted bottom deposition contours for 10 wells at the MODU DWG Pre-Drill site during the summer season under maximum current conditions. 11 Figure 8. Stage I Predicted bottom deposition contours for 38 wells at the DUQ Figure 9. DWG site during the summer season under maximum current conditions. 12 Predicted bottom deposition contours for 4 wells at the Southern Subsea Site during the summer season under maximum current conditions. 13 Figure 10. Stage II predicted deposition contours from a multiple well (10) release from the 26 well, 11 m below MSL at the DWG DUQ location during the summer season under average current conditions. 14 Figure 11. Stage II predicted deposition contours from a multiple well (4) release from the 26 well, 11 m below MSL at the Southern Subsea Site during the summer season under average current conditions. 15 ii

6 List of Tables Table 1. Seasonal Current Conditions....2 Table 2. Stage I drilling specifications at the MODU DWG Site Pre-Drill Wells....2 Table 3. Stage I drilling specifications at the MODU Southern Subsea Site Wells....3 Table 4. Stage I drilling specifications at the DUQ DWG Site Wells....3 Table 5. Stage II drilling specifications at the MODU DWG Site Pre-Drill Wells....4 Table 6. Stage II drilling specifications at the MODU Southern Subsea Site Wells....4 Table 7. Particle size distribution and associated fall velocity...4 Table 8. Stage I MODU DWG Site Pre-Drill Wells maximum deposition thickness and area covered by sediment greater than 1 mm thick for 10 wells....9 Table 9. Stage I DUQ DWG Site Wells maximum deposition thickness and area covered by sediment greater than 1 mm thick for 38 wells....9 Table 10. Stage I MODU Southern Subsea Site Wells maximum deposition thickness and area covered by sediment greater than 1 mm thick for 4 wells....9 Table 11. Stage II MODU DWG Site Pre-Drill Wells maximum deposition thickness and area covered by sediment greater than 1 mm thick for 10 wells....9 Table 12. Stage II MODU Southern Subsea Site Wells maximum deposition thickness and area covered by sediment greater than 1 mm thick for 4 wells Table 13. Projected combined deposition results from the Stage I 36 well and the Stage II 26 well at the MODU DWG Pre-Drill site for a 10 well release...16 Table 14. Projected combined deposition results from the Stage I 36 well and the Stage II 26 well at the Southern Subsea site for a 4 well release...16 Table 15. Projected combined deposition results from the Stage I 36, Stage II 26 wells and the Stage I 26 well at the MODU DWG Pre-Drill and DUQ DWG sites for 10, 10 and 38 well releases, respectively...17 Table 16. Average predicted results for all simulated well releases Table 17. Average projected results for combinations of mud and drill cutting dispersion simulations...19 iii

7 Introduction In support of the Phase III Environmental Impact Assessment (EIA) for the Azeri, Chirag, Gunashi Field offshore Baku, Azerbaijan, Applied Science Associates (ASA) has conducted a drill cuttings study to establish the mixing, dispersive transport and settlement of all potential material released from platforms, located approximately 110 km offshore Baku, Azerbaijan (Figure 1). The simulation of the mud and drill cuttings from the platform sites was conducted using ASA s MUDMAP modeling system (Appendix 1). This report presents a description of the MUDMAP model system, the methodology and data employed in the study and the modeling results. Figure 1. Location of drilling platforms offshore Baku, Azerbaijan. 1

8 Mud and Drill Cuttings Simulation Specifications The simulation of the release of mud and drill cuttings from the platforms, located approximately 110 km offshore Baku, Azerbaijan (Figure 1), were conducted, using ASA s MUDMAP modeling system (described in Appendix 1), during summer and winter periods under average and maximum current conditions (Table 1) as described by the ASA Caspian Sea model developed for the Phase I EIA. Five drilling specifications were simulated, in two stages, and are presented in Tables 2-6. Tables 2-4 present the specifications for the first stage and Tables 5-6 present the specifications for the second stage. Table 7 presents the particle size distribution and associated fall velocities of the released material. The fall velocities show that 90% of the material is relatively large ( µm) and will settle relatively quickly depending upon the release depth. While the remaining 10% of the particles will reside in the water column and be transported further away from the platform. Table 1. Seasonal Current Conditions. Season Current Condition Start Time Principle Current Orientation Winter Maximum 21 January at 1600 hrs North-Northeast Winter Average 09 January at 1200 hrs Southwest Summer Maximum 05 August at 1600 hrs Northeast Summer Average 22 July at 0000 hrs Southwest Table 2. Stage I drilling specifications at the MODU DWG Site Pre-Drill Wells. Parameter Specification Location: E N 36 top-hole section (seawater): Section length: 150 m Cuttings Generation/Discharge Rate: m/hr Volumes: Cuttings: 180 m 3 26 top-hole section (seawater/bentonite): Discharge Location: Discharge Orientation Water Depth: Seawater: 359 m 3 Total: 539 m 3 Section length: 350 m Cuttings Generation/Discharge Rate: 9.86 m/hr Volumes: Cuttings: 173 m 3 WBM: 104 m 3 Total: 277 m 3 To seafloor Vertical / upwards 175m 2

9 Table 3. Stage I drilling specifications at the MODU Southern Subsea Site Wells. Parameter Specification Location (Northern Subsea Site) E N 36 top-hole section (seawater): 26 top-hole section (seawater/bentonite): Discharge Location: Discharge Orientation Water Depth Section length: 150 m Cuttings Generation/Discharge Rate: m/hr Volumes: Cuttings: 180 m 3 Seawater: 359 m 3 Total: 539 m 3 Section length: 350 m Cuttings Generation/Discharge Rate: 9.86 m/hr Volumes: Cuttings: 173 m 3 WBM: 104 m 3 Total: 277 m 3 To seafloor Vertical / upwards. 275 m Table 4. Stage I drilling specifications at the DUQ DWG Site Wells. Parameter Specification Location: 26 top-hole section (seawater/bentonite): Discharge Location 26 Section: Discharge Orientation Water Depth: E N Section length: 350 m Cuttings Generation/Discharge Rate: 9.86 m/hr Volumes: Cuttings: 173 m 3 WBM: 104 m 3 Total: 277 m 3 To seafloor via -138 m below sea surface Vertical / downwards 175 m 3

10 Table 5. Stage II drilling specifications at the MODU DWG Site Pre-Drill Wells. Parameter Specification Location: E N 26 top-hole section Section length: 350 m (seawater/bentonite): Cuttings Generation/Discharge Rate: 9.86 m/hr Volumes: Cuttings: 173 m 3 Discharge Location: Water Depth: WBM: 104 m 3 Total: 277 m 3 To seafloor via caisson@ -11m from the sea surface 175m Table 6. Stage II drilling specifications at the MODU Southern Subsea Site Wells. Parameter Specification Location (Northern Subsea Site) E N 26 top-hole section (seawater/bentonite): Discharge Location: Water Depth Section length: 350 m Cuttings Generation/Discharge Rate: 9.86 m/hr Volumes: Cuttings: 173 m 3 WBM: 104 m 3 Total: 277 m 3 To seafloor via caisson@ -11m from the sea surface 275 m Table 7. Particle size distribution and associated fall velocity. Nominal Grain Size (microns) Specific Gravity Percentage of Total Mass Fall Velocity (m/hr)

11 Description of Current Field The current fields used for this study were supplied by the ASA Caspian Sea Model developed during the Phase I Azeri, Chirag, Gunashi EIA (ASA 2001). The computational domain of the hydrodynamic simulation consisted of the entire Caspian Sea in order to minimize the complexity of environmental forcing data. The computational grid developed for this area was handled through the application of ASA s step-wise-continuous-rectangular gridding strategy (Isaji et al. 2001). In the northern Caspian Sea coarse grid resolution, on the order of 20 km, is sufficient in order to capture the large scale dynamics and appropriate volumetric transport of water. The grid resolution was increased in the southern Caspian, 41.5 N southward, to approximately 5 km while a very fine scale grid of 2.5 km was applied within the Baku region of study. Figures 2 and 3 show the entire computational grid and the fine resolution grid within the Baku region, respectively. The hydrodynamic model was validated through a comparison to current measurements collected by the Azerbaijan International Operating Company along a proposed pipeline route between Chirag and Sangachal in the Caspian Sea for the winter season from 01 February 2000 to 01 April Figure 4 shows the location of the data collection points designated KP174, KP145, KP115, KP85, KP65, and KP45. The hydrodynamic model was then applied to the winter and summer seasons for the year Figures 5 and 6 present representative current patterns predicted by the hydrodynamic model for the winter and summer seasons, respectively. A complete description of the environmental data, validation and application of the ASA Caspian Sea Model can be found in the ASA report Hydrodynamic and Dispersion Modeling for the Azeri, Chirag, Gunashi Field Offshore Baku, Azerbaijan (ASA 2001). Figure 2. Caspian Sea hydrodynamic simulation computational grid. 5

12 Figure 3. Computational grid offshore Baku. Figure 4. Current measurement data collection sites. 6

13 Figure 5. Characteristic hydrodynamic model output for the winter season. Figure 6. Characteristic hydrodynamic model output for the summer season. 7

14 Mud and Drill Cuttings Dispersion Simulation Results MUDMAP model simulations were run at the MODU DWG Pre-Drill site, the MODU Southern Subsea site and at the DUQ DWG site using the parameters given in Tables 2-6, for the summer and winter seasons under average and maximum current conditions (Table 1). At each site and for each seasonal current condition single and multiple well runs were conducted. The multiple well scenarios consisted of 10 wells at the MODU DWG Pre-Drill location, 38 wells at the DUQ DWG location and 4 wells at the MODU Southern Subsea site. Tables 8-12 provide the characteristics for the multiple well releases, of the sediment deposits predicted by the MUDMAP model. The tables list the bottom area covered by a sediment deposit that is greater than 1mm thick, the maximum horizontal extent to the 1 mm contour from the discharge location and the maximum sediment deposit thickness at the site. Figures 7-10 present representative deposition patterns for each multiple well simulation and details of each simulation are presented in Appendices 2-6. The simulations conducted for the 10 well multiple release during Stage I, from the MODU DWG Pre-Drill site, predicted an average area covered out to the 1 mm contour of m 2 with an average maximum horizontal extent from the release location of 230 m and an average maximum deposition thickness of 220 cm. The simulations conducted for the 38 well multiple release during Stage I, from the DUQ DWG site, predicted an average area covered out to the 1 mm contour of m 2 with an average maximum horizontal extent from the release location of 940 m and an average maximum deposition thickness of 217 cm. The simulations conducted for the 4 well multiple release during Stage I, from the Southern Subsea site, predicted an average area covered out to the 1 mm contour of m 2 with an average maximum horizontal extent from the release location of 78 m and an average maximum deposition thickness of 77 cm. The simulations conducted for the 10 well multiple release during Stage II, from the MODU DWG Pre-Drill site, predicted an average area covered out to the 1 mm contour of m 2 with an average maximum horizontal extent from the release location of 109 m and an average maximum deposition thickness of 70 cm. The simulations conducted for the 4 well multiple release during Stage II, from the Southern Subsea site, predicted an average area covered out to the 1 mm contour of m 2 with an average maximum horizontal extent from the release location of 99 m and an average maximum deposition thickness of 24 cm. The difference between the results of the simulations can be attributed to the variations in current speeds between the release locations, the vertical release location and the total mass of the mud and drill cuttings. For example the maximum deposition thickness at the MODU DWG site, during Stage I, is larger than that during Stage II due to the depth of the release since the material released during Stage II is near the surface of the water column it will disperse over a larger area. However, the maximum deposition thickness at the MODU DWG site, for both Stages I and II, is larger than that at the Southern Subsea site due to slightly weaker currents to the north and the fact that the total mass of material released from the MODU DWG site is 2.5 times greater than that released at the Southern Subsea site. 8

15 Table 8. Stage I MODU DWG Site Pre-Drill Wells maximum deposition thickness and area covered by sediment greater than 1 mm thick for 10 wells. Season Current Condition Area Covered by > 1mm Thickness (m 2 ) Maximum Horizontal Extent of 1 mm Thickness Summer Maximum Summer Average Winter Maximum Winter Average Maximum Deposition Thickness (cm) Table 9. Stage I DUQ DWG Site Wells maximum deposition thickness and area covered by sediment greater than 1 mm thick for 38 wells. Season Current Condition Area Covered by > 1mm Thickness (m 2 ) Maximum Horizontal Extent of 1 mm Thickness Summer Maximum Summer Average Winter Maximum Winter Average Maximum Deposition Thickness (cm) Table 10. Stage I MODU Southern Subsea Site Wells maximum deposition thickness and area covered by sediment greater than 1 mm thick for 4 wells. Season Current Condition Area Covered by > 1mm Thickness (m 2 ) Maximum Horizontal Extent of 1 mm Thickness Summer Maximum Summer Average Winter Maximum Winter Average Maximum Deposition Thickness (cm) Table 11. Stage II MODU DWG Site Pre-Drill Wells maximum deposition thickness and area covered by sediment greater than 1 mm thick for 10 wells. Season Current Condition Area Covered by > 1mm Thickness (m 2 ) Maximum Horizontal Extent of 1 mm Thickness Summer Maximum Summer Average Winter Maximum Winter Average Maximum Deposition Thickness (cm) 9

16 Table 12. Stage II MODU Southern Subsea Site Wells maximum deposition thickness and area covered by sediment greater than 1 mm thick for 4 wells. Season Current Condition Area Covered by > 1mm Thickness (m 2 ) Maximum Horizontal Extent of 1 mm Thickness Summer Maximum Summer Average Winter Maximum Winter Average Maximum Deposition Thickness (cm) 10

17 Figure 7. Stage I Predicted bottom deposition contours for 10 wells at the MODU DWG Pre-Drill site during the summer season under maximum current conditions. The minimum thickness depicted is 1 mm. 11

18 Figure 8. Stage I Predicted bottom deposition contours for 38 wells at the DUQ DWG site during the summer season under maximum current conditions. The minimum thickness depicted is 1 mm. 12

19 Figure 9. Predicted bottom deposition contours for 4 wells at the Southern Subsea Site during the summer season under maximum current conditions. The minimum thickness depicted is 1 mm. 13

20 Figure 10. Stage II predicted deposition contours from a multiple well (10) release from the 26 well, 11 m below MSL at the DWG DUQ location during the summer season under average current conditions. 14

21 Figure 11. Stage II predicted deposition contours from a multiple well (4) release from the 26 well, 11 m below MSL at the Southern Subsea Site during the summer season under average current conditions. 15

22 Combined Deposition Results A presentation of the combined results for certain simulations conducted during Stage I and II are presented below. Specifically, a combination of the deposition results from the Stage I 36 well and the Stage II 26 well at the MODU DWG Pre-Drill site for a 10 well release, the results from the Stage I 36 well and the Stage II 26 well at the Southern Subsea site for a 4 well release, and the results from the Stage I 36, Stage II 26 wells and the Stage I 26 well at the MODU DWG Pre-Drill and DUQ DWG sites for 10, 10 and 38 well releases, respectively, were requested to be studied. However, since Stage II was unplanned at the onset of the study and the 36 and 26 well sections were modeled during Stage I as a single release at the MODU and Southern Subsea sites it is not possible to directly combine the results. However, a projected combination is possible due to the wide range in the release depths between the two stages. The method of constructing the projected combinations consists of reducing the results from Stage I at the MODU and Southern Subsea sites by 60%. This will provide an approximation to a release only from the 36 well section since out of the total release of 457 m 3 only 180 m 3 is released from this section. The largest deposition footprint between the Stage I and Stage II results will then be determined and assumed to represent the projected combination in addition to the maximum deposition thickness being directly summed between the simulations. The projected combined results as specified above are presented in Tables and representative projected regions of potential impact can be represented by the figures in Appendices 4,5 and 6 for the multiple well simulations. Table 13. Projected combined deposition results from the Stage I 36 well and the Stage II 26 well at the MODU DWG Pre-Drill site for a 10 well release. Season Current Condition Area Covered by > 1mm Thickness (m 2 ) Maximum Horizontal Extent of 1 mm Thickness Summer Maximum Summer Average Winter Maximum Winter Average Maximum Deposition Thickness (cm) Table 14. Projected combined deposition results from the Stage I 36 well and the Stage II 26 well at the Southern Subsea site for a 4 well release. Season Current Condition Area Covered by > 1mm Thickness (m 2 ) Maximum Horizontal Extent of 1 mm Thickness Summer Maximum Summer Average Winter Maximum Winter Average Maximum Deposition Thickness (cm) 16

23 Table 15. Projected combined deposition results from the Stage I 36, Stage II 26 wells and the Stage I 26 well at the MODU DWG Pre-Drill and DUQ DWG sites for 10, 10 and 38 well releases, respectively. Season Current Condition Area Covered by > 1mm Thickness (m 2 ) Maximum Horizontal Extent of 1 mm Thickness Summer Maximum Summer Average Winter Maximum Winter Average Maximum Deposition Thickness (cm) 17

24 Summary In support of the Phase III Environmental Impact Assessment (EIA) for the Azeri, Chirag, Gunashi Field offshore Baku, Azerbaijan, Applied Science Associates (ASA) has conducted a drill cuttings study to establish the mixing, dispersive transport and settlement of all potential material released from platforms, located approximately 110 km offshore Baku, Azerbaijan. The simulation of the mud and drill cuttings from the platform sites was conducted using ASA s MUDMAP modeling system during summer and winter periods under average and maximum current conditions as described by the ASA Caspian Sea model developed for the Phase I EIA. Single and multiple well drilling specifications were simulated: At the MODU DWG Pre-Drill site and the MODU Southern Subsea site, 36 and 26 hole sections were simulated with the spoils released at the seabed in addition to a release from the 26 hole section at -11m depth, with 10 and 4 multiple wells, respectively. While at the DUQ DWG site a 26 hole section was simulated with the mud and cuttings released at a depth of 138 m below the sea surface, with 38 multiple wells. An additional analysis to determine the projected area of impact due to a combination of the simulations was conducted. The current fields used for this study were supplied by the ASA Caspian Sea Model developed during the Phase I Azeri, Chirag, Gunashi EIA (ASA 2001). The computational domain of the hydrodynamic model consisted of the entire Caspian Sea in order to minimize the complexity of environmental forcing data. The hydrodynamic model was validated through a comparison to current measurements collected by the Azerbaijan International Operating Company along a proposed pipeline route between Chirag and Sangachal in the Caspian Sea for the winter season from 01 February 2000 to 01 April 2000 and applied to the winter and summer seasons for the year The average area covered to the 1 mm contour, the maximum horizontal extent to the 1 mm contour and the maximum deposition thickness are presented in Tables 16 and 17 for the mud and cuttings simulations and the combination analysis, respectively. Table 16. Average predicted results for all simulated well releases. Simulation # Stage Location Well Sections 1 I MODU DWG 2 I DUQ DWG 3 I Southern Subsea 4 II MODU DWG 5 II Southern Subsea Release Depth (m) Area Covered by > 1mm Thickness (m 2 ) Maximum Horizontal Extent of 1 mm Thickness 36 and Seabed m and Seabed m m Maximum Deposition Thickness (cm) 18

25 Table 17. Average projected results for combinations of mud and drill cutting dispersion simulations. Combined Simulations Area Covered by > 1mm Thickness (m 2 ) Maximum Horizontal Extent of 1 mm Maximum Deposition Thickness (cm) Thickness 1(36 ) and (36 ) and (36 ), 3 and In the studies conducted in support of Phase I and II, all of the cuttings were released from the water column which resulted in the prediction of largely dispersed thin layers of material. While the majority of the simulations for this study occurred at the seabed. Such releases will most likely minimize turbidity and environmental impact zone but the potential for interaction of the mound with the platform sub-structure exists. If further studies of this type are to be commissioned it is recommended that measurements of the mounds thickness and location be collected in conjunction with the bottom currents shortly after operations have ceased and be provided to the modeling contractor. This will assist in future model validation and the potential evaluation of long-term mound erosion and migration. 19

26 References Applied Science Associates (ASA), Hydrodynamic and Dispersion Modeling for the Azeri, Chirag, Gunashi Field Offshore Baku, Azerbaijan. Final Report to URS Dames & Moore, August Isaji, T., E. Howlett, C. Dalton, and E. Anderson Stepwise -Continuous Variable- Rectangular Grid Hydrodynamics Model. In: Proceedings of the Twenty-fourth Arctic and Marine Oilspill Program (AMOP) Technical Seminar, Edmonton (Alberta) Canada, pp , June 12,

27 Appendix 1: MUDMAP Description MUDMAP is a personal computer-based model developed by ASA to predict the near and far field transport, dispersion, and bottom deposition of drill mud s and cuttings and produced water (Spaulding et al; 1994; Spaulding, 1994). In MUDMAP, the equations governing conservation of mass, momentum, buoyancy, and solid particle flux are formulated using integral plume theory and then solved using a Runge Kutta numerical integration technique. The model includes three stages: convective descent/ascent, dynamic collapse and far field dispersion. It allows the transport and fate of the release to be modeled through all stages of its movement. The initial dilution and spreading of the plume release is predicted in the convective descent/ascent stage. The plume descends if the discharged material is more dense than the local water at the point of release and ascends if the density is lower than that of the receiving water. In the dynamic collapse stage, the dilution and dispersion of the discharge is predicted when the release impacts the surface, bottom, or becomes trapped by vertical density gradients in the water column. The far field stage predicts the transport and fate of the discharge caused by the ambient current and turbulence fields. MUDMAP is based on the theoretical approach initially developed by Koh and Chang (1973) and refined and extended by Brandsma and Sauer (1983) for the convective descent/ascent and dynamic collapse stages. The far field, passive diffusion stage is based on a particle based random walk model. This is the same random walk model used in ASA s OILMAP spill modeling system (ASA, 1999). MUDMAP uses a color graphics-based user interface and provides an embedded geographic information system, environmental data management tools, and procedures to input data and to animate model output. The system can be readily applied to any location in the world. Application of MUDMAP to predict the transport and deposition of heavy and light drill fluids off Pt Conception, California and the near field plume dynamics of a laboratory experiment for a multi-component mud discharged into a uniform flowing, stratified water column are presented in Spaulding et al. (1994). King and McAllister (1996, 1998) present the application and extensive verification of the model for a produced water discharge on Australia s northwest shelf. GEMS (1998) presents the application of the model to assess the dispersion and deposition of drilling cuttings released off the northwest coast of Australia. References Applied Science Associates (ASA) OILMAP Technical and User s Manuals, Narragansett, RI. Brandsma, M. G. and T.C. Sauer The OOC model: Prediction of short term fate of drilling mud in the ocean, Part I: Model description and Part II: model results, Proceedings of Workshop on an Evaluation of Effluent Dispersion and Fate Models for OCS Platforms, Santa Barbara, California, February 7-10, GEMS, Quantitative assessment of the dispersion and seabed depositions of drill cutting discharges from Lameroo-1 AC/P16, prepared for Woodside Offshore Petroleum, prepared by Global Environmental Modeling Services, Australia, June 16, A-1

28 King, B, and F. McAllister Modeling the dispersion of produced water discharges, APPEA Journal 1998, pp King, B. and F. McAllister The application of MUDMAP for investigating the dispersion of produced water discharges from Harriet A on Australia s Northwest shelf, report to Australian Petroleum Production and Exploration Association, prepared by Australian Institute of Marine Sciences, Townsville, Australia, August Spaulding, M. L., T. Isaji, and E. Howlett MUDMAP: A model to predict the transport and dispersion of drill muds and production water, Applied Science Associates, Inc, Narragansett, RI. Spaulding, M. L., MUDMAP: A numerical model to predict drill fluid and produced water dispersion, Offshore, Houston, Texas, March A-2

29 Appendix 2: Stage I Predicted Discharge Results at the MODU DWG Site Pre-Drill Well Single Well Results MODU DWG Site Pre-Drill Wells maximum deposition thickness and area covered by sediment greater than 1 mm thick. Season Current Condition Area Covered by > 1mm Thickness (m 2 ) Maximum Horizontal Extent of 1 mm Thickness Summer Maximum Summer Average Winter Maximum Winter Average Maximum Deposition Thickness (cm) A-3

30 Predicted bottom deposition contours for a single well at the MODU DWG Pre-Drill site during the summer season under maximum current conditions. The minimum thickness depicted is 1 mm. A-4

31 Predicted bottom deposition contours for a single well at the MODU DWG Pre-Drill site during the summer season under average current conditions. The minimum thickness depicted is 1 mm. A-5

32 Predicted bottom deposition contours for a single well at the MODU DWG Pre-Drill site during the winter season under maximum current conditions. The minimum thickness depicted is 1 mm. A-6

33 Predicted bottom deposition contours for a single well at the MODU DWG Pre-Drill site during the winter season under average current conditions. The minimum thickness depicted is 1 mm. Multiple Well Results A-7

34 MODU DWG Site Pre-Drill Wells maximum deposition thickness and area covered by sediment greater than 1 mm thick. Season Current Condition Area Covered by > 1mm Thickness (m 2 ) Maximum Horizontal Extent of 1 mm Thickness Summer Maximum Summer Average Winter Maximum Winter Average Maximum Deposition Thickness (cm) A-8

35 Predicted bottom deposition contours for 10 wells at the MODU DWG Pre-Drill site during the summer season under maximum current conditions. The minimum thickness depicted is 1 mm. A-9

36 Predicted bottom deposition contours for 10 wells at the MODU DWG Pre-Drill site during the summer season under average current conditions. The minimum thickness depicted is 1 mm. A-10

37 Predicted bottom deposition contours for 10 wells at the MODU DWG Pre-Drill site during the winter season under maximum current conditions. The minimum thickness depicted is 1 mm. A-11

38 Predicted bottom deposition contours for 10 wells at the MODU DWG Pre-Drill site during the winter season under average current conditions. The minimum thickness depicted is 1 mm. Appendix 3: Stage I Predicted Discharge Results at the DUQ DWG Site Well A-12

39 Single Well Results DUQ DWG Site Wells maximum deposition thickness and area covered by sediment greater than 1 mm thick. Season Current Condition Area Covered by > 1mm Thickness (m 2 ) Maximum Horizontal Extent of 1 mm Thickness Summer Maximum Summer Average Winter Maximum Winter Average Maximum Deposition Thickness (cm) A-13

40 Predicted bottom deposition contours for a single well at the DUQ DWG site during the summer season under maximum current conditions. The minimum thickness depicted is 1 mm. A-14

41 Predicted bottom deposition contours for a single well at the DUQ DWG site during the summer season under average current conditions. The minimum thickness depicted is 1 mm. A-15

42 Predicted bottom deposition contours for a single well at the DUQ DWG site during the winter season under maximum current conditions. The minimum thickness depicted is 1 mm. A-16

43 Predicted bottom deposition contours for a single well at the DUQ DWG site during the winter season under average current conditions. The minimum thickness depicted is 1 mm. A-17

44 Multiple Well Results DUQ DWG Site Wells maximum deposition thickness and area covered by sediment greater than 1 mm thick. Season Current Condition Area Covered by > 1mm Thickness (m 2 ) Maximum Horizontal Extent of 1 mm Thickness Summer Maximum Summer Average Winter Maximum Winter Average Maximum Deposition Thickness (cm) A-18

45 Predicted bottom deposition contours for 38 wells at the DUQ DWG site during the summer season under maximum current conditions. The minimum thickness depicted is 1 mm. A-19

46 Predicted bottom deposition contours for 38 wells at the DUQ DWG site during the summer season under average current conditions. The minimum thickness depicted is 1 mm. A-20

47 Predicted bottom deposition contours for 38 wells at the DUQ DWG site during the winter season under maximum current conditions. The minimum thickness depicted is 1 mm. A-21

48 Predicted bottom deposition contours for 38 wells at the DUQ DWG site during the winter season under average current conditions. The minimum thickness depicted is 1 mm. A-22

49 Appendix 4: Stage I Predicted Discharge Results at the Southern Subsea Site Well Single Well Results MODU Southern Subsea Site Wells maximum deposition thickness and area covered by sediment greater than 1 mm thick. Season Current Condition Area Covered by > 1mm Thickness (m 2 ) Maximum Horizontal Extent of 1 mm Thickness Summer Maximum Summer Average Winter Maximum Winter Average Maximum Deposition Thickness (cm) A-23

50 Predicted bottom deposition contours for a single well at the Southern Subsea site during the summer season under maximum current conditions. The minimum thickness depicted is 1 mm. A-24

51 Predicted bottom deposition contours for a single well at the Southern Subsea site during the summer season under average current conditions. The minimum thickness depicted is 1 mm. A-25

52 Predicted bottom deposition contours for a single well at the Southern Subsea site during the winter season under maximum current conditions. The minimum thickness depicted is 1 mm. A-26

53 Predicted bottom deposition contours for a single well at the Southern Subsea site during the winter season under average current conditions. The minimum thickness depicted is 1 mm. Multiple Well Results A-27

54 MODU Southern Subsea Site Wells maximum deposition thickness and area covered by sediment greater than 1 mm thick. Season Current Condition Area Covered by > 1mm Thickness (m 2 ) Maximum Horizontal Extent of 1 mm Thickness Summer Maximum Summer Average Winter Maximum Winter Average Maximum Deposition Thickness (cm) A-28

55 Predicted bottom deposition contours for 4 wells at the Southern Subsea Site during the summer season under maximum current conditions. The minimum thickness depicted is 1 mm. A-29

56 Predicted bottom deposition contours for 4 wells at the Southern Subsea Site during the summer season under average current conditions. The minimum thickness depicted is 1 mm. A-30

57 Predicted bottom deposition contours for 4 wells at the Southern Subsea Site during the winter season under maximum current conditions. The minimum thickness depicted is 1 mm. A-31

58 Predicted bottom deposition contours for 4 wells at the Southern Subsea Site during the winter season under average current conditions. The minimum thickness depicted is 1 mm. A-32

59 Appendix 5: Stage II Predicted Discharge Results at the MODU DWG Site Pre-Drill Well Single Well Results Stage II MODU DWG Site Pre-Drill Wells maximum deposition thickness and area covered by sediment greater than 1 mm thick for a single well. Season Current Condition Area Covered by > 1mm Thickness (m 2 ) Maximum Horizontal Extent of 1 mm Thickness Summer Maximum Summer Average Winter Maximum Winter Average Maximum Deposition Thickness (cm) A-33

60 Predicted deposition contours from a single well release from the 26 well, 11 m below MSL at the DWG DUQ location during the summer season under average current conditions. A-34

61 Predicted deposition contours from a single well release from the 26 well, 11 m below MSL at the DWG DUQ location during the summer season under maximum current conditions. A-35

62 Predicted deposition contours from a single well release from the 26 well, 11 m below MSL at the DWG DUQ location during the winter season under average current conditions. A-36

63 Predicted deposition contours from a single well release from the 26 well, 11 m below MSL at the DWG DUQ location during the winter season under maximum current conditions. A-37

64 Multiple Well Results Stage II MODU DWG Site Pre-Drill Wells maximum deposition thickness and area covered by sediment greater than 1 mm thick for 10 wells. Season Current Condition Area Covered by > 1mm Thickness (m 2 ) Maximum Horizontal Extent of 1 mm Thickness Summer Maximum Summer Average Winter Maximum Winter Average Maximum Deposition Thickness (cm) A-38

65 Predicted deposition contours from a multiple well (10) release from the 26 well, 11 m below MSL at the DWG DUQ location during the summer season under average current conditions. A-39

66 Predicted deposition contours from a multiple well (10) release from the 26 well, 11 m below MSL at the DWG DUQ location during the summer season under maximum current conditions. A-40

67 Predicted deposition contours from a multiple well (10) release from the 26 well, 11 m below MSL at the DWG DUQ location during the winter season under average current conditions. A-41

68 Predicted deposition contours from a multiple well (10) release from the 26 well, 11 m below MSL at the DWG DUQ location during the winter season under maximum current conditions. Appendix 6: Stage II Predicted Discharge Results at the Southern Subsea Site Well A-42

69 Single Well Results Stage II MODU Southern Subsea Site Wells maximum deposition thickness and area covered by sediment greater than 1 mm thick for a single well. Season Current Condition Area Covered by > 1mm Thickness (m 2 ) Maximum Horizontal Extent of 1 mm Thickness Summer Maximum Summer Average Winter Maximum Winter Average Maximum Deposition Thickness (cm) A-43

70 Predicted deposition contours from a single well release from the 26 well, 11 m below MSL at the Southern Subsea Site during the summer season under average current conditions. Predicted deposition contours from a single well release from the 26 well, 11 m below MSL at the Southern Subsea Site during the summer season under maximum current conditions. A-44

71 Predicted deposition contours from a single well release from the 26 well, 11 m below MSL at the Southern Subsea Site during the winter season under average current conditions. A-45

72 Predicted deposition contours from a single well release from the 26 well, 11 m below MSL at the Southern Subsea Site during the winter season under maximum current conditions. A-46

73 Multiple Well Results Stage II MODU Southern Subsea Site Wells maximum deposition thickness and area covered by sediment greater than 1 mm thick for 4 wells. Season Current Condition Area Covered by > 1mm Thickness (m 2 ) Maximum Horizontal Extent of 1 mm Thickness Summer Maximum Summer Average Winter Maximum Winter Average Maximum Deposition Thickness (cm) A-47

74 Predicted deposition contours from a multiple well (4) release from the 26 well, 11 m below MSL at the Southern Subsea Site during the summer season under average current conditions. A-48

75 Predicted deposition contours from a multiple well (4) release from the 26 well, 11 m below MSL at the Southern Subsea Site during the summer season under maximum current conditions. A-49

76 Predicted deposition contours from a multiple well (4) release from the 26 well, 11 m below MSL at the Southern Subsea Site during the winter season under average current conditions. A-50

77 Predicted deposition contours from a multiple well (4) release from the 26 well, 11 m below MSL at the Southern Subsea Site during the winter season under maximum current conditions. A-51