Om DREAM - ERMS modellen for beregning av regulære utslipp på sokkelen

Transcription

1 Om DREAM - ERMS modellen for beregning av regulære utslipp på sokkelen Henrik Rye m. fler SINTEF, Trondheim 1

2 ERMS project, Background Based on the Norwegian government s White Paper no. 58 and SFTs Zero discharge report of 1999, the offshore operators in Norway are facing the challenge of: Zero harmful discharges, within This has demonstrated the need for a quantitative discharge management tool, enabling the industry to document the strategy and actions to meet this requirement. 2

3 ERMS Environmental Risk Management System Participants: Statoil, Norway Norsk Hydro, Norway Total, France Agip, Italy Petrobras, Brazil Conoco/Phillips Exxon/Mobil Shell Duration:

4 EIF = Environment Impact factor. A measure for potential environmental risk, that is, damage on marine organisms from a discharge to sea. EIF is defined as being proportional to the water volume (or sediment area) where PEC/PNEC > 1. PEC = Predicted Environmental Concentration. Concentrations in the recipient calculated with the DREAM model. Concentrations are calculated as a function of x, y, z and time. PNEC = Predicted No Effect Concentration. The largest concentration of a product or a chemical expected to cause no measurable environmental effects. For offshore chemicals the PNEC value is determined from acute toxicity testing results values divided by an assessment factor. 4

5 Calculation of PEC in the DREAM model 3D-concentration field Parameters Wind Currents Biodegradation Evaporation Adsoption to particulates 5

6 1 30'E 1 45'E 2 00'E 2 15'E 2 30'E 2 45'E 20 km Calculation of EIF 61 20'N 61 20'N 60 50'N Example of the calculated risk contributions for the concentration field. Red area indicates the water volume where the concentrations exceed the PNEC level, that is, PEC/PNEC > 1 for the red area 'N 61 00'N 61 10'N 61 00'N 60 50'N Risk Map Time Series 5:00: 'E 1 45'E 2 00'E 2 15'E 2 30'E 2 45'E 6

7 Ocean currents used in the DREAM model. Snapshot of the surface currents calculated with the ECOM- 3D model. Geographical resolution 4 km. 7

8 Regular discharges from the offshore industry to the sea: Produced water (DREAM) Chemicals Natural compounds (PAH s, phenols, heavy metals) Drill cuttings and mud (ERMS) Cuttings (rock particles) Barite (particle matter, inclusive metals) Dissolved (and other) chemicals 8

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10 Example of particle spread in ambient ocean currents: 21 00'E 21 02'E 21 04'E 21 06'E 21 08'E 21 10'E 21 12'E 21 14'E 1 km 71 28'N 71 29'N 71 30'N 71 30'N 71 29'N 71 28'N 0:23: 'E 21 02'E 21 04'E 21 06'E 21 08'E 21 10'E 21 12'E 21 14'E 10

11 Deposition of cuttings on the sea floor: 1 44'00"E '45"E 1 43'30"E 1 43'15"E 1 43'00"E 1 42'45"E 200 m 58 30'00"N 58 30'00"N 58 29'50"N 58 29'50"N 58 29'40"N 58 29'40"N 58 29'30"N 58 29'30"N 1 44'00"E 1 43'45"E 1 43'30"E 1 43'15"E 1 43'00"E 1 42'45"E 15:12:00

12 Risk areas/volumes are to be calculated for: Water volume where PEC/PNEC > 1 for Chemical stress (toxicity) Particle stress in the water column (barite) Sediment surface area where PEC/PNEC > 1 for Chemical stress (toxicity, including heavy metals in barite) Burial Oxygen depletion Change in grain size 12

13 ERMS: Oxygen balance before discharge: 13

14 ERMS: Modeling of mixing of sediment 14

15 Sediment surface area where PEC/PNEC > 1 (TNO) Burial Change in grain size Oxygen depletion Chemical stress (toxicity) Sum risks for all 4 stressors = 5 % probability of damage limit 15

16 Example of a deposition calculation for a sediment layer impacted by drilling discharges: 9 52'E 9 53'E 9 54'E 9 55'E m 66 41'45"N 66 41'45"N 66 41'30"N 66 41'30"N 66 41'15"N 66 41'15"N 66 41'00"N 66 41'00"N 66 40'45"N 10:17: 'E 9 53'E 9 54'E 9 55'E 66 40'45"N

17 Example of a risk calculation for a sediment layer impacted by drilling discharges (ERMS): 9 52'20"E 9 52'30"E 9 52'40"E 9 52'50"E 9 53'00"E 9 53'10"E 200 m 66 41'15"N 66 41'20"N 66 41'25"N 66 41'25"N 66 41'20"N 66 41'15"N 66 41'10"N Sediment Risk Map: Total risk 3:20: '10"N 9 52'20"E 9 52'30"E 9 52'40"E 9 52'50"E 9 53'00"E 9 53'10"E 17

18 How to deal with time (TNO) Toxicant concentrations, oxygen changes, grain size changes and burial all change over time EIF sediment over time 160 EIF (area m 2 ) burial oxygen toxicants grainsize integrated time in months 18

19 Example of a risk calculation for a sediment layer impacted by drilling discharges (ERMS): Time development chart Grain size Oxygen Thickness Weighted EIF Attach_Cu Attach_Cr Attach_Zn Attach_Pb Attach_Hg Attach_Cd Time (days) Glydril MC Bestolife 3010 NM OCR 325 AG 19

20 SVAN, September 2003

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22 ERMS and relation to PROOF: Comparing impact on cages with ERMS risk calculations for the water column (PROOF Validation of methods, RF/Steinar Sanni). Comparing sediment model with ERMS field data, developing a species dependent bottom sediment model (part of the PROOF PEIOFF project)..? Radioactivity in produced water (PROOF RAIV, IFE v. Dag Øistein Eriksen). Modeling fates and effects in the environment (both water column and sediment). 22