PWSRCAC Response System Optimization Project PWS RCAC Board - PowerPoint PPT Presentation

PWSRCAC Response System Optimization Project PWS RCAC Board Meeting Meeting May 4, 2017

Research Question • What is the optimal configuration of containment, skimming, and storage (primary and secondary) for nine PWS recovery systems (three open-water and six nearshore) over a five-day simulated spill response assuming favorable weather conditions?

Weir Skimmer

Oleophilic Disc Skimmer

Scenario

Operational Periods

What Are We Optimizing? • The amount of oil recovered for a given operational period • Trying to match De-rated Encounter Rate with De-rated Skimmer Rate and make both as high as possible

RESULTS • Open-Water Response Systems – Base Case – Optimized • Nearshore Response Systems – Base Case – Optimized • Secondary Storage Analysis – Nearshore

Recovered Fluids

TRANSREC/GRAMREC - BASE CASE 38,067 bbl

CB8 BARGE- BASE CASE 53,012 bbl

VALDEZ STAR - BASE CASE 14,290 bbl

TRANSREC/GRAMREC - OPTMIZE

CB8 BARGE- OPTIMIZE

VALDEZ STAR- OPTIMIZE

NEARSHORE BASE CASE Weir Disc 25000 25000 20000 20000 Free Water Water in Emulsion CB4 15000 15000 Oil BBL BBL BBL 10000 10000 5000 5000 2,236 bbl 2,076 bbl 0 0 1 2 3 4 5 6 7 8 9 10 OP 1 2 3 4 5 6 7 8 9 10 25000 25000 20000 20000 15000 15000 CB2 BBL 10000 10000 5000 5000 1,573 bbl 1,860 bbl 0 0 1 2 3 4 5 6 7 8 9 10 OP 1 2 3 4 5 6 7 8 9 10 25000 25000 20000 20000 J-boom 15000 15000 BBL 10000 10000 5000 5000 2,236 bbl 593 bbl 0 0 1 2 3 4 5 6 7 8 9 10 OP 1 2 3 4 5 6 7 8 9 10 OP OP

CB4 WEIR - OPTIMIZE

CB4 DISC - OPTIMIZE

CB2 WEIR - OPTIMIZE

CB2 DISC - OPTIMIZE

J-BOOM WEIR - OPTIMIZE Essentially the same as CB4 Weir

SECONDARY STORAGE - OPTIMIZE

Secondary Storage Optimal Operating Area Size for 10 Offload Stations

Secondary Storage Model Radius X nm

Secondary Storage Model Secondary Storage Barge

Secondary Storage Model Skimming System Primary Storage Barge

Secondary Storage Model

Secondary Storage Model

Secondary Storage Model

Secondary Storage Model

Secondary Storage Model Inputs: • Radius • Slick thickness • OP length • Time step length • Number and specs. of skimming systems • Number and specs. of mini-barges • Number of offload stations • Number of iterations Outputs: • Status of everything at each time step • Total fluids recovered • Total oil recovered

Secondary Storage Model Scenarios: • Assumed 120 vessels in a scenario • Varied number of skimmers and and mini- barges to utilize all 120 vessels (each skimming system uses 3 vessels and each mini-barge uses one vessel) • e.g. 20 skimmers and 60 mini-barges (20 x 3 + 60 = 120) • Ran every combination from • zero skimmers, 120 mini-barges • 60 skimmers, zero mini-barges • Ran for weir skimming system with 10 and 18 offload stations on secondary storage barge • Ran for disc skimming system with 6 and 10 offload stations on secondary storage barge • Ran for 2 nm to 40 nm radius • Ran each scenario 100 times

Secondary Storage Model 20 skimmers 60 mini-barges 19,419 bbl 0 40 WEIR SKIMMERS 18 Offload Stations 2 nm area

Secondary Storage Model 14 skimmers 78 mini-barges 13,040 bbl 0 0 40 WEIR SKIMMERS 10 Offload Stations 2 nm area

Secondary Storage Model d e M t i m i n i i l - - b r e a m r g m e i - k l S i m i t e d 0 40 WEIR SKIMMERS 18 Offload Stations 2 nm area

Secondary Storage Model Mini-barge-limited Station-limited Skimmer-limited 0 0 40 WEIR SKIMMERS 10 Offload Stations 2 nm area

Secondary Storage Model

Secondary Storage Optimal Weir Skimming Systems

Secondary Storage Optimal Disc Skimming Systems

Secondary Storage Optimal Decanting Mini-Barges • In OP 4 a weir skimmer can fill a mini-barge in 22 minutes • When full, the mini-barge will hold 189 bbl of free-water • The capacity of the de-cant pump is 17 bbl/hr • Thus it will require 8.9 hours to decant 80% of that free- water • Considering the time it would take run back and forth to the Secondary Storage Barge at 5 kts, rig/de-rig, and pump-out the mini-barge, the mini-barge would have to be at least 20.8 nm away from the Secondary Storage Barge for decanting to make sense.

Considerations • Potential oil recovery is valuable as a comparative metric only. • Real-world testing and training are critical. • Oil properties and weather conditions impact results. • Realistic equipment assumptions are critical. • Results regarding disc skimmers could apply to oleophilic skimmers generally.

FINDINGS • Oleophilic skimmers have significant advantages over weir skimmers due to the lack of free-water recovered. • The sooner systems are deployed the better total oil recovery will be for the response. • Open-water systems are encounter rate limited. Improvements to these systems can be achieved by increasing the swath-width.

FINDINGS • Nearshore systems are pump rate limited and can be improved by increasing skimmer capacity. • Secondary storage will require more offload stations if weir skimmers are used, compared to disc skimmers. • The optimal configuration for weir skimming systems is 18 offload stations, 20 skimming systems and 60 mini-barges. • The optimal configuration for disc skimming systems is 10 offload stations, 26 skimming systems and 42 mini-barges.

FINDINGS • Total oil recover declines by about 2% per nm from the secondary storage barge. • Large operating areas require more mini-barges to operate efficiently. • Decanting mini-barges is not efficient.