Offshore Oil Platform Waste Management Steven J Filkin Director, Percival Filkin EHS Limited What is an oil platform? •  An oil pla)orm or “oil rig” is a structure used to house workers and machinery required to drill and/or produce oil and natural gas from wells in the sea floor; •  Pla)orm may be fixed to the ocean floor, or be floaCng; •  There are as many as 6,500 pla)orms of various types throughout the world; •  All materials needed must be brought in by a ship (supply vessel) or generated on-­‐board; •  Everything produced by the pla)orm must be either dealt with on board or shipped back to shore. Basically it is a stand-­‐alone village far out to sea… This presents substanCal engineering, environmental, human resource, and logisCcal challenges Typically, pla)orms are self-­‐sufficient in energy, water and many aspects of waste management, and are designed to have minimal environmental impact. Potential Environmental Implications Oil has directly toxic effects EutrophicaCon Localised thermal effects Underwater noise Smothering of marine mammals and seabirds Marine liUer patches have formed at ocean gyres •  Accidental release • 
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TOPSIDE JACKET Waste generating operations on an offshore platform AcCviCes relaCng to drilling, well installaCon and oil or gas producCon AcCviCes associated with providing welfare and accommodaCon for the workforce Oil well drilling and well installation •  Rotary drilling bits are Cpped with diamond or carbides matched to the strata •  Drilling muds are used to cool the bit and flush away the drill cuXngs •  The well is lined with telescopic steel casings which needs to be cemented into the host rock •  A gravel pack is typically added to the boUom to screen out unwanted sand/silt Rotary drill bit Oil well drilling and well installation Waste generated by… Oil well drilling and well installation Drill cu@ngs Rock debris excavated from drilling the well Drilling mud A mulC-­‐funcConing substance that acts as a lubricant, coolant, and flushing agent Cement returns Surplus cement from cemenCng the steel casings into the well shaY Water-­‐based muds – e.g. sodium silicate, potassium chloride Synthe:c-­‐based muds – e.g. diesel or synthe:c oils Production of oil “ProducCon” means the extracCon and basic pre-­‐treatment of oil before it is pumped to shore •  Oil deposits contain formaCon water known as “produced water” •  Oil deposits may also contain a significant amount of sand and fines called “produced sand” •  Associated gas dissolved in the oil is also produced Waste generated by… Pre-­‐treatment of extracted oil De-­‐watering Produced water (i.e. contaminated water) De-­‐sanding Produced sand (i.e. oily sand) Degassing Associated gas (from the oil reserve) Pipeline maintenance Pigging of export pipelines The pipelines must be cleaned regularly Pigs Waste generated by… Pigging of lines “Pigging waste” Waste generated by… Provision of utilities DesalinaCon (reverse osmosis) Salt-­‐rich permeate Power generaCon Sewage treatment Nitrogen oxides, Treated effluent CO2 & sludge Housing of the workforce Most pla)orms have two enCre crews – one for a day and one for a night shiY Waste generated by… Housing of the workforce These wastes include all those that are produced to accommodate the crew on-­‐board DomesCc waste, galley wastes (paper, cardboard, glass, plasCc), grey water, black water (sewage) Disposal routes Released to atmosphere Back to shore Supplies from land Re-­‐injected to the reservoir Regulatory Standards These govern which wastes can be released to the environment, and how or where. •  Commitments made in the ESIA documents which cite a range of relevant internaConal standards •  Principal source of regulatory requirements stem from the MARPOL ConvenCon 1972 •  IFC Guidelines •  The Marine SanitaCon Device (MSD) must comply with the US Coast Guard standards The disposal approaches have to ensure that any releases are in equilibrium with the marine ecosphere. Treatment on-­‐board •  MaceraCon of food wastes to the requirements of the MARPOL ConvenCon Annex V •  Treatment of sewage and discharge of the effluent in compliance with MARPOL MAC •  Segregated drainage networks to prevent cross contaminaCon of clean rainwater •  All waste water goes through an oil skimmer to remove residual or accumulated oil Disposal routes Released to atmosphere Releases to atmosphere CombusCon gases •  On deck generators (gas & diesel-­‐fired) release nitrogen oxides , carbon monoxide and parCculates by dispersal Gas flaring •  This is primarily an emergency relief system and to purge systems of explosive atmospheres •  Flaring of associated gas released from the oil deposit Disposal routes Discharges to the sea-­‐bed Drill cuXngs •  Rock debris extracted with water-­‐based muds is cleaned to recover drilling mud and then dispersed onto the sea-­‐bed Drilling mud •  Only low-­‐toxicity, water-­‐based or biodegradable drilling muds are permiUed to be discharged at sea Cement returns •  The cement that is forced out the top of the well casing may be discharged to the sea-­‐bed Discharges to the sea Salt-­‐rich permeate •  Highly concentrated sea water from the desalinaCon process is released back to the sea Treated effluent •  Discharge of the effluent below the sea surface in compliance with MARPOL MAC DomesCc wastes and grey water •  May be discharged provided no floaCng debris is present •  Food wastes must be <25mm to comply with the MARPOL ConvenCon Annex V and discharged below the sea surface via the caisson Discharges to the sea Cooling water •  Sea water is liYed and treated for use as a cooling medium •  Sea water is used for cooling equipment on the pla)orm, e.g. compressors •  World Bank guidance states that it has to be within 3° of the ambient temperature, 100m from the release point Drainage •  There is a segregated drainage system •  A mixture of clean rainwater, run-­‐off and deck washwater is discharged to the sea Disposal routes Re-­‐injected to the reservoir Re-­‐injection into the reservoir Drill cuXngs •  Rock debris contaminated with adhered syntheCc-­‐based muds is milled to allow it to be injected into the reservoir Drilling mud •  SyntheCc-­‐ or oil-­‐based muds are re-­‐
injected as they cannot be released into the sea Produced water •  From the de-­‐watering of extracted oil •  Injected back into the oil reservoir for pressure maintenance Produced sand •  Clean sand removed from the producer wells is slurried with the drill cuXngs for reinjecCon Disposal routes Back to shore Shipped to shore DomesCc & galley waste •  Primary segregaCon onboard and secondary segregaCon onshore at the transfer staCon •  Recyclables are recovered and residual waste is sent to landfill Medical waste •  Treated onshore – sterilised and incinerated or landfilled Sewage sludge •  AYer sewage treatment onboard the sludge is containerised and shipped to shore for further treatment Shipped to shore ProducCon chemicals •  Used chemicals are placed in secondary containers •  SegregaCon of incompaCble substances Maintenance wastes •  Wastes arising from servicing and repairing equipment are segregated and recycled where possible Drill cuXngs & muds •  Drill cuXngs (rock debris) and adhered syntheCc-­‐based muds may be shipped-­‐
to-­‐shore in specially designed cuXngs boxes for ITD treatment Shipped to shore Contaminated water •  Dirty water, contaminated seawater, bilge water, etc may be containerised and shipped to shore Pigging waste •  Waxy deposits from the inside of the pipelines •  Treated and re-­‐used by the refinery Source segregation •  As with most waste management systems source segregaCon is the key to success •  Colour coding provides most convenient and is well proven method •  Housekeeping standards have to be high Platform –
Originator
Vessel
Quayside
Onshore
Transporter
Fill in WTN secCons A&B. Retain the WHITE COPY and file on the pla)orm. Pass the other copies to the Vessel. Reconcile WHITE COPY with the BLUE COPY when it is returned by the Receiver. Fill in WTN secCon C1. Upon arrival to the Quayside pass all copies to the Port Coordinator. Fill in WTN secCon C2. Remove the PINK COPY and return it to the Vessel. Pass the other copies to the Onshore Transporter. File PINK COPY on the Vessel. Fill in WTN secCon D. Remove the LILAC COPY and return it to the Quayside. Pass the other copies to CWAA. Transfer
Station
Fill in WTN secCon E. Remove YELLOW COPY and return it to the Transporter. File LILAC COPY on the Quayside. Keep YELLOW COPY. Keep the GREEN COPY. Stamp BLUE COPY SecCon E and return it to the Pla)orm. Mitigating Environmental Impacts •  Waste segregaCon, management and disposal planning •  ImplementaCon of relevant internaConal best pracCce •  BPEO assessment to idenCfy opCmum disposal/recovery techniques •  Waste management hierarchy •  Sub-­‐surface disposal where appropriate down-­‐hole straCgraphy is present Concluding thoughts •  Offshore pla)orm waste management systems have been opCmised to suit the operaCng constraints onboard •  All waste disposal and recovery techniques must be jusCfied by the latest scienCfic and engineering data and a BPEO assessment •  The innovaCve engineering soluCons developed to increase efficiency also meet environmental quality criteria Any questions?