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Generation of waste within the oil & gas sector

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Module 2

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Contents

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    • What is waste & why is it a concern?
    • Definition of hazardous waste
    • The European Waste Framework Directive
    • Wastes specific to oil & gas sector
    • Radioactive Materials within oil & gas sector

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What is waste and why is it a concern?

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Waste definition

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    • Waste means any substance, or object, which the holder discards, or intends, or is required, to discard.
    • All forms of waste and their management have the potential to damage health and the environment.
    • Waste generation must be minimised whilst re-use & recycling optimised – reducing the amount of waste for disposal.

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Waste or not waste?

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A material is not classified as a waste if:

    • Further use of the material is certain
    • A market, or demand, exists for such material
    • The material fulfills the technical requirements for the specific purposes
    • The use of the material is lawful and will not lead to overall adverse environmental or human health impacts

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Definition of hazardous waste

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    • Hazardous waste is waste that poses substantial threats to public health or the environment.
    • In all countries, the treatment, storage, transportation and disposal of hazardous waste should be strictly regulated and monitored.
    • International oil companies should adhere to international standards irrespective of where they are operating.

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Definition of hazardous waste

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    • Hazardous wastes can be divided into two major categories: characteristic wastes and listed wastes.
    • Characteristic hazardous wastes are materials that are known or tested to exhibit one or more of the following four hazardous traits:
      • Ignitability
      • Reactivity
      • Corrosivity
      • Toxicity

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Definition of hazardous waste

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    • Listed hazardous wastes are materials specifically listed by regulatory authorities as hazardous wastes which are from non-specific sources, specific sources, or discarded chemical products.
    • These wastes may be found in different physical states such as gaseous, liquids, or solids.

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Disposal of hazardous waste

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    • A hazardous waste cannot be disposed of by common means like other waste products.
    • The physical and chemical state of a haz-waste will determine the appropriate disposal option.

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Treatment trends with hazardous wastes

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Properties which make waste hazardous

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  • HP2 ― Oxidising

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  • HP3 ― Flammable

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  • HP4 ― Irritant
  • HP5 ― Specific target organ toxicity (STOT)

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  • HP6 ― Acute toxicity

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  • HP7 ― Carcinogenic

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  • HP8 ― Corrosive

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  • HP 11 – Mutagenic

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  • HP 13 – Sensitising

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  • HP 14 – Ecotoxic

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Management of hazardous waste

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    • Hazardous waste shall not be mixed with other waste
    • Dilution in order to avoid requirements is forbidden
    • Proper packaging, storage, labeling
    • Hazardous waste shall ONLY be treated by licensed/authorised contractor and premises
    • Delivering of hazardous waste shall be notified to the Environmental Authority

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Wastes specific to oil & gas sector

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Waste from drilling activities

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Waste from drilling activities:

    • Drilling waste (cuttings and mud)
    • Produced water
    • Oily waste (oil emulsion and oil contaminated water)
    • Chemicals
    • Radioactive waste (scales from pipelines and other equipment aggregates some of the radioactive substances)
    • Drainage water
    • Domestic water
    • Sewage
    • Solid waste

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Impacts of different types of waste

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Water-based drilling fluids (WBDF)

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    • The base fluid mainly comprises water
    • But, also contains sea water, salts, clay
    • WBDF are used in exploration wells, top-hole sections and in simple wells

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WBDF effects when discharged

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    • Limited effects when discharged on land or in surface water due to low toxicity.
    • Impacts would tend to be harmful rather than hazardous.
    • But, should be contained in lined pits, along with cuttings, and treated due to high pH and high salt content.

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Oil Based Drilling Fluids (OBDF)

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    • Oil is the base fluid
    • Chemicals are added to cool, lubricate, move out cuttings
    • OBDF is used in long, complicated wells (deviated wells, horizontal wells, complex geology)
    • Are used in the reservoir zone

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OBDF effects when discharged

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    • Severe effect if discharged on land or offshore
    • Also be harmful to public health
    • Both drilling fluids and cuttings must be taken to treatment plants to be reclaimed or destroyed

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Produced water

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Produced water is generated from the reservoir along with oil or gas – and contains several chemicals:

    • Inorganic salts
    • BTEX (benzene, toluene, etylbenzene, xylene)
    • Alkylphenols
    • Organic acids
    • PAH (poly aromatic hydrocarbons)
    • Heavy metals
    • Low-radioactive components
    • Dispersed oil
    • High temperature

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Discharged of produced water

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    • Will potentially have long-term effects including hormone interfering, mutagenic, reprotoxic effects.
    • Effects from discharged is very dependent on:
      • Quantity
      • Composition - oil & chemicals content
      • The receiving environment (land, surface water, streams or rivers, ground water)
    • Estimated to be most important contribution to offshore pollution in the North Sea!

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Emissions to air

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    • CO2 , NOx and SO2:
      • From energy production in gas turbines, generators and diesel engines
      • From flaring
      • From well testing
    • VOC – volatile organic components:
      • From storing and offloading of oil by truck or vessel
      • From venting, leakages
    • PAH and black carbon (soot):
      • From flaring and well testing
    • Effects:
      • Climate change
      • Acid rain
      • Acidification of water

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Gas flaring

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    • Flaring of associated gas is not necessary – but can be undertaken if for safety reasons
    • Gas may be used directly for power generation
    • Gas may be sold to local market (but pipelines and buyer necessary)
    • Gas may be injected back into the well
    • Avoiding flaring is the preferred option for environmental and cost perspectives

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Generator reporting requirement

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    • Status of the activities
    • Discharges and emissions
    • Accidental discharges
    • The use and discharges of chemicals
    • Handling of waste

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Decommissioning

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    • The operators’ responsibility do not stop when the reservoir is exhausted
    • Need to plan how to stop production and carry out decommissioning
    • Carry out cleaning of facilities and pipelines, and surrounding areas, in an environmentally friendly manner
    • Leave the area as it was found, or better!
    • Carry out environmental monitoring after cessation

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Radioactive materials within the oil & gas sector

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Naturally Occurring Radioactive Materials (NORM)

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    • Cuttings from any well may contain Naturally Occurring Radioactive Materials (NORM) reflecting what is present in the soil/rock.
    • Cuttings can, on occasions, set-off radiation alarms at disposal facilities due to elevated NORM levels.
    • Common examples of NORM include uranium, thorium, potassium and radium.

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Other uses of radioactive material

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    • Other uses of radioactive material includes well logging and evaluating the integrity of internal welds and seams in pipes and tanks.
    • Such uses are unlikely to yield radio-active waste unless the tools get lost in the waste.
    • They are extremely expensive, so very unlikely to occur.

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Thank you

UNEP-Norway Partnership

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United Nations Avenue, Gigiri

PO Box 30552 – 00100 GPO Nairobi, Kenya

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www.unep.org