Assessment of the discharges, spills and emissions from offshore oil & gas operations on the Danish Continental Shelf 2018-2022
Executive Summary
This report presents the discharge, spill and emission data from offshore oil and gas operations on Danish Continental Shelf (DCS) over the period 2018 - 2022 and the assessment of the data. The annual data is provided in the Appendix 2.
Level of Activity
The Danish Continental Shelf is a mature oil and gas province within the OSPAR region and production is declining. However, there is still a moderate level of oil and gas production, although this has decreased by almost 51 % in the reporting period from 2018 to 2022, which is partially due to shut down and redevelopment of some installations.
Discharges & spills
The total quantity of dispersed1oil (aliphatic oil) discharged to sea from produced water and displacement water fluctuated between a high of 136 tonnes in 2018 and a low of 95 tonnes in 2020 but overall remained fairly stable during the period of 2018–2022 with average of 116 tons/year.
Produced water and displacement water are the main contributors to the oil discharges from the petroleum industry. The total volume of produced water and displacement water discharged saw a decline from approximately 22 million m3/year in 2018 to a low of 16 million m3/year in 2020.
Full Report
One installation on the DCS failed in 2018 to meet the performance standard for oil content as an annual average. However, the maximum amount of oil discharged with produced water exceeding the performance standard was 0,034 tonnes in 2018.
The total number of oil spills to the sea less than 1 tonne was high in 2018 (30) but decreased thereafter. The quantity of oil released was generally low but was unusually high in 2018, due to an accidental release of diesel oil from a defect valve on one of the installations.
Chemicals
The total quantity of chemicals reported used offshore varied over the period. In 2019, 27 302 tonnes of chemicals were reported used. Of this, only 0,24 % belonged to the category “substitution chemicals” and 0,02 % to the category List of Chemicals for Priority Action (LCPA). One operator used the latter category in a small amount in 2019.
The total quantity of chemicals discharged into the sea over the period 2018 – 2022 varied from approx. 10 967 tonnes in 2019 to a low of 4 419 tonnes in 2020. Of these chemicals only 0,26 % belonged to the substitution chemicals category in 2019. This amount rose to 0,66 % in 2021 mainly due to DK re-classification of sodium hypochlorite. No LCPA substances were discharged during the period.
The number of smaller chemical spills to sea was relatively high although the quantity of chemicals spilled decreased during the period from 2018 to 2022. The number of larger spills remained low but there was a peak in the quantity spilled in 2022 due to a specific incident with leakage of scale inhibitor at one installation.
Atmospheric Emissions
Atmospheric emissions are not regulated by OSPAR measures, but they are reported annually to OSPAR. For carbon dioxide (CO2), a downward trend between 2018 and 2020 was observed followed by a rather stable emission from 2020 to 2022.
The emission of nmVOC2 and methane (CH4) fluctuated between 700 tonnes in 2020 to 1 900 tonnes in 2022 for nmVOC and for methane ranging from 3 400 tonnes in 2018 to 2 000 tonnes in 2022.
Emissions of sulphur dioxide (SO2) and nitrogen dioxide (NOx) were relatively stable in the period.
1“Aliphatics” and “aromatics” are defined by the reference method set in OSPAR Agreement 1997—16 (Solvent extraction, Infra-Red measurement at 3 wavelengths). In that context, “aliphatics” and “dispersed oil” mean the same thing.
2nmVOC = Non-methane Volatile Organic Compounds