Tendances dans les déversements, les rejets et les émissions provenant des installations pétrolières et gazières offshore

D8 - Teneurs en contaminants

D8.1 - Teneurs en contaminants

Message clé:

Les hydrocarbures et les produits chimiques offshore sont rejetés régulièrement dans le milieu marin durant les opérations pétrolières et gazières. L’évaluation des déversements et des rejets démontre que les mesures prises par OSPAR ont entraîné des diminutions des rejets des hydrocarbures ainsi que des produits chimiques offshore les plus néfastes.

Zone Évaluée

Récapitulatif Imprimable

Contexte

Figure 1. Origines des rejets et émissions provenant des installations offshore

Les substances les moins néfastes utilisées dans l'industrie sont considérées comme posant peu ou pas de risque (PLONOR) pour le milieu marin. Les produits chimiques les plus nocifs du point de vue de la toxicité, la bioaccumulation et la biodégradation sont considérés comme candidats pour la substitution.

L’objectif stratégique d’OSPAR en ce qui concerne les activités pétrolières et gazières offshore est de prévenir et de supprimer la pollution et de prendre les mesures nécessaires à la protection de la zone maritime contre les effets préjudiciables des activités pétrolières et gazières offshore. Ceci est réalisé en fixant des objectifs environnementaux et en améliorant les mécanismes de gestion.

Les apports chimiques au milieu marin provenant de l’industrie pétrolière et gazière varient selon l'activité effectuée (Figure 1). Les hydrocarbures sont rejetés principalement avec l’eau de production, qui contient des substances présentes à l’état naturel et des adjuvants chimiques, certains étant répertoriés comme substances dangereuses. Les hydrocarbures et les produits chimiques sont également rejetés pendant la phase d'exploration, au cours des opérations de forage, bien que, dans la mesure du possible, les produits chimiques les plus nocifs ne soient pas employés et ne sont pas rejetés fréquemment.

Figure 2. Production totale de 2009 à 2014 dans la zone maritime OSPAR

Le pétrole et les produits chimiques pénètrent aussi dans le milieu marin à la suite de déversements accidentels.

Production de gaz et de pétrole dans la zone OSPAR

La zone maritime OSPAR est un secteur mature de production de pétrole et de gaz. La production totale a régulièrement diminué au cours de la période d’évaluation. La Figure 2 montre la tendance à la baisse de la production.

Routine operation of production platforms and drilling installations leads to the release of hydrocarbons and other chemicals to the sea, including naturally occurring substances, especially through discharges of produced water and during drilling operations.

Accidental oil and chemical spills can also arise from different sources during routine operations.

Oil Discharges

The main source of hydrocarbons discharged during routine production operations is produced water. This is the water that comes from the reservoir with the oil and gas. Produced water contains dispersed oil and hazardous substances that occur naturally in the reservoir, such as heavy metals, aromatic hydrocarbons, alkyl phenols and radionuclides. Following treatment on the installation, the produced water also contains residues of process chemicals, including corrosion inhibitors and emulsifiers.

The OSPAR performance standard sets an upper limit of 30 mg l-1 for dispersed oil in produced water discharged to sea.

Chemical Discharges

Drilling requires the use of fluids that may contain a range of chemicals. These chemicals may be water-based or based on organic-phase fluids (e.g. lighter oil fractions and synthetic fluids). Drilling fluids are generally recycled, but as it also binds to rock fragments (cuttings) a proportion will be disposed to sea or returned to shore for treatment and disposal.

Production operations also use chemicals to aid separation of oil, gas and produced water, to provide corrosion protection and to maintain the offshore process and utility plant. Some of these chemicals are discharged in the produced water.

Chemicals used in exploration and production are categorised by OSPAR as PLONOR (Posing Little or No Risk to the environment), Substitution (those substances meeting the criteria set out in OSPAR Recommendation 2006/3) or as Ranking(neither PLONOR nor substitution). 

Oil and Chemical Spills

Oil and chemicals also enter the marine environment through accidental spills.

Oil and Gas Production

The OSPAR area is a mature oil and gas production area and total production of oil and gas in the OSPAR area has been steadily falling over the period of the assessment. Figure 2shows the downward trend in production.

OSPAR Measures

Since 1986, OSPAR has been taking measures to reduce pollution and minimise impacts on the marine environment from the offshore oil and gas industry. These include:

  • Measures to reduce oil in produced water;
  • Restrictions on the use and discharge of organic-phase drilling fluids;
  • Phasing out and replacement of substitution chemicals, to be implemented by 2017;
  • A harmonised mandatory control system to promote a shift towards the use of non-hazardous substances; and
  • Banning of dumping or leaving in place of disused offshore installations (subject to derogation in certain specified cases).

To support the objectives of OSPAR’s Offshore Oil and Gas Industry Strategy, almost all offshore operators now follow OSPAR's promotion of environmental management systems for offshore installations and have adopted approved schemes.

All Decisions, Recommendations and Agreements of relevance to this assessment are listed at the end of the document.

OSPAR Reports

This assessment sheet is based on the data collated in the Annual Reports prepared by the OSPAR’s Offshore Industry Committee (OIC) Expert Assessment Panel (EAP) on discharges, spills and emissions from offshore oil and gas installations. These data are available from the OSPAR website.

The data used for the 2009 to 2014 assessment were from the 2013 OSPAR report on discharges, spills and emissions from offshore oil and gas installations (OSPAR report 2013) and the 2014 data agreed at the EAP meeting in January 2016 (shortly to be published on the OSPAR website).

This assessment method used basic linear regression, best professional judgement and observation.

Résultats

Les résultats indiquent une évolution à la baisse générale pour plusieurs indicateurs :

  • La quantité d’hydrocarbures dispersés rejetés avec l’eau de production a diminué de 18 % entre 2009 et 2014 ;
  • L’utilisation de produits chimiques sur la liste OSPAR de produits chimiques devant faire l’objet de mesures prioritaires (LCPA) a diminué de plus de 90 % depuis 2009 et en 2014 aucun produit chimique de la liste LCPA n’a été rejeté ;
  • Il y a eu une diminution de 30 % dans l'utilisation de produits chimiques portant des avertissements de substitution et les rejets de ces produits chimiques ont diminué de 40 % entre 2009 et 2014.

The OIC EAP examines and reports annually on discharge, spill and emission data[1].  An assessment of data for the period 2009 – 2014 shows downward trends in the amount of dispersed oil discharged in produced water, use of chemicals on OSPAR’s List of Chemicals for Priority Action, and the use of chemicals carrying substitution warnings.

  • The amount of dispersed oil discharged in produced water decreased by 18% over the assessment period

In 2009, 4900 tonnes of dispersed oil were discharged in produced water. The amount of dispersed oil discharged in produced water has continued to decline despite a recent increase in produced water discharged (Figure 3).

 
 

Figure 3. Quantity of produced water discharged and quantity of associated dispersed oil discharged to the OSPAR Maritime Area 2009 – 2014. (Note different scales on primary and secondary y axes).

  • The use of LCPA chemicals has reduced by over 90% since 2009 and in 2014 no LCPA chemicals were discharged

In 2009, more than 1200 tonnes of LCPA were used, and nearly 150 tonnes discharged. In 2014, just over 100 tonnes were used and none discharged (Figure 4).

Figure 4. Quantities of substances on the list of chemicals for priority action used and discharged to the OSPAR Maritime Area from 2009 to 2014

  • The use of chemicals carrying substitution warnings has decreased by 30% while the discharge has decreased by over 40%

In 2009, more than 10 000 tonnes of substances identified as candidates for substitution were used, and 1735 tonnes discharged. In 2014, just over 7500 tonnes were used with just over 1000 tonnes discharged (Figure 5).

Figure 5. Use and discharge of chemicals with substitution warning (tonnes)

There was a 50% decrease (but no clear trend) in the number of installations exceeding the 30 mg l-1 dispersed oil in produced water performance standard between 2009 (31) and 2014 (16), and the amount of oil discharged in exceedance of the performance standard decreased by more than 70% over this period (see Figure 6).

Figure 6. Number of installations with discharges exceeding performance standard, with quantity of dispersed oil discharged by these installations

It was not possible to determine any positive or negative trends in the number of oil and chemical spills between 2009 and 2014 (Figure 7), or in the quantity of oil and chemicals spilled (Figure 8)[2]. It is evident that the majority of chemicals spilled are PLONOR chemicals.

 

[2] Incidents resulting in spills are extremely variable and a small number of large spills can adversely affect any attempts to assess trends.

Figure 7. Quantity of oil spilled (tonnes) and number of spills

Figure 8. Quantity of chemicals spilled (tonnes - note, substitution chemicals on different scale)

[1] These reports are published annually by OSPAR and are available on the OSPAR website

[2] Incidents resulting in spills are extremely variable and a small number of large spills can adversely affect any attempts to assess trends.

Conclusion

Des tendances à la baisse ont été observées en ce qui concerne :

  • La quantité d’hydrocarbures dispersés rejetés avec l’eau de production ;
  • L’utilisation et le rejet de produits chimiques LCPA ; et
  • L’utilisation et le rejet de produits chimiques portant des avertissements de substitution.

La réduction progressive des hydrocarbures dispersés rejetés avec l’eau de production a été réalisée par l’entremise de l’application des normes précisées dans la recommandation OSPAR 2001/1 relative à la gestion de l’eau de production des installations offshore, telle qu’amendée par la recommandation 2006/4 et la recommandation 2011/8.

L’abandon progressif de l’utilisation des produits chimiques LCPA a été réalisé grâce à l’application de la recommandation 2005/2 sur les objectifs environnementaux visant les rejets, par l’industrie de l’offshore, de produits chimiques qui sont sur la liste OSPAR 2004 des produits chimiques devant faire l’objet de mesures prioritaires, ou qui contiennent des adjuvants qui y figurant.

Les réductions dans l’utilisation et le rejet des substances portant des avertissements de substitution peuvent être directement attribuées à la mise en œuvre de la recommandation 2006/3 sur les objectifs environnementaux visant les rejets, par l’industrie de l’offshore, de produits chimiques qui sont ou qui contiennent des substances ayant été identifiées comme étant candidates à la substitution.

Une diminution du nombre d’installations dépassant la norme de performance de 30 mg d’hydrocarbures dispersés par litre d’eau de production rejetée en mer est relevée, quoiqu’on ne constate aucune tendance nette. Les tendances à la baisse sont pour la plupart le résultat direct des mesures adoptées par OSPAR et de leur mise en œuvre par l’industrie pétrolière et gazière offshore.

Aucune tendance n’est observée en ce qui concerne :

  • Les quantités de produits chimiques déversées;
  • Le nombre de déversements d’hydrocarbures;
  • La quantité d’hydrocarbures déversée.

Il n’a pas été possible de déceler des tendances positives ou négatives en ce qui concerne le nombre de déversements d’hydrocarbures ou de produits chimiques, ni en ce qui concerne la quantité d’hydrocarbures et de produits chimiques déversée, à cause de la nature imprévisible de ces événements.

The OIC EAP examined and assessed data reported on discharges, spills and emissions, from 2009 to 2014 for this assessment. Several trends were identified.

Downward trends were observed for:

  • Amount of dispersed oil discharged in produced water;
  • Use and discharge of LCPA chemicals; and
  • Use and discharge of chemicals carrying substitution warnings.

The gradual reduction in dispersed oil discharged in produced water has been achieved through the application of standards detailed in OSPAR Recommendation 2001/1 for the Management of Produced Water from Offshore Installations, as amended by OSPAR Recommendation 2006/4 and Recommendation 2011/8.

The phasing out of LCPAs was achieved through the application of OSPAR Recommendation 2005/2 on Environmental Goals for the Discharge by the Offshore Industry of Chemicals that Are, or Contain Added Substances, Listed in the OSPAR 2004 List of Chemicals for Priority Action.

Reductions in the use and discharge of substances carrying substitution warnings can be directly attributed to the implementation of OSPAR Recommendation 2006/3 on Environmental Goals for the Discharge by the Offshore Industry of Chemicals that Are, or Which Contain Substances Identified as Candidates for Substitution.

Many of the downward trends have clearly been achieved as the direct result of measures adopted by OSPAR and their subsequent implementation by the offshore oil and gas industry.

Although a trend was not discernible, the observed improvement in the number of installations exceeding the OSPAR performance standard of 30 mg l-1 oil for dispersed oil in produced water discharged to sea over the period of the assessment may be partly attributed to efforts made through annual reporting, where Operators are obliged to report reasons for exceedance and action being taken to prevent future exceedances.

No trends were observed for:

  • Quantities of chemicals spilled;
  • Number of oil spills; and
  • Quantity of oil spilled.

It was not possible to determine any positive or negative trends in the number of oil and chemical spills, or in the quantity of oil and chemicals spilled.[3]

 

[3] Incidents resulting in spills are extremely variable and a small number of large spills can adversely affect any attempts to assess trends.

Lacunes des connaissances

En 2012 OSPAR a adopté la recommandation 2012/5 sur une approche basée sur le risque pour la gestion des rejets d’eau de production provenant des installations offshore. Cette approche n’est pas en vigueur assez longtemps pour pouvoir juger de son impact sur la qualité du milieu marin. Cette question sera abordée une fois de plus amples informations seront disponibles.

OSPAR Quality Status Report 2010

OSPAR report on discharges, spills and emissions from offshore oil and gas installations in 2013

OSPAR report on discharges, spills and emissions from offshore oil and gas installations in 2014 (in prep)