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Muddied Waters

A Survey of Offshore Oilfield Drilling Wastes and Disposal Techniques to Reduce the Ecological Impact of Sea Dumping

by Jonathan Wills, M.A., Ph.D., M.Inst.Pet., for Ekologicheskaya Vahkta Sakhalina (Sakhalin Environment Watch); 25th May 2000

The Law on Offshore Wastes Discharges in Different Jurisdictions

Go to Previous Page: OSPAR

OSPAR (continued)

At present there are four main OSPAR measures regulating the majority of discharges and emissions from offshore installations:

  1. PARCOM Decision 92/2 on the Use of Oil-based Muds - this was the start of the ban on OBM discharges;
  2. PARCOM Recommendation 92/6 on Best Available Technology for Produced Water Management on Offshore Gas and Oil Installations - this set the 40ppm oil:water content for produced water discharges;
  3. PARCOM Decision 96/3 on a Harmonized Mandatory Control System for the Use and Reduction of the Discharge of Offshore Chemicals - this co-ordinated the different countries' regulations;
  4. PARCOM Decision 97/1 on Substances/Preparations Used and Discharged Offshore - this attempted, unsuccessfully, to make a list of banned substances.

All are currently under review within OSPAR and the legislation is likely to change in 2001, after a 12-month delay caused by disagreements between member states over which substances should be banned, which should be treated as "Preparations Used and Discharged Offshore Which Are Considered to Pose Little or No Risk to the Environment" (PLONOR) (For details, see: OSPAR. 1999a. List of Substances / Preparations Used and Discharged Offshore Which Are Considered to Pose Little or No Risk to the Environment (PLONOR). 1999-9), and on issues such as toxicity testing and environmental monitoring methods. In February 2000 several new measures were agreed in draft form at OSPAR's Working Group on Sea-based Activities (SEBA 2000), which, if adopted by OSPAR this year, will supersede PARCOM 92/2, PARCOM 96/3 and PARCOM 97/1 on 16 January 2001.

The current negotiations are designed to eliminate the confusion that has arisen as a consequence of the failure to agree a list of banned offshore chemicals under the PARCOM Decisions 94/1 (OSPAR. 1994. Decision 94/1 on Substances/Preparations Used and Discharged Offshore. Paris Commission. Paris) and 97/1 (OSPAR. 1997. PARCOM Decision 97/1 on Substances/Preparations Used and Discharged Offshore. OSPAR. Brussels) on "Substances/Preparations Used and Discharged Offshore". In 1994 the European Community, France, Spain and the United Kingdom lodged reservations that, in the words of one senior observer (An informant who spoke on condition of anonymity. pers. comm. April 2000) at the talks, "indicate that already then the original concept of this Decision, i.e. to stipulate what the substances/preparations shall be subject to strong regulatory control by national authorities (Appendix 1) or shall not be discharged from offshore installations in the maritime area (Appendix 2), was not unanimously supported".

The OSPAR session that passed the 97/1 resolution made high-minded reference to the precautionary principle and proclaimed that "high risk substances should be strictly regulated and their use phased out, even though there is insufficient information on their occurrence in sea water, sediments and marine biota". Delegates recognised that "large quantities of chemicals are used and discharged offshore by the industry". But all they could achieve, in the words of the same senior observer, was "merely an editorial up-date" with "some substances added to Appendix 1, others deleted". The proposals do, however, make it clear that users of chemicals will have to tell the authorities (at least in private) what they are. The new guidelines say, in bold type: "Please note that trade names will not be accepted as compositional information." (See Appendix 13, below: OSPAR Guidelines for Completing the Harmonised Offshore Chemical Notification Format (HOCNF), as proposed by SEBA, 2000.)

Unfortunately, far from being a model for other countries to follow, the PARCOM 94/1 and 97/1 sessions turned out to be examples of the overlap and confusion that can result when politicians put economics before the environment and scientists allow commercial considerations to dilute their professional advice.

The PARCOM 97/1 resolution had two appendices under the heading "List of banned substances". Appendix 1 listed substances whose use or discharge offshore should be "subject to strong regulatory control by national authorities":

  • Ferric chloride;

  • Hydrochloric acid;

  • Metasilicate;

  • Phosphoric acid;

  • Potassium hydroxide;

  • Sodium hydroxide;

  • Sodium hypochlorite;

  • Potassium iodide;

  • Formaldehyde;

  • Glutaraldehyde;

  • Glycerol;

  • Diethylenglycol;

  • Triethylenglycol;

  • Acetone;

  • Calcium Stearate.

Delegates went on to decide "the substances/preparations listed in Appendix 2 shall not be discharged from offshore installations in the maritime area". Three years later, the list of banned chemicals in Appendix 2 reads as follows: "No substances/preparations currently assigned."

The main reason for the failure to draw up a list of forbidden substances was repeated and sustained objection from national governments, notably the British, following what may be described as the strongest representations by the oil companies who would have to meet the costs of compliance. As in the US, elected politicians permitted and encouraged commercial corporations to influence the process of law-making, in a way unimaginable for private citizens, professional associations, trades unions or environmental organisations (For further discussion of this phenomenon, see: Steiner, R. 1993. Government, Industry and Public Management of the Seas in the 21st Century. Marine Policy, September 1993, 399-403).

There are other, equally curious, facets of OSPAR's decisions and recommendations. For example, Article 3 of Annex 3 to the OSPAR Convention reads:

  1. Any dumping of wastes or other matter from offshore installations is prohibited.
  2. This prohibition does not relate to discharges or emissions from offshore sources.

This terminological curiosity is explained by the fact that "wastes" only refers to cleaning materials, such as washing-up liquid and toilet cleaners, and other household chemicals used on board.

By 1996, OSPAR was already moving towards a system of "acceptance criteria for toxicity, biodegradability and bioaccumulation of drilling fluids" which would measure the ecological effects of whole muds and mixtures, rather than individual components, and controlling overall discharge quantities. Decision 96/3 also listed substances liable to cause taint and prescribed uniform testing methods. As in the US and Canada, governments in effect agreed to negotiate improvements with the industry rather than lay down the law and enforce it. The shift from outright bans on named substances to case-by-case controls and self-regulation made for an enormously complicated, bureaucratic process and created extra administration costs for industry, but these costs were lower than the price of total compliance and zero discharge.

The latest proposals before OSPAR, while "recognising that marine pollution by drill cuttings and their associated organic phase drilling fluids (OPF) should be avoided and prevented to the greatest possible extent" (OSPAR. 2000. Draft Measures Proposed by the OSPAR Working Group on Sea-based Activities (SEBA), February 2000. Amsterdam) are silent on discharges of WBM-contaminated cuttings which, apparently, are to be allowed to continue. The draft regulations (Ibid), which will form the new OSPAR regime for minimising marine pollution from drilling wastes, set out the following operating principles:

3.1.1. Contracting Parties shall ensure that no OPF shall be used for the purpose of drilling in the course of an offshore activity or discharged into the maritime area without prior authorisation from the national competent authority. In reaching a decision on any authorisation, Contracting Parties shall apply to the management of OPF contaminated cuttings:

a. the principles of the Harmonised Mandatory Control System for the Use and Reduction of the Discharge of Offshore Chemicals as set out in [the applicable OSPAR Decision];

b. Best Available Techniques (BAT) and Best Environmental Practice (BEP) as set out in Appendix 1 of the OSPAR Convention;

c. the waste management hierarchy set out in Appendix 1 to this Decision.

3.1.2. The use of diesel oil based drilling fluids is prohibited.

3.1.3. The discharge of whole organic-phase drilling fluids to the maritime area is prohibited.

3.1.4. The discharge into the sea of cuttings contaminated with OBF at a concentration greater than 1% weight/weight on dry cuttings is prohibited.

3.1.5. The use of OPF in the upper part of the well is prohibited. Exemptions may be granted by the national competent authority for geological or safety reasons.

3.1.6 The discharge of cuttings contaminated with synthetic fluids shall only be authorised in exceptional circumstances. Such authorisations shall be based on the application of BAT/BEP as set out in Appendix 1 of this Decision.

The draft proposals also prescribe "Best Available Techniques" (BAT) and "Best Environmental Practice" (BEP) "within the context of the 'five Rs' waste management hierarchy":

The reduction of discharges of OPF-contaminated cuttings is the primary focus of this Decision. Examples of measures to be taken with a view to reducing discharges are e.g. prohibition on use in the upper well section except where technically necessary, horizontal drilling, slim hole drilling.

Operators will choose techniques from a range of options e.g. mud treatment plants, shale shakers, centrifuges and washing systems for cuttings, i.e. those technologies that maximise reuse consistent with safe and efficient drilling. Use of mass balance (volumetric) reporting will enable national authorities to check that reuse is being carried out effectively.

Recycle / Recover
In order to avoid discharges to the sea of OPF-contaminated cuttings, recycling/recovery measures should be implemented (e.g. recovery for re-use of the organic phase by distillation onshore or offshore, use of shale shakers and centrifuges).

Residue disposal
The following options for the management of OPF-contaminated cuttings residue should be considered:

  • transportation to shore of cuttings for OPF processing (e.g. oil recovery and residue disposal);
  • re-injection of cuttings;
  • offshore treatment of cuttings with the aim of achieving the target technology standard of 1% weight/weight fluid on cuttings, and the discharge of the cleaned residue;
  • when cleaned residues of cuttings contaminated with synthetic fluid cannot meet that standard, national competent authorities may authorise discharge to the sea having regard to the toxicity, biodegradability and bioaccumulation of the drilling fluid concerned and of the hydrography of the receiving environment.

All these principles and techniques could, of course, be applied equally well to WBM cuttings but so far OSPAR has not extended stricter controls on WBMs. However, according the Department of Trade & Industry (DTI spokesman, Aberdeen, May 2000. pers. comm), the UK delegation to OSPAR is "currently drafting regulations to govern the use and discharge of offshore chemicals including those used in all drilling muds."

The scale of the problem is shown in the table below, from which it will be seen that in 1998 only 29% of the 560 installations in OSPAR waters were practising zero discharge operations. Of these, only 45 (8%) were oil installations, the majority being gas platforms (56 - 10%) and seabed wellhead systems (61 - 10.9%). OSPAR clearly has some way to go if it is to deal effectively and comprehensively with all offshore drilling wastes and the UK more than most

Table 2: Offshore installations making zero discharges to the sea and air in OSPAR waters, 1998. Source: OSPAR, London. May 2000

Country Oil Gas Drilling Sub-sea Total
Germany 0 0 0 0 0
Spain 0 1 0 4 5
Ireland 0 0 0 1 1
Denmark 32 0 0 0 32
Netherlands 2 12 0 7 21
Norway 10 1 0 20 31
United Kingdom 1 42 3 29 75
TOTAL 45 56 3 61 165

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"Muddied Waters":



List of Abbreviations

Summary of Conclusions

Drilling Waste Streams from Offshore Oil and Gas Installations

The Law on Offshore Wastes Discharges in Different Jurisdictions:

The OSPAR Convention

United Kingdom



United States

Inviting Regulation

Environmental Effects of Drilling Waste Discharges

The SBM Controversy

"Non-Water Quality Environmental Impacts"


Drill Cuttings

Produced Water

Minimising Waste Discharges and Their Effects

Reinjection Offshore

Cleaning Produced Waters

List of Main Sources

Selected References



Articles on Offshore
Oil&Gas; and Environment

Impact of Offshore Oil&Gas; Industry


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