Publication Abstract

Evaluation of the pattern of use and discharge of substitutable chemicals in UK waters by the Offshore Oil and Gas industry from 2000 to 2012

LOWFILE3:\Chemistry in the Oil Industry\2013\FINAL POSTERS\Offshore Oil & Gas chemical use and discharge as part of production activities.pdf

 

Evaluation of the pattern of use and discharge of substitutable chemicals in UK waters by the Offshore Oil and Gas industry from 2000 to 2012

Max La Vedrine, David Sheahan, Rosalinda Gioia, Linda Hughes, Lynn Jones, Silke Kroeger, Cheryl Moran, Claire Phillips, Bob Rowles, Steve Supple Centre for Environmental Fisheries and Aquaculture Science, Cefas, Lowestoft Laboratory, Pakefield Road, Lowestoft, Suffolk, UK, NR33 0HT.

Introduction

The regulation of chemicals used by the offshore oil and gas industry on the UK continental shelf (UKCS) has evolved from a consideration of chemical toxicity only into a more comprehensive assessment and management of the risks posed. Cefas on the behalf of DECC register products to be used on the UKCS, using information provided by chemical suppliers, and the products are ranked based on their hazardous properties. The information presented is based on reported use and discharge of chemicals as part of production operations.

Between 2006 and 2012 541,442 tonnes of products were used, the largest tonnage contributors were gas hydrate inhibitors (136,250), scale inhibitors (57,469), hydrogen sulphide scavengers (52,930) and corrosion inhibitors (45,704).

In total deoilers accounted for 3432 tonnes used and well stimulation chemicals 932 tonnes. In total 25 function classifications had recorded use >1000 tonnes, 35 had recorded use >100 tonnes and 52 out of the 59 product functions had some reported use between 2006 and 2012.

Despite gas hydrate inhibitors accounting for more than a quarter of the entire product function types used in total they contributed to less than 150 Kg of substitutable substance discharge.

The highest substitutable substances discharged by product function are shown in Figure 4. Substitutable substances associated with corrosion inhibitors, scale inhibitors, demulsifiers and water clarifiers accounted for more than 91% of all substitutable substance discharge.

Key Observations

The quantities of different substance classes discharge on the UKCS between 2000 and 2012 are shown in Figure 1. In 2000 substitutable substances represent 10.2% of the total of all substances discharged, and in 2012 it was 2.8%.

In 2006 an OSPAR decision was made to move from whole chemical toxicity to individual substance toxicity. In response to OSPAR Recommendation 2006/3 the UK set out the UK National Plan to identify substances of greatest environmental concern and introduced a timeframe for the phase-out of their use, or discharges to be eliminated, or continued use and/or discharge to be formally justified.

There are four UK National Plan priority levels each with staged target dates, the first priority Level 1 target date is December 2010 and Level 4 is December 2016. Figure 2 shows the amount of substitutable substance discharge represented by UK National Plan level for the years 2006 to 2012.

Conclusions and Forward Look

If non-substitutable substances are developed for the four highest substitutable product function types this would potentially contribute to a large decrease in substitutable substances used and discharged.

Between the 2006 and 2012 a total of 397 products were discharged containing a substitutable substance(s), 10 of these products account for 53% of all substitutable substances discharged and 7 of these are UK National Plan Level 2 products. If these key contributing products are able to be successfully phased out or their discharge is reduced or eliminated this would result in a large decrease in substitutable discharge within the next couple of years.

It is recognised that there would be challenges associated with doing this, for example UK National Plan Level 2 corrosion inhibitor products accounted for 1689 tonnes and 33.5% of all substitutable product discharge in 2012, in the same year 931 tonnes of non substitutable corrosion inhibitors were also used. In the majority of occasions where a non substitutable corrosion inhibitor product was used at an installation it was also used in combination with a substitutable corrosion inhibitor.

A direct swap to using only non substitutable corrosion inhibitors may not offer the same desired performance. If ineffective corrosion inhibitors are used there is a risk that this may lead to the corrosion and failure of infrastructure and equipment.

However offshore operators have been able to identify alternative products which either have a lower priority level or are completely non-substitutable and following successful trial periods they have been able to switch products. Some offshore operators have also been able to reinject chemicals to reduce their substitutable discharge.

© Crown copyright 2013

M. La Vedrine*, D. Sheahan*, R. Gioia*, L. Hughes*, L. Jones*, S. Kroeger*, C. Moran*, C. Phillips*, B. Rowles*, S. Supple*

Conference: Chemistry in the Oil Industry XIII: Oilfield Chemistry – New Frontiers