Waste disposal

The quantity of ‘general’ and ‘special’ wastes returned to shore in 2005 continues the downward trend, with only 66,065 tonnes requiring disposal. Quantity of cuttings returned to shore in 2005 totalled 58,590 tonnes. This rise in drill cuttings is attributed to both increased drilling activity and increased use of organic phase drilling fluids, which cannot be discharged to the sea.

Figure 8: UKCS Waste Disposal by Type 2001-2005

Overall tonnage of waste requiring disposal has decreased since 2004. However, the quantity of waste being sent to landfill has increased, with 70,840 tonnes requiring disposal in 2005. The percentage amount of waste recycled remains relatively constant at 21%. Waste to energy and incineration shows a significant downturn from 2004.

Figure 9: UKCS Waste Disposal by Route 2001-2005

Marine acoustic discharges, noise

The issue of marine noise addressed in the past concluded that the acoustic energy emitted during exploration and production operations does not significantly affect marine mammals, fish or fisheries. However, recognising that the NGO community believe that the evidence base for these conclusions is insufficient, UKOOA is monitoring a major OGP study on noise in the marine environment, in which member companies are participating.

Decommissioning

The industry has committed itself to a programme of decommissioning suspended wellheads that are now unlikely to be used in any development. The aim of this programme is to reduce the number of suspended wellheads which are greater than six years old to below 100. This activity increased significantly in 2005 with 26 suspended wells abandoned compared with 16 in 2004. This level of activity is forecast to be sustained in 2006.

Figure 10: UKCS Number of Open-water Suspended Wells, 1998-2007

The figure below shows the projected timing for the decommissioning of facilities over the next few decades, based on current oil & gas price assumptions. Total decommissioning costs are in the range £15-19 billion based on DTI estimates. During 2004/5 two large structures, N.W. Hutton (steel) and Frigg MCP01 (concrete) concluded both informal and statutory consultations of their decommissioning programmes, which include derogations to OSPAR 98/3. N.W. Hutton received official approval of the final programme from the Secretary of State for Trade and Industry in April 2006.

Figure 11: UKCS Structures Decommissioning Profile, 2000-2030