UKOOA Drill cuttings initiative final report, February 200

Abstract

This paper focuses on the following questions:

“1. What is the rate of loss of hydrocarbons to the water column?

2. What is the area of the seabed where the biological impact from the

cuttings can be discerned (e.g. THC footprint above 50 mg/ kg as proxy)?

3. What is the rate of change of this contaminated area and specifically, in the period of tenure of the operator, is it getting larger or smaller?”

From the Summary. “In an effort to remove some of the subjectivity around the three questions…, limits of             potential environmental insignificance/ significance have been investigated. The limits identified by UKOOA are:

If the rate of loss of hydrocarbons to the water column from a cuttings pile is greater than 100 Te/ year, then the potential environmental impact is considered significant.

The potential environmental impact of a cuttings pile is considered insignificant if the rate of loss of hydrocarbons to the water column is less than 10 Te/ year, and the area of seabed at greater than 50mg/kg over time, is less than 500 km2 year.

Should a scientific investigation…suggest that the site is of insignificant potential environmental impact then UKOOA believe that natural degradation would appear to be the best environmental strategy. Noting that public consultation proposed in the Action Programme above would be needed to ensure that any issues surrounding industrial responsibility had been adequately addressed by the operator, and that the scientific investigation would need to address local issues such as spawning grounds etc.

Should a scientific investigation as recommended in the Action Programme…suggest that the site is of significant potential environmental impact i.e. > 100 Te hydrocarbons/ year to the water column, then UKOOA believe that covering or recovery would appear to be the best environmental strategy. Should the scientific investigation suggest that either or both of the limits of insignificance are expected to be exceeded by a particular site but remain below the significance boundary then the best environmental strategy is less clear. Exceeding the limits does not imply that significant environmental impact is taking place but more that insignificance cannot be demonstrated beyond reasonable doubt within the period of tenure of the operator. A specific assessment of the management options of cover, recover and natural degradation, together with a programme public consultation is recommended for selecting lasting and environmentally sound solutions under these circumstances.”