Waste Disposal – Background and Key Developments

Offshore waste management is tightly regulated, and a similar level of legislation applies when waste is brought onshore. The majority of wastes produced offshore are transferred onshore, but there are limited options for their disposal.

Types of waste generated offshore vary and include drill cuttings and powder, recovered oil, crude contaminated material, chemicals, drums, containers, sludges, tank washings, scrap metal and segregated recyclables. Other wastes include NORM scale; however disposal of this scale is a special case. The type of waste therefore influences the available options of disposal routes.

UKCS Oil and Gas producers submit data on wastes sent onshore for disposal to the Environmental Emissions Monitoring System (EEMS). This data is listed by both operator and installation and is recorded in categories. In addition, EEMS also reports, at a general level, the fate of the waste.

Commonly, offshore wastes are sent to onshore landfill, and the second most popular route of disposal is incineration, or recycle and reuse where appropriate. Other options for disposal include converting waste to energy (using wastes to generate energy – such applications include waste oils being used to generate heat), stabilisation and treatment (which allows wastes to be used in other applications such as landfill capping), composting or, finally, disposal of wastes under consent.

Oil & Gas UK is in the process of collating a record on the fate of wastes once they are brought onshore for disposal.

Waste Disposal – Key Statistics and Commentary

The quantity of ‘general’ and ‘special’ wastes returned to shore in 2005 continues the downward trend, with only 57,470 tonnes requiring disposal. Quantity of cuttings returned to shore in 2005 totalled 51,910 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.

UKCS Waste Disposal by Type 2001-2005

UKCS Waste Disposal by Route 2001-2005

Waste Disposal – Supplementary Statistics and Commentary

For further information on waste disposal, please see;
www.oilandgasuk.co.uk/issues/environment/wastedisposal.cfm

Marine Acoustic Discharges – Background and Key Developments

Marine Noise is a highly emotive issue as it may affect cetaceans (large marine mammals, such as whales, dolphins and porpoises). Although it is an area where the overall impacts are difficult to quantify, the UK oil and gas industry is taking steps to minimise any possible impacts. This is particularly true prior to any acoustic, geological or seismic surveying in the initial exploration phases of a project.

OGP (the International Association for Oil & Gas Producers) has launched a major $21 million study on noise in the marine environment, which Oil & Gas UK is monitoring and our member companies participating in. Initial studies have established that noise generated from offshore operations present a low risk to marine life, but due to a lack of data for sensitive species, this statement cannot be adequately defined in all cases. However, with time and research we are gaining a greater understanding of the issue.

Seismic surveying refers to the geophysical exploration for oil and gas using acoustic methods. Sound energy (pressure pulses) is released from a source being towed by a vessel, and this signal is reflected off the seabed. Hydrophones record the reflected signal which will be altered depending on the type of rock it reflects from. In this way, it is possible to detect potential oil or gas bearing rocks.

It is acknowledged that there may be an environmental impact using sound energy to explore for oil and gas. For this reason, the use of acoustic/seismic surveying is very highly regulated, and various procedures (e.g. soft start, using initial very low levels of sound to encourage marine mammals to leave the survey area) must be followed in any programme of surveying.

Further information on legislation surrounding seismic surveying activity can be accessed at;

Oil & Gas UK Environmental Legislation Website
(http://www.ukooaenvironmentallegislation.co.uk/)

JNCC Guidelines (http://www.jncc.gov.uk/page-1534)