Abstract

The management and disposal of Naturally Occurring Radioactive Material(NORM) scale is oil and gas industry issue which attracts public and international interest. NORM, as low activity radioactive waste, presents special handling and disposal challenges due its potential risk to personnel, health, long term effects on food chains, habitats and future generations. Media influence on public perception of radioactivity often eclipses logic and sound technical argument, will be reviewed as part of risk management.

A critique of current NORM decontamination techniques offshore and onshore will be presented in terms of HSE and other risks, together with insights into the future. Estimates of NORM scale generation in oil and gas and planned future decommissioning demand an acceptable NORM management strategy for the future.

NORM disposal is an issue where the industry must "walk the talk" on sustainable development and not leave an accumulating problem which may impair future generations. A comparison will be made between the acceptable discharge of NORM and radio nuclides in production water offshore and the accepted disposal options available from onshore decontamination (inshore discharge, storage or onshore re-injection). A summary of approaches to NORM management and disposal in North Sea and other counties facing this issue will be presented. The case for NORM reinjection offshore (in an isolated reservoir)will be addressed, although it has not been accepted as a disposal route to date in the UK. Re-injection is widely practiced in the USA.

NORM management and disposal options will be considered in terms of risk management (safety, health environment, sustainable development, financial/reputation) together with a formula for risk ranking geared to decision making. This can be used by the industry to enhance public understanding of radioactivity, and promote convergence in decision making by industry and stakeholders on the risks and benefits of NORM disposal options.

What is NORM and Where Does It Come From?

Low levels of NORM are ubiquitous in the environment-decay products of U238, Th 232, and K40 and their decay products. The radioactive component of oilfield scale consists of decay products of naturally occurring 232Th and238U, in the oil and gas bearing sediments. Seawater also naturally contains some NORM radio nuclides and concentrations may be increased by the addition of industrial emissions to sea, rivers and the atmosphere.

Occurrence of NORM in the Oil and Gas Industry

NORM (Naturally Occurring Radioactive Material) is deposited in oil and gas production and processing facilities and is associated with the presence of oil, natural gas and produced water. Petroleum industry NORM usually consists of scale in pipes and vessels (oil, produced water) and thin coatings lining gas processing components. Waste streams from oil and gas processing operations contain NORM (Veil and Smith 1999, Chamber et al 1994). The main types of oil and gas industry NORM are summarised in Table 1.

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