Abstract

PTT Exploration and Production Public Company Limited (PTTEP) strive at all times to ensure that incidents affecting the health and safety of its employees, contractors and members of the public, and the ecological environment shall not occur. The NORM: Radionuclide Analysis Project was initiated in 2003 by the Nuclear Technology Department, Chulalongkorn University, with the cooperation of academic institutions, private enterprises, the Thai government and private service companies, to develop systematic methodologies for characterization of NORM in Thai industry and acquire useful data regarding NORM characteristics throughout the industries for improvement of safety hygiene and environmental standards.

The project has revealed systematic methodologies to determine the concentrations of NORM content in all potential sources and receptors- the "Cradle to Grave" concept.

The NORM characterization project at PTTEP was conducted from 2003 to 2006 by focusing on 3 main areas:

  1. PTTEP1 onshore oil production asset,

  2. Bongkot offshore gas & condensate production asset, and

  3. PTTEP Petroleum Development Support Base, where used equipment and wastes from Bongkot were stored.

In this paper, the application of the developed methodologies and results obtained from the long-term and systematic study on NORM characterization of studied areas numbers 2 and 3 above will be presented.

1. Introduction
NORM in Oil & Gas I1ndustry

The problem of Naturally Occurring Radioactive Materials or "NORM" in the petroleum industry has been recognized to the extent that American Petroleum Institute(API) proposed options for disposal of NORM wastes produced in the oil and gas industries. The main NORM issues in this industry arise with production facilities associated with oil and gas reservoirs.

The source for most oil and gas NORM is dissolved radium that is transported to the surface in the produced water waste stream. Radium dissolution and precipitation depend on the formation water salinity, pH, temperature, and pressure. Dissolved radium either remains in solution in the produced water, or, under proper conditions, coprecipitates with barium, strontium, or calcium to form either hard sulfate scales or more granular silicate and carbonate sludges. The oil and gas production stream passes through a separator where the oil, gas, and water are divided into separate streams based on their different fluid densities. Most of the solids removed in the separator accumulate there. The product may also be treated using a heater/treater to separate oil from produced water and sludge. Figure 1 shows the oil and gas processing equipment and where NORM can accumulate over time.

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