DISCOVERY OF RADIOACTIVE BARIUM-SULFATE SCALE IN PANCANADIAN PETROLEUM PRODUCING OPERATIONS IN SOUTHEASTERN ALBERTA

Radioactive Barium Sulphate scale was discovered in the downhole equip ment of a well in Countess ''O'' Pool during a routine workover. The r adioactivity of the scale was determined to be in the range of 140 to 250 Bq/g, exceeding the limit of 75 Bq/g above which it is considered a radioactive waste material. This discovery raised issues related to personnel health, environmental impact, the extent of the problem, pre vention, as well as handling and disposal of the scale. This paper dis cusses the positive steps taken by PanCanadian in addressing these iss ues. A brief review of radioactive materials is provided. PanCanadian' s experience with respect to employees' right to know, safe work proce dures, radiation monitor selection, radiation surveys, the strategy fo r barium sulphate scale prevention including inhibitor selection and a pplication is covered in some detail. Issues such as scale removal met hods for pipes, valves and fittings, as well as transportation, storag e and subsurface disposal of contaminated materials are also covered.