Reduction of NORM Waste in the Oil and Gas Industry with Indirect Heated Vacuum Distillation Technology

Abstract

Abstract One of the most pressing challenges currently in the oil and gas industry is the management of natural occurring radioactive material (NORM) or technologically enhanced NORM (TENORM) containing wastes. The exploration and extraction operations of oil and gas are frequently executed in subsurface formations that contain natural radionuclides such as 226Ra, 228Ra, 222Rn, 210Pb, 40K etc. The natural radioactivity present in the oil and gas extraction sites can be significantly enhanced (>10,000 Bq kg−1) due to technological and human activities creating TENORM waste. TENORM is caused by the concentration and accumulation of natural occurring radionuclides in the internal surfaces of equipment, producing wastes such as scale and sludge formations in pipes. In addition, NORM is concentrated in the produced by-products from oil extraction such as water. Radionuclides present in oily wastes often form complex compounds leading to different forms of sedimentation such as sulfates, silicates, carbonates, and in several cases, mercury is also a major contaminant found. This mixture of contaminants poses challenges for transport, treatment, and safe final disposal. As a result, currently there are limited NORM waste management solutions apart from temporary storage facilities. In 2022 at the International Conference on Management of NORM in Industry, one of the main challenges in the oil and gas industry was reported as the lack of waste disposal options in several countries. With increasing NORM waste quantities several consequences may arise such as space limitations in disposal sites and increasing operational costs. Volume reduction techniques such as gravitational separation, extraction and enzyme pre-treatment, in-situ flocculation, physical separation, and chemical treatment, etc. have been also applied to NORM to reduce the costs associated with the disposal of the waste. Disposal techniques involving deep well injection such as slurry fracture injection, sub-fracture injection or cavern well injection have been investigated and applied in several countries. However, injection techniques have several limitations such as the requirement of a distinct geological formation, the potential risks associated with leaks or earthquakes, and the difficulty to inject slurries and pasty materials because it can clog the wells.