Produced Water Purification Technology in Laboratory Conditions for Soda Production

Produced waters are a constant companion of oil and gas fields. In the field, they occur in the same layers as the oil or gas deposit, as well as in the actual aquifers (horizons). Huge volumes of wastewater with high concentrations of toxic substances can have a negative impact on the environment. Their increased danger is due to pollutants such as oil and oil products, chemicals, acids, alkalis, surfactants, and solid mineral particles. Therefore, the purification of produced waters is an urgent task. Purified produced waters are a new source of mineral raw materials that can replace traditional raw materials in the production of soda ash. In this paper, a method is proposed for purification produced waters into brine for the purpose of further use for soda production. The object of study was the produced water of PAO Tatneft named after V.D. Shashina. The properties and composition of produced water of were studied, which showed that the main ions in formation water are chloride ions and sodium ions, and there are also calcium ions, magnesium ions, potassium ions and other ions. This composition makes it possible to attribute this produced water to brines. First of all, experimental studies were carried out on the purification of produced water from traces of oil products and iron by passing the brine through a layer of zeolites and activated carbon, since the content of oil products was 1.05 mg/l. The brine was purified from calcium and magnesium salts by the soda-caustic "wet" method. A brine with zero content of calcium and magnesium ions was obtained.