Daqing Crude Oil Dehydration

ABSTRACT Due to the process of water injection applied in Daqing Oil Field development the water content in the wet oil increases gradually year by year. It is considered an important technical subject to dehydrate the wet crude so as to achieve the oil quality required for outward transport and refining. Daqing crude oil is paraffin-based, with wax content of 28.7%, pour point of 26°C, viscosity of 23.79C. P at 50°C and specific gravity of 0.86, and also contains natural emulsifiers such as gels, asphaltines and naphthenic acids, etc. With these properties, a more stable water-in-oil emulsion has been formed during the crude exploition, thus caussing certain difficulties in the crude dehydration. This paper, based on the practice in Daqing crude oil dehydration, mainly deals with the process of thermo-chemical and D.C electro-chemical dehydration, on the following subjects, such as the optimum selection and application of demulsifiers, the technology of determining electrode space of each individual layer in the electric dehydratύr, automatic control of electric field and requlation for oil-water interface etc. After dehydration by D.C electro-chemical process, the crude contains less than 0.3% of water, and oil content in the effluent water is controlled to below 0.3%, completely satisfying the requirement specified for the crude oil export abroad and refining in the country.