В мире научных открытий (Mar 2018)
NUCLEATION AND FORMATION OF GAS HYDRATES DEPENDING ON THE PHYSICAL AND CHEMICAL PROPERTIES OF OILS
Abstract
Formation of gas hydrate plugs in oilfield pipelines is one of the major complicating factors for oil recovery in cold regions and on shelf. Hydrate prevention in the pipelines makes oil recovery more complex and expensive. Formation of gas hydrate plugs in oilfield pipelines is one of the major complicating factors for oil recovery in cold regions and on shelf. Hydrate prevention in the pipelines makes oil recovery more complex and expensive. A complex study of the oils of different fields in Western Siberia and their emulsions prepared at a concentration of 50% was carried out. Technically important characteristics, such as viscosity, density, pour point, and group composition were considered for native oils and their emulsions. In the paper the influence of the oil composition on formation of oil-wet hydrates. Water-in-oil emulsions of the investigated oils were applied in the model experiment of nucleation and formation of gas hydrates. Oil YuT, of all the studied, showed a positive reaction of nucleation and formation of gas hydrates. The level of biodegradation of crude oil is an important indicator of nucleation and formation of hydrates. The process of biodegradation in the field conditions has a significant impact on the quality of crude oil in terms of its chemical composition and physical properties. IR Fourier spectroscopy was used to identify functional groups of specific molecular structures, that determine the level of biodegradation. Analysis of the FTIR spectra of oils showed that: absorption bands of saturated aliphatic hydrocarbons (1465–1377 cm-1), aromatic (1610 cm-1) and carbonyl groups of carboxylic acid (1710 cm-1) dominate in all spectra of investigated oils. Field observations have shown that some streams of water, gas and crude oil do not form gas hydrate plugs during petroleum production even when operating within thermodynamic conditions for hydrate formation. The results suggest that the ability of oils to form gas hydrate plugs can be associated with metabolic products that are formed during biodegradation of petroleum hydrocarbons.
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