Purpose. Substantiate the method of typification of oil deposits of the Dnipro-Donetsk basin to create their classification by metal content. The relevance of such studies is due to the strengthening of requirements for environmental protection and comprehensive processing of mineral resources, which is determined by a number of Ukraine laws, resolutions of the Cabinet of Ministers, as well as the requirements of the State Commission on Mineral reserves to the quality and content of geological materials. Methodology. The factual basis of the work was the results of X-ray fluorescence analyzes of metal content in oils from the deposits of the Dnipro-Donetsk basin. These results were statistically processed with calculations of descriptive statistics and assessment of the peculiarities of the distribution of metal contents in oil from each field to justify the choice and calculation of normalized contents. Given that one of the most effective procedures for simplifying and minimizing the data set to create natural classifications is cluster analysis, to achieve this goal, clustering of oil deposits was carried out by various methods, which are implemented in the most popular professional statistical software platforms “STATISTICA” and “SPSS”. Results. To perform a cluster analysis of metal contents of 36 deposits of the Dnipro-Donetsk basin: Bakhmachsky, Pryluky, Krasnozayarsky, Kachalivsky, Kremenovsky, Karaykozovsky, Korobochkinsky, Kulychikhinsky, Lipovodolinsky, Monastyrychovsky, Marastyrishchevsky, Malostyrishchevsky, Malostyrishchevsky, Malostyrishchevsky, , Raspashnovsky, Sofiyivsky, Sukhodolivsky, Solontsivsky, Solokhivsky, Talalayevsky, Trostyanetsky, Turutynsky, Kharkivtsy, Shchurynsky, Yuryevsky, Yaroshivsky, Khukhryansky, Sagaidatsky №1, Sagaidatsky №13, Kybybitsy, Kyshtsy №5 №56 and Kybytsivsky №1 by different methods, analysis of clustering results and substantiation of selection of the most optimal of them for further development of natural classification of deposits by metal content in oils. Scientific novelty. To establish a weighted centroid method of cluster analysis, as the most optimal for the subject-free researcher division of oil fields by metal content (including vanadium) into taxa. Practical significance. The practical significance of the results of the work is that the constructed dendrograms of clustering of deposits by vanadium content in oils can be used as a basis for developing classifications of these deposits for environmental and technological assessment in the future. The proposed methodological approach can be used in the future to divide other groups of geological objects into natural taxa. Key words: oil fields, X-ray fluorescence analysis, metals, cluster analysis, dendrogram, weighted centroid method.

Purpose. To establish the peculiarities of the total content of metals in oil deposits of the Dnipro-Donetsk depression and to develop a classification of deposits by this indicator. Methodology. The factual basis of the research was the results of analyzes of metals in oil from 36 deposits of the Dnipro-Donetsk depression. With the help of X-ray fluorescent analysis, at least 30 oil samples from each deposit for metals content were investigated. The deposits are selected according to the principles of maximum completeness of geochemical information, their finding in different oil and gas areas of the Dnipro-Donetsk depression, different composition of the oil system, different geological types of traps, different structure of deposits and different ages of oil collectors. X-ray fluorescent analysis was performed on the energy-dispersive spectrometer "SPRUT" SEF 01. The time of accumulation of the spectrum 600 sec. Preparation and analysis were carried out according to the standard of ASTM D 4927 - "Determination of the elemental composition of components of lubricants by X-ray fluorescent spectroscopy with dispersion by wavelength". Correlation and regression analysis was carried out by methods that were implemented in the most popular professional statistical software platforms "Statistica" and "SPSS" and their analysis in geological concepts. Findigs. To evaluate the central characteristics of the total content of metals in oil, the deposits considered more correctly use not the arithmetic mean, but the median. It is proved that the total content of metals in oil considered is associated with a reverse correlation connection with resin content, the values of the modern temperature of the productive horizon, the modern depth of productive horizon, the mineralization productive horizons; and direct correlation with the concentrations of nickel, manganese, mercury, chromium, vanadium, aluminum, cobalt, zinc, iron, paraffin, asphalt, sulfur and oil viscos boiling and oil density. Scientific novelty. It consists in the development of the natural classification of oil deposits by the overall content of metals, and to establish a connection of this indicator with the concentration of individual elements of impurities, the main components of oil and the main geological and technological indicators of deposits of the Dnipro-Donetsk depression. Practical significance. Is to establish the concentrations and the possibility of forecasting the total content of metals in the Dnipro-Donetsk depression, which in turn provides the opportunity to solve the topical problems of practical direction. The solution of a number of industrial-raw materials based on the assessment of oil as an ore raw material, since the content of some elements in them sometimes exceeds ore concentrations, so there is a possibility of their concomitant industrial removal from by-products during processing processes. The solution of technological issues, which are caused by the negative impact of some elements contained in oil, on the geological environment, production technologies and the equipment used in the course of their extraction and processing.

Literature review and analysis of previous studies of the problem was carried. The main scientific works on the research topic, as well as the main directions and stages of the study are indicated. Similar studies that were conducted on the territory of Ukraine are considered. The results of the study of heavy metals in oil samples taken from a large oil and gas region from more than thirty deposits of Ukraine are presented. All current and non-working fields are considered. The geological structure of the oil and gas province, as well as the main geochemical features of the formation of mineral deposits are considered. The main forms of finding target metals, as well as possible ways of transferring these elements in the earth’s crust are given. Samples were investigated using x-ray fluorescence and neutron activation analysis. The obtained research data in the framework of two selected methods are combined for analysis. The results obtained within the same geological structure are compared with each other to determine the effect of the physical conditions of sediment formation on the microcomponent composition of crude oil. They also compared the effect of physical conditions on the properties of oil and their ability to accumulate heavy metals. Possible causes of the abnormal accumulation of heavy metals due to the close occurrence of oil and formation water are noted. According to the results obtained, a graph is constructed of the dependence of the mineralization of oil on its depth. An exponential graphical approximation is presented to display the general trend of dependence. Possible sources and ways of migration and accumulation of heavy metals in hydrocarbons are analyzed. The concept of the migration of heavy metals in oil is proposed in conjunction with the ore mineralization of adjacent and adjacent deposits. Possible causes of differences in the concentrations of heavy metals in oil of various geological structures are indicated, as well as the main possible causes of measurement errors and complications in the selection of each of the analysis methods are specified.