Features of vanadium geochemistry in oils from the oil and gas fields of Eastern region of Ukraine

Abstract

The results of long-term studies of the geochemical features of vanadium in the oil from 36 deposits of the Eastern oil and gas region of Ukraine. Based on the results of correlation and regression analyses, the nature and forms of the relationship between the vanadium content in oil and nickel, zinc, chromium, manganese, cobalt, iron, mercury, aluminum and the total content of these metals were determined; average capacity of the productive horizon; oil density value; oil viscosity value; resin content; the density of formation water from the productive horizon; sulfur content in oil; actual depth of the productive horizon; actual temperature of the productive horizon; actual pressure of the productive horizon; oil boiling point; paraffin content; the value of mineralization for formation water from the productive horizon; content of asphaltenes. Correlation coefficients, pairwise linear regression equations as well as curves that illustrate relationships between these parameters are obtained. Based on the results of the cluster analysis, a dendrogram of the results for clustering by means of the weighted centroid method of the considered fields by the content of vanadium in the oils was elaborated. Based on the results of clustering by means of the weighted centroid method, the first natural classification of oil and gas fields of eastern region of Ukraine according to the content of vanadium in oils was developed. It has been proven that heteroatomic low-molecular sulfur-containing components of the petroleum system are the main concentrators of vanadium in the oil for the studied deposits. It has been shown that, based on the results of the cluster analysis, sample average values of vanadium concentrations that vary significantly between individual deposits or groups of deposits for established ranges could be interpreted in terms of qualitative assessment as follows: abnormally low; low; below average; average; above average; high; abnormally high. The implementation of this kind of approach makes it possible to visually compare and interpret in terms of geology various scale and various indicators of oil deposits obtained by means of experimental study.