MAGNETIC MINERALOGICAL ANALYSIS OF SOILS AS A PART OF THE INTEGRATED GEOLOGICAL AND GEOPHYSICAL MODEL FOR THE HYDROCARBON PROSPECTING

Abstract

Magnetic minerals form or alter in the presence of hydrocarbons, making them a potential magnetic proxy for identifying hydrocarbon migration pathways. We concentrate in the precision magnetic mineralogical analyzes to understand what magnetic minerals in soil from the hydrocarbon fields are responsible for the magnetic signal. To illustrate the results of our studying, we consider the study area of the hydrocarbon deposits near the village Balabanivka, Bogodukhiv district, Kharkiv region. A collection of soil samples is represented by deep medium-humus chernozems. The thermomagnetic analyzes, hysteresis parameters, and isothermal remanent magnetization curves (IRM) were studied for the samples collected near the well (point PR 28) and at the area located out of the hydrocarbon influence zone (point PR 0403). To study the thermomagnetic parameters, different types of the magnetization and magnetic susceptibility (MS, χ), and hysteresis loops we used the Variable Field Translation Balance (VFTB) instrument. The results are confirmed by the highest values of the gas geochemical parameters. The MS variations at temperatures ranging from 200 to 400 ˚C may reflect the presence of either iron sulphides or maghemite. The magnetite occurs for all soils. The wasp-waisted hysteresis loops identified either a mixture of two magnetic minerals (magnetite and hematite) and the admixture of the superparamagnetic and larger grains of the same minerals.