GEOCHEMICAL CRITERIA IN PROSPECTING FOR HYDROCARBONS IN THE EAST OF THE DNIEPER-DONETS DEPRESSION

Abstract

The article has reviewed hydrocarbon geochemical prospeting criteria in the east of Dnieper-Donets depression among which gas-, hydro-, lithogeochemical and biogeochemical methods are distinguished. These criteria are based on identification of oil and gas halos scattering components and specific associations of items-indicators that show possible presence of oil and gas bowels of the earth.

Natural spatial coincidence of geochemical halos scattering (litho, hydro and atmogeochemical anomalies) in zones of hydrothermal mineralization in rocks with hydrocarbon geochemical anomalies has been discovered. This occurs in the zones of modern thermomasstransfering on fluid dynamically open areas of regional deep faults within anticlinal structures.

During the search for hydrocarbons in the east of DDD contrasting gas geochemical and hydrogeochemical anomalies of deep accumulations of oil and gas have been revealed. They can be formed in overlain sequences regardless of lithological features and rock complexes. This phenomenon is characteristic of neotectonic activation areas and high intensity thermal field, where due to increased energy potential in the rock mass upward migration of fluids is enhanced.

Another indicator of gas and oil accumulates are specific hydrocarbon formations of gas geochemical schemes and hydrogeochemical zoning and hypsometric position of the upper limit of "methane zone."

It has been established that one of the most important search criteria of gas and oil accumulations is space-time correlation and the formation of hydrocarbon and hydrothermal minerals accumulations. If the hydrothermal mineralization in rocks of a geological structure is younger than processes of gas and oil accumulation, prospecting for hydrocarbon deposits in its depths is almost hopeless.