THERMOBARIC CONDITIONS OF OIL AND GAS CONTENTS AND PREDICTING OF HYDROCARBON PHASE STATE (ON THE EXAMPLE OF THE BILCHE-VOLYTSA OIL-AND GAS-BEARING AREA

Abstract

Formulation of the problem. This paper illustrates the use of the dimensional analysis to assess a hydrocarbon phase state. It is known that the phase state establishment of the hydrocarbon system has an important role in prospecting and exploration of oil and gas fields. Information about the hydrocarbons phase state is required in hydrocarbons supplies counting and planning of measures in respect of the increase in the coefficient of their extraction. The purpose of the article. To create the methodology to establish the hydrocarbons phase state in a geological environment, to increase the efficiency of oil and gas indices measuring based on fundamental for the dimensional analysis π-theorem. Methods. Estimation of hydrocarbon phase state was based on dimensional analysis of their physical and chemical properties and thermobaric conditions of free gases, condensates and oils occurrence from more than 200 objects that gave fluid inflex in the fields of Bilche-Volytsa oil- and gas-bearing area. To describe the environment we used: temperature and pressure in the stratum, depth of bedding of stratum, the average density and average molar mass of stable hydrocarbons mixture. Results. The distribution of thermobaric parameters of hydrocarbon deposits within the Bilche-Volytsa oil- and gas-bearing area was analyzed. The character of a change in the coefficient of hydrostatics was shown to be dependent on peculiarities of the structural-tectonic construction of the investigation area. As a result, we obtained two dimensionless parameters: the criterion of Z 1 , which shows the ratio of hydrocarbon energy compression system to the energy of thermal motion and equals one for ideal gas and hypsometric criterion Z 2 – the ratio of the potential energy of the mass raised to the height to the energy of thermal motion. The areas of numerical values Z 1 and Z 2 criteria, that describe the phase state of hydrocarbon, were identified. Scientific novelty and practical significance . It has been found that dimensionless criteria Z 1 and Z 2 allow, with the available information about the depth of the deposit, density and molar mass of hydrocarbons and reservoir temperature and pressure, to set the phase state of the hydrocarbons system in the oil- and gas-bearing sedimentary complex. The established Bilche-Volytsa oil- and gas-bearing area has two different geothermic regions: more heated north-west and less heated south-east.