Geoinformatika 2021; 3-4(79-80) : 89-98

УДК 553.24;553.21/24;553.9

Petroleum potential of Armenia based on the concept of «Dehydration of rocks within the Earth’s crust as the main source of hydrocarbon genesis

A.V. Harutyunyan

National Polytechnic University of Armenia 0009, Yerevan, Teryan street 105, Armenia, e-mail: ah7995232@gmail.com, avhk@seua.am

Purpose. Based on the proposed concept on the genesis of hydrocarbons within the Earth’s crust, it will identify criteria in this region, the presence of layers with reduced velocities, deep faults, cover structures, etc. . Using geological and geophysical data available in the region, to determine the source and mechanism of formation of oil and gas, migration and their accumulation in layers with reservoir properties. To identify the approximate location of the oil and gas bearing structure, the depth of occurrence from the surface, to determine the approximate point and depth of the well. The purpose of this work is to identify oil and gas bearing structures in various regions of the Earth on the basis of the pro-
posed concept with appropriate criteria. As an example, the territory of Armenia, which is located within the Lesser Caucasus, is presented.

Design/methodology/approach. The results of studies of seismic, electrical, density and other properties of rocks at high pressures and temperatures, as well as the available actual geological and geophysical material, allow us to identify the approximate structure and composition of the Earth’s crust, as well as to identify the nature of some geodynamic processes. In particular, it was found that the process of dehydration of minerals at various depths of the Earth’s crust is accompanied by an explosion, the release of various hydrogen-containing components, hydrocarbons, geofluids, etc. Further along the deep faults, they migrate to the upper horizons of the Earth’s crust and accumulate in fractured rocks of the crystalline basement and in sedimentary layers with reservoir properties.

Findings. The territory of Armenia is located within the Lesser Caucasus, which is characterized by seismicity, volcanism, deep faults, the presence of ophiolite structures, etc., in the Earth’s crust, at various depths, layers with reduced and increased seismic wave velocities, as well as layers of geofluids at depths of 800-3200 m have been identified. Studies at high pressures and temperatures of serpentinized rocks from the ophiolite belts of Armrnia have shown that at various pressures at a temperature of 450-500C, the mineral serpentine is dehydrated. The process is accompanied by an explosion, abrupt changes in volume, the release of gases and geofluids. The study of the composition of geofluids by chromatographic methods revealed low-molecular and high-molecular hydrocarbons. The analysis of the results obtained at high pressures and geological and geophysical actual data allowed us to present a new concept about the formation of hydrocarbons at different depths of the crust, in different regions of the Earth. We do not exclude the genesis of hydrocarbons also by organic and deep mantle paths. Examples are presented in our publications.

The practical significance and conclusions. The proposed concept is applicable in various regions of the Earth. As an example, the territory of Armenia located within the Lesser Caucasus is chosen. There are 16 criteria of the concept on the territory of Armenia there are 12 criteria. After the Spitak earthquake, geological and geophysical studies were carried out in large volume on the territory, including Seismic and Magnetic Telluric sections covering 50-60 km of depth.The sections were used to compile the composition and structure of the Earth’s crust to depths of 50-60 km. The location of serpentinized layers and lenticular structures are established on the specified section. The evolution of the Earth’s crust from oceanic to modern continental crust is also presented. The sections of dehydrating areas within serpentinized structures, the formation of magmatic foci (in situ), the release of hydrocarbons, geofluids, hydrogen-containing products and their migration along deep faults to the upper horizons and their accumulation in sedimentary layers with reservoir properties are presented. In the presented section, two structures located at depths of 4-12 km are considered as oil and gas bearing, since these structures have reduced seismic wave velocities, low density, and a low-power cover layer extends over them. The roof of the structure is available to modern drilling equipment. It is proposed after performing detailed seismic studies to determine the point and depth of the well.

Keywords: serpentinized rocks, hydrogen, dehydration, genesis of hydrocarbons, covers structures, hydrocarbon structures, faults.