Geofizičeskij žurnal

In memory of Petro Oleksiyovych Burtnyi (04.08.1941―09.04.2024)

2024-04-24T19:41:23+03:00

9 квітня 2024 р. пішов з життя Петро
Олексійович Буртний

Geothermal Energy Potential Assessment and Utilization in the Absheron Oil and Gas Region

2024-04-11T11:48:06+03:00

The Relevance: The Absheron oil and gas region, located in the northwestern part of the South Caspian Basin, plays a pivotal role in understanding sedimentary deposits across various geological periods. This study delves into the Lower Tabasir deposits within the key fields of the Absheron archipelago, shedding light on their lithological composition and contributing to a comprehensive understanding of the region’s geological significance.

The Aim: With a primary objective of evaluating geothermal energy potential, this research centers on the Bibiheybat deposit on the Absheron Peninsula. By employing meticulous temperature and pressure measurementsand advanced modeling techniques, the study aims to analyze the distribution of the geothermal energy throughout the field.

Methods: Detailed temperature and pressure measurements and modeling using the Surfer program. Laboratory evaluations of the rock samples’ thermal properties make the geothermal energy calculations evenmore precise.

Results: The findings of this study offer insights into the distribution patterns of geothermal energy within the Bibiheybat deposit. Temperature and pressure distribution maps illustrate variations across the field. The proposed conversion scheme presents an avenue for efficient geothermal-to-electricity transformation. Ultimately, this research underscores the pivotal role of geothermal resources in shaping sustainable energy strategies for the future, while promoting a more ecologically conscious approach to energy utilization.

The influence of hydrocarbons on the physical properties of sea bottom sediments of the Black Sea of different stages of diagenesis under conditions of high pressures and temperatures and the degree of saturation

2024-01-05T11:11:41+02:00

In this work, we have a specific task, namely: what effect do petroleum products have on the physical properties of sediments when they replace the moisture contained in them, and is it possible to register the accumulation (localization) of petroleum products on the bottom of certain areas of the Black Sea using geophysical methods. In other words, it is necessary to evaluate changes in the elastic, magnetic, and electrical parameters of bottom sediments in connection with filling them (or replacing them with seawater) with organic gas-liquid media. For the first time, the results of complex laboratory studies of the influence of hydrocarbons on the propagation velocities of longitudinal waves, magnetic susceptibility, specific electrical resistance and relative electrical permeability in bottom sediments are presented. Possible signs of hydrocarbons in geophysical fields are outlined.

As a result, two opposite effects of the influence of hydrocarbons on elastic-density properties (propagation of elastic longitudinal waves) in the upper and deeper horizons of sediments under normal temperature conditions were established. The effect of different stages of diagenesis (in conditions of conditionally high temperatures, heating more than 100°C) in the presence of saturation of the sample with petroleum product leads to an increase in the propagation speed of elastic waves in muds. This effect can take place in natural conditions during the formation of localization - at depths corresponding to these temperatures. It is possible to outline the localization of petroleum products by sediment hardening zones, areas with higher V_P and ρ, and, therefore, an intense reflection of the seismoacoustic signal, which can be search signs for the search for petroleum product localizations in layers of unconsolidated sediments. The results of the research show that an increase in temperature even in samples not saturated with carbohydrates leads to a small change in magnetic susceptibility. Saturation of sediments with carbohydrates leads to an increase in the intensity of this process. It was established that under the influence of hydrocarbons, the specific electrical resistance of marine sediment samples increases by several orders of magnitude, and the relative dielectric constant decreases by several units.

Prospectivity of Pliocene-Miocene deposits of the Khasilat field of the Absheron oil and gas bearing region according to surface and well seismic data

2024-04-11T11:03:21+03:00

The article begins with a history of commercial hydrocarbon production in the Absheron Peninsula, which is one of the oldest oil and gasbearing regions in the world. Despite the long exploitation of hydrocarbons here, this region has a strong industrial potential, especially in the lower Pliocene and underlying sediments. A lithological-stratigraphic boundary separating the Qala Suite of the Productive Series into two parts has been delineated by a Well Logging complex. The lower part is most likely represented by sandstones deposited during the transgressive phase of development of this part of the peninsula, while the upper part is characterized by complete and incomplete regressive cycles. The boundary of stratigraphic unconformity was marked, and also the boundary of thermobaric system change can be synchronously connected with it. As for the older sediments, their prospectivity is indicated by commercial production of hydrocarbons in the adjacent areas.

An indirect indication of oil and gas prospects of the underlying fields is the identification of a zone of Abnormal Formation Pressure in the Khasilat field according to the Vertical Seismic Profiling results of two wells.

The results of reinterpretation of 3D seismic data are widely reported in the article. Temporal thickness maps suggest a large river delta in the area during the formation of the Qala Suite deposits. Obviously, the appearance of numerous deltaic channels and straits was associated with gentle slopes and shallow depths of the coastal part of the basin where the delta was formed. Based on the constructed map of temporal thicknesses between the seismic horizon confined to the QaS-2 and SH-IV strata, which in the conventional time scale represents the paleorelief at the start of the formation of the Qala Suite deposits, the most favorable areas for the accumulation of sandy sediments were determined.

Thermodynamic conditions of granitization and metamorphism of rocks in the northwestern part of the Ukrainian shield

2023-12-28T12:14:53+02:00

The article examines the RT conditions of the formation of granites of the Sheremetyevo and Zhytomyr complexes and the metamorphism of rocks of the Teteriv series of the Volyn megablock of the Ukrainian Shield, the role of fluids in granitization. According to thermodynamic modeling, the appearance of granites is a link in the redistribution of heat and matter in the plume process. This proves the analysis of all known geological and petrological data. During the accumulation of the primary volcanogenic-sedimentary stratum, magmatic melts formed in the mantle’s melting centers located at different depths appeared many times. The formation of the melting layer in the crust is caused by conductive heating caused by its sublayering by ultrabasic melts. Temperatures of the melting point at a depth of 15 km exceed 650 °C. An increase in the gradient above it from 20 to 35 °C/km causes metamorphism, and the influx of melts and solutions through deformation zones ¾ metasomatic transformations and the formation of migmatites.

Where the upper part of the thermal asthenosphere is brought to the surface, you can see unmoved granites. At the intersection of several permeable zones (faults), granite massifs are formed, in which quartz-feldspar rocks crystallize. It is shown that the modern surface was on the border of metamorphosed rocks and the melting center in the Proterozoic time. Such a location does not contradict the existence of Archean rocks at greater depths — the level of thermal asthenosphere that produces granites.

A century-long tendency of change in surface air temperature on the territory of Ukraine

2024-01-29T14:21:48+02:00

Early historical meteorological observations of air surface temperature on 11 meteostations in Ukraine (since 1808) were analyzed. However, since a larger number of stations have time series of temperature starting in 1821—1825, for more reliable estimates of the linear trend, the period 1824—2021 was required. The trend is 0.78 °C per 100 years for this period.

According to the analysis of meteorological data, the average annual surface air temperature on the territory of Ukraine in 1900—2021 was 8.6±0.9 °C. However, for the more recent period of 1991—2020, it increased to 9.5±0.9 °C. The temperature in Ukraine exhibited an increase of 1.31±0.42 °C per 100 years during 1900—2021. Over the last 30 years, a more pronounced increase in annual surface air temperature, by 0.79±0.08 °C per decade, was observed.

Changes in the temperature regime exhibit spatio-temporal patterns. In most parts of Ukraine in 1900—2021, a temperature increase is within 1.5—2.0 °C per 100 years. Simultaneously, some parts of northern, northwestern, and eastern regions, as well as the Vinnytska and Zaporizhzhska oblasts, are characterized by more intense warming, reaching 2.0—2.5 °C per 100 years, in contrast to southwestern, southern regions, and the territories adjacent to the Ukrainian Carpathians, where the temperature rise is within 1.0—1.5 °C per 100 years.

Temperature anomalies from 1900 to 2021 indicate the lowest annual averages occurred in 1933, 1956, 1976, 1985, and 1987, while the highest annual averages were observed in 2007, 2015, 2019, and 2020.

Between 1900 and 2021, the average monthly air temperature in Ukraine substantially increased in colder months (from October to March), ranging from 0.7 to 2.0 °C per century. Simultaneously, warmer months (from April to September) saw an elevation ranging from 1.0 to 1.9 °C per century. In the 1991—2020 norm, an overall warming trend of 0.5—1.3 °C per decade was observed. Notably, January showed a slight decrease in the warming rate, with a trend value of –0.1 °C per decade.

An indicator of the seasonality of climatic conditions is the amplitude of surface air temperature (A). In Ukraine, the average amplitude A was 12.7±1.1 °C from 1900 to 2021 and 12.5±0.8 °C from 1991 to 2020. Analysis of the temperature amplitude over the 20th century and the early 21st century revealed a general tendency of decreasing A values (the trend is –0.5 °C per 100 years), primarily due to warming in the colder months. However, from 1991 to 2020, the trend in A values was only –0.001 per decade, attributed to a significant temperature rise during the warmer months.

Based on the analyses of the Johansson-Ringleb continentality indices in Ukraine, the indices’ values were determined to be 59.3±3.7 for the period spanning from 1900 to 2021, and 59.0±3.4 from 1991 to 2020. An overarching trend indicates a decrease by 0.4 % per 100 years. However, from 1991 to 2020, a contrasting pattern emerged, revealing an increase by 6.4 % per decade.

The three scenarios of annual average surface temperature changes in Ukraine (SSP1-2.6, SSP2-4.5, and SSP3-7.0) relative to pre-industrial levels in the late 19th century, based on greenhouse emissions scenarios by 2100, are discussed.