Nikola Botoucharov

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• PhD
• Professor (Associate) at Sofia University "St. Kliment Ohridski"

The first boreholes in the Tarnovo depression, located in the central Southern Moesian platform margin zone (Bulgaria), drilled at the end of the 1970s, display intervals of unusually thin, irregular and lens-like interbedding of shales and siltstones in the Middle Jurassic succession. Their specific lithological, log and seismic features, which re...

The Moesian Platform occupies a wide area in Bulgaria and Romania, being surrounded to the north and west by the South Carpathians and to the south by the Balkans. The lithostratigraphic division of the representative cross-sections of the Triassic system is performed for both countries. The applied methodology in defining the lithostratigraphic un...

The generative potentials of four core samples of pure to silty shales of the Stefanets Member (Etropole Fm.) from the Central South Moesian platform margin, Bulgaria have been evaluated by geochemical proxies. Extractable organic matter, i.e. “free” and “bound” bitumens, was characterized by ap- proaches of organic geochemistry. Biomarkers were tr...

The main object of this research is Stefanets Member (Aalenian-Lower Bajocian substage). It is located at the base of Etropole Formation (Etropole Fm.) and consists mainly of shale and siltstones. The study area is located in the South Moesian platform margin (SMPM) and neighbouring border zone of Iskar-Yantra step, where Lower-Middle Jurassic sedi...

Rock samples from the Early to Late Cretaceous marine and non-marine strata of Livingston Island, South Shetland Islands, Antarctica, were studied. Organic matter (OM) originates predominantly from terrestrially-derived organic particles. Mostly highly fragmented plant remains, and locally vitrinite/semifusinite as part of plant compressions/imprin...

We report new V, Ni, S, and Hg data for four condensates and seven crude oils from Central Northern and Eastern Bulgaria. The samples have relatively low trace metal contents compared with other published crude oils and condensates. These properties facilitate their production and reduce environmental concerns for trace metal release from the proce...

Three intervals of Early-Mid Jurassic black argillaceous rocks belonging to the Southern Margin of the Moesian Platform and western Fore-Balkan units, are traditionally considered the main hydrocarbon source charging numerous small oil and gas deposits along the Bulgarian sector of the Moesian Platform (Georgiev, 2000). Petrological data indicates...

This study deals with the geodynamic evolution in the Tarnovo depression, contributes to a better understanding of the burial and thermal history, and gives a model of the generation of hydrocarbons from the Lower–Middle Jurassic rocks. The implications of the complex heat flow scenario for the timing of hydrocarbon generation from the Stefanets Me...

The Lower–Middle Jurassic sedimentary rocks from Northern Bulgaria represent important stratigraphic markers and a potential source for oil and gas accumulation. Here, we present preliminary major and trace element results for 22 sedimentary rock samples from the Bachiishte, Ozirovo, and Etropole Formations collected from the Balkanides and the Moe...

The level of scientific knowledge about a gas hydrate deposit (GHD) in the northern deep-water part of the Bulgarian Exclusive Economic Zone (BEEZ), energy, climate and environmental problems determine the need of urgent creation and realization of a Bulgarian program for gas hydrate development. We present a review of this knowledge and define 3 p...

Sediments of Stefanets Mb. (Etropole Fm.), consisting mainly of shale and siltstones, are investigated by Rock-Eval pyrolysis. The samples from the Middle Jurassic section (Bajocian in age), outcropping within the western part of the Balkan orogenic system in Bulgaria, were analyzed to study their hydrocarbon generative potential. The obtained TOC...

The territory of North Bulgaria includes two major tectonic units-Balkanides (the segment of the East-Eu-ropean Alpine orogen) and its foreland-Moesian Platform. The study area is located in the South Moesian platform margin (SMPM), central and western parts of the Forebalkan and their neighboring border zones. The SMPM is the most subsided part or...

Десетилетия наред съществува нестихващ интерес към нефтените проучвания в Мизийската платформа, Централна Северна България. Той се дължи основно на откритите находища и залежи с различни размери и запаси. Реинтерпретацията на геоложката,геофизичната и сондажната информация, както и съвременните интегрирани 3Д геоложки и резервоарни модели ще улесня...

There is a long-standing interest in the petroleum exploration of the Moesian Platform in Central Northern Bulgaria due to the discovered fields of different sizes and resources. Although some of them are in a late stage of development or have already been depleted, there are still less studied areas with perspective potential. Recently some promis...

The main objective of the study is to determine the lithofacial characteristics of the Doirentsi Formation reservoir carbonates in the range of the south-central part of the Moesian platform by XRD and XRF analyzes. The obtained results demonstrate the chemical and phase composition and supplement the field description of the Middle Triassic limest...

This paper aims at showing some of the problems and the main mistakes in the seismostratigraphic subdivision of the Black Sea Quaternary. It suggests a way to eliminate and solve them. For this purpose, three examples of seismic stratigraphic subdivisions are considered. They include seismic records in three scales from the southwestern (SW) part o...

In the Bulgarian offshore zone of the Western Black Sea basin, hydrocarbon deposits of different scales have been established. There are also favorable geological and geochemical preconditions for the formation of gas hydrates.

The aim of this work is to reconstruct the variations of the total gas hydrate (GH) masses of the Danube deep-sea fan after 0.265 Ma BP. The PetroMod™ model developed in GEOMAR, Germany is for basin analysis of the Western Black Sea for 98 Ma. Geological structure is from 2D seismic of the Black Sea consortium “Geology without limits”. Results show...

The aim of Stage 1 of the FNI project GEOHydrate is to prove the hypothesis that gas hydrates deposits (GHDs) create measurable temperature and heat flow (T&HF) anomalies on the seafloor. We use a PetroMod™ model for 98 Ma basin analysis of the Western Black Sea basin, developed in GEOMAR, FRG. The model was run 2 times – with and without GH format...

The aim of this work is to reconstruct the variations of the total gas hydrate (GH) masses of the Danube deep-sea fan after 0.265 Ma BP. The PetroMod™ model developed in GEOMAR, Germany is for basin analysis of the Western Black Sea for 98 Ma. Geological structure is from 2D seismic of the Black Sea consortium “Geology without limits”. Results show...

The discovered industrial and semi-industrial hydrocarbon reservoirs, seeps and offshore gas hydrate fields in the Bulgarian Exclusive Economic Zone (BEEZ) are evidence of the generation and migration of oil and gas in the Western Black Sea basin. Marine gas hydrates from the deep water palaeodelta of Danube are seismically studied recently, but th...

The study presents a geochemical appraisal of key well core samples from Stefanets Member (Etropole Fm.), from the eastern part of the West Forebalkan, Bulgaria. Extractable organic matter, i.e. “free” and “bound” bitumens, was characterized by geochemical methods. Biomarkers were tracked, quantified and correlated. Parameters calculated on the bas...

The main objective of the study is to outline the surface distribution of the modern and paleo-heat flow in order to reconstruct the thermal history of the Western Black Sea basin in relation to the origin and stability of gas hydrates. Key borehole section models confirm the basic theory for the opening of the basin, as well as variations in paleo...

Sofia University “St. Kliment Ohridski” is the first Bulgarian and the highest academic institution with more than a century long educational and scientific traditions. Geology is part of the university from the very beginning in the area of Natural sciences. It is an example of the effective interaction between the educational processes and implem...

Nowadays we are gradually running out of sedimentary basins to explore and the reserves of conventional oil which can be produced easily are limited. This is the reason why many of the petroleum companies look for other types of resources. Moreover, we are increasingly investing in unconventional hydrocarbons including heavy oil. The objects in thi...

The study area is in the Moesian Platform and more precisely in its southern most subsided part – South Moesian Platform Margin. The research object is Triassic section reached by boreholes in the Agatovo and Suhindol countryside area. The data base is mainly from 4 key wells - from west to east R-1 Agatovo, R-2 Suhindol, R-2 Agatovo and R-1 Suhind...

Triassic period marks the beginning of the Mesozoic evolution of the Bulgarian territories after the end of the Hercynian tectogenesis, denudation of the Hercynian orogen and the final formation of Late Permian arid plain. Triassic geological evolution took place in the geodynamic setting of the passive continental margin and deploying locally exte...

The geodynamic evolution of the study area, restored from numerous well section data, demonstrates increased tectonic and basin subsidence during Late Permian-Early Triassic, Late Triassic and Early Jurassic rifting phases as well as after Mid-Cimmerian compression. There is a distinct trend for higher burial rates and depths of sediments from cent...

The aim of the research is to analyze vitrinite reflectance measurements, their distribution and define temporarily “oil and gas windows” of Middle Triassic and Lower-Middle Jurassic source rocks in the study area. The input data includes patterns based on more realistic and complex geodynamic model. It is being used mostly in finding the limitatio...

Content I Basic knowledge of the fossil fuels. II Composition and characteristics of primary OM. III Transition of the OM to the insoluble state. Diagenesis of OM; diagenetic loses estimation. IV Catagenesis of OM. Identification, elemental composition and stricture of kerogen. Kerogen types and its evolutionary curves. V Balance of kerogen convers...

The objectives of the study are to outline the thermal maturity variations during Mesozoic and highlight the possible trends according to geodynamic history of the central southern part of the Moesian Platform. More than 120 rock samples were selected from 29 wells for vitrinite reflectance measurements on microscope Leica DMRX with a micro photome...

Central North Bulgaria occupies a wide area in the Moesian Platform and its southern platform margin. The territory has been a major exploration target in searching for oil and gas since 50 years now. The most of the economic fields are concentrated in the western and south-western parts of Central North Bulgaria. The oil and gas fields are connect...

The Triassic sediments in the Moesian Platform are very well explored. The study area is in the Bulgarian territory and covers central part of the South Moesian Platform Margin and adjoining zone to the north. The Triassic rocks there are characterized by considerable diversity, thickness and burial depths. Among them Mitrovo Fm. (T2lad-T3crn) cont...

The interest in the Dolna Kamchia basin during the last 25 years is connected with the results from the exploration in the Bulgarian part of the Western Black Sea and adjacent onshore areas. Many oil companies were attracted (British Gas, Texaco, Enterprise Oil, OMV and others) carrying out significant amount of geological and seismic work. They dr...

Rock-Eval pyrolysis is an exceptionally reliable and effective method in analysis and evaluation of source rocks. The suitable core or cutting sample choices, consequence of processing and investigations are indispensable condition for successful scientific applications. This study demonstrates geochemical data of representative pyrolysed Permian,...

The purpose of the study is to model thermal history, heat flow distribution and define temporarily “oil and gas windows” of Lower-Middle Jurassic sediments in the Central South Moesian Platform Margin. Lower-Middle Jurassic series consist of shallow to deepwater sediments with total thickness locally up to 1200-1300 m in the study area. Some shale...

The oil and gas perspectives of the Triassic rocks in the Central South Moesian Platform Margin are evaluated on the basis of a complex geological analysis. The geodynamic evolution of the region during Triassic was dominated by failed rifting phases, followed by Early Cimmerian orogeny. These events have predestined tectonic processes and sediment...

The investigation includes three oil accumulations (Dolni Dubnik, Gradina and Bohot), situated in different stratigraphic levels in southern Moesian platform edge, and two source samples from most promising Triassic source interval (Mitrovo Fm.). They are compared by biomarker correlations using GC, GC-MS techniques. Dolni Dubnik economic oil, Grad...

Sensitivity maturity analysis is being used mostly in finding the best fitting parameters for thermal modeling. The sensitivity of the models in Beglej-Kalenik area demonstrates the importance of heat flow history - subject to uncertainty due to complicated geology. The specific analysis includes patterns based on two models complex and constant),...

Vitrinite reflectance (%Ro) analysis is the major method in definition of thermal maturity of sediments. The rock katagenetic alterations can also delineate the thermal history of well sections, structures, zones and sedimentary basins as shown in this case study for North Bulgaria. The well R-1 Dragana data modeling visualizes a local heat flow, t...

The analyses conducted in this paper are based mainly on the lithofacies characteristics of the well-penetrated Triassic series in the South Moesian Platform Central Margin. The purpose is to achieve better understanding of depositional environment and lithological composition of the sediments. Besides the detailed observation and study of the Tria...

Collection and analysis of well data is important process, allowing a reconstruction of the penetrated rocks. Numerous charts and diagrams illustrate all sorts of geological information. Some of them are demonstrated and generalized by well sections from southwestern part of the Central North Bulgaria. Logs together with well core and cuttings are...

There are five economic fields situated in the Central South Moesian Platform Margin (CSMPM) and adjacent teritories. They are accumulated in various Mesozoic sedimentary formations (dominated by Middle Triassic carbonates and Lower Jurassic clastics) and complex structural zones. The thermal evolution of the region and the origin of hydrocarbons i...

Most of the discovered hydrocarbon fields in Bulgaria are concentrated in transition zone between the Moesian Platform and South Moesian Platform Margin. The major reserves are accumulated in the Middle Triassic and Middle Jurassic sediments. Long time the hydrocarbon potential of the Mesozoic sequence was connected only with Triassic deposits with...

Mitrovo Fm. (T2) demonstrates fair gas potential, but Bukorovo member of Ozirovo Fm. (J1) and Stefanetz member of Etropole Fm. (J2) show good to very good oil and gas potential in the studied area. Available data allow modelling and characterization the features of oil and gas windows as well as the time of hydrocarbon generation from perspective s...

The South Moesian Platform Margin and adjacent territories are the main oil and gas exploration targets for the last decades. The petroleum potential of the studied area is concentrated in the Mesozoic section, which is composed of variety of sedimentary facies. Geodynamic evolution of the region is dominated by rifting phases (P2-T1, T3, J1, K2),...

The South Moesian Platform Margin (SMPM) is one of the perspective zones for petroleum exploration. Most of discovered oil/gas fields are located in the southern zone of CN Bulgaria along the transition stripe between the Moesian Platform and its Southern margin. Long time the origin of discovered Triassic oil/gas accumulations in Bulgaria was gene...

The main purpose of this study is to make seismic-stratigraphic interpretation and 3-D modeling of Tertiary succession in Kamchia basin offshore. The studied basin is located in Western Black Sea region between the East Balkan thrust-folded belt and the Moesian Platform southern edge. The Kamchia basin evolution is controlled by the N-NE propagatio...

Long time the origin of the hydrocarbons in the fields was genetically connected with Triassic sourcing without any convincing proves. Only during the last decade the modern geochemical studies (Rock Eval and GC-MS analyses) have been conducted. The biomarker correlations showed that the main crude oils in Bulgaria are most likely generated by the...

Since the last decades of 20'h century there is a continued interest towardsthe deep-water sediments, including those deposited and/or re-deposited by the bottom currents. The main purpose of this paper is to characterize and describe the formation and reservoir properties of the Middle Jurassic bottom-current deposits in the Tarnovo depression. Th...

Most of the discovered oil and gas fields in Bulgaria during of about 50 years exploration are concentrated in western part of the country along the transition zone between the Moesian Platform and its Southern margin. The major reserves are accumulated in the Mid - Triassic carbonates (Anisian and Carnian) and in the basal Lower Jurassic clastics....