12th Congress of the Balkan Geophysical Society

The Moesian Platform is a significant tectonic unit in the foreland of the Carpathians and Balkans, spanning across southern Romania and northern Bulgaria. It forms an elongated, west-east oriented structural unit defined by faults, extending into the Western Black Sea Basin up to the continental slope, where it gradually transitions into oceanic-type crust. Although by definition it is considered a stable tectonic unit, the Moesian Platform has played a significant role in the geological history of the region. It is widely accepted that Moesia collided with the emerging Carpathian-Balkan orogens during Cretaceous through Miocene. This collision was crucial in forming the Carpathians’ double-bend, generating significant extensional forces within the Moesian Platform during Pliocene-Quaternary. Originating in the research for the “Intramoesian Fault: Geophysical detection and regional active (net)tectonics and geodynamics” PhD thesis ( Stanciu, 2020 ), the Moesian Platform is an area of our interest for deciphering the geotectonic history, its (neo)tectonic features, geological structures and complex geomorphology.

The research area within the Pannonian Basin presents a complex geological setting, intricately divided into four distinct lithostratigraphic units. These units share similar lithological-petrophysical characteristics and respond to well-log measurements. In this case study, we delve into the application of Wave Equation-Based AVO (WEB-AVO) for precise lithology prediction, on an onshore oil reservoir within a sandstone-conglomerate formation. The WEB-AVO algorithm represents a seismic inversion scheme wherein the elastic wave equation is iteratively solved. Notably, it accounts for multiple scattering, mode conversions, and transmission effects across the target interval. The key steps of the WEB-AVO approach are initial elastic property estimation, wave-equation deployment and scattering effects, and direct solving for compressibility and shear compliance. A distinctive feature of WEB-AVO lies in its direct solution for compressibility (K, the reciprocal of bulk modulus) and shear compliance (M, the reciprocal of shear modulus). Unlike conventional AVO inversion techniques that focus on impedances, this approach provides more relevant information for quantitative interpretation. For the lithology prediction, we used a Bayesian classification algorithm for build facies volumes. Classification was done based on Kappa and M data in 6 wells, both absolute and contrast (relative) as input data. These results underwent significant analysis to validate their reliability. The result of the prediction illustrates very good match between the measured and predicted lithology logs for wells. Results of our research showcase the efficacy of employing elastic properties derived from WEB-AVO inversion for lithology prediction within a sandstone-conglomerate oil reservoir in the Pannonian Basin. Rather than dismissing observed non-linear events as mere noise, we recognise their significance. These unconventional seismic responses provide valuable additional information. By incorporating these events into our workflow, we enhance our understanding of subsurface properties. WEB-AVO demonstrates its predictive robustness beyond well locations. Elastic property predictions extend away from wells, enabling comprehensive reservoir characterisation. Notably, this method achieves efficiency gains by eliminating the need for specialised preconditioning—unlike traditional linear inversions. In summary, the integration of WEB-AVO inversion offers a powerful tool for lithology prediction, even amidst complex seismic data.

The reprocessing of vintage data in Central Asia aimed to preserve true amplitude relationships, high signal-to-noise ratio, and high-resolution recording for possible comprehensive kinematic and dynamic interpretation. Modern techniques were expected to be utilised, with potential new solutions designed to achieve this goal.

Geophysical methods are becoming an increasingly valuable tool even for agricultural applications. Agricultural geophysics investigations are commonly focused on delineating small- and/or large-scale objects/features within the soil profile (∼ 0 to 2 m depth) over very large areas. The study was carried out at a farm site in Ahmadu Bello University, to delineate subsurface structures with depth. It revealed the lithological units in the study area. The analyses have revealed various lithological units from the results of the inverted sections along the profiles. The study area has shown clearly two distinct layers, overburden and weathered basement. The overburden layer is clayey sand, sandy clay, and laterite. This laterite soil show very high resistivity anomaly that may be referred to as consolidated laterite. The weathered layer which contains medium grained sand with clay and feldspar materials also has the presence of fractured part that could act as the aquifer in the area. From the subsurface properties, this farm land may have low agricultural yield or may limit the cultivation potential of the region, but the region may be good for underground water yield.

The field of Oil and gas is indeed a well-packed area or jurisdiction when the topic of what contributes most to the Nigerian economy comes up for discussion. In this stead, it should not be a surprise that this paper has been brought to aid the reader with between understanding of some of the important parts within the industry. This paper stands to distill the reins of oil and gas in Nigeria with respect to ownership in recurring situations. Herein, there would be recourse made to the different theories which have been concocted in trying to give a definite answer to the topical issue. Also, the writer seeks to take the reader herein on an academic journey from jurisdiction to jurisdiction with respect to the provisions in these countries apart from Nigeria on who owns Oil and Gas at law’; reference being made to legislations such as the Land Use Act, Petroleum Act, amongst others. A delve into political history concerning the tussle between the State and Federal Government concerning ownership of mineral resources would also be made. Whilst all these are achieved, the writer would also expound on ownership with respect to gas flares, an inherent output of the Gas mineral source and the different theories concerning ownership.

Mono-channel recording systems with a Boomer seismic source are very cheap and can be easily deployed in sensitive environments such as lagoons or busy harbors ( Zecchin et al. 2008 ). The price paid for these advantages is the lack of signal redundancy typical of multi-channel records, which makes it possible to estimate wave propagation velocity and angle-dependent reflectivity, and to improve the signal-to-noise ratio by stacking or migration. In this paper, we show that some of this information can be obtained by inverting the amplitudes and traveltimes of shallow primary reflections and their multiples, using a single offset in a Boomer survey.

The study explores a hybrid optimization algorithm designed to address ill-posed well-logging inverse problems, combining Singular Value Decomposition (SVD) and Damped Least Squares (DLSQ) techniques. The research leverages interval inversion, utilizing series expansion for identifying petrophysical properties across depth intervals, ensuring precision amidst nonlinearity challenges. Initially employing the SVD approach ensures stability by thoroughly evaluating eigenvalues before shifting to the faster DLSQ method, optimizing efficiency as convergence nears completion. Testing on synthetic and real field data from a gas-bearing reservoir in Egypt’s Western Desert validates the algorithm’s capacity to predict reservoir characteristics such as lithology, porosity, and saturation with improved accuracy. The findings highlight the heterogeneous nature of the reservoir, mainly comprised of sandstone layers interspersed with shale laminations. This approach not only provides computational efficiency but also enhances characterization and decision-making in reservoir development by accommodating uncertainties and capturing variations in reservoir quality.

Cabyle is one of the most important ancient cities in Southern Bulgaria with almost uninterrupted habitation for over a millennium between 4th c. BC and 6th c. The continuous human presence in the area has led to a spatial overlap and intertwining of diverse remains from several historical periods, the localization and contouring of which presents a great challenge for geophysical methods as well. The use of car-towed multisensor magnetic gradiometry was instrumental for mapping extensive areas and turning the focus on prospective locations, while possibly revealing a new bath complex beyond the city walls. ERT helped to distinguish geological faults from massive walls. GPR was most successful in outlining the plan of an important part of the Late Roman town, whereas aerial photography indicated a massive building with East-West orientation outside its limits. Archaeological excavations informed by the survey results demonstrated a very close match between the features on the GPR model and the excavated architectural remains. This case study may serve as a perfect illustration of the usefulness of integrated application of geophysical methods for strategic decision-making and long-term management plans of archaeological parks and monuments.

Geophysics education primarily emphasizes its applications in resource exploration, understanding Earth’s structure, addressing environmental challenges (such as landslides analysis, assessing soil pollution impacts, and evaluating climate change effects), as well as in engineering contexts (e.g., site characterization, rock property analysis, non-invasive infrastructure monitoring, and the study of induced seismicity and land instability). In addition, public awareness of geophysics tends to be limited to a few prominent areas, such as its role in studying earthquake-prone regions and resource discovery. However, Geophysics can serve the community in other forms as well. The role of geophysics in addressing both global and local security challenges is often underrepresented in academic curricula, typically limited to applications such as detecting unexploded ordnance (UXO) or locating munition stockpiles from past conflicts, including World War I, World War II, regional military conflicts and guerrilla warfare. In this context, this paper emphasizes the need to expand geophysics educational curricula to include topics such as the analysis of seismic and acoustic data to depict signals from military actions or (illicit) weapon testing, along with practical training in data interpretation for these purposes. The curriculum should also address the application of magnetometry and electromagnetic methods for detecting landmines and explosive remnants of war (ERW) and integrating geophysics with remote-sensing and UAV technology to enable safer surveying in high-risk areas. Specialized training for geophysical teams in mine and explosive ordnance detection is also essential for enhancing survey safety.

Geophysical techniques are essential in underground mine planning as they offer critical insights into subsurface geology, ore bodies, structural features, and potential risks. Electrical Resistivity Tomography (ERT) is a widely used geophysical technique in this field. In the current study, ERT is applied to delineate the extent, geometry, and continuity of subsurface voids. By identifying high-resistivity zones related to ore bodies, mining operations can be better optimized, including excavation planning and hazard mitigation. ERT surveys also provide crucial details about geological structures, such as faults, fractures, and bedding planes, aiding in understanding ore deposition and designing safer, more efficient mining layouts.