Authors:István Nemes, Szilvia Szilágyi Sebők, and István Csató
Due to the global oil price crisis in 2014, one of the MOL's preventive/reactive measures was to identify geologically or commercially risky elements within their portfolio. This involved reevaluation of all geologic data from Field A in the Volga-Urals Basin. In re-evaluating Field A, several unexpected challenges, problems and pitfalls were faced by the interdisciplinary team performing the task of building a new database, quality checking, and interpreting data dating back to 1947. To overcome these challenges related to this mature field, new approaches and fit-for-purpose methods were required in order to achieve the overall goal of obtaining a reliable estimation of remaining hydrocarbon potential. In the first phase a first-pass 3D geologic model was constructed, along with wrangling, cleaning and interpreting 70 years of subsurface data. This paper focuses on the main challenges involved in evaluating or reevaluating reservoir aspects of a mature field.
The primary challenges were related to the estimation of remaining in-place hydrocarbon volumes, the optimization of infill well placement, the identification of primary and secondary well targets, the identification of critical data gaps, and the planning of new data acquisitions. The hands-on experience gained during the development of the geologic model provided invaluable information for the next steps needed in the redevelopment of the field.
Authors:Szilvia Szilágyi Sebők, István Csató, and István Nemes
The paper presents a study of a Lower Carboniferous (Visean) clastic sequence commonly called Bobrikovsky Formation, deposited in the Volga-Ural Petroleum Province, Orenburg Region. Our investigation included sedimentological description of core samples from hydrocarbon wells and well log correlations. Facies were identified by well log patterns and calibrated by core sedimentology. The Bobrikovsky Formation is proposed to be interpreted as an overall transgressive-regressive succession in a nearshore-tidal environment. Transgressive lagoon-estuary and barrier island facies became regressional lagoon fill-type settings.
Authors:Ádám Bede, Roderick B. Salisbury, András István Csathó, Péter Czukor, Dávid Gergely Páll, Gábor Szilágyi, and Pál Sümegi
The Ecse-halom is a burial mound (kurgan) in the Hortobágy region of Hungary. Built in the Late Copper Age/Early Bronze Age by nomadic people from the east, it now stands on the border between two modern settlements. A road of medieval origin runs along this border and cuts deeply into the body of the mound. The southern half of the mound was plowed and used as a rice field, and later a military observation tower was built on top of it. Despite this disturbance, the surface of the mound is in decent condition and provides a home for regionally significant, species-rich loess steppe vegetation. The mound comprises two construction layers as indicated by magnetic susceptibility and thin-section micro-morphological analysis. Examination of organic compounds and carbonate content at various levels showed different values, which suggest a variety of natural and anthropogenic stratigraphic layers. Mid-sized siltstone fraction is dominant in the section. The layers originate from the immediate vicinity of the mound, but have different characteristics than present-day soils. These mounds contain a valuable record of cultural and environmental conditions occurring at the time of their construction, and also serve as a refuge for ancient loess vegetation; therefore their conservation is highly recommended.