The hydrodynamic conditions of the Volyn-Podillya oil and gas-bearing region

2018 Geology Geography Ecology  
The purpose of the paper was to study hydrodynamic peculiarities of the aquifers of Volyn-Podillya oil and gas-bearing region and their impact on the formation and conservation of gas deposits. The research area is located in the western Ukraine and covers the structures of the Eastern European and the Western European platforms. At present, Lokachi and Velyki Mosty gas fields are discovered here in the deposits of the Middle and Upper Devonian. Non-commercial volumes of gas and oil were
more » ... and oil were received in some exploration wells. Research methodology was based on the evaluation of water initial formation pressures and static levels that were obtained from the funds of the State Enterprise "Lvivgazvydobuvannia" and State Enterprise "Zakhidukrgeologia". The formation pressures were transformed to one plane of comparison. Also the hydrodynamic characteristics were studied in this work on the basis of the hydrostatic coefficient (P f/P e) in order to evaluate the impact of the factors that determine the nature and form the state of the hydrodynamic field. The maps of the formation pressures and hydrostatic coefficients were constructed and interpreted. Results of researches. It was found out that the parameters of hydrodynamic fields of the Upper Proterozoic, Cambrian, and Lower-Devonian aquifers complexes of the Volyn-Podillya ORG have the features of an exfiltration system. The hydrodynamic tension extends from the most abyssal parts of the sedimentary basin to its peripheral parts. Formation pressures are caused by an increase in the volume of waters due to their squeezing out of clay sediments that have the ability to significant compression into weakly compression sandy rocks. The hydrodynamic energy of the Middle-Upper Devonian aquifer complex is directed from the periphery to its central (the most submerged) part. The peripheral parts have the characteristics of the infiltration water-pressure system. It was established that the hydrodynamic field of the Volyn-Podillya ORG compared with the Bilche-Volytsya ORG is marked by a much lower power due to weak effect of exfiltration in the aquifers and the absence of sustained lithological and tectonic screens. The lateral hydrodynamic field, investigated on the basis of the hydrostatic coefficient, increases from the south to the north. A certain spatial relationship of the isolines of hydrostatic coefficient with diagonal disjunctive breaks is observed. This can determine them as a way of the water-hydrocarbon mixtures migration. Gas deposits of Lokachy and Velyki Mosty fields are located in areas with higher values of the hydrostatic coefficient. Distribution of the hydrostatic coefficient in the section of Lokachi gas field indicates the connection of its overhydrostatic values with the existing gas deposits. Hydrodynamic isolation of the structures promoted conservation of hydrocarbon deposits from mechanical and biochemical destruction.
doi:10.26565/2410-7360-2018-49-03 fatcat:xajbucufybhu7oitns2273gk5m