Current hydrogeochemical profile of groundwater in the Middle Jurassic hydrogeological complex of the Lyaminsky oil and gas field

The aim of the study is to identify the influence of some parameters of the geological environment on the formation of the current hydrogeochemical profile in the Middle Jurassic hydrogeological complex (layers YU2-4) of the Lyaminsky oil and gas field in Western Siberia.The factors controlling the changes in the chemical composition of the groundwater (geotemperatures, influence of neotectonics, etc.) after the process of sedimentation and water accumulation were analysed on the basis of the lithogenetic theory of the transformation of the composition of groundwater during geological evolution. In the course of the research, correlation coefficients were obtained for the value of groundwater mineralisation in the complex with the modern and paleotemperatures of the Tyumen suite, the porosity coefficient and the depth of the foundation. The obtained results allowed assuming that the current hydrogeochemical profile of the Middle Jurassic hydrogeological complex is the result of the consistent action of the whole complex of factors. The results of the analysis showed that the influence of neotectonic processes on the current hydrogeochemical profile is quite probable. The reasons for the heterogeneity of mineralisation, apart from neotectonic processes, may be different, but in any case, the identification of relationships such as "Mineralisation - a parameter of the state of the geological environment" indicates a change in the concentration of salts in groundwater after their accumulation together with sediment.