D 5.1 Static model data verification, Zalecze & Zuchlow site
Most important data like geological characteristic of the study area, well logs, results of the laboratory analyses and well tests were collected by the site operator (PGNiG). In all analysed wells, except one, the well logs were made in the years 1971 - 1979, therefore their quality is closely connected to the methods and the technological level of measuring and recording equipment available at that time, which was actually very low compared to the present state. AGH verified provided data in terms of their quality and applicability.
Using previously worked out methods, physical models were calibrated. This continuous, digital prediction in the profile of wells allows the derivation of porosity, saturation of rocks with irreducible and mobile water, absolute permeability, relative permeability as well as phase permeability for water and gas.
Calculated permeability values remain in close correlation with flow values obtained in the course of sampling specific formation levels. This congruence, logically resulting from calibration procedure – already used in other geological regions and described in previous chapters – validates the use of models for permeability analyses in the area of gas fields Żuchlów and Załęcze, and probably also in the neighboring fields as well. Described interpretation work has been done using data from 26 wells located mainly in the close surroundings of Załęcze and Żuchlów fields, producing porosity (PHI), shale content (Vsh) other mineral element fraction volume. Well logs cover whole geological profile and can be used not only for a better margin control of reservoir models but also for improving the quality of regional parametric model.
Geomechanical simulations concluded that fault and cap rock integrity at the Żuchlów site did not present any risk during the period of gas production and will not during the scheduled CO2 injection operation provided that the reservoir pressure remains below the initial pressure.