Reservoir parameters of lithostratigraphic successions of the lower Paleozoic strata in the Polish part of the Baltic region based on laboratory studies and well logs

Abstract

For lithostratigraphic successions of the lower Paleozoic strata in the Polish part of the Baltic Sea between the Slupsk Block and Courland Block, assessment of petrophysical properties was carried out with the use of mercury porosimetry and well logging results. The porosimetric measurements allowed to determine critical rock parameters and to distinguish genetic types of reservoirs. To complete the information on reservoir parameters, available well logs were used. The logs allowed identification of Cambrian strata in boreholes and the distinguishing of several lithostratigraphical units. Results of the porosimetric measurements demonstrated the strongly heterogeneous character of the pore space in the Cambrian rocks, with generally very weak reservoir properties. Fractured and porous-fractured rock space is a principal feature here. Well log anomalies confirmed the diversified lithological development of the Cambrian profile and the somewhat better reservoir parameters of rocks of the Paradoxides paradoxissimus Superzone and the shaly character of the Eccaparadoxides oelandicus Superzone. From the point of view of volumes of potential hydrocarbon accumulations, the capacity of the Cambrian deposits is low, but this is a basic feature of reservoir rocks with fractured and fractured-porous space.