CHARAKTERYSTYKA POZIOMÓW ZBIORNIKOWYCH I USZCZELNIAJĄCYCH W OBRĘBIE STRUKTUR ZAOSIA I JEŻOWA POD KĄTEM GEOLOGICZNEGO SKŁADOWANIA CO2 NA PODSTAWIE DANYCH Z GŁĘBOKICH OTWORÓW WIERTNICZYCH

Abstract

GEOLOGICAL CHARACTERIZATION OF THE RESERVOIR AND SEAL LEVELS IN THE ZAOSIE AND JEŻÓW STRUCTURES AS A CANDIDATE SITE FOR CO₂ STORAGE ON THE BASIS OF THE DATA FROM DEEP BOREHOLES

Abstract. Zaosie anticline is one of the three structures selected as having the best conditions for geological CO₂-storage in the Bełchatów region. It has been tested by 6 deep wells: Buków 2, Buków 1, Zaosie 3, Zaosie 1, Zaosie 2 and Budziszewice IG 1. Additionally, information from the Jeżów IG 1 borehole, drilled on the top of the nearby Jeżów anticline, is added. That structure is located north-east of the Zaosie
anticline. Both the structures are characterized by similar geological feature and petrophysical parameters of rocks. Potential reservoirs and seals were selected based on analysis of archival data (geophysical logs, cores) and new petrophysical tests. Interpretation of the geophysical logs from deep wells of the described structures included lithological sections of Middle and Lower Jurassic and Triassic rocks, identification of aquifers and impermeable levels, and mudding and total porosity profiles. Additionally, vertical variability of water mineralization was determined, pointing at the boundary between fresh and salt water. Significant thickness, good reservoir properties and proper depth give sufficient grounds to select the Lower Jurassic sandstone levels of the Drzewica Fm. (Upper Pliensbachian) and the upper part of the Ostrowiec Fm. (Sinemurian) from the Zaosie and Jeżów anticlines as potential reservoirs for CO₂ storage. Seal horizons to those formations are fine-grained rocks of the Ciechocinek Fm. (Lower Toarcian) and the Gielniów Fm. (Lower Pliensbachian) respectively. Mentioned parameters also confirm usefulness of the structures for CO₂ storage. However the criterion of water mineralization (>10 g/dm³ ), which was defined in these wells based on interpretation of geophysical logs, can be the factor which eliminate the Zaosie and Jeżów structures as potential CO₂ storage reservoirs.