Middle Miocene Stratigraphic Traps in Drava Depression, Croatia

Natasa Nastasic*, Zeljko Ivkovic, and Josip Bubnic
INA-Naftaplin, Croatia
*[email protected]

The main aim of this study is to present an interpretation of potential stratigraphic traps by using seismic attributes and well data. It is possible to predict the occurrence of stratigraphic traps and the spatial distribution of facies through the interpretation of depositional paleoenvironments. The area of interest is in the northwestern part of Drava Basin, situated in the southern rim of Pannonian Basin, Croatia. The interpretation was applied to the Miocene Moslavacka Gora Formation consisting of lithotamnium limestones and biocalkarenite sandstones. These sediments form one of the main reservoirs in the largest onshore Croatian gas-condensate Molve field. We integrated well data from this field and seismic attributes from an undrilled area to reconstruct the paleoenvironment. Coherence, amplitude and peak-spectral frequency slices for flattened seismic horizons revealed sedimentary bodies suitable for delineation as potential stratigraphic traps. Based on the well data and seismic-attribute maps, a sediment thickness map was constructed. A high-energy fluvial delta system was interpreted. Stratigraphic traps are proposed in linear sandy distributary channels, mouth bars and backreef sediments. Deltaic sediment bodies were very complex to interpret and sometimes impossible to track. However the seismic attributes helped us to obtain a clearer picture of the depositional environment. We used recent delta systems as analogues for the occurrence and possible thickness of sediments. Due to the mature exploration stage of this area and lack of undrilled structural traps, it is necessary to apply techniques that will introduce stratigraphic traps as a main exploratory target.

AAPG Search and Discovery Article #90077©2008 GEO 2008 Middle East Conference and Exhibition, Manama, Bahrain