Abstract: The Depositional Environment of the Oncophora Beds in the Altprerau Area/Austria and its implications for future Exploration

HAMILTON, WALTER, AND KUCHER, FRITZ*

The Altprerau/Wildendurnbach Area is located in the northernmost parts of Lower Austria. The areal size is approximately 100km² and has been explored by 33 wells. Gas in commercial quantities has been found in the Laa Beds, the Oncophora Beds and the Malmian Carbonates.

The depositional environment of the main gas producing unit - the Oncophora Beds - is interpreted to be a fully marine, turbiditic sediment derived from the approaching Waschbergzone thrust sheets to the east of the study area.

To better understand the depositional history of the Oncophora Beds, nine cores were analyzed and all existing wells were integrated into a grid of cross-sections. Production data from the Wildendurnbach field and the Altprerau field were used to estimate potential future production possibilities. Available geochemical analyses of gases and formation waters were incorporated in the study to further highlight the depositional environment of the Oncophora Beds.

Existing seismic lines were checked for mis-ties. Only the surveys with comparable acquisition and processing parameters were used to map several key-horizons.

In light of the reviewed data, a tectonic/depositional model for the area is given and previous attempts to explain the tectonic/depositional setting are being discussed.

AAPG Search and Discovery Article #90942©1997 AAPG International Conference and Exhibition, Vienna, Austria