Abstract: Stratigraphic Framework of Miocene Sandstone Reservoirs, Matzen Field, Austria

FINLEY, R.J., KNOX, P.R., BALTAS, P., and SKOLNAKORN, J

Matzen Field in the Vienna Basin of northeast Austria produces oil and natural gas primarily from Middle to Late Miocene (Badenian--Pannonian) sandstones and is the largest onshore oil and gas field in Middle Europe. The field is currently being evaluated for advanced recovery and shows substantial potential for reserve growth; initial work has focused on the depositional and genetic stratigraphic framework. Major (3rd-order) cycles are bounded by shales and/or by Lithothamnion-rich intervals.

The field's major reservoir, the Matzen Sandstone (16th Badenian), is onlapped by a series of shales capped by a pronounced maximum flooding surface (MFS80). Progradation of a system with delta front relief of up to 150 m deposited the overlying Lower Badenian 3rd-order cycle, which includes the other primary oil reservoirs, the 12th through 8th Badenian. A maximum flooding surface (MFS58) marks the boundary between this cycle and the overlying Badenian-Sarmatian 3rd-order genetic cycle, which includes the deltaic reservoirs of the 7th Badenian through 8th Sarmatian. The overlying Upper Sarmatian 3rd-order genetic cycle, bounded by MFS40 and MFS20 (the latter near the Sarmatian-Pannonian boundary), begins with a shale up to 70 m in thickness and includes more thickly beaded 7th through 3/4th Sarmatian sandstone reservoirs each isolated by more than 20 m of shale. The overlying Lower Pannonian 3rd-order genetic cycle contains the 5th through 3rd Lower Pannonian gas reservoirs, which were deposited as a series of delta lobes and channels, each up to 70 m in thickness.

Each of the 3rd-order genetic cycles is distinct in reservoir style and hydrocarbon charge. This general depositional and genetic stratigraphic framework will serve as the basis for detailed reservoir characterization studies leading to specific opportunities for reserve growth.

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