OIL-AND-GAS-FIELDS - TRANSFER ZONE RELATIONSHIPS, THRACE BASIN, NW-TURKEY

In the Th race basin, oil and gas a re produced from carbonate a nd sa ndstone reservoirs of Eocene and Oligocene age. Detailed geological an d geophysical studies reveal that earlier and Eocene structures were i nfluenced by basement paleotopography resulting from late Cretaceous m ovements between the Arabian and Anatolian plates while latest Miocene structures were generated by splays of the North Anatolian Fault in t he Thrace basin. The Eocene structures, which contain the Hamitabat ga s and Devecatagi and K. Osmancik oil fields, trend in a NE-SW directio n. However, Miocene structures which are gas producers in the Karacaog lan and Umurca fields, are oriented in a NW-SE direction, parallel to the strike of the main faults which accommodate the transfer zones in the Thrace basin. The transfer zones occur between faults that dip in opposite directions (conjugate) and in the same directions (synthetic) . The formation of reservoir zones, improvement of reservoir character istics and generation of oil and gas in the oil window zone were influ enced by the timing of faulting and appearance of the transfer zones i n the Thrace basin. (C) 1997 Elsevier Science Ltd.