Possible Oil and Gas Traps Related to a Wrench-Fault Zone in Hungary

Abstract

The Szolnok-Maramures flysch zone, penetrating deep into the Great Hungarian Plain, is an appendix of the inner Carpathian flysch. The biggest gas field of Hungary (found in 1960) is in this zone. Since 1960, the flysch zone was explored thoroughly but nothing comparable was found; however, most of the boreholes had some hydrocarbon indications. The Szolnok area represents the western termination of the flysch zone with some minor gas fields. From recent seismic data, the authors determined the dominant tectonic style of the extremely complex tectonic features: wrench faulting. In the presented seismic time sections, all possible hydrocarbon traps are in connection with strike-slip movement: (1) domes in upper Pannonian Pliocene clastic sediments (probability is low because of listric faults in the top zone); (2) channels in the lower Pannonian delta series (probability is higher but the danger of open listric fault still exists); (3) closed highs above the dome of positive flower structure of the fly, in the lower Pannonian marine sequence; (4) similar situation in Badenian-Sarmatian neritic to terrestrial sediments and volcanic-sedimentary formations (these last two represent most finds); and (5) the overthrust plane (terminating the flysch with crushed crystalline schists) and the Miocene sediments trapped beneath itmore » while the two blocks of Mesozoic and Precambrian basement moved by, forming ideal trapping conditions for the hydrocarbons moved by, forming ideal trapping conditions for the hydrocarbons generated in the flysch and in older Mesozoic source rocks.« less