Journal of Petroleum Geology, Vol.8,
No.4, pp. 463-474, 1985
©Copyright 2000 Scientific Press,
Ltd.
A PERMIAN BEACH IN THE
ZECHSTEIN DOLOMITES OF WESTERN POLAND: INFLUENCE ON RESERVOIRS
Tadeusz Marek Peryt*
* Instytut Geologiczny, ul.
Rakowiecka 4, 00-975 Warszawa, Poland.
Abstract
Zechstein ooid grainstones, which have
formed a narrow belt (several hundred meters in width) along the
basin-facing platform margin, have been greatly affected by
fresh-water diagenesis, resulting in contrasting reservoir
characteristics. Fresh-water diagenesis, which was related to a
beach environment, was closely accompanied by dolomitization;
there was competition between the dissolution of aragonitic ooids
and their dolomitization. Dissolution of aragonitic ooids can
produce an excellent intragranular porosity when early diagenetic
dolomite cements form prior to dissolution (Kaldi and Gidman,
1982), or it can produce a non-porous fabric of overcompacted
deformed "spastoliths". Although burial diagenesis
significantly modified the reservoir characteristics of the
Zechstein ooid grainstones, a very irregular pattern of early
meteoric-related diagenesis is the main reason why discoveries
are so unpredictable in the Zechstein.
