ACCESSORY MINERALIZATION OF DOLOMITE RESERVOIRS AS THE FACTOR OF FLUIDS VARIABILITY COMPOSITION

References: 17th International Multidisciplinary Scientific GeoConference SGEM 2017, www.sgem.org, SGEM2017 Conference Proceedings, ISBN 978-619-7105-98-8 / ISSN 1314-2704, 29 June - 5 July, 2017, Vol. 17, Issue 11, 11-18 pp, DOI: 10.5593/sgem2017/11/S01.002

ABSTRACT

Oil-saturated Visean dolomite reservoirs were studied from the Tatarstan Republic, east of Russian platform. The main methods of study were X-ray and SEM analysis. Dolomite forms interstratified dense and porous layers with thickness of 0.5-4.0 m in oil-saturated parts of reservoirs. The dolomites are characterized by rhombic form of crystals. Many of them have crystal growth zones as alternate micro-layers with different iron content. In the pore space of dense dolomites find some iron accessory minerals such as siderite and pyrite. There are accessory crystals of quartz and aggregates of microcline in cavernous of porosity dolomites. Based on the heterogeneous composition of dolomites and their accessory minerals associations were modeled stages and hydrochemical parameters variation of fluids before oil charge.

Keywords: dolomites, accessory minerals, quartz, microcline, siderite, pyrite