Journal of Petroleum Geology, Vol.16, No.3, pp. 313-322, 1993

©Copyright 2000 Scientific Press, Ltd.

PETROPHYSICAL CHARACTERISTICS OFTHE MIDDLE EOCENE LAUMONTITE
TUFF RESERVOIR, SAMGORI FIELD, REPUBLIC OF GEORGIA

M.E. Grynberg*, D. Papava*, M. Shengelia*, A. Takaishvili*, A. Nanadze* and D.K. Patton**

* Georgian Oil, 65 Kostava St., Tbilisi 380015, Republic of Georgia.

** Earth Sciences and Resources Institute, University of South Carolina, Columbia, SC 29208, USA. Current address: Kolkhis Oil and Gas, 7537 S. University Blvd., No. 206, Littleton, Co., 80122, USA.

Abstract

In the Samgori field, near Tbilisi in the Republic of Georgia, changes in reservoir properties caused by alteration of middle Eocene volcanogenic rocks control the amount of oil and gas these rocks will yield. These changes, which include fracturing, development of vugs, and laumontite zeolitization, impart a vertical and lateral variability, thus giving rise to irregular petrophysical properties of the rock such as filtrational capacity, elastic deformational properties, and productivity. Indicative of such differences is the large variation in initial recovery from one well to another.