Fadila Bessa¹

(1) SONATRACH, Algiers, Algeria

ABSTRACT: The Dolomitic Reservoir D2 of Hassi R'mel Field:Sedimentological Characterization and Petrophysics

The present work consists of reservoir properties characterization of the D2 of Hassi R'mel field. The D2 is a dolomitic horizon which represents a lithostratigraphic marker correlative over all the triassic province from the South to the North. It is hettangian in age, dated by palynology. Approximately 200 wells have been studied on petrophysics with only 14 sedimentologically analyzed in details. The core description and the microscopic samples revealed that the D2 is made of a succession of many facies : - dolomite with laminated structures, frequent algal mats, fenestrae and emergence cast. - Dolomite massive or rarely with festoon crossbedding . - lag composed of the dolomitized lithoclasts, oo-peloids and bioclasts. The oolithic facies with the dissolved ooliths and fenestrae facies without plugging , present the best reservoir quality specially the porosity. The available data (core and logs ) have allowed us to assess the reserves at 48 109 Std.m3 in the reservoir D2. The iso-value maps done in the reservoir D2 allow : - to visualize the irregular variation of porosity - permeability at regional scale . - to determine the best reservoir quality zones (Northeastern part of the Hassi R'mel field and Hassi R'mel Oil Rim) where the porosity could reach 34% and the permeability could exceed a value of 10 md.

AAPG Search and Discovery Article #90906©2001 AAPG Annual Convention, Denver, Colorado