Petrophysical properties evaluation using well logging of the upper sand member of Zubair Formation in Zubair oil Field, Southern Iraq.

Abstract

The present study aims to determine the petrophysical properties into the upper sandstone member of Zubair Formation at Zubair oil Field by using interpretation a number of different borehole logs for the open wells (Zb-40, Zb 84, Zb-114, Zb-212, Zb-233). These Properties include shale volume (Vsh), effective porosity (Øe), water saturation (SW), permeability(K) and Pore throat type classification R35.The petrophysical properties (Vsh) ,( Øe) and (SW) were drawn for each reservoir unit to determine the direction of the improvement of reservoir characteristics within the selected wells. Depending on gamma- ray log Zubair Formation with in the Zubair oil Field was divided into reservoir units (AB, DJ, and LN) and non-reservoir units (C, and k). The well Zb-84 revealed increases in Vsh was in all the units of Zubair Formation, while the decrease in Vsh in well Zb-114 were obtained in unites AB, and LN. The average of the effective porosity in well Zb-233 in all units was high while low values were obtained in well Zb-84 in unit AB, and LN. There is an increase in water saturation in well Zb-40 in the unit AB while the low values were recorded in well Zb-84 in unite DJ. The petrophysical analysis shows improved porosity and hydrocarbon saturation towards the northern part from studied oil mainly in the well (Zb-40) and the petrophysical characteristics were in unit LN. The dominate type of Pore throat type was between macro - mega pore and meso – mega pore types.