GEOPHYSICS LETTERS

Ghalib, M. et. aL 31The bulk volume water, calculated in the available wells to theNullipore section, indicates that it is near to be constant or close tocopstant. This refers that the formation is in irreducible watersa~ration. In well-252, as an example, the BVW plotted curve onFigure-14 exhibits that the calculated bulk volume water rangingbetween, 0.06 to 0.07 which is an indicator that the zone is composedof very fine grain size. The bulk volume water in the section changesin little parts to be decreased. These decreased values in the bulkvolume water may be not related to increase in grain size, but it isrelated to vuggy porosity (where vuggy porosity has low values forbulk volume water).From the calculated water saturation and hydrocarbon saturation, wefound that the Nullipore section in well-252, as an example, is stainedwith hydrocarbon in zones (stained hydrocarbon zones), whichintercalated with wet zones (water bearing zones) as represented onFig. (14).The qualitative interpretation to the resistivity logs indicate that thewet zones are related to shallow resistivity (LLS) and deep resistivity(LLD) with no separation in readings. In zones which are stained withhydrocarbon, there is an increase in the readings of the deep resistivity(LLD) than the shallow resistivity (LLS) with small separation. Thisseparation is an indicator to hydrocarbon staining as shown on Fig.(14), as an example which represents some of the recorded logs inwell-252.Log derived permeability formula is used to calculate permeabilityin well-252 as an example. The calculated permeability is rangingbetween "20 to 620 mil.darcy" in zones, these high permeable zonesintercalate with zones of less permeability ranging between "0.2 to 2mil.darcy". These intercalated permeable and less permeable zonescoincide with intercalation between hydrocarbon zones and waterbearing zones as represented on Fig. (14).The Elan program is used in petrophysical evaluation of the studiedwells. This program gives a quantitative .determinationof porosity,