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This research work is an attempt to confirm the sub-surface Jurassic sequence present in the Meyal field and to delineate promising location for test drilling. The Meyal field, one of the major oil and gas producing fields, lies in the active foreland and thrust belt in the Potwar basin of Pakistan. Petroleum play components of the Jurassic sequence encountered in the Meyal field were analyzed by seismic and well log data, acquired in this area. Based on lithological interpretation, Jurassic sequence was divided into upper and lower parts. Petrophysical interpretation including formation water resistivity, water saturation, hydrocarbon saturation, and permeability suggests presence of potential reservoir in lower sandstone part of the Jurassic sequence. Wells are drilled at the top of the pop-up structure which are indicated by the time and depth contour maps to obtain overall structure of the area.

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Abstract:The Aghajari Formation, called also the Upper Fars, develops throughout the Folded Zagros Zone and its thickness in the type section in southwest of Iran is 2966 meters. To analyze the sedimentary basin of this Formation, lithofacies, architectural elements and petrofacies of the related deposits in a section in southeast of Sarvestan in Fars Province of Iran with a thickness of 2221.45 meters were examined. Microscopically studying thin sections, the petrography and the occurrence of the deposits were determined. In this section, 16 lithofacies, 10 architectural elements and 2 sandstone petrofacies were identified. The lithofacies were divided into two major and minor groups, in which the major lithofacies consist of coarse‐grained (Gh, Gp, Gt and Gm), medium‐grained (Sh, Sp, St, Sl, Sm, Sr and Ss and fine‐grained ones (Fm, Fl and Fsm), and the minor lithofacies were evaporative and mixed silisiclastic‐carbonate. The identified architectural elements are CH, SB, GB, LA, DA, CR, CS, LV, LS, CH (FF) and FF. By combining evidences from facies analysis and architectural elements together, the Aghajari Formation was divided into three parts in which the related sedimentation environments, from top to bottom, are gravel, gravel‐sand and fine‐grained meandering river respectively. There have also been playas and shoreface in the lower part. Based on petrography, the sandstones of this formation were classified into two groups: litharenite and sublitharenite. The origin of these deposits (sandstones) was appointed to the recycled orogeny and the source of quartz is low and medium to high metamorphic rank. Using the field evidences, the paleocurrent direction was achieved indicating the direction of the paleocurrent from northwest to southeast at the time of deposition. It is hoped that these data can be used in the interpretation of the basin and reconstruction of the paleogeography in the local and regional scales.

The Late Miocene-Pliocene Aghajari Formation is exposed throughout the Folded Zagros Zone and consists of fluvial sediments. Detailed petrographic studies of sandstone samples from the Aghajari formation contain abundant quartz and lithic grains with subordinate feldspars, accessory amounts of micas. The feldspar content mostly ranges from 0 to 5 %. The abundance of lithic grains shows a wide range of variation (5.9 to 69.8 %). Although the lithics are mainly sedimentary, but fragments of metamorphic rocks are observed. Micas, including both muscovite and biotite, are generally less than 5 % of the total detrital grains. On the basis of the framework composition (point counting), the sandstones are classified as lithic arenite and sublitharenite. The modal analysis data of 75 collected (medium size and well sorted) samples, imply a recycled orogen (quartzose and transitional recycled) tectonic provenance. Moreover, petrographic point count data indicate the sources of quartzs are low-grade and middle to high-grade metamorphic rocks. Also quartz-rich (sedimentary) and granitic/gneissic are parent rocks for the Aghajari Formation sandstones.