The Euphrates Formation (Lower-early middle Miocene) shallow water carbonates, western Iraq was studied in order to determine its microfacies and depositional environment. According to the benthic foraminiferal assemblage along with other skeletal and non-skeletal components, Fourteen microfacies associations types (F1-F14) are recorded and distributed as: Lime mudstone, miliolids wackestone, alveolinids wackestone, echinoids wackestone, bioclastic packstone, peliods packstone, miliolids packstone, peneroplids packstone, rotaliids packstone, miliolids grainstone, peliods grainstone, ooids grainstone, miliolids-peneroplids grainstone, and peneroplids grainstone that were deposited in three facies belts, restricted marine, shoal, and open marine environments. Based on field observations, microfacies analysis and sequence stratigraphic concepts, the Lower Miocene successions is represented by four order cycles (A, B, C and D) they are mostly asymmetrical showing slightly lateral variation in thickness and symmetry. These cycles represent a succession episode of sea level rises and stillstands. The nature of these cycles reflects variation in the relative sea level resulted from eustatic and tectonic subsidence. Cycle A is underlain by Anah Formation, while cycle C is overlain by SB1 Fatha Formation. According to sequence development, the study area shows low rate of subsidence and the major controlling factor that effect is eustatic sea level fluctuation.

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Geochemical  and Palynological  analysis were carried out to assess hydrocarbon potential     and  palaeoenvironmental deposition for  (27) core and cutting rock samples recovered from selected oil exploratory wells , Makhul-2 (Mk-2),Qarachuq-1 (Qc-1) and Qarachuq-2(Qc-2), TaqTaq-1(Taq-1), Butmah-15 (Bm-15), Ajeel-8 (Aj-8)and Jabal kand( Jk -1) ,encountered from Butmah Formation ( Lower-Middle Liassic) ,  Sargelu Formation (Middle Jurassic )  and Naokelekan Formation  (upper Jurassic ) .The value of palynological analyses in the undertaken study is to resolve stratigraphic and palaeoenvironmental consequences of Jurassic Period in Iraq  , thus the  profuse of plant cuticle   of translucent phytoclast in the  basin of deposition  refers  to proximal deposi tional environment due to their specific gravity of this type of plant cuticle , whereas the  opaque organic matter produced either from highly oxidized environment or from forest fire residues could refer  due to its light specific gravity to distal depositional environment that this type could transported far from the continents toward the aquatic environment . Recurring Type A Amorphous kerogen indicates Oil –Prone beside various amorphous types (B, C, D) within Zagros Fold Belt. The specified palynomorphs recovered from palynological analysis declared so many indications to   determine the potentiality of source rocks .Almost all slides shows spores and pollen, phytoclasts and amorphous organic matter. Extracted resins and pigments are indicating toxic environment of type II-III kerogen that generates oil with subordinate gas.Geochemical analysis can aid also the undertaken study by determination the Terrestrial origin and kerogen type II-III .Previously proved that all crude oils within this sub- basin is belong to family A (sourced from Middle Jurassic Sargelu Formation) nearby local   basins of family B (sourced from U. Triassic Kurra chine,   and Rhaetic Baluti Shale Formation). Jurassic Period is considered as a generative hydrocarbon rock unit by means of both optical and chemical approaches definitely in the Great Kirkuk region and surrounding areas in North Iraq. Meanwhile the current studies focused on the western desert as promising reservoirs related with hydrocarbon pathways from Mesopotamian Basin.