The Middle Jurassic scilisiclastic doposit has a good exposure in the East of the Binaload Zone and composed of conglomerate, sandstone and high amounts of fine grained sediments. The lower and upper boundaries of section are sharp respectively with Mashhad phylite and limestone. In this study lithofacies analysis in order to interpretation depositional environment and the origin of tectonic setting of Jurassic silisiclastic deposits in Binaload Zone were investigated in Baze hoz section, soth of Mashhad. Relying on the facies characteristics and stratal geometries the silisiclastic succession are divided into 10 lithofacies in the 160 meter thick. lithofacies are classified into 4 categories including coarse grain (Gcm, Gmm, Gh, Gp), medium grain (Sh, Sr, Sm), fine grain (Fl, Fm) and biochemical (C). Based on the following evidence, the Jurassic silisiclasic sediments have been deposited in Delta river system: Sedimentary facies: coarsening upward deposit, coal deposite, Leave fossils, syneresis crack and unidirectional sedimentary structures such as ripplemark, cross bedding, lack of Bi-directional structure. Petrographic studies led to the identification 6 petrofacies conglomerate and sandstone. Plotted data on Qt, F, L diagram, indicate recycled orogene for this deposits. Also plot data on Basu and Q, F, L diagrams, respectively shows low to medium grade metamorphic and hiumid climatic condition for sandstones of Jurassic sediments for these deposits at the time of formation. According to Turan and Iran clash pages and closing the Paleo-Tethys Sea in NE Iran Jurassic sediments in the study area composed of erosion of upland areas. These results indicate a wet weather conditions.

Detail description of texture and composition of 880 samples from Upper Red Formation sandstones in central part of its basin directed to identification of major petrofacies. On this basis, 17 petrofacies in the south and 16 petrofacies in the north successions were distinguished and described comprehensively. Major components variation of petrofacies through measured sections is used for analysis of source region and diagenetic history. A distinct diversity in the source rocks composition is indicated from component variation analysis. Major characteristic of the petrofacies and detrital mode analysis of sandstones indicate deposition in a back arc setting in which block faulting controlled accommodation development. Active tectonic setting of the basin is responsible for textural properties of the petrofacies. Composition of the petrofacies and its variation through measured sections was mainly controlled by source rocks characteristics. Diagenetic features of the petrofacies are significant enough to necessitate thorough diagenetic study prior to and depositional and/or provenance investigation

The Middle Jurassic siliciclastic sediments are exposed in the Binalood Mountain ranges in NE Iran. They are composed of conglomerate and sandstone with minor amounts of fine grain siliciclastic sediments. Based on Field observations, 13 lithofacies, including Gmm, Gcm, Gmg, Gp, Gh (gravelly), Sh, Sm, Sr, Sp, St, Se, Sl (sandy) and Fl (muddy) and five architectural elements (SG, GB, CH, SB and FF) have been identified. These lithofacies and architectural elements indicated that the Middle Jurassic siliciclastic sediments may have been deposited in gravelly braided type fluvial depositional systems. Petrographic studies led to recognition of two petrofacies, including conglomerates (monomictic and polymictic) and sandstones (quartzarenite, sublitharenite and litharenite) Sandstone petrofacies analysis show that these sediments derived from recycled orogenic tectonic setting.The recycled orogenic provenance in northeast Iran has formed between Turan and Iran plates during closure of Paleo-Tethys (Late Triassic time). This closure created a foreland basin and the Middle Jurassic siliciclastic sediments were deposited in this basin. These informations will help in a better understanding the tectonic setting in NE Iran.

Clastic deposits of the Faraghan Formation (Late Permian, Sakmarian) are present in different outcrops in the Zagros area and some wells in the Persian Gulf Basin. The presence of these clastics represents the existence of an extended clastic system on the north-east of the Arabian plate. The Faraghan Formation unconformably overlies Zakeen sandstone (Devonian) and grades upward into Dalan carbonate (Upper Permian). To study the Faraghan Formation some thin sections were prepared from cuttings of some wells in the central part of the Persian Gulf and then they were studied. Results show of this study that the Faraghan Formation consists of quartz arenite, sandy siltstone and sandy claystone petrofacies and carbonate mudstone, bioclast wackestone and bioclast packstone microfacies. Based on sedimentary characteristics and spatial relationships between the petrofacies, this formation was deposited on a linear shoreface environment (floodplain, shoreface and offshore sub-environments). Main diagenetic processes consist of compaction, dissolution, cementation, neomorphism, sericitization and dolomitization. Heterogeneity of the Faraghan Formation lithology and variety of environmental conditions and diagenetic features make this formation a good candidate for hydrocarbon reservoir studies.

Lithofacies analysis and interpretation of architectural elements of Oligocene silisiclastic deposits in Binaload Zone were investigated in Baghshan-Gach area, north of Neyshabour. This study led to identification of 14 lithofacies and 4 architectural elements in the sequence of 150 meter thick. Lithofacies are classified into three categories including coarse grain (Gmg, Gcm, Gmm, Gh, Gp and Gt), medium grain (Sh, Sp, St, Sr, Sm and Sl), and fine grain (Fl, Fm). The architectural elements are CH, SB, LV and SG. It is interpreted that Oligocene silisiclasic sediments have been deposited in braided river system, based on lithofacies analysis and architectural elements. Petrofacies analysis indicates that these rocks had oroigin from the magmatic arc and deposited under arid climatic condition. paleocurrent analysis represents that the river was flowing from NE to SW direction.

The present study investigates lithofacies and petrofacies in details and also reconstructs the depositional environment of the Paleocene siliciclastics of the Kerman Formation located in NE Central Iran, which is composed significantly of polymictic conglomerate bodies intercalated with some minor sandstone beds. Through detailed sedimentological studies (e.g., dominant grain size, degree of clast rounding and sorting, texture, and stratification), five lithofacies have been identified: clast-supported massive conglomerate (Gcm), matrix-supported massive conglomerate (Gmm), horizontally stratified conglomerate (Gh), horizontally bedded sandstone (Sh), and massive sandstone (Sm). Petrographic analysis revealed three petrofacies composed of petromict conglomerate, volcanic arenite, and feldspathic litharenite; gravels chiefly made up of basalt and andesite, as well as fewer limestone and agglomerated tuff. The lithofacies associations are related to sedimentary gravity flow (SG) and channel-fill sandstone bodies (CH) deposited in alluvial fan and braided fluvial systems. This research provides important insights into the sedimentary environments of the Kerman Formation.

In this study, depositional environment of the Faraghan Formation has been interpreted in Darang #1 well. Petrography studies of the cuttings led to identification of five petrofacies that according to their abundance include: lithic arenite, quartz arenite, greywacke, hybrid arenite and mudstone. More than 90 percent of this succession is composed of lithic arenites with volcanic rock fragments and fine grained quartz arenite. In this study, we combined petrofacies analysis and gamma ray logs to reconstruct sedimentary environment of this formation. According to our data, six sedimentary facies has been identified. Therefore the Faraghan Formation has been deposited in the upstream parts of delta plain to delta front in the lower part and shallow marine in the upper part of the succession which grades upward into a carbonate shelf deposit of Dalan Formation.

The goal of this study was to use petrographic and other sedimentary features to experimentally interpret depositional environment of Faraghan Formation (Lower Permian). Golshan Gas Field is located at about 180 km southeast of Bushehr between South Pars and North Pars and Ferdowsi Field. In this study, 130 thin sections of cutting belonging to petrofacies and facies analyses have been studied, and 8 petrofacies and 5 carbonate facies were identified in the well. Textural maturity of sediments, such as well sorted and rounded quartz grains, show that the Faraghan Formation was deposited in coastal and shallow marine environments. The identified facieses has been deposited in Sabkha, estuarine, foreshore, shoreface and offshore subenvironments.

Evaluation of hydrocarbon saturation is very important in oil reservoirs calculations. Archie equations are the basic relations for evaluating rock saturation. The coefficients of these equations are determined by laboratory experiments. Archie presented these coefficients, which are constants for sandstone. However, since carbonate rocks show drastic variations in texture and pore type, Archie coefficients, which are more sensitive to pore type, should be determined for different types of carbonate rocks. Uncertainty in these coefficients causes many errors in saturation evaluation especially in the determination of the volume of oil in place. Cementation exponent is the main factor, which causes error in determining saturation. In this study Archie parameters (a and m) are determined in the laboratory for various petrofacies based on petrographic studies and CT-scan images. Due to high dependence of seismic wave velocity on pore shape in carbonate rocks, petrofacieses were also determined by using wave velocity deviation logs. Subsequently, Archie parameters were determined for each petrofacies. The results showed that cementation exponent increases with increasing velocity deviation values. It is concluded that correlation coefficient in different petrofacies obtained from velocity deviation logs is comparatively higher than the same for petrographic study. Considering the fact that petrophysical data are more accessible than the core-based petrography data, the method presented in this study seems to be a more useful approach in determining Archie coefficients.

Petrofacies analyses of Asmari Formation carried out on thin sections, obtained from oil wells of number 11, 85 and 89 in Ahvaz oil field, show 5 carbonate-evaporate microfacies associations (related to a carbonate ramp) and 2 siliciclastic petrofacies. Point counting data plotted on Qt93.34 F4.10 Lt2.59 Qm86.75 F4.10 L9.15 diagrams imply the cratonic and recycled orogen tectonic provenance. Furthermore, these results and the other petrographic evidences indicate a source rock with sedimentary and low to medium degree metamorphic composition for Ahvaz sandstone. Combining the obtained results with global sea level changes, variation in sediment supply and regional and local tectonic evolution, assisted us to recognize 6 evolutionary stages for Samara basin. In fact, Asmari Formation deposited in a carbonate-evaporate ramp with different amount of sediment influx through the time.