In this paper, electrofacies in ASMARI formation in Gachsaran oil field were determined using multi resolution graph-based clustering method (MRGC), This oil field is located in the southwest of Iran. The determination of electrofacies in this field is performed by using the combination of image logs and other well logs obtained from one of the wells in the field. In order to obtain an exact evaluation, environmental corrections were performed on the logs. The comparison of lithology results, shale volume, porosity, and water saturation with determined facies, using clustering analysis by applying image logs, shows acceptable agreement between the obtained electrofacies and the corresponding lithological results, and represents a new categorization of the formation. This new categorization has reservoir aspects; the variations of the petrophysical properties in each facies are unique and the variations of these indices are determined in individual facies. Moreover, by considering the span of the identified electrofacies, the reservoir and non-reservoir layers are distinguished based on the performed zoning.

The study of electrofacies is a useful petrophysical analysis method in oil-well exploration and evaluation of reservoir characteristics, particularly when the wells lack actual geological data. In order to interpret the electrical facies of the Bangestan group in Ghalea-Nai oil field, three surface sections were chosen and studied for petrographic and petrophysical features. This resulted in the identification of seven microfacies including: wackstone-wackstone, wackstone, sponge (spongy) spicule oligosteginid, bioclast wackstone-packstone, benthic foraminifera rudist wackstone-packstone, peloidal bioclast packstone-grainstone, peloidal microbioclast packstone-wackstone, pelagic foraminifera wackstone-packstone and oligosteginid wackstone-packstone. Porosity percentages and high quality lithofacies of the Bangestan reservoir were identified by "Geolog software", using petrographic data including: neutron, sonic (sound) and resistivity logs on predominant lithology. Based on these results, and also using of lithology determinant intersecting logs, the major identified lithologies are: limestone, dolomite and limestone with minor amounts of dolomite. Based on these results the identified porosity percentages varies between well. No.3 with 18% (the highest porosity), well No.2. with about 10% and well No.4 with 6% (the lowest porosity). The sedimentary microfacies conforming to high quality reservoir were recognized based on electrical investigation and using of MRGC clustering method. This microfacies which belong to Ilam-Sarvak formations are represented by bioclast peloidal packstone-grainstone and sponge spicule oligosteginid packstone-wackstone, respectively.

In this paper, an ultra-broad bandwidth, low noise, and high gain-flatness CMOS distributed amplifier (CMOS-DA) based on a novel gain-cell is presented. The new gain-cell that enhances the output impedance as a result the gain substantially over conventional RGC is the improved version of Regulated Cascode Configuration (RGC). The new gain-cell based CMOS-DA is analyzed and simulated in the standard 0.13 mm-CMOS technology. The simulated results of the proposed CMOS-DA are included 14.2 dB average power gain with less than±0.5 dB fluctuations over the 3-dB bandwidth of 23 GHz while the simulated input and output return losses (S11 and S22) are less than -10 dB. The IIP3 and input referred 1-dB compression point are simulated at 15 GHz and achieved+8 dBm and -6.34 dBm, respectively. The average noise figure (NF) in the entire interest band has a low value of 3.65 dB, and the DC power dissipation is only 45.63 mW. The CMOS-DA is powered by 0.9 V supply voltage. Additionally, the effect of parameters variation on performance specifications of the proposed design is simulated by Monte Carlo simulations to ensure that the desired accuracy is yielded.

The permeability of reservoir parameters is important in the calculation and modeling reservoir plays a role. Measured directly via cores taken from the reservoir layer can be achieved. But due to the limited amount of core taken in a field and laboratory methods as well as high cost; use indirect methods to determine the wells without core permeability is great value. In this study, using clustering methods using petro physical logs permeability values were measured and analyzed. For this purpose, petro physical logs Ilam Formation selection of 8 wells and addition of data measured in vitro permeability 3-ring is used to compare the results. Log permeability effective porosity in the well using the parameters A with the core permeability data, estimates and then check the accuracy of estimates, calculations also took place in other fields of study. In the next step, using clustering method, was estimated permeability. Then the results with experimental data and correlation coefficient, the best method is introduced.

Primary objective of this project is introducing the best clustering method to determine the Electrofacies in without core wells. Electrofacies concept in fact is a deterministic or analytical method for clustering petrophysical well-log data. They can indicate changes in geological features or reservoir. Electrofacies is defined based on clustered data, and placement of logs and similar data in the same group which is differentiated from other groups. In this study, different clustering methods were studied and compared with each other. Among these methods, the best method was introduced as MRGC method. For this purpose, the Geolog software was employed to use four clustering methods including Multi Resolution Graph based Clustering method (MRGC), Ascendant hierarchical method (AHC), Self-organizing neural networks method (SOM) and dynamic clustering method (DYNCLUST) to determine the reservoir electrofacies in Salman 2S-05 well. Thus, 9 electrofacies were determined in each clustering. Electrofacies produced by the best clustering method (MRGC), using well logs including GR, DT, RHOB and NPHI. They were sorted based on reservoir quality from good to poor. This study was performed on the Arab member. Arab member is the main reservoir in Salman field, and the highest oil production (70%) from this formation has been reported.

The best reservoir intervals, i.e. pay zone in a well interval, include some sections of a reservoir formation with the highest hydrocarbon volume and the lowest water volume. In the present study, in the interval of a carbonate gas reservoir, pay zones were determined using two completely different methods. In the first method of pay zone determination, i.e. cut-off method, intervals were specified by determining cut off for two petro-physical parameters of porosity (PHIE) and effective water satu- ration (SWE). In the second method, namely clustering method, the zones were determined by combining clustering log data and new method of multi-reference graph cut (MRGC). Based on National Iranian Oil Company (NIOC) standards, in the first method, cut offs were considered 3 and 55 for PHIE and SWE of a gas reservoir respectively. In the clustering method, two models were applied; in one model, raw data were considered, while in the other one the evaluated logs were taken into account. With respect to the accumulation of hydrocarbon in the isolated facies in the two models, the model with evaluated logs showed higher accuracy. Finally, the accuracy of determining pay zones in the two models was investigated and compared. Given that the two methods were completely different, the accuracy of both methods to determine pay zones was observed at a very high level; the two methods were also highly consistent. As a result, in addition to cut-off method, clustering method can also be used to determine pay zones.

Fahliyan limestone formation belongs to the Khami group، one of the oil and gas reservoir rocks in the southwest of Iran. This study is divided in two parts; in the first part، the reservoir characteristics of Fahliyan formation were evaluated in the well studied by taking into account the conditions of falling and gas effect on reading charts. Accordingly، lithology، by using neutron-density and M-N plots، was diagnosed to be limestone plus some mineral dolomite; the average of petrophysical parameters including effective porosity (PHIE)، effective water saturation (SWE)، and hydrocarbons in flashed zone and virgin zone were calculated to be 2.1، 56، 0.4، and 1.1% respectively. The pay zones and the average of petrophysical parameters in these zones by determining cut-offs for the two parameters of effective porosity (PHIE >= 2.2) and effective water saturation (SWE<= 55) were calculated. In the second part، the reservoir facies and non-reservoir facies were grouped by MRGC method and the sequence was partitioned into two reservoir and non-reservoir facies; the average of petrophysical parameters was compared between the two facies. There was good agreement between the specified reservoir facies and production zones in the total sequence evaluated. Finally، the reservoir main parts were identified for extracting gas and reservoir zoning was carried out in the interval studied.

Electro-facies analysis is a sure method in clustering petrophysical logs analysis that can well indicates the changes of geologic charactereristics of the different lithostratigraphic units as well. Petrographic studies of 120 prepared thin sections of the upper parts of the Sarvak Formation in studied oilfield, Southwestern Iran, has resulted in definition of 6 microfacies sedimentary types. These data suggested that the middle Creataceous sediments in the studied area were predominantly deposited in two subenviornments of patch organic barrier and lagoon corresponding to inner and shallow a homoclinal ramp. In addition, using petrophysical logs in the studied well, 10 electrical facies were determined. By analyzing the data petrophysical in Geolog software, 10 electerical facies were optimized and then their number was reduced to six. According to good adaptation of optimized electerical facies with sedimentary microfacies, we would generalized obtained dresults to all parts of the Sarvak Formation. Study of porosity changes in the electrical diagrams such as CGR corrected Gamma, and sonic curves in mentioned well, indicated a significant reduction in facies porosity of 1 to 6. In addition, the results showed that the reservoir quality reductionin studied microfacies is corresponded to Bioclastic Rudist debris floatstone/ Rudstone, Benthic foraminifera Rudist debris wackestone / packstone, Benthic Foraminifera peloid Grainstone/Packstone, with High diversity benthic foraminifera wackestone / packstone, Peloid bioclastic wackestone /packstone with Low diversity benthic Foraminifera and Mudestone/Wackestone, respectively. In this study, we concluded that comparison and correlation sedimentary facies with electric microfacies provide an efficient method to study the quality of the hydrocarbon reservoir system that especially can be used in other wells with no core.