مجله پژوهش نفت
پیاپی 107 (مهر و آبان 1398)

The Kangan Formation (Early Triassic) is one of the most important source rocks in the gas fields of the southern Zagros and the northern Persian Gulf. The studied gas field is located in the west of Hormozgan province and is one of the most important gas fields in Iran and the world. In order to evaluate the depositional environment and sedimentary sequences of this formation in the wells, microscopic studies as well as analysis of petrophysical charts, especially gamma-ray log, have been studied which this resulted in the identification of seven microfacies, of which these facies were deposited in four depositional subenvironments as tidal flat, lagoon, mainly shoal and open marine, and two third-order sedimentary sequences with a second-order sequence boundary (correlative conformity), each of which consists of a system tract of TST (often consisting of tidal flat and lagoon facies) and HST (often containing shoal facies) was formed. This study was also carried out with the aim of investigating the quality and expansion of reservoir zones and its relation with sedimentary sequence and depositional environments. In previous studies, the Kangan Formation has been classified into four general zones in terms of petrologic characteristics, but in this research with relying on available digital files from well studies and extending this information in the software space, and finally combining the interpretive information of the existing output charts, including gamma-ray logs, sonic log, density log, effective porosity log, and stratigraphic column with thin sections and sedimentary sequences, Kangan Formation in the well of the field was divided into three general zones in terms of reservoir.

Considering the importance of deep desulfurization of commercial diesels in accordance with the global standards, in this study, the oxidative desulfurization of a commercial diesel of Tehran Oil Refinery using MoO3/γ-Al2O3 catalyst has been fully investigated. The synthesized catalyst has been characterized using FT-IR, SEM, EDS, BET and XRD analyses. The effect of Mo loading and main process variables (temperature, O/S molar ratio, catalyst amount, reaction time and type of extraction solvent) have been investigated. Acetonitrile has been suggested as the most effective solvent. The stability of the catalyst has been evaluated. The evaluation has shown the main effect of other hydrocarbons of the commercial diesel on the catalyst stability in addition to the effect of ODS products and water impurity adsorption on the catalyst surface. The results have indicated a very good catalytic role of MoO3/γ-Al2O3 in ODS of the diesel. Finally, at the optimal process variables, about 90% of sulfur compounds which have been present in the diesel with initial sulfur concentration of 590 ppmw have been removed using one step extraction of sulfones by acetonitrile.

Carbonate formations are typically heterogeneous and anisotropic; hence, dipole sonic logs have great efficiencies in evaluating their geomechanical and petrophysical parameters. In this study, the various uses of DSI logs and processing approaches of its modes are presented as a case study in one of the SW Iranian fields. For this purpose, data from three modes (i.e. 3, 4, and X-dipole) of DSI logs, conventional logs, image log and porosity-permeability core data have been used. Moreover, using the DSI log data, it has been found out that stress state in the studied well is strike slip-normal, and the pore pressure is close to the hydrostatic pressure. In addition, regarding to the wellbore breakouts, the maximum horizontal stress direction is to NE-SW. Moreover, the fast shear wave azimuth is often aligned with the maximum horizontal stress direction. Furthermore, using the DSI log data, energy, traveltime and Dt anisotropies were calculated. The Dt anisotropy increases in fracture and washout zones and traveltime anisotropy which is affected by washouts. In this study, the factors which affect the reflection of the Stoneley waves, and the chevron patterns creation, have been investigated. Also, the most important factor in this case is the wellbore washouts. Finally, it has been found out that the Stoneley permeability has a relatively good correlation with the core permeability.

DME-enhanced water flooding is considered as a novel enhanced oil recovery method. In this method, DME-rich water is injected into an oil reservoir. In addition, upon the contact of DME-rich water with trapped oil in the reservoir, DME partitions between the oleic and the aqueous phase. Due to the partitioning process DME transfers from the aqueous phase into the oleic phase until reaching a thermodynamic equilibrium. Consequently, two zones are generated in the oleic phase: 1- an interface region, which is DME-rich, and 2- the DME-free zone, which is far from the interface. The variation of DME concentration in the oleic phase causes a DME transfer from the DME-rich zone into the DME-free zone due to the molecular diffusion. The DME dissolution in the oleic phase causes an oil swelling process and thus an increase in the saturation of the oleic phase along with oil viscosity reduction. Moreover, both effects improve the oleic phase mobility leading to a more favorable oil displacement efficiency in porous media. The present work demonstrates the feasibility of application of DME-enhanced water flooding in recovery of heavy oils via a 1D modelling study. Therefore, several pieces of work were performed to achieve proper results. First, mass conservation of components was combined with the Darcy equation while using a constant partition coefficient (linear PVT model) to obtain governing fluid flow equations. Then, the system of equations was completed using auxiliary equations and equations were combined to reduce the number of independent variables. Afterwards, equations were numerically solved using a finite difference scheme to find the independent variables, i.e. pressure and saturation of the aqueous phase, and also concentration of DME in the aqueous phase. Numerical modeling results showed that the use of DME-enhanced water flooding improves oil recovery in heavy oil reservoirs. For instance, the DME-enhanced water flooding led to an additional oil recovery of 17 percent of the OIIP on top of water flooding oil recovery. Moreover, results showed the injection of DME-water into the porous media causes the formation of an oil bank and also a reduction in the water cut. Furthermore, it was shown that a part of DME can be recovered at the injection well, and this can affect the project economy positively. Finally, the results showed the potential application of DME in the recovery of heavy oil.

In this report, the amount of emissions of benzene, toluene, ethylbenzene and xylenes (BTEXs) in the exhaust gas of numerous domestic and foreign automobiles including PrideTM, Peugeot 405TM, Thunder (L90) TM, Peugeot 206TM TibaTM, and Mazda 3TM and SamandTM both in the absence and presence of a catalyst, were measured in the Tehran city. To this end, first the BTEXs content of the exhaust gases was absorbed on activated carbon cartridges and then extracted by using solvent system. Finally, the concentration of the extracted pollution was identified and measured through gas chromatography Equipped with a flame ionization detector (GC/FID). The results clearly show that the volume of this emitted pollution of domestic automobiles comparatively is much higher than that of the foreign cars tested (The average BTEX concentration in the exhaust car of the pride vehicle was 13.3 parts per million versus 0.1 parts per million for the Mazda3.). From the domestic cars after PrideTM, Peugeot 405TM had the highest (6.13 parts per million BTEX concentrations in the exhaust), and SamandTM with a catalyzer system (1.49 parts per million BTEX concentrations in the exhaust) had the lowest amounts of the emitted pollutants. Due to the multiplicity of domestic vehicles in comparison with foreign cars in Iran and naturally in Tehran, it is expected that these compounds in the air of Tehran and other large cities will be higher than the permissible ambient air (average annual rate of 5 micrograms per m3). Finally, the results of other investigations confirm this. In addition, the results of this research will provide a meaningful initial assessment for the implementation of complementary research to lead organizations responsible for improving the quality of the environment, fuel suppliers and care companies.

The application of polymers is one of the key techniques in different improved oil recovery (IOR) methods, namely polymer flooding, surfactant-polymer flooding, and alkaline-surfactant-polymer (ASP) flooding. Contact between polymers and surfactants in the reservoir, however, may cause some interactions between the two materials, leading to undesirable changes in their performance. In addition, flooding with polymeric surfactants is an attractive solution to this problem. Moreover, polymeric surfactants, in which hydrophobic groups are attached to hydrophilic polymers, simultaneously exhibit some properties of polymers and surfactants such as increasing the viscosity of solution, reducing the interfacial tension between water and oil, and also changing the wettability of the reservoir rock. In this study, polyacrylamide is hydrolyzed and using a zwitterion hydrophobic group, a new zwitterionic polymeric surfactant is synthesized. FTIR and HNMR identification tests verified the success of the process. The impact of hydrolyzed polyacrylamide (HPAM) and zwitterionic polymeric surfactant on water-oil interfacial tension, fluid viscosity, and shear rate were measured in the presence of CaCl2, MgCl2, K2SO4, and NaCl. Our results show that while HPAM reduced the interfacial tension to 13.65 mN/m, hydrophobically modified zwitterionic polyacrylamide (HMZPAM) reduced interfacial tension to 4.41 mN/m. While in similar conditions Hydrolyzed polyacrylamide reduces the interfacial tension to 13.65 mN/m. In salinity of 10,000 Mg/L, the viscosity of HPAM and HMZPAM were measured as 62 cP and 174 cP respectively. HMZPAM also showed better properties in elevated salt concentrations and shear rates. Finally, at the shear rate of 400 S-1, the apparent viscosity of HPAM and HMZPAM were equal to 0.14 cP and 1.06 cP respectively.

In this paper, natural zeolites of clinoptilolite, ferrierite, and mordenite were chemically modified and used as support of NiMoW catalysts. The NiMoW based catalysts were characterized by XRD, FESEM, and FTIR. In all studied catalysts, according to XRD, NiO exists in small crystallites but XRD peaks attributed to MoO2, MoO3 or WO3 were not observed. FESEM indicted NiMoW-Ferr had small particles with high dispersion and strong interaction. Moreover, lower Si/Al ratio and higher population of metal oxides in NiMoW-Ferr nanocatalyst was confirmed by FTIR. Finally, among studied nanocatalysts, evaluation of synthesized samples in oxidative desulfurization of dibenzothiophene showed NiMoW-Ferr had supreme activity of 92.8% of dibenzothiophene removal in 250 ppm, 0.2 g of catalyst, 60 °C and 60 min reaction time.

The impact of brine salinity and ion composition on wettability alteration of carbonate reservoir has been studied extensively in recent years. In these researches, the effect of salt water without considering the water-soluble amphiphilic compounds of crude oil has been investigated. In this study, the effect of water-soluble amphiphilic compound of crude oil beside ionic composition of MgCl2 and CaCl2 salt, on wettability alteration of oil-wet calcite surface were investigated. In this turn, distilled water and salt water of MgCl2 and CaCl2 with ionic strength of 0.5 molar were contacted to the crude oil for two weeks to be saturated with crude oil amphiphilic compounds. The effect of these compounds on water properties are examined with pH and total organic carbon (TOC) tests. In the next step, the effect of these compounds on wettability alteration of oil-wet calcite surface were investigated with exposing the oil-wet surfaces to the saturated and pure (without contact with crude oil) water samples and measuring the contact angle of oil droplet. The obtained results show that a low amount of acidic and basic compounds of crude oil (with higher portion of acidic compounds) were dissolved in contacted waters. The wettability of both surfaces which exposed to the pure and saturated waters changed toward water-wet. However, the changes in the presence of pure waters are much more than saturated waters. The results reveal that as well as water-soluble amphiphilic compounds the presence of similar rock composition ions in water can prevent the wettability alteration. In this turn, the wettability alteration of surfaces exposed to the CaCl2 salt waters (in both group of waters) were low and in saturated water was lower.

Hydrocarbon sewage and the related environmental problems have an caused urgent need for speedy consideration. At the same time, water purification for essential uses has been an incentive for researchers to separate sewages by microfiltration processes over the recent years. In this study, separation of oil-in-water emulsion by cellulose acetate membrane in microfiltration processes has been investigated experimentally and numerically. In the laboratory section, the permeate flux for pure water and oil-in-water emulsion has been obtained at the same and at different trans-membrane pressures. In the simulation section, the steady-state permeate flux has been predicted by the law of Darcy in the COMSOLv5.3 environment and compared against experimental data. The comparison results have shown that the permeate flux predicted values for feed containing oil droplets under steady-state conditions has had errors of 15% and 35% at operating pressures of 1 and 2 bar, but the error  for pure water has been equal to 5%. the oil-in-water emulsion may be due to not having considered membrane structure, neglecting pore blocking and concentration polarization layer resistances in the Darcy’s equation. By solving mixture equations, mass transfer and  the law of Darcy in the computational domain simultaneously, the effects of various parameters such as cross-flow velocity and trans-membrane pressure on concentration polarization layer thickness and outlet velocities have been analyzed. Finally, when feed cross-flow velocity has increases from 0.1 to 1.1 m/s, the concentration polarization thickness has decreased by 52%, and when trans-membrane pressure has increased from 1 to 2 bars, the maximum velocity of permeate flow increased by almost 190%.

In this study, two oil samples from Asmari and Sarvak reservoirs (well No#23) in Pazanan oil field and one oil sample from Khalij reservoir (well No#1) in Khaviz oil field were subjected to geochemical analyses using Gas Chromatography (GC) and Gas Chromatography Mass-Spectrometry (GC/MS) techniques. Quantitative assessment of the oil components using liquid chromatography method revealed that oil samples have a greater amount of saturated hydrocarbon component than the aromatic and polar. Classification of the crude oil samples based on different components shows that the Asmari and Sarvak reservoir oil in Pazanan oil field and Khalij reservoir oil in Khaviz oil field are paraffinic, mainly paraffinic to paraffinic - naphthenic and paraffinic – naphthenic respectively. The biomarker ratio obtained from C29 Sterane ββ∕(ββ+αα) versus C29 Sterane 20S/(20S+20R) diagram demonstrates that the oil samples were produced at the maximum stage of the oil producing window and have relatively high thermal maturity. The DBT/Phen versus Pr/Ph diagram shows that the Asmari oil samples have been produced from carbonate-shale, and Sarvak and Khlij oil samples have been produced from carbonate-marl source rocks. Also, triangular C27, C28, C29 sterane diagram indicates that the source rocks have been deposited in open marine to parallic environment. Also, oil has been generated from organic matter with type II kerogen as inferred from Pr/nC17 versus Ph/nC18 diagram. The proximity of the Carbon Preference Index (CPI) to the number 1, indicates high maturity level for source rocks. Absence of oleanane biomarker in oil samples suggests that oils be produced from lower-Cretaceous source rocks. Oil-oil correlation using distinctive biomarkers allowed to plot the stellar graph.  Finally, the even/odd ratio of normal alkanes determines that the oil samples from Asmari, Sarvak, and Khalij reservoirs have been produced from a variety source rocks.

In this research, the improved heterojunction of BiFeO3 were synthesized by a facile and cost-effective method, for hydrogen generation through photocatalytic overall water splitting. Moreover, XRD, FTIR, FESEM, PL, and UV-vis were applied to characterize the structural and optical properties of the synthesized samples. The photocatalytic reactions were carried out in a quartz photoreactor with effective volume of 160 mL exposed to UV irradiation. In spite of the fact that the perovskite type BiFeO3 micro cube, g-C3N4 nanoparticles and ZnS nanosheets were not capable for hydrogen generation significantly, the composite samples showed the favorable photocatalytic activity. The highest rate of hydrogen production was about 160 μmol.h-1.g-1, and it was obtained by optimal sample.

based drilling fluid, rheology modifier and enhanced oil recovery. Moreover, structure and microstructure of these polymers are of important in above-mentioned applications. Acrylamide homopolymer and acrylamide/styrene copolymer were synthetized using micellar polymerization for application in the water-based drilling fluid. FTIR, NMR and some theoretical calculations were used to characterize (micro)structure of the polymers. In addition, conversion was obtained using gravimetric method. Ubbelohde viscometer was used to evaluate viscosity- average molecular weight. Apparent viscosity was measured by Brookfield viscometer. Synthesized polymers were used in the water- based drilling fluids with three different concentrations and rheological and fluid loss properties were evaluated before and after hot rolling at 120 °C for 16 h. Moreover, FTIR and NMR results showed successful synthesis of the homo- and copolymers with high conversions. Average hydrophobic styrene block length was calculated by theoretical method to be 3. Results showed that both conversion and molecular weight values were higher in the case of synthetized homopolymer. It was attributed to increase in the possibility of chain transfer to surfactant in the micellar copolymerization reactions. Results showed that despite higher molecular weight in the acrylamide homopolymer case, viscosities of the acrylamide/styrene copolymer aqueous solutions were better in similar concentrations. It was attributed to the hydrophobic association between styrene units. Finally, results showed that both homo- and copolymer caused an improvement in the rheology and fluid loss properties of the water- based drilling fluid. Although rheological properties were reduced after hot rolling or in the presence of salt in the drilling fluids, drilling fluids prepared with acrylamide/styrene copolymer showed more ability to preserve their rheological properties due to the formation of physical network resulting from the hydrophobic associations.