Journal of Petroleum Science and Technology
Volume:3 Issue: 2, Autumn 2013

Alkyl imidazolines have been reportedly used in a wide range of industrial formulations with different applications. Ethoxylated alkyl imidazolines with appropriate ethoxylation degrees can be used as antioxidants and retarders in the formation of peroxides resulting from oxidation in hydrocarbon media. In this work، ethoxylated imidazolines were shown to be more effective in hydrocarbon media in comparison with reference antioxidants. According to the experimental results، ethoxylated alkyl imidazolines (12 moles EO)، as an antioxidant، were twice as efficient as zinc dialkyldithiophosphoric acid (ZDDP).

Epoxy powder coatings containing zinc aluminum phosphate (ZAP) and zinc phosphate (ZP)، which are the 2nd and 1st generation of phosphate-based pigments respectively، were applied to the surface of mild steel sheets. The anticorrosive performances of the coated samples were studied using electrochemical impedance spectroscopy (EIS). Cathodic disbonding resistance and the adhesion performance of the two coating systems were measured by cathodic delamination and pull-off test respectively. The charge transfer resistance and double layer capacitance obtained from EIS revealed the greater anticorrosive performance of the coating modified by zinc aluminum phosphate compared to the one treated with zinc phosphate. While an electrolyte diffuses in the organic coating، phosphate pigments dissolve and make a passive layer on the surface of mild steel. Due to the more solubility of ZAP in comparison with ZP، the cathodic desbonding resistance and adhesion of the epoxy powder coating containing ZAP were greater than those of ZP-loaded powder coating. The results show that the anticorrosive performance of the epoxy powder coating containing ZAP is better than that of the epoxy powder coating modified with ZP.

This paper is concerned with asphaltene deposition in fluid flowing through pipelines. Brownian diffusion and drag، gravitational، thermophoresis، buoyancy، and shear removal are considered as possible mechanisms in the asphaltene deposition process. The thermo-physical properties of the fluid were obtained from Iranian oil fields. A model was used in the pipeline deposition modeling to predict the asphaltene deposition rates under flow conditions. The effects of particle size، temperature gradient، and fluid velocity were studied on asphaltene deposition rate. The results showed that، among the above-mentioned mechanisms، the gravitational and thermophoresis forces played a significant role in the formation of the deposit under the flow conditions. To verify the model، some predictions were compared with the available aerosol deposition data in the literature.

1 Center for Separation Processes Modeling and Nano-Computations، School of Chemical Engineering، College of Engineering، University of Tehran، P. O. Box 11365-4563، Tehran، Iran2 Oil and Gas Center of Excellence، University of Tehran، Tehran، IranABSTRACTIn this work، the adsorption of the anionic dye، Congo red (CR)، from aqueous solution by using tea waste (TW) has been carried out at 30 °C. The equilibrium sorption isotherms and kinetics were investigated. The equilibrium adsorption was studied by the Langmuir and Freundlich models of adsorption. The experimental results manifested that the Langmuir isotherm was the best model for the adsorption of CR by TW and implied the monolayer adsorption of CR on TW with the adsorption capacity of 40. 6 mg/g at 30 °C. The kinetic data resulted from batch experiments were analyzed using pseudo-first-order and pseudo-second-order models. It was found that pseudo-second-order model provided the best fit for the experimental data (R2>0. 99). The results illustrated that both silica and Fe2O3 nanoparticles increased the adsorption of CR on TW by about 5% and 10% at 30 °C، respectively. The results suggested that TW should be a potential low-cost adsorbent for the removal of CR from aqueous solution.

In this study، tea waste (TW) is employed for the removal of Congo red (CR) from aqueous solutions in a fixed-bed column at 30 °C. The breakthrough curves of the adsorption process of CR on TW at three different flow rates are determined. The results revealed that the breakthrough curves were dependent on flow rates in a manner in which a lower flow rate was in favor of the CR adsorption in the column-mode process. As the flow rate increased from 4. 6 to 6. 6 mL/min، the amount of dye uptake capacity decreased from 1. 78 to 1. 53 mg/g. The effect of the presence of Fe2O3 on the adsorption of CR on TW is also studied at 30 °C. The results showed that the presence of nanoparticles increased the adsorption uptake of CR by about 32%. Moreover، four novel models are developed for the prediction of the breakthrough curves resulted from the experimental data. The results of the models were in good agreement with experimental data (R2>0. 99). The statistical parameters confirm the suitability of the models.

The narrow operating window between pore pressure and fracture pressure makes drilling difficult in some operations. A feasibility study of managed pressure drilling (MPD) is carried out on Iran Darquain oil field. The previous wells drilled in this field showed that mud returns were lost during drilling Gadvan formation. The present work addresses this problem by means of surface back pressure application in Darquain oil field. The methodology employed in this study is based on hydraulic analysis calculations and comparative drilling operation pressures. The DZxION MPD software performs hydraulic analysis using the API RP 13D rheological model and calculates the annular pressure drop to compare the pressures and the required back pressure، if needed. Using a mud weight of 14. 31 ppg and exerting 100 psi static back pressure، the wellbore pressure profile got slightly overbalanced. When the mud pumps are in service، no back pressure is required. The problem is resolved and no kick or loss is observed using a MW of 14. 31 ppg and a static back pressure of 100 psi. As a result، the managed pressure drilling technology is useful in Iran Darquian oil field through using a lower mud weight in order to overcome the circulation loss in Sarvak formation. This study is based on hydraulic analysis calculations and comparing the drilling operation pressures in Darquain oil field. For analyzing the pressure regimes throughout the well، DZxION managed pressure drilling software performs hydraulic analysis. This software calculates annular pressure drop and equivalent circulating density to compare the pressures and required back pressure، if needed. By using this method to drill the well، some advantages were gained: the mud weights used to drill the well، the number of casing strings، and the number of changing mud weights were reduced.

The biodesulfurization (BDS) of sulfur compounds in fossil fuels is a process to reduce sulfur dioxide emissions that cause environmental pollution. Gordonia alkanivorans RIPI90A is able to convert dibenzothiophene، an organic sulfur compound in petroleum، to 2-hydroxybiphenyl (2-HBP) in 4S pathway. In this study، (DBT)، DszA and DszB، DBT sulfone monooxygenase، and desulfinase were respectively isolated from G. alkanivorans RIPI90A. PCR amplified fragments were obtained by using primers designed based on known sequences from G. alkanivorans RIPI90A. They are identified as dszA and dszB and have shown high similarity compared to Rhodococcus erythropolis IGTS8 (88% for dszA and 88% for dszB). Subsequently، dszA and dszB genes were expressed under the control of T7 promoter in Escherichia coli. The recombinant proteins were purified to achieve homogeneity using Ni-agarose column chromatography. The molecular mass of the purified DszA and DszB were determined to be 51. 9 and 39. 2 kDa respectively by using SDS-polyacrylamide gel electrophoresis. DszA showed a Km of 0. 14±0. 005 mM and a maximal velocity of 0. 004±0. 0004 mM/min. DszB showed a wide substrate range in a way that all aromatic sulfonates compounds acted as its substrate; as it seemed the active site was suitable for the sulfonated aromatic rings. The Km and Vmax values of DszB were calculated to be 1. 81±0. 02 mM and 6. 55 ± 0. 005 µM/min respectively using 4-Amino-3-hydroxy-naphthalene-sulfonic acid as a substrate.

A typical Iranian carbonate matrix block surrounded by an open fracture was modeled in order to understand the fracture-matrix interaction and realize how to model the interaction best. The modeling was carried out by using a fine-scaled Eclipse model in the single porosity mode (the fractures were explicitly modeled). The model was extended to a stack of 6 matrix blocks to understand block-to-block interaction under both water and gas injection scenarios. The results and conclusions obtained from the single porosity single block and 6-block model were used in order to optimize the full field model. The simulation results showed that gas injection worked as a major recovery mechanism for medium and good rock types at all block heights and for poor rock type with block heights of more than 2 meters. The oil recovery results were in the same range for the single and six-stack block model، but the delay of oil recovery by gas gravity drainage is clearly seen in the six-stack block results indicating a period of at least 8-10 years required for reaching ultimate oil recovery for typical block heights. The water injection simulations showed that water imbibes drained the matrix block in a short time dependent on water front advancement in the fracture system surrounding the block. From the simulation results، it was concluded that the water imbibition process was a fast recovery mechanism for all block heights dependent on injection rate and fracture volume which had to be flooded to achieve full recovery of the block. The expected recovery factor of drained oil to initial oil in place after water injection was in the range of 15-35 % for poor to good rock types and different block sizes in the range of 1-5 meters. The results were highly influenced by wettability conditions in the reservoir.