Iranian Journal of Oil & Gas Science and Technology
Volume:6 Issue: 3, Summer 2017

This research reported a new method of removal of Pb� water by using a nano zero valent iron (nZVI) assisted ultrasonic wave. At first, nZVI was synthesized by an ultrasound assisted method. Particles morphology and surface composition were characterized by FESEM, XRD, and EDX. The XRD patterns showed that the crystallinity of the nZVI prepared using ultrasonic conditions was higher than the conventional method. According to the EDX pattern, 67% of particle composition was nZVI. The synthesized nanoparticles were then utilized as a Fenton-like catalyst for the removal of Pb� water using an ultrasound assisted method. In the present study, ultrasound power, temperature effects, nZVI, and reaction time were optimized. From the studies, it has been observed that removal does not increase indefinitely with an increase in ultrasound power, but it instead reaches an optimum value and decreases with a further increase in the ultrasound power. The removal of Pb򚒭 with increasing temperature, nZVI, and H2O2 concentration. The result indicated that the efficiency of hydrocarbon removal by this novel method was 97.87%.

Hydrochloric acidizing is a routine operation in oil fields to reduce the mechanical skin. In this paper, practical acidizing in a typical carbonate oil reservoir located in the southwest of Iran is practiced, which shows an unexpected improvement after acidizing. To understand the acidizing effect on reservoir rock, the formation rock is analyzed on different scales. An acidizing laboratory test is also carried out on formation core samples to understand the acidizing performance. The results show that the main feature of this reservoir is its dominated secondary porosity and its special pattern of distribution. Practically, this porosity percolation has caused high mechanical skin during drilling and a large productivity improvement after acidizing. The acidizing increased the ultimate recovery of the reservoir with existing wells and prolonged the production plateau.

Gas-condensate reservoirs contain hydrocarbon fluids with characteristics between oil and gas reservoirs and a high gas-liquid ratio. Due to the large gas-liquid ratio, wellhead choke calculations using the empirical equations such as Gilbert may contain considerable error. In this study, using drill stem test (DST) data of a gas-condensate reservoir, coefficients of Gilbert equation was modified; 26.7% of DST data has uncertainty. In these data, due to a problem of flow transmitter, the water flow rate is recorded equal to zero. This makes the mean absolute error of 5% in the measuring of total liquid phase flow rate. Because of uncertainty in the water flow rate in some DST data, the coefficients were optimized for two sets of data to investigate the effect of water flow rate on the calculations. The first dataset was the complete set of DST data, and, in the second, data were filtered with the elimination of uncertain data. The regression results showed that the whole data have a mean absolute error of 5.1%. For this regression, the uncertain data had a mean absolute error of 8.6%, while the error of the remaining data was 3.9%. In this case, for 38% of uncertain data, the mean absolute error was more than 10% indicating that these data are the major factor of the error. Mean absolute error for the filtered dataset was 3.0%. Error reduction was due to the elimination of data with uncertainty. In this case, 3% of the total data had a mean absolute error of more than 10%. In other words, 5% error of the liquid phase flow measurement that includes 26.7% of data caused an increase of 2.1% in the error of calculations. This showed that the elimination of uncertain data causes a remarkable reduction in error. To study the effect of temperature on choke calculations, wellhead temperature was considered as a variable in the Gilbert equation form. The regression results showed that the mean absolute error of 3.0% does not change, and the wellhead temperature has no considerable effect on the choke calculation accuracy.

Gas injection into carbonate formations is one of the most important activities to protect oil reserves that can guarantee a steady production. On-time injection of enough gas can result in the recovery of billions barrels of oil. In addition, it can preserve a huge amount of gas for the next generations. If the reservoir depth is shallow, or the reservoir fluid has a little amount of intermediate components, the flooding of rich gases is highly recommended. In the designing of a miscible injection process, firstly the minimum miscibility pressure should be measured or determined analytically. In this study, first the PVTi software is implemented to evaluate the miscibility of different injected gas, including carbon dioxide, nitrogen, methane, and different proportion of hydrocarbon gases. Subsequently, E-300 software is used to predict the recovery of the gas injection into the formation under study from one of the Iranian carbonate onshore fields. The investigation of the optimum injection rate as well as finding the proper layer of injection is investigated in details. The results show that the CO2 flooding after a long natural production period result in higher efficiency than the miscible injection of methane at the early stage of production.

In this research, the reactive absorption of carbon dioxide in an aqueous solution of NH3, H2O, and NaOH has experimentally been investigated. The experiments were carried out in an absorption pilot plant in different operational conditions. The composition and temperature of both gas and liquid phases were obtained during the column height. The concentration of molecular and ionic species in the liquid phase was calculated using the principles of electrolyte and Pitzer model. In the experiments, the effect of sodium hydroxide concentration on carbon dioxide absorption was considered. The results revealed that the concentrations of ionic and molecular species in the liquid phase drastically influence the absorption rate of carbon dioxide. Also, the results showed that the absorption rate of carbon dioxide was increased by increasing ammonia and sodium hydroxide concentration.

The adsorption and separation properties of 3A zeolite are investigated by using Grand Canonical Monte Carlo (GCMC) simulation. To obtain the adsorption isotherms of water, methyl mercaptan, and methane on 3A zeolite, COMPASS Force Filed is used. The adsorption isotherms of the pure components and the ternary mixtures of water, methyl mercaptan, and methane on 3A zeolites are calculated. The Sips Model is taken into account for the description of water adsorption on 3A zeolite. In addition, the effects of pressure and temperature on the adsorption of components are examined. The results demonstrate that the water has high adsorption selectivity on 3A zeolite, and this kind of adsorbent is a good candidate for the dehydration of natural gas.