PETROLEUM RESEARCH
Year:2018 | Volume:28 | Issue:100 |Papers Count:13

Seismic noise can be divided to random and coherent in reflection survey. The ground roll is a coherent noise in land seismic data that has high energy، high amplitude، low frequency and low velocity. It usually masks the reflections. Therefore، it must be attenuated in the seismic data processing. In this paper، we proposed a modification on the common offset common reflection surface method to attenuate ground roll and random noise. The CO CRS stacking operator is a hyperbola; therefore، it fits the hyperbolic reflections in the prestack data. Ground roll and random noise has linear and uncorrelated traveltime respectively. When the CO CRS operator is applied to the data، the reflection events can be detected by the coherency analyses. High coherency values belong to the reflection events، and low values indicate that no events with hyperbolic traveltime are detected. As a result، when the events are distinguished، any event with non-hyperbolic traveltime can be muted. We applied the proposed method on two real land data sets. The new method was compared with the f-k filtering and conventional CO CRS stacking after the f-k filtering. Results showed that the proposed method attenuated aliased ground roll better than the f-k filtering and conventional CRS. Further investigation was the effect of reflection amplitudes on ground roll attenuation by the CO CRS stacking. For a better attenuation، the minimum coherency of reflections had to be higher than the maximum coherency of the ground roll. Therefore، the intersection of the minimum reflections coherency and the maximum ground roll coherency is an SNR threshold (dB) for ground roll attenuation with FO CRS stacking.

Surface active agents (surfactants) as the most important chemicals to enhance oil recovery (EOR) can reduce interfacial tension between the injected aqueous solution and the oil in a reservoir. They change wettability of the porous media to release and move the remaining oil trapped in the pores and throats towards the well. According to the important roles of the surfactants، it is necessary to predict their performance for EOR process. In this research، two data-based mathematical models were developed to estimate interfacial tension of the oil، salty water and anionic surfactant system using 598 experimental data. To obtain the correlations between the independent variables and the objective function، genetic programing has been applied. Squared correlation coefficient (R2) of the models is 0. 946 and 0. 9387; moreover، root-mean-square deviation (RMSD) of the models is 3. 4439 mN/m and 3. 3261 mN/m respectively. Simplicity and acceptable estimation are particular features of the models.

Heat treatment furnaces play an important role in refinery and petrochemical systems. The emission of a huge amount of environmental pollutants such as nitrogen oxides (NOx) and carbon dioxide (CO2)، along with the cost of repairs and periodic overhauls have given more attention to the optimization of the furnaces. Flameless combustion as a newly emerging process، with features such as reducing emissions of pollutant gases، uniform distribution of temperature profile along with reducing thermal stresses، and noise pollution in the torch، promising to change the conventional combustion systems and move them toward emission، operational، and maintenance costs reduction. In this study، the burner made by Sholeh-Sanat Company was investigated using the computational fluid dynamics under pre-heating conditions and oxygen concentrations of 3 and 6%. The furnace performance was considered in steady flameless conditions with eddy-dissipation concept (EDC). Flameless combustion characteristics were obtained in the torch and compared to conventional combustion; moreover، the temperature peaks were eliminated، and the temperature profile became more uniform. Also، in the 6% state، the mass fraction of nitrogen oxides and carbon dioxide compounds were observed to be about 400 and 3000 times decreasing respectively. Working under 3% mode، more uniform temperature profile and less nitrogen oxides were observed.

In this paper، a new experimental method is applied، and the capability of different Loss Control Materials (LCMs) in bentonite mud – which has the highest use in Iran’ s oil and gas wells – is investigated. At first، particle size distribution of LCMs is calculated based on API standards. Then، the loss of bentonite mud in different slots is evaluated using Bridging Materials Testing (BMT) apparatus. Usage of three dimensional fractures is one of the most important points of this research، which makes the experiment conditions so similar to the real conditions of well. It should be mentioned that LCMs show their best efficiency only when they can internally block the fractures. Also، in this research، RI-LQ material is for the first time used to control the lost circulation of bentonite mud. The results of these experiments showed that a mixture of RI-LQC and Quick Seal with Concentrations of 20 and 5 pounds per barrel and RI-LQC and RI-LQF mixtures with concentrations of 18 and 7 pounds per barrel have the least amount of loss circulation and are effective in controlling sever losses.

This paper presents soft sensor as a multiphase flow meter. Nonlinear observer with Ensemble Kalman filter (EnKF) by Navier Stocks equations for inline flow is used to estimate the oil and gas flow. Finite element method and EnKF are used along two scenarios; in addition، in the first scenario، the estimation is done with the refinery output measurement; and in the second scenario، this estimation is done with the production unit output measurement. In this article، we don’ t use primary element for multiphase flow measurement، instead of that flow will be estimated using some secondary variables (like pressure، temperature، output single phase flow، phase fraction and etc that can be measured directly with high accuracy). Results of comparison between two mentioned scenarios show that also the estimation with output measurement is not accurate، but the accuracy and repeatability of second scenario (estimation with production unit measurement) is in the acceptable standard range. Thus we can conclude that this soft sensor can be used as a backup for primary system and also as a primary system for multiphase flow measurement.

In this paper، a novel modeling method is presented using Mamdani fuzzy approach by introducing a new fuzzy concept، named Fuzzy Composition Variable. Fuzzy Composition Variable tries to combine the mole (or mass) fraction variables of the model in one variable. This variable tackles the problem of a high number of fuzzy rules when using Mamdani approach. The proposed method is capable of modeling complex systems with a large number of variables (including molar composition) with an acceptable performance، bypassing solving various types of mathematical equations governing the system and calculating several parameters. To demonstrate the capabilities of the proposed approach، it was implemented to modeling the equilibrium flash separation of crude oil. The overall prediction accuracy of the model (with a manageable number of rules) was obtained more than 85%، without using an optimization procedure.

In situ stresses are considered as pivotal factors in rock sciences in addition to petroleum engineering issues including wellbore stability and hydraulic fracturing. In situ stresses are mainly estimated by costly and time consuming methodologies directly. Moreover، the outcomes of these approaches are limited to a certain depth of the well. Therefore، these methods cannot be generalized. In the present study، a model based on the shear moduli and Poro-elastic parameters in an environment under transverse isotropic conditions has been employed whereby the results further discussed. Elastic parameters، strength، and in situ stress according to the hypotheses underlying the both models were calculated for a well in the west of Iran. Shear moduli-based method is proposed to predict the maximum horizontal stress. Here، acoustoelastic parameter was set to 0. 52. Of course، C66/C44< 2 is not much acceptable. However، the stresses were calibrated using the cores. Although this method enabled to predict the revers faulting regime correctly، however regarding the model، stress has been underscored and the outputs are not consistent with the calliper log. Subsequently، Poro-elastic based mechanical model in accordance with caliper log estimated a more reliable in situ stress under transverse isotropic conditions. Furthermore، break-out and break-down have been properly determined that could be due to the shale layers within the formation.

Environmental pollutions originated from fossil fuel cause to consider the development of rigorous rules to remove sulfur containing compounds and achievement of novel process to follow the mentioned of rigorous rules. In this regard and for the first time، new Dawson-type vanadium polyoxotungstate emulsion catalysts، [TBA]6+xP2W18-xVxO62 (x= 0، 1، 3، 5) have been synthesized successfully for oxidative desulfurization of sulfur compounds and characterized by using element analysis، FTIR، 31P MAS NMR and UV-vis DRS. These catalysts were used to oxidize sulfur-containing components، dibenzothiophene and benzothiophene by using hydrogen peroxide under mild conditions ( temperature lower than 100 oC and atmospheric pressure). The activity of catalysts has been grow by increase in number of vanadium in the structure of heteropoly anion. The reactivity of sulfur compound، dibenzothiophene was much more than benzothiophene. The emulsion catalyst with the highest number of vanadium، [TBA]11P2W13V5O62، could oxidize 85 % of dibenzothiophene and 50 % benzothiophene after 75 minutes، under temperature 60 oC and by using hydrogen peroxide 30 v-% in oxygen to sulfur mole ratio 4.

In this study، nanocomposite PES based membranes were prepared by using sulfonated silicon dioxide (SiO2-SO3H) nanoparticles through phase inversion method. PVP and N-N-dimethylacetamide were used as pore former and solvent respectively. The effect of nanoparticles’ concentration on the separation performance of prepared membranes was studied. The structures of membranes were investigated by scanning electron microscopy (SEM) and scanning optical microscopy (SOM). Obtained results showed modified membranes had significant improvements in flux and rejection with increasing sulfonated silicon dioxide nanoparticles. Also، the tensile strength increased in the range of 15 to 25% for prepared membranes containing naniparticles. Results showed that nanocomposite membrane containing 0. 1 wt. % SiO2-SO3H nanoparticles has an increase in the flux of 200% compared to the unmodified membrane and salt rejection of 75%. Also، the flux decreased the ratio of the optimum sample was 7. 14 that showed better antifouling properties with decreasing of 75% relative to the PES one.

The purpose of this study is determination of reservoir quality in different zones of Kangan reservoir formation in a well located at one of hydrocarbon fields in south of Iran. This study was performed to evaluate the reservoir petrophysical characteristics of Kangan formation using probabilistic method. In this study، the effective parameters on the reservoir quality comprising of porosity، permeability and water saturation were selected. Then، the effect of each of these parameters was investigated on the reservoir quality، and as a result، a new index or formula، called developed reservoir quality index، was introduced. Based on the importance of each of these parameters in the introduced reservoir quality، different values were selected for the coefficients A، B، C، and powers α ، β and γ in the formula، and consequently، the best values of these coefficients and powers were obtained by plotting the developed reservoir quality index in terms of water saturation، and maximizing the amount of regression or determination coefficient. In order to determine the validity of the formula introduced as the developed reservoir quality index for other reservoir formations، this formula were used for the Sarvak carbonate formation in an oil field. DRQI and RQI were plotted for units of Kangan reservoir formation versus depth and compared. The calculated results of DRQI indicate that the zone K2 of the Kangan Formation has an appropriate reservoir quality in terms of the developed reservoir quality index. The results of the petrophysical evaluation of the Kangan formation are also shown the same result.

Large amounts of waste from various stages in the process of refining crude oil are produced in the Persian Gulf in Iran. This waste is a viscous oil sludge containing high amounts of petroleum derived hydrocarbons. So oil sludge is environmental concerns and should be treated. Biological treatment (bioremediation) to deal with a wide range of organic pollutants and petroleum hydrocarbons is useful. In this study، the oil sludge has been obtained from the contaminated site from Bahregan area in the Persian Gulf of Iran. Some oil sludge containing bacterial consortium، Chemotaxis in synthetic Mineral semisolid agar medium was used for the isolation of alkane degrading bacteria from oil sludge biodegradation of octadecane، hexadecane، naphthalene، and anthracene were determined. Strains isolated in this study were identified by 16S rRNA gene sequencing as Thalassospira and Chromohalobacter. They are Gram negative and belonged to Rodospiracea which could hydrolyzed aromatic and linear oil compound.

In order to enhance adhesion and corrosion performance of an epoxy coating، epoxy-Nano silica and epoxy-silane coatings were prepared in 0. 5، 1، 2، 3، 4 and 5 wt. %، then they were applied to carbon steel substrate. Adhesion test was performed on the prepared coatings using pull off test، furthermore corrosion performance evaluated against salt spray conditions، and it was shown that there is a direct relationship between adhesion and corrosion resistance of both types of coatings. Initial temperature of decomposition (ITD) and temperature of maximum weight loss (Tmax) which obtained from thermo gravimetric analysis (TGA) of epoxy-silica coating showed a right shift to upper temperatures. Dispersion and distribution evaluation of Nano-silica in epoxy matrix was carried out using SEM images. It was found that an increase in the Nano-silica concentration is resulted in poor dispersion and distribution of nanoparticles، and consequently، the coating formed a non-uniform film with large cracks. DSC thermo grams of epoxy-silica coatings showed that incorporation of Nano-silica in epoxy matrix have several effects on the heat of reaction and kinetic of curing، so that this inorganic filler hindered curing reaction. In total، it is proved that epoxy-silica coating demonstrated better performance as a protective coating for carbon steel substrate in comparison with the epoxy-silane system.