PETROLEUM RESEARCH
Year:2016 | Volume:26 | Issue:87-2|Papers Count:18

Monitoring of fluidized bed hydrodynamics is an essential issue. In this work, a new method, based on comparison of attractors of reference and evaluation time series, was applied to investigate the fluidized bed hydrodynamics by analyzing the bed vibration signatures. The experiments were carried out gas-solid fluidized of 15 cm inner diameter and 2 m height for three particle sizes, different velocities, and three probe heights. The measured signals of different sand and aspect ratio were compared based on the null hypothesis. The attractor of a system has been reconstructed by applying time delay embedding theory on measured values. The results indicate that the S-statistics method can detect small Changes in gas velocities, the particle size and aspect ratio of the sand. The importance of this method is its ability on the detecting of changes in the hydrodynamic of fluidized bed and provide of changes for controlling these variations.

One of the most characteristic parameters of an organic hydrocarbon is aromatic and aliphatic contents determination. Aromaticity content of an organic hydrocarbon can affect on variety of properties such as boiling range, viscosity, stability, heat resistance and compatibility with other materials. Nuclear magnetic resonance spectroscopy (NMR) is the most efficient and effective technique for determination of protons (1H) and carbons (13C) aromatic and aliphatic content in organic hydrocarbons. Presence of hydrogen and carbon atoms in hydrocarbon materials such as, kerosene causes the nuclear magnetic resonance spectroscopy studies to be performable on the atoms. Kerosene is the most known materials in oil industries that it is including wide range organic hydrocarbons. Depends on source of this material, aromatic and aliphatic contents of kerosene can be different. Nuclear magnetic resonance spectroscopy results show that kerosene (for example from Aldrich Co.) has 3.589% aromatic hydrogens and 9.462% aromatic carbons.

The tensile test in the weld and heat-affected zone of welded structures give global results due to the presence of various metallurgical microstructures in these regions. The best way to estimate the strength of material in these areas is converting the results of hardness test to yield strength (or ultimate strength) by empirical relationships. In this study, the hardness test was carried out in various areas of the girth welded steel pipe used in Iranian natural gas transportation projects. Then, dimensionless parameters Rya (the average residual stress over material yield strength), Rym (the maximum residual stress over material yield strength), Ru2 (the difference in residual stress over material ultimate strength) and Ru3 (the difference between maximum and minimum of three-dimensional residual stresses over the material ultimate strength) were presented to determine the actual mechanical behavior of structure for the first time. Hardness and tensile tests identify the minimum yield strength in the heat-affected zone adjacent to weld gap. The increase in hardness values from the root pass to the next passes is consistent with increase in the carbon content. Identification of maximum Rya criterion and critical mode of reduced static strength (reducing of stress design) in the center of weld gap on the outer surface of the pipe are consistent with tensile test results. The rupture zone in the tensile test with highest Rym criteria represents the effect of residual stresses on the static behavior of structure (in addition to the hydrostatic nature of residual stresses). The sharp decline in Ru2 criteria is consistent with the exponential reduction in impact strength perpendicular to the weld gap. It can be concluded that with regard to the effect of plane stresses (in thin-walled pipes) Ru2 criterion is more appropriate in assessing the impact strength of steel than Ru3.

The main application of sequence stratigraphy is recognition of reservoir and non-reservoir intervals in hydrocarbon- bearing formations. So, it is very important to construct a suitable sequence stratigraphic-based model reservoir zonation schem. The transgressive-regressive model is comprehensively used for this purpose. Sequence stratigraphy of Kangan and upper Dalan formations in South Pars Gas Field has been done based on the EXXON model in this study. Four 3rd order sequences were determined; each sequence contains LST, TST and HST. In Kangan sequences (KS1 and KS2) and lower sequence of upper Dalan Formation (UDS2), the reservoir quality changes similarly. The LST has low reservoir quality due to the high anhydrite content while TST has good reservoir properties. The HST is not a good reservoir again with considerable anhydrite content. In the upper sequence of upper Dalan Formation, there is a reverse order. Regarding the considerable relative sea-level fall at the end Permian time, the anhydrite content is high in TST, while UDS1-HST has good reservoir quality due to dissolution influenced by meteoric water. Results of this study show that the applied model has a considerable ability for carbonate reservoirs zonation.

According to the benefits of oxidative desulfurization (ODS) and ultrasound assisted oxidative desulfurization (UAOD) processes and in order to industrialize these processes, it is necessary that the kinetics of these processes be studied and modeled, so as to be able to design and simulate them in semi industrial and industrial scale. Therefore, kinetics modeling of oxidative desulfurization reaction of 4, 6-DMDBT over molybdenum catalyst supported on alumina has been investigated. For expression of reaction kinetics equations, Langmuir Hinshelwood and Eley Rideal mechanisms have been used. Genetic algorithm was used for optimization. Based on, Langmuir-Hinshelwood and Eley Rideal models results, Langmuir-Hinshelwood mechanism can describe the kinetic behavior of UAOD and ODS processes. Micro kinetics equations and rate determining step are identified according to the results of the models.

The reservoir electrofacies study is one of important subjects in hydrocarbon reservoirs scope now. Determination of the high reservoir quality zones can play an important role in production view of the hydrocarbon reservoir and their development. Electrofacies is defined on the basis of clustering which is grouping all similar log data in unique set and distinguished it from other sets. In the present research at first using SOM, MRGC and DC methods, primary model of electrofacies in a number of field’s wells has been determined. Electrofacies have determined by different methods correlated with identified flow unit’s derived Core storage capacity (phie*h) -flow capacity (K*h) data, and SOM method has been chosen among them for clustering which had the highest accordance.9 created Initial electrofacies reduced to 4 electrofacies according to the analogy of some parameter; such as, porosity and gamma logs. This electrofacies have been generalized for entire filed resulting in creation of a model with separation capability of the deferent reservoir zones. This model shows a decrease in reservoir quality from the upper part to the bottom of the reservoir also depicts reservoir quality changes whole the studied field.

Capital investment in the petroleum industry had been constantly faced with the risk due to uncertainties in the prediction of reservoir performance. So investors need accurate estimates of the uncertainties to reduce the investment risk in this industry. Statistical methods of risk analysis in petroleum industry are faced with limitations because of various assumptions. In this paper, uncertainty of gas recovery factor from water drive gas reservoirs will be investigated using four different methods including: (1) experimental design theory and response surface methodology, (2) multiple realization tree, (3) relative variation factor and finally (4) integrated mismatch method. This study shows that the greatest uncertainty in estimating the gas recovery factor of these reservoirs is associated with reservoir permeability, wellhead pressure, aquifer permeability and tubing diameter and therefore by reducing the uncertainty in the calculation of these four factors, investment risk can be reduced. Also a multiple realization tree method has high accuracy (relative error less than 3%) with respect to the other three methods in estimation of most probable valve of gas recovery factor.

Porosity is a petrophysical property used for reservoir 3D modeling and prediction of production scenarios for the purpose of economic decisions play an important role in field and reservoir management. In this study, drilling data (logs) from 3 wells and geostatistical method including sequential Gaussian simulation were used to predict porosity pertophysical property. Sequential Gaussian simulation is widely used for porosity model construction since it is easily applied and is flexible in real heterogeneous conditions. In this method, with the available data including values and coordinates values of the same parameter in unknown points can be predicted. In Sequential Gaussian method cells having certain values from petrophysical parameters are taken into account. After, constructing reservoir structural model and analyses of petrophysical data, simulations models for 5 reservoir units of Sarvak and Dariyan reservoirs (1, 2, 3 and 4) in the studied filed were established for porosity with high precision.

This research discusses the effect of gravel pack size on sand production by designing and manufacturing machine and a numerical model for simulating sand and gravel pack production. Different rocks and fluids can be tested under different stresses to simulate sand and gravel pack using this machine and the numerical model. In this study, sand with certain aggregation, gravel in different sizes, and water were used to simulate production of sand and gravel pack. PFC3D was used to create a numerical model. Sand size between 0.22-1.1 mm and gravel sizes between 3.54.76 mm, 4.769 mm, 9-12.6 mm, and 12.6-16.8 mm were used in the numerical model and gravel sizes between 4.76 – 9 mm and between 9.25 -19 mm were used in the physical model. The results obtained from the modeling showed that in the numerical model with the gravel pack sizes between 3.5-4.76 mm, production of sand was minimal; in the physical model with the gravel pack sizes between 4.76-9 mm, sand production was less and output flow rate of the fluid was more. In addition, the results of the physical model showed that after putting gravel pack, fluid production rate decreased over time and reached a constant amount. Therefore, it may be proposed that size of gravel pack between 4.76-9 mm is more suitable as far as fluid production rate and sand production prohibition is concerned.

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.

A series of nanostructured LaAPSO-34 catalysts was synthesized with different Si/Al ratios via hydrothermal method. La incorporation into zeolite framework could result in reduction of catalyst acidity and causing the enhancement of catalyst life time. The as-synthesized catalysts were characterized by XRD, FESEM, EDX, BET and FTIR techniques and tested for methanol to light olefins (MTO) process. XRD results showed that the crystallinity intensified by increasing the Si/Al ratio up to 0.2. Afterwards, it declined and FESEM images revealed that by increasing Si/Al ratio, the growth of the cube-shaped chabazite particles was be more complete. The presence of the constituent elements and uniform distribution of them were observed by EDX analysis. BET results showed that by increasing Si/Al ratio, specific surface area of the nanostructured LaAPSO-34 catalysts increased. FTIR spectrums confirmed framework vibrations of chabazite in different Si/Al ratios. The obtained results of catalytic performance tests illustrated that increasing the Si/Al ratio from 0.1 to 0.3 led to enhancement of catalyst life time. Moreover, it has been found that by increasing the reaction temperature, methanol conversion increased. For the most active catalyst, Si/Al=0.3, the complete conversion was obtained at T=400-500°C. Moreover, by increasing Si/Al ratio, light olefins selectivity of nanostructured LaAPSO-34 catalysts declined to approximately 60% after 600, 2000 and 2600 min time on stream, respectively.

In this research, mean drop size in a bench scale Kuhni column was experimentally and theoretically investigated. To measure the mean droplet size the imaging and image processing techniques were used. Two standard systems include toluene-water (high surface tension) and normal butyl acetate-water (mean surface tension) used in the experiments. Continues and dispersion phases flow rate and rotor speed are examined as variable in this study. Drop size was measured in rotor speed range 90-240 rpm and continues and dispersion phase flow rate range 18-24 lit/hr. The results showed that mean drop size was decreased with increasing rotor speed. Also the results showed that mean drop size was increased by increasing of continues and dispersion phases flow rate. The comparison of parameter effects on mean drop sized showed that continues and dispersion phases flow rate are very weaker than rotor speed.

Programming and designing the non-linear models cover a wide range of applications. Various scholars all around the world are engaged in taking this action and their main goal has been identified as providing efficient computational algorithms with the ability of evaluating the non-linear models. Nelder_Mead algorithm is among the most popular ones. Selecting a proper policy in energy concerns is dependent upon the estimation of the reserves and the expenditures incurred in negotiation of oil contracts. Those models capable of predicting the future supplies and their relative volume are valuable. However, traditional prediction models are not efficient enough and that’s why the researchers endeavor to find new methods for modeling the oil reserves. This paper aims to develop a new model to estimate the oil reserves by using exploratory and statistical data. It also tries to evaluate the model in one of famous the oil field by using Nelder_Mead algorithm.

Pore pressure and Fracture gradients are the key inputs for geomechanical applications. Knowledge of these pressures is essential for cost-effective drilling, safe well planning and efficient reservoir modeling. The main objective of this study is to determine the safe mud weight windowusing well log data at one of the gas fields in south of Iran. To obtain this goal, the formation pore pressure and fracture gradient are estimated. The formation pore pressure is estimated from well logging data by applying Eaton’s prediction method with some modifications. In order to determine the fracture pressure, the estimated pore pressure is used along with calculating Poisson’s ratio from compressional and shears velocities. The estimated fracture and pore pressures are used as the top and bottom limits of the safe mud weight window. Finally, in order to generate the 3D model, well-log-based estimated fracture and pore pressures are upscaled and distributed along the 3D structural grid with a geostatistical approach in Petrel software. The obtained model is validated using a mud weight data which was not used in the modeling. The result shows that the estimated model is appropriate for the purpose of drilling plan.

The importance of filters in drinking water systems is increasing because it can remove considerable percentage of bacteria and diseases-causing microorganisms with minimal cost. In this context, the use of sand filters to removes water turbidity is common. The backwashing of sand filters remove deposits which are formed on the sand bed. Optimization of the backwash operation has a particular importance due to the volume of water used for backwashing sand filters (about 2-3% of the volume of filtered water). The measurement of wastewater turbidity in the operations can be an appropriate criterion for evaluating the effectiveness of Backwash operations. In this study, the Backwash operation of three sand filters are optimized by examination of the plots of turbidity versus time during the backwash of filter. In this study, backwash operation of three sand filter beds made of quartz sand particles has been studied. The results show that the optimized pattern of backwashing operation can be proposed by changing the air blowing time of backwash operation.

In this study the effect of xanthan gum biopolymer and tallow-amin-poly-ethylene glycol surfactant on the properties of water based drilling mud has been studied. The effect of biopolymer or surfactant and mixtures of them with different ratios has been investigated on effective viscosity, shear stress and amount of filtration. The result shows that rheological and filtrate controlling properties of fluid with the polymer-surfactant mixture have better operational condition than fluids with only polymer or surfactant. The biopolymer-surfactant mixtures have also better linear curve on high shear rates. The cases, which consist of biopolymer-surfactant mixture have better filtrate controlling in comparison with samples which have only biopolymer. In the cases with only surfactant the amount of filtrate much higher than desirable amount with respect to polymeric and combinating cases. Filter press experimens was also carried out in high pressure and temperature. It is observed that the amount of filtrate increased with higher rate than low pressure and temperature.