mostafa keshavarz moraveji

Carbon dioxide (CO2) gas flooding has long been regarded as a popular method of improving oil recovery as it can reduce the carbon footprint in the atmosphere through carbon storage and CO2 sequestration. Miscible flooding is considered the most efficient way to reach the maximum oil recovery factor. However, not only do not all oil reservoirs experience pressures above miscibility but also due to difficulty in retaining reservoir pressure in the desired region, numerous miscible flooding operations experience pressure decline below minimum miscibility pressure (MMP). In these circumstances, a near-miscible process seems to be attainable and practical compared with a miscible injection. In the current study, we exclusively focus on pore-scale near-miscible CO2-oil displacement. In this regard, the effective near-miscible region is determined based on the available criteria in the literature. Then at the lower-pressure limit of the defined near-miscible region, Phase-Field coupled with the Navier-Stokes equation as the numerical approach is implemented to investigate the CO2-Oil displacement by capturing the diffusive interface properties and hydrodynamic properties of fluids. Quantitative analysis of results, to better realize the pore-scale mechanism of oil recovery demonstrated that if the pressure conditions are maintained throughout the modeling in the effective near-miscible pressure region, almost significant amounts of by-passed oil in the pores from small to large to be recovered and the oil recovery increased from 50% to more than 90% approaching the results of miscible gas injection. This outcome can accentuate the significance of near-miscible CO2-EOR in operation applications.

Research subject:

 Investigation of the effect of temperature on the polymer flooding performance at the pore scale, leads to an understanding of the behavior of the polymer solution in porous media with varying permeability.

Research approach:

 In this study, the effect of temperature on flooding of polyacrylamide polymer on enhanced oil recovery in two homogeneous micromodels at 25 and 70 °C was investigated. The polymer solution and DW were injected at the injection rate of 1 μl/min up to 1 PV into the micromodel and the amount of produced oil and the movement of the injected fluid in the porous medium were analyzed. In addition, polymer rheology and injected fluid viscosity were measured for better analysis of results. Then the results were compared with flooding of distilled water as the control test.

Examining the flood results, it was found that on the one hand, the temperature factor helped to increase oil recovery by reducing the viscosity of the oil. On the other hand, it has reduced the role of injected fluid viscosity in oil extraction by reducing the viscosity of the polymer. The results showed that the phenomenon of fingering decreases in the case of polymer injection, and the rate of improvement of oil recovery during polymer and water flooding in both micromodels increases with increasing temperature. Also, the rate of improvement of oil recovery during polymer flooding in the A micromodel increased from about 43% at ambient temperature to more than 51% and in the B micromodel from about 51% to more than 60% at 70 °C. In fact, it can be said that the flow pattern and stability of the polymer solution front and consequently the ultimate oil recovery are significantly affected by the morphology of the pores, the shape and the throats pores.

The effects of adding nanoclay to improve the thermal and mechanical properties of polypropylene (PP) copolymers grade (EPD60R) used in the pipe industry were investigated. To improve the dispersion of the nanoclay in the polymeric matrix, a 30 wt%  of nanoclay master batch was first prepared by mixing PP matrix maleic anhydride PP oligomer (PP-g-MA) and Cloisite® 15A (C15A) nanoclay. The prepared master batch was used to produce nanocomposites with 2 and 5 wt% nanoclay. The nanocomposites were analyzed by XRD (X-ray diffraction), SEM (Scanning electron microscopy), DSC (Differential scanning calorimetry), TGA (Thermogravimetric analysis), and other mechanical tests. The XRD and SEM results indicated the occurrence of an intercalated layer structure in the nanocomposites. Thermal properties of the nanocomposites were investigated using DSC and TGA tests. The crystallinity of the 2 wt% nanoclay was improved by about 59.23% in the nanoclay reinforced samples. As the content of nanoclay increased, the composite exhibited higher thermal degradation temperature. Performing a limiting oxygen index (LOI) test on the samples showed that the addition of nanoclay to the EPD60R matrix increased the flame retardancy by 12.58%. The tensile modulus of the nanocomposites was improved compared to the pure polymer, while the elongation at break and at yield showed a reduction. To investigate the nanocomposite in pipe application, a pipe (external diameter 110.8 and thickness 3.65 mm) was manufactured in a special tube extruder machine with 2 wt% of C15A.  Tests of the tube’s physical and mechanical properties indicated that its ring stiffness increased by 25% compared to the pure PP.

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.

Advanced oxidation processes (AOPs) suggest a highly reactive, nonspecific oxidant namely hydroxyl radical (OH•), that oxidize a wide range of pollutants fast and nonselective in wastewater and water.

In this work, the nitrogen-doped titanium dioxide nanoparticles were primed by sol-gel method, characterized by X-ray diffraction and Scanning Electron Microscopy (SEM), for the degradation of Acid Red 40 (AR 40) solution in water. The effectiveness of the treatment method applied for the degradation of AR 40 based on AOPs was investigated.

The three various key parameters were optimized by using response surface modeling, namely: pH, TiO2-N concentration and the initial AR 40 concentrations. The optimized values were obtained at pH = 11, TiO2-N concentration = 0.09 g/L, and the initial AR 40 concentration = 19 mg/L.

Under the optimum conditions, performance of photocatalytic degradation reaches 92.47% in 1 hr. Kinetic constant was evaluated using first-order equation to obtain the rate constant, K.

Having accurate values of the parameters which mainly govern the industrial processes in hand is the key aspect to handle the process and optimize it. To deal with this challenge, some mathematical models have been developed and modified to be epidemic. This Study aims to present the simulation of gas-solid flow in fluidized bed dryer. Numerical solution of two-dimensional, axis-symmetrical cylindrical model for both phases is the very base on which this study is conducted. Some of the versatile parameters like inlet gas velocity and temperature, diameter and density of particles during drying process went under magnification and also challenges of heat transfer along the bed are investigated and discussed in detail. Solid temperatures in the center and on the surface which are greatly affected by time as well as results of the study are shown. At the end, model outputs are compared with experimental data which shows reasonable agreement and good match.

Ohmic heating as a novel heating method in biological, food and pharmaceutical industries especially in sterilization process was known. In this research, the Ohmic heating and effective parameters influences experimentally investigated. For investigation the Ohmic heating behavior, Hydrocolloid solutions in Ohmic cell in some stage have been used. First, electrical conductivity of hydrocolloid solution with 4, 5.5 and 6.33% concentration was studied and determined that reported that temperature increasing resulted increasing the electrical conductivity linearity. With increasing the dispersed concentration, electrical conductivity increased. In order to study the effect of salinity on the electrical conductivity, sodium chloride (0.25-1% concentration) was added and results showed that addition of salts, increases efficiency the electrical conductivity. In order to study the effect of electrolyte content on temperature-time profile and heating rates citric acid was added. Addition of salt into the solution has efficient effect on the temperature-time profile, that in solution with 3.3% concentration and 1% salinity reached 70 °C just after 253 s that records shorter time for increasing the temperature from 20 to 80 oC and highest electrical conductivity. The effect of electrolyte (acid) on temperature-time profile in comparison with salt is not considerable. With measuring the solution temperature with thermocouples in the cell, uniformity of heating throughout the solutions was studied. From experimental result, it can be resulted that Ohmic heating rate dependent to electrical field distribution and heating uniformity is dependent to current concentration and system geometry.

The paper describes the effect of temperature, ammonia concentration and feed flow rate on nitrifying treatment of wastewater usage Computational Fluid Dynamics (CFD) for two phase bubbly flow in a split cylindrical airlift reactor with a 0.085 m initiator diameter and 0.505 m height. Superficial gas velocity was used as the operational parameter, air was used as the dispersed phase, and wastewater containing ammonia was used as continuous phase. Temperature enhancement in a constant O and NH concentrations, resulted the 2 4 + increase of reactions rate also NO had an increase of about 3 times as much. By the feed flow rate increase, 2 - O consumption increase and the rate of NO production increase more than NO but decrease the reactions 2 2 3 - - efficiency decrease in a constant time. NH concentration enhancement leads to the increase of O 4 2 + consumption and better reactions efficiency at higher NH concentration, NO concentration increases more. 4 2 + - Modeling results are compared with the experimental data. The CFD modeling results show suitable agreement with the experimental data.