مصطفی کشاورز مروجی

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.

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.

Summary Due to the importance of the rate of penetration and hole cleaning in directional wells to reduce the costs, after detection of critical inclination, the relationship between the effective parameters has been studied in an experimental flow loop. The cuttings, used in the tests, have had a specific size distribution in three types of sand, silica and limestone. The results illustrate that the hole cleaning index (HCI) of powder types in comparison to non-powder types is higher. The effects of bit and pipe rotation on the HCI have been studied in this research work. In this regard, there is an optimum point of the HCI for each of these effects. The end point and the length of the cutting bed have the same behavior. The larger density and lower size cuttings, compared to the lower density and larger size cuttings have higher HCI. In addition, the effect of the shape and size distribution of cuttings on the HCI seems to be remarkable.  Introduction Reparability, durability, cost, drill ability and many other parameters are important in using the bits. Based on these parameters and the softness or hardness of the formation, a bit is selected. The cuttings that are generated in directional drilling, based on the bit type and formation type, have different sizes, shapes, densities and volumes. In this paper, the hydraulic effect after releasing the wait on bit is discussed. Hole cleaning is a key parameter in extended reach drilling, especially in critical inclination periods, where the probability of the different sticking types is increased. The critical inclination is the angle that has the worst hole cleaning. In this research, by applying discrete angles in laboratory tests, one specific angle is determined as the critical point, and in this regard, the effect of size, shape, density and volume of cuttings are studied.

In this research, the effects of surface active agents on the hydrodynamic parameters and mass transfer characteristics in an internal loop airlift bioreactor with packed were investigated. Overall gas holdup, liquid circulation velocity and mixing time as the hydrodynamic parameters and volumetric mass transfer coefficient as the mass transfer characteristics were considered. Twenty five cylindrical packings were horizontally set inside the reactor. The experiments were carried out with two various surface active agent solutions containing cationic and non-ionic surfactants at a concentration of 5 ppm at the aeration velocities of 0.19-0.97 cm/s under ambient conditions (atmospheric pressure and temperature of 25 °C). The packings installation reduced the liquid circulation velocity, gas holdup, and oxygen volumetric mass transfer coefficient, while increased the mixing time compared with the unpacked column. Furthermore, bubble diameter was reduced around 30%, while they got the same diameter in the systems containing the surface active agents. It was concluded that the mixing time and gas holdup increased, whereas oxygen mass transfer coefficient and liquid circulation velocity decreased in the presence of surface active agents

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.

In this research, Ohmic heating has been introduced as a new method in heating systems for biological, food and medical industries and various commercial aspects of its for industrial application and research efforts have been studied. After introducing this heating system, present models are investigated and theoretical results in simulations and modeling cases were presented. Also, used tools and systems for this heating technique in experimental and commercial usage as an appropriate alternative for traditional heating method were fully explained. Finally challenges related to development of this method are expressed.

Airlift bioreactors form one of the most important classes of gas-liquid contactors that are extensively used in chemical and biochemical processes especially in oil and gas industries. These bioreactors have some advantages respect to CSTR and BCR’s especially in bioprocesses. In this article, various kinds of airlift bioreactors have been investigated. Design or scaling of the bioreactors is depend on the hydrodynamics turnover, that inclusive using parameters such as gas velocity, void fraction, liquid velocity and mixing. Because of the rigorous interaction, behavior study of these bioreactors are complicated. In this research, effective hydrodynamics parameters in the airlift bioreactors are investigated.