مجله پژوهش نفت
پیاپی 125 (مهر و آبان 1401)

Estimation of the breakthrough time of injected fluid in water injection process is useful for process design and injection pattern during reservoir development. Conventional approach to this is to use reservoir simulation. An alternative is to use percolation theory approach. However, some of the assumptions used in developing the scaling function of breakthrough time such as similarity of viscosity of both injection and production fluids limits its applications to field scale. In this study, we use the dimensionless time approach for breakthrough which is based on a characteristic time. By using various reservoir simulation cases the effect of fluids viscosities was studied. The results showed that the suitable characteristic time for scaling of breakthrough time depends on both NTG and viscosity ratio of phases in a power law form with exponent of 1.3.

The main purpose of this study is to determine the molecular arrangement in lamella and the role of Marangoni convection in foam stability in the presence of nanoparticles. Experiments were conducted in two different foam systems of (1) anionic nanoparticles-cationic surfactant (CTAB) and (2) anionic nanoparticles-anionic surfactant (SDS). Observations showed that the effective mechanisms of stability are different. Although nanoparticles increase the stability of both foam systems, the presence of nanoparticles in the like-charge system improves foamability. In contrast, in the unlike-charge system, foamability decreases with the increment of nanoparticle concentration. The most influential factor in the foam stability in the like-charge case is the repulsive force which sends more surfactant molecules to the interface. Surface tension results demonstrate that Marangoni flow restitutes the negative impact of gravity drainage and increases the foam stability. In contrast, In the unlike-charge system, the presence of nanoparticles at the interface increases detachment energy significantly, and as a result, the stability boosts. The accumulation of nanoparticles in the interface changes it to a solid-like and high elasticity surface; thus, Marangoni flow is lost.

Inactivation of Ni catalysts in the dry reforming of methane process has been one of the issues of concern. The use of active and base phase promotors and the synthesis of Ni-CO / Al2O3-MgO catalysts by impregnation method have been considered in our research. The main focus of this study is to evaluate the effect of addition of the promotors on the performance of synthesized catalysts in wall-coated microchannel reactor. XRD, BET and FESEM analyzes have been performed to determine the characteristics of the synthesized samples. The use of amplifiers increases the catalyst activity and makes it more stable.

Shurijeh Formation is deposited in Kopeh Dagh sedimentary basin, and it is one of the gas reservoirs in northeastern Iran. Khangiran gas field with a northwest-southeast structure is located in the northeastern part of Khorasan Razavi province. The purpose of this study is to investigate facies, sedimentary environment and diagenetic processes that have been effective on the reservoir quality of Shurijeh Formation in the studied wells. Based on petrographic studies on thin sections of Shurijeh Formation in the studied wells, nine main rock facies including Sandy Conglomerate, Quartz Arenite, Sublitarnite, Subarcose, Quartz Wackes, Claystone/Shale, Nodular Anhydrite, Sandy Dolomudstone and Sandy Dologrenston have been identified that are located in the tidal, river, flood plain and meandering sedimentary zones. Petrographic studies of thin microscopic sections show that diagenetic processes in three marine, meteoric and burial environments have affected the Shurijeh Formation. The primary processes affected in the facies of Shurijeh Formation include cementation, bioturbation, primary dolomitization and anhydrite. Finally, using image log, petrophysical log and combining the results of thin section studies in the key well of Khangiran field, was determined that in most cases there is a good conformity between the results of image log, thin sections and petrophysical log.

The study of sedimentary characteristics of carbonate formations as one of the main hydrocarbon reservoirs is important. In this research paper, we used thin section, and petrophysical logs data to analysis of facies, sedimentary environment and diagenetic variation of the Ilam Formation (Bangestan group). Thin sections petrography revealed that the Ilam Formation which was deposited as a full series in western part of the Gachsaran oil field and characterized by a neritic facies indicating a shallow marine. The sedimentary facies of Ilam Formation are mainly limestone, and sometimes shaley limestone (in restricted part of the basin). The lack of Coniancian-Turonian sediments in wells drilled in eastern part of the field can be related to erosional phase after Cenomanian-Turonian and developement of paleoheight parallel to Khark-Mish fault. The determined facies are deposited over a carbonate platform (shelf type) in three sedimentary environments: shoal, lagoon and semi restricted lagoon. The petrographic characteristics of detected facies of Ilam Formation revealed that they were experienced different diagenetic realms such as marine, meteoric, and burial and during uplift periods. These sediments then influenced by diagenetic processes such as micritization, compaction, cementation, neomorphism, solution, fracturing and replacement (dolomitization, hematitization, and pyritization). The dominant porosity types are interconnected vugs, fracture and channel which are played a profound effects on the variation of reservoir quality. The measurements of petrophysical parameters present that the averages of porosity, water saturation and net to gross ratio are varied in the Ilam reservoir, but these parameters are generally 2.3%, 88% and 0.016, respectively. In view of low values of porosity, the role of fractures and diagenetic processes are important in the reservoir quality. The paleohigh presence in eastern section is not only affected on facies distribution, but it also has an important role in subsequent evolution. Therefore, the quality of the Ilam reservoir is a function of sedimentation, diagenesis, and tectonic activity; and therefore, it will be variable in different parts.

In this study, Cu2O nanoparticles were first synthesized electrochemically, and the synthesized nanoparticles were used to modify nanofiltration membranes.  Different concentrations of nanoparticles were included as an additive in PES as a membrane matrix for the preparation of PES/Cu2O nanofiltration membranes. The prepared membranes were analyzed by Fourier transform infrared (FT-IR), scanning electron microscopy (SEM). FTIR analysis showed the formation of favorable bonds in the synthesized nanoparticles and prepared membranes.  The separation performance of membranes was investigated with pure water flux and MgCl2 removal.  The results showed the highest pure water flux of 36.78 L/m2h for M1 at 0.05 wt.% Cu2O nanoparticles. In addition, the MgCl2 rejection increased to 72% at 2 wt.% Cu2O nanoparticles for M5.

In this study, the effects of pH and ultrasonic waves on the performance and stability of CuO have been studied. The CuO nanofluid (deionized water-based) was used to increase the boiling heat transfer coefficient. Boiling heat transfer coefficient of fluid increased by the addition of nanoparticles into the fluid, but due to the instability of nanoparticles by increasing temperature and time, nanoparticles were precipitated on the heat transfer surface. Therefore, it led to a reduction in the boiling heat transfer coefficient. Moreover, it is necessary to obtain the optimal concentration of nanoparticles in the fluid to determine the minimum amount of deposition. The use of methods to reduce the deposition of nanoparticles such as increasing the stability of nanoparticles and also an optimal concentration made an increase in heat transfer coefficient. To overcome this challenge, two conventional methods were employed including pH change (9.5, 10 and 10.5) and ultrasonic radiation (with 25%, 50%, and 75% of power). The results indicated that the maximum enhancements of boiling heat transfer coefficient were achieved at nanoparticles concentration of 0.125% under ultrasonic radiation with 50% power and the pH value of 10 as average of 37.48% and 22.68%, respectively.

In this study, 3D model of effective porosity in heterogeneous Sarvak reservoir in one oil filed located in Dezful Embayment has been constructed. Therefore, geostatistics method has been applied for porosity propagation along with using trend maps of seismic attributes as well as seismic cube as secondary variable for Collocated co-kriging. Thus, the different seismic attributes including Attenuation, Envelope, RMS amplitude, Sweetness and Acoustic impedance attributes have been provided. The multiple attribute property has been used for preparing the related trend maps to be used in porosity modeling. Moreover, electrofacies analysis has been done via applying MRGC algorithm in order to control porosity distribution in 3D reservoir model. In this study, we tried to consider the trend maps, electrofacies, and seismic acoustic impedance cube along with applying geostatistics algorithms for 3D porosity propagation. Based on this study, the lower Sarvak has better reservoir quality than the Upper Sarvak due to developing of good reservoir facies. According to this study, the accuracy of the porosity model increases when it is used simultaneously seismic data and electrofacies, resulted in decreasing uncertainty of porosity distribution.

This investigation studied the separation of asphaltenes from the vacuum bottom, using industrial solvents such as normal pentane, hexane, and heptane. The central composite design (CCD) as a response surface methodology (RSM) method was applied to optimize the process. The weight percentage of asphaltene and the yield of de-asphalted oil (DAO) had been achieved at 0.447 and 48%, respectively, under optimum economic conditions (normal hexane solvent, solvent to feed ratio of 9.5 mL/g, and extraction temperature of 25 °C). The statistical study indicated that the response surface quadratic model for the mentioned parameters was significant and a perfect correlation between the statistical model and experimental data was found. Furthermore, according to an analysis of variance (ANOVA), the temperature of extraction and the quadratic interaction of the solvent to feed ratio parameter have shown a significant impact on the weight percentage of asphaltene. In general, the results suggest that the introduced approach is an efficient and economical technique to increase residual fluid catalytic cracking unit (RFCC) capacity and production of high-quality bitumen.

Artificial lifting utilizing electrical submersible pump is widely used to increase oil production from wells. A suitable control system is required in order to increase efficiency of ESP system and to avoid damage to pump and to increase safety of ESP production. Automatic control of ESP unit is not a trivial task due to the high number of parameters and variable involved. Many methods have been proposed for control of ESP lifted wells. Most methods rely on a linear model of ESP lifted well and controller designed based on this linear approximation. Linear model and controllers can fail if the process undergoes large changes in operating conditions or huge disturbances are introduced to process. Other methods solve dynamic equations governing the ESP lifted well operation. Although these methods are highly accurate; however, they are computationally expensive, and they cannot be implemented on conventional control systems. In this paper, a nonlinear dynamic model is developed for ESP lifted well. The model is then utilized inside a Nonlinear Model Predictive Control (NMPC) System. The developed model and controller performance is then tested and assessed under various scenarios. The developed controller performance shows proper reference tracking and disturbance rejection properties while the process constraint are completely satisfied.