مجله پژوهش نفت
پیاپی 133 (بهمن و اسفند 1402)

One of the key and influential factors that affect reservoir quality is the occurrence of effective diagenetic processes, including dolomitization, anhydritization, and dissolution (moldic and vuggy porosities). This research focuses on studying these processes in the Upper Dalan Member and Kangan carbonate formation located in the Central Persian Gulf. Initially, a comprehensive analysis of petrography was conducted to examine the effects of diagenesis at different depths within core samples from key well. Subsequently, well logs such as NDS, Vp/Vs, RHOB, VDL, and SPI were utilized to create electrofacies related to dolomitization, anhydritization, and dissolution using MRGC method. By applying the geostatistical kriging method to the data of electrofacies from twelve wells, three-dimensional models of dolomitization, anhydritic cementation, and dissolution processes were constructed at a field scale. Based on the sedimentary model of ramp carbonate depositional environment in the Permian-Triassic and the dolomitization model of seepage-reflux, it has been determined that in horizontal sections, the major dolomitized and anhydritic portions are predominantly observed in the southern and middle parts of the field. In the vertical sections, based on the minimum sea-level surfaces (middle K4, lower K3, upper K2, middle K2, and upper K1), the major dolomitized portions are observed in Upper K1, Upper K2, and Lower K3. The major anhydritic portions are found in Upper K1, Middle K2, and Lower K3 to the top of the boundary with K4. Considering that dissolution predominantly occurs in areas exposed to water and that most moldic and vuggy porosities are formed as a result of dissolution, dissolution is more prevalent in the southern to middle parts of horizontal sections. Consequently, there is a higher concentration of moldic and vuggy porosities in these southern to middle parts of horizontal sections. In vertical sections as well, moldic and vuggy porosities align with those seen in upper K1, upper K2, and lower K3.

In water-cooled and moderated reactors, radiolysis is the source of hydrogen, deuterium, and oxygen production, as well as hydrogen peroxide (deuterium peroxide). Modeling the radiolysis phenomenon from a safety perspective is crucial for predicting the production of corrosive or explosive compounds. In this study, a gamma radiolysis model was developed for light and heavy water, and ode15s was selected as the appropriate solver for the model. The validation results of the developed model indicate an error of less than 5%. The absorbed dose effect in the range of 0.5 to 100 Gy/s, temperature in the range of 20 to 70 °C, and the effect of initial hydrogen (deuterium) concentration in the range of zero to 50 ppb were investigated for both light and heavy water. The results showed that gamma radiolysis has more obvious effects on light water compared to heavy water, and the rate of change in the concentration of oxidizing compounds, oxygen, and hydrogen (deuterium) peroxide, is lower than the rate of change in hydrogen (deuterium) concentration. The maximum difference between the final concentration of hydrogen and deuterium occurs at an absorptive dose of 100 Gy/s, where the produced hydrogen concentration is 3.5 times higher than the produced deuterium concentration from radiolysis. As the temperature increases from 20 to 70 °C, the stable concentration of radiolysis-produced compounds decreases by a maximum of 70% for hydrogen and 50% for deuterium. Increasing the initial concentration of hydrogen (deuterium) always reduces the concentration of oxidizing species (oxygen, hydrogen (deuterium) peroxide). However, the graph of produced hydrogen (deuterium) exhibits an optimal threshold (20 ppb for hydrogen and 10 ppb for deuterium). Therefore, by controlling the absorptive dose, temperature, and initial hydrogen concentration to the optimum values, corrosion resulting from the production of oxidizing agents and hydrogen (deuterium) explosions can be prevented.

One of the most important methods of increasing extraction from carbonate reservoirs is to change the wettability of the reservoir rock with the emergence of nanotechnology, which played a significant role in the framework of methods of increasing Oil Recovery. The purpose of this project is to use nanofluids containing inorganic nanoparticles, which are economical and environmentally friendly. For this purpose, first, 3 types of inorganic nanoparticles SiO₂, Al₂O₃ and TiO₂, which were converted into nanometer size powder by mechanical method (Ball mill). Then, 3 nanofluids containing SiO₂, Al₂O₃ and TiO₂ were prepared along with dispersants and stabilizers. By performing the contact angle test, it was found that the contact angle of the oil drop on the oil-wet carbonate rock changed from 132.1° to 87.1° after coating with nanofluid with a concentration of at least 0.01 wt.%. Then the optimal concentration of nano fluid and the optimal time of thin section aging in nano fluid were determined, and the values of these parameters were 0.01% by weight and 7 days, respectively. In the following, it was shown that the stone coated with these nanofluids maintains its wettability well. Based on the interfacial tension test, it was shown that the interfacial tension decreased from 24.029 mN/m (water and oil) to 4 mN/m (nanofluid and oil) at ambient temperature. Finally, by conducting the Core Flooding test on the oil wet plugs, the investigations show that in the flooding test, the volume of extracted oil increased by 42.06% in the case of water injection to 60.09% in the case of nanofluid injection. (Residual oil decreased from 9.64 cm³ to 6.64 cm³ respectively.) In fact, the flooding recovery factor increased by 18% compared to the previous state.

In the last two decades, due to the establishment of environmental protocols and international laws such as the Kyoto and Copenhagen agreements, simultaneous storage and EOR using carbon dioxide as the main greenhouse gas has been considered. Injecting gases from combustion is one of the methods of extracting hydrocarbon gases that can minimize problems and challenges. In this study, the technical and economic analysis of the idea of injecting combustion gases (Flue gas) as an efficient, available, and cheaper method than other gas injection methods is discussed. The technical results of this project include laboratory studies and simulation outputs of the actual reservoir model performance and economic studies based on the latest price evaluations.

Today, one of the acceptable methods that has attracted the opinion of many engineers in the field of new drilling technologies is the drilling of oil and gas wells using laser technology, which has many advantages over old drilling methods. Although this type of drilling has not been done operationally. Therefore, the simulation of laboratory conditions at the bottom hole for such complex operations, like other common methods, seemed to be necessary which we will be able to create a comprehensive and accurate engineering plan and program in order to perform the mentioned operations on a field scale. The construction of laboratory pressure chamber to simulate drilling operations with the help of laser could be a big step in the direction of completing and developing this technology as quickly as possible. In the present article, the results of carbonate rock samples were evaluated using the aforementioned chamber in order to investigate the effect of laser radiation on this rock sample in bottom-hole conditions. Therefore, the stone samples inside the chamber under pressure are subjected to laser radiation to study and investigate the amount of changes in parameters such as temperature, pressure, radiation time and even the effect of thermal stress on the window designed and under pressure. Finally, it was examined the changes made in stone and glass during and after laser irradiation. It is worth mentioning that the radiation time increased by 5 seconds compared to the no-pressure state, as well as an increase in 24 degrees Celsius in the temperature parameter inside the chamber, as well as a 10 psi increase in the pressure inside the chamber, among the results of this test. On the other hand, by conducting rock mechanics tests, a significant decrease in compressive modulus before and after laser irradiation on the rock sample was happened.

Carbonation reaction in the calcium looping is a chemical process in which carbon dioxide reacts with solid calcium oxide, resulting in the production of calcium carbonate. This reaction holds significant importance as an effective method for reducing the concentration of carbon dioxide present in the atmosphere and rapid controlling of climatic changes.The carbonation reaction at two temperatures of 550 and 650°C was modeled using kinetic models of shrinking core, random pore and fractal-like. Kinetic and diffusion constants, which are two important parameters in the chemical and diffusion in the product layer controlling stages, were calculated based on experimental data. The results showed that paying no attention to the slow diffusion stage at 650°C in shrinking core model leads to increase of difference between the predicted and experimental data until 5% at the end of reaction. The results of random pore model showed that despite considering the slow stage, the fracture appeared in the model caused a 3% difference between the predicted and experimental data at the beginning of the slow stage, reached to about 5% at the end of reaction. The fractal-like model results were completely consistent with the experimental data and only a 1.5% difference was observed at the final minutes of reaction. The fractal-like model was applied to predict the carbonation reaction conversion up to 30 consecutive cycles at 650°C. The results showed that due to the sharp decrease in the free surface of the adsorbent in the early moments, as expected, the conversion percentage decreased by 38%between cycles 1 and 10, and then decreased and reached to 4% for cycles between 20 and 30.

In the present study, a data-driven soft sensor is designed based on a state-dependent parameter modeling method using the Local Instrumental Variable (LIV) approach for a polyester resin production batch process. Data from an industrial process has been used for soft sensor modeling. To design an accurate soft sensor, the non-stationary characteristic of the process is considered in the calculations by adopting the output variable of the previous moment to the set of input variables. The number of input variables of the final model was reduced from 23 variables determined by process knowledge to only 4 variables for viscosity and 3 for acidity number in this study. The final model of the soft sensor was trained with the data of one batch, as a result, the time and amount of calculations were significantly reduced. The performance results of the LIV method by MAE, RMSE, and R2 indicators were obtained as 0.0015, 0.0019, and 0.9999 for viscosity and 0.0030, 0/0094, and 0/9995 for acidity number, respectively for the batch process of polyester resin production. Compared to other soft sensor modeling methods, the LIV model predicted the quality index variables (QIV) of the product more accurately using less number of batches and input variables for model training.

As oil and gas resources play an essential role in energy, oil and gas industry technologies have also developed rapidly in recent years, such as smart drilling technology, smart oil and gas transmission pipelines, and digital offshore platforms. The oil and gas industry has four aspects: business, management and decision-making, monitoring and cyber security. Finally, the state of application programs, the level of understanding of block chain in the security of the Internet of Things in the oil and gas industry, opportunities, challenges and risks and the development process are examined. Therefore, the main goal of the research is to provide a model of block chain mechanisms for the security of the Internet of Things in the Iranian National Oil Company. The nature of the current research is exploratory and qualitative data is used in it. The statistical population of the research is the experts and professors of doctorate in management and information technology in the oil and gas industry (NISOC). In this context, the researcher used the snowball method to achieve theoretical saturation, and the researcher achieved theoretical saturation after structured interviews with 10 elites and experts. Data analysis was done with the qualitative method of Foundation Data Theory and Maxqda2020 software. The findings indicate that the causal factors affecting the block-chain mechanisms for the cyber security of the Internet of Things in the oil and gas industry in the form of three concepts, including data aggregation and storage (network), validation and identity management and key management and data encryption were identified. Also, influential background factors include nine concepts of financial resources, management, distribution of infrastructure services, data confidentiality, system stability, scalability, accessibility, transparency, expertise. and intervening (environmental) factors include seven concepts of environment. Operational standards, standards and procedures are the nature of data for mechanisms in various industries, social environment, cultural environment, government laws and regulations, political relations and the strategies of block chain mechanisms for the cyber security of the Internet of Things, in the form of six concepts of electronic health, creating a secure layer, smart transportation, smart networks, the use of smart block chain contracts, the design of industrial Internet of Things (IIOT) devices, and the consequences And the results of the implementation of block chain. Mechanisms for the cyber security of the Internet of Things in the oil and gas industry of the National Company of the Southern Oil Rich Regions(Nisoc), including the attitude of reducing production costs, high capacity for storage, intelligent field, organizational agility, environmental dynamics, security, System accessibility, improvement of the user interface, the quality of information (distribution and variety of information) and the speed of data processing.

The main advantages of surfactant flooding, including the reduction of the interfacial tension between the aqueous surfactant solution and the residual oil and wettability alteration, make it a very potential method for the enhanced oil recovery processes. Since the surface activity of surfactants and their critical micelle concentration (CMC) can be improved by mixing them, this study was aimed to evaluate the binary mixture of various surfactants, including cationic quaternary ammonium surfactant (CTAB), anionic surfactant (AOT) and non-ionic (Tween 80) with an imidazolium-based ionic liquid ([C12mim] [Cl]) in the volume ratio of 2:1. Binary surfactant mixtures have been investigated in low and high salt concentrations (650 ppm and 38350 ppm) to see the effect of salt concentration on each of the binary mixtures. After investigation of the interfacial tension of each of these mixtures, the phase behavior of each of them was investigated. In addition, the wettability alteration on dolomitic carbonate rock has been investigated. To simultaneously investigate the two mechanisms including interfacial tension reduction and wettability alteration, the spreading coefficient and capillary number were calculated. The results showed that despite the decrease in the interfacial tension of crude oil from 8.72 mN/m to less than 0.5 mN/m, this improvement has no significant impact on the creation of a favorable microemulsion and change the wettability alteration of dolomitic rock into strongly water wet state, as a result, no significant changes in the capillary number and spreading coefficient were obtained.

In many cases some barriers like low permeability, secondary porosity and decreasing in formation permeability due to damages casued by drilling, asphaltene and other problems confine oil production rate in unacceptable region and These problems reduce percentage of oil recovery from these reservoirs, These problems can be solved by utilizing hydraulic fracture method. A new model based on cohesive zone method coupling stress-seepage damage filed is developed to simulate the interaction between hydraulic fracture and natural fracture with using ABAQUS software. The effect of differential stress and approaching angle on the intersection between hydraulic fracture and natural fracture, as well as the effect of natural fracture cementing strength on the geometry of  hydraulic fracture propagation, have been investigated. While the hydraulic fracture initiates, propagates, and intersects with the natural fracture, it can either deflect into it or cross it by severing the natural fracture. The greater the approaching angle and differential stress , the easier it is for the hydraulic fracture to cross the natural fracture.The behavior of hydraulic fracture changes from deflection to crossing as the natural fracture cementing strength is increased.