مجله پژوهش نفت
پیاپی 117 (خرداد و تیر 1400)

Facies are often imported in reservoir modeling because the petrophysical properties of interest are highly correlated with facies type. Knowledge of facies constrains the range of variability in porosity and other petrophysical properties. But on the other hand, proper study and modeling of facies requires considerable time and money in reservoir studies and also, due to the fact that the three-dimensional distribution of facies in many studies has not been able to significantly reduce uncertainty, Facial modeling has not received much attention, especially in carbonate reservoirs. In this study, after modeling the facies in a carbonate reservoir, comparison of porosity simulation has been performed using three-dimensional distribution of facies and without using it. In this study, SIS method was used to simulate facies and SGS method was used to porosity simulation. Also to investigate the reduction of model uncertainty with the seismic data integrating, Acoustics impedance has been used as secondary data in porosity simulation. Besides that, neural network analysis was performed on a set of seismic attributes to get facies probability cubes. These probability cubes was entered as a trend in the simulation of the facies. Examination of the error rate in blind wells showed that it is appropriate to use SIS and SGS geo-statistical methods in case of sufficient data in a carbonate reservoir and with the use of seismic data and the distribution of facies in porosity simulation, uncertainty was reduced to an acceptable level, with an average of 87% of the model being valid.

With the discovery of sizeable sour gas fields in recent years and the reduction of sulfur prices, the economic unattractiveness has been added to the operational and environmental problems of sulfur recovery methods. The alternative solution to deal with the troublous acid gas flow resulting from sour gas sweetening is the acid gas injection into geological formations. It protects the environment from toxic and greenhouse gases and creates new opportunities for enhanced oil and gas recovery. This method’s economic attractiveness and the ever-increasing strictness of environmental laws have increased research interest in acid gas sequestration and EOR studies in recent years. There was no thorough literature review to be used as a comprehensive and rapid guide by researchers interested in acid gas studies. This review article tries to clarify the challenges and requirements that researchers may face in selecting the appropriate study technique and experimental apparatus design in acid gas studies. After reviewing reservoir rock and fluid interactions with acid gas and possible formation damage mechanisms, the importance of core-flood experiments for simulating the multi-phase flow inside geological formations in acid gas injection projects shall be explained. We will present the research areas explorable with such experiments and evaluate, compare, and analyze the several experimental techniques and prominent experimental apparatuses available in the literature used to understand the multi-phase flow and monitor the internal rock and fluid system during acid gas injection. Finally, specific safety considerations for acid gas study laboratories will be provided.

Optimal reservoir management, modeling and production, depend on understanding the connectivity between production wells in an oil reservoir. Using numerical simulation and a reservoir permeability map can clear this feature, however, it is a time-consuming method and the presence of uncertainty in the input data of simulators leads to employ other methods to understand the feature. Having new sensors that are permanently placed in the wellbore, large amounts of production data (production rate and bottom hole pressure) are available. In recent years, intelligent data-driven techniques have been used to work with the large amount of data obtained from production wells. This paper uses a data-driven approach based on detecting important production well events during its production life. Important well events are divided into three categories: (1) increasing, (2) decreasing, and (3) no flow (shut in the well by operator). These events are identified using derivative and slope of the production figures and some limiting factors. Afterwards, the algorithm has to find the related events between the production wells, and based on the importance of the events, the inter-well connectivity among production wells is determined which it is shown as a connectivity map. A synthetic reservoir was first developed in the Eclipse simulation software, and the three high-permeability streaks were considered between three well pairs. Next, its production data were used as the data-driven model’s input, which it is programmed in MATLAB software, in order to identify the three high-permeability streaks via the data-driven model.

Due to increasing environmental pollution, the use of renewable energies is very important. Proton Exchange Membrane Fuel Cell (PEMFC) is for producing renewable energy, which is applied in a wide range of fields due to its many merits, such as low emissions, high power density and high efficiency. Dimension of components of PEMFC plays an important role on its performance. In this article, Numerical solution are performed by assuming two phase, steady and isothermal. The effect of channel dimensions and thickness of gas diffusion layer, catalyst layer and membrane were studied on the performance of the PEMFC. This analysis involves studying two indicators of maximum power density and average current density, which it was investigated in a wide range of voltage operations. The results show that determining proper dimensions for cell components has a great impact on the performance. By comparing the effect of dimensions on two indicators, different rankings are obtained. Channel width and thickness of polymer membrane have the most important role in determining cell performance. Good correspondence between numerical results and experimental data is achieved.

Fluid permeability is one of the most important parameters in reservoir characterization. In this study, permeability calculated from different models and compared with the laboratory measured permeability in a hydrocarbon field in the central part of the Persian Gulf. The permeability models used in this study include Winland, Swanson, Pittman, and Dastidar. In this analysis, 50 mercury injection experiments from Dalan and Kangan formations were used. Conclusions indicate that Swanson and Winland permeability models are the best reservoir permeability prediction models for the Kangan and Dalan carbonate formations, respectively. Swanson’s model unlike other models considers the effects of pore throats in mercury injection curve as the main factor, which it has a key role in permeability prediction. In carbonate environments, there is not specific relation between porosity and permeability. Therefore, models that considered porosity as a factor for permeability prediction show less accuracy. The reservoir’s lithology (carbonate or clastic), because of the different facies and lithology, have various petrophysical features. In this manner, the models that have been calibrated based on carbonates lead to a better prediction in the carbonates in comparison with models which calibrated based on clastic or both.

During recent years, Gemini ionic liquids (ILs), as a new type of surfactants, have gained much attention due to their significant interfacial activity. Accordingly, use of these materials to reduce crude oil-water interfacial tension (IFT) and to enhance oil recovery is much advantageous. In this study, effects of concentration, temperature and pH on the crude oil-water IFT in the presence of Gemini IL surfactants were investigated. For this aim, alkyl chain length imidazolium based gemini ILs of [C4im-C4-imC4][Br2] and [C8im-C4-imC8][Br2] were synthesized and used. By measuring IFT of the system, under different conditions, the corresponding variations were considered. Results revealed the strong effect of alkyl chain length and concentration on the IFT, leading to, respectively, 72.5 and 97.5% reductions under critical micelle concentrations and temperature of 298.2 K. The Gemini IL surfactants were stable at high temperatures and under a wide range of pH, and that their performance was significantly promoted with these factors. In theoretical investigation, it was revealed that the experimental data were nicely consistent with the Frumkin adsorption isotherm and the obtained parameters with reasonable variations.

Rate production and final recycling rates are heavily influenced by permeability as a dynamic parameter, but this parameter is low in some carbonate reservoirs and requires an appropriate solution to increase it. The purpose of this study was to investigate the effect of injection and confining pressure in a laboratory study of the permeability of reservoir rocks during acid-bed corrosive operations. Considering this approach, 6 samples of carbonate reservoir rock from one of Iran’s oil fields have been prepared. After determining the physical and mechanical properties of the samples, the effect of the confining pressure and the injection pressure on permeability variations and optimal flow rates were studied. Examination of the results of the experiments as well as the CT scans of the samples after acidizing operation showed that permeability increased to an acceptable level in all samples. In lower injection rates, the acid has enough time to react with the rock, wormholes are well-formed, and the rest of the sample space retains its density to a large extent, but by increasing acid injection rates, there are wormholes changing themselves with the complete destruction of the primary core section, and the remaining density has been reduced. This is accompanied by a combination of the two above-mentioned behaviors, by increasing the rate to a maximum. This has led to an increase in over 530 times permeability over the initial value of the sample. However, there is a slight difference between the formation time of the formation of wormholes in the injected sample with maximum discharge and the sample injected with a minimum. However, there is a slight difference between the formation time of wormholes in the injected sample with maximum rate and the sample injected with a minimum.

In this investigation, the Maastrichtian deposits in the west of Fars area, have been studied along a NE-SW trending transect perpendicular to the Zagros. The Maastrichtian deposits in Fars area show a shallowing-up trend from pelagic marls and turbiditic facies of the Gurpi/Amiran Formations, outer-mid platform carbonates of the Tarbur Formation and restricted inner platform dolomitic/evaporitic limestones and marls of the lower Sachun Formation. On this basis, 12 facies types have been determined in 6 facies belts from basin to barrier, open and restricted lagoon and tidal flat in a carbonate rimmed shelf setting. These sedimentary facies and environments are organized in five 4th order depositional sequences. The sequence architecture shows a migrating foreland basin with a wedge-shaped geometry along the transect. The foreland basin is characterized by wedge shaped geometry and the subsiding and shallowing up depositional sequences with progradational patterns from the platform carbonate over the pelagic basinal facies.