مجله پژوهش نفت
پیاپی 124 (امرداد و شهریور 1401)

One of the challenges of directional drilling is guiding the bit in the appropriate direction so that it follows the planned path with minimal error. Improving the follow-up of the designed trajectory is especially important when the drilled layer is thin and if the drilling accuracy is low, it causes some problems in the well. In such cases, using smart tools, such as rotary steerable system (RSS) technology, is inevitable. In this paper, the Perneder-Detournay’s analytical method, which models the directional drilling system as a nonlinear delayed system with uncertainty, is used. To date, no proof of stability based on Lyapunov function has been performed to make this system intelligent. The main innovation of the present paper is that it has been able to provide a new formulation for system equations so that it is possible to use the Lyapunov function of delayed systems to prove system stability. For this purpose, in addition to reducing the order of the system, the nonlinear terms of the system have also become indefinite and entered the system. With these two changes, the optimal Lyapunov function for robust control of a linearly delayed system with uncertainty is extracted and by converting the Lyapunov function to linear matrix inequality (LMI) and then solving the LMI using the Mosek solver, the directional drilling system has been made smart and simulated. Finally, the tracking problem for the directional drilling system is solved. At all stages, the force coming from the RSS side is within the operational range of the directional drilling. Comparison of simulation results with previous works shows the improvement of the performance of the proposed intelligence method.

Fluid flow simulation and solid phase deformations in porous media are important steps in management and development of oil production of reservoirs. Since fluid simulation in all scales has severe computational cost, multiscale models have been developed recently. Moreover, the role of solid phase deformation in fluid flow and in oil production could not be neglected. In this research, the new mixed multiscale-multiphysics model has been developed. .the new model of mixed multiscale Multiphysics has been developed.  In the present model, not only could the role of elastic deformation in the fluid flow be considered, but also, plastic deformation affecting in the oil production rate could be regarded. The development of the base geotechnical model is performed with respect to the yield surface criterion and none associated flow role theory with the aid of implicit integrating and return mapping. The results were compared with other numerical method and also experimental results and reasonable agreement were achieved. Moreover, the computational efficiency of the present model is proved through the precise analytical calculation. The results confirm that the new model could simulate an oil production rate in an appropriate manner with the high computational efficiency.

Identifying and locating stratigraphic traps is more difficult than structural traps because they are dependent on facies changes and their distribution follow the condition of the basin and the sedimentary environment. Accordingly, the three - dimensional seismic data based on seismic attributes provide a better way to establish lateral relationships with geological features. The purpose of this research is to identify the stratigraphic meandering channels by applying appropriate attributes on seismic data. For this purpose, three dimensional data from one of the northeastern fields of the Iran were employed by using Petrel software. Afterwards, the relevant attributes were applied on the raw sections and their reservoir characteristics were interpreted and surveyed. Through stratigraphic interpretations, the geometrical position of the meandering channels located in the Shurijeh Formation was better revealed by the envelope and extended spectral decomposition attributes. The spectral decomposition attribute was effective in revealing the geometry of meandering channels in seismic sections, and the envelope attribute confirmed the existence of meandering channels by showing bright spots related to stratigraphic oil traps. These results show good agreement with the results of lithological, facies, reservoir properties, and petrophysical interpretations of Shurijeh Formation in the study area.

In the present study, the process of optical degradation of methyl orange dye pollutant was studied using BiOI / Clinoptilolite nanostructured photocatalysts to investigate the effects of clinoptilolite natural zeolite support and BiOI nanoparticle loading on photocatalytic activity. For this purpose, different amounts of BiOI photocatalysts on clinoptilolite (10, 20, 30 and 40 wt.%) were synthesized via sonochemical-precipitation method. The synthesized photocatalysts were characterized by XRD, FESEM, EDX, PL and UV-vis techniques. The results of identification analyzes indicate the accuracy of the synthesis of synthetic samples. By examining the effect of operating parameters, the maximum amount of methyl orange photocatalytic removal (100%) was obtained under optimal reaction time of 2 hours, 5 ppm pollutant concentration and 0.5 g/L amount of photocatalyst under ultraviolet light. Also, by examining different kinetic models for the selected catalyst, the conformity of the second-order, modified Freundlich, parabolic diffusion models with the methyl orange removal process with R2 >0.99 was confirmed. In addition, as expected from the results of UV-vis analysis, the optimal B (30)/CLT photocatalyst showed desirable performance under visible light radiation for the degradation of dye (82%).

Sand production in sandstone reservoirs is a vital issue in oil and gas fields due to the damage and economic problems it entails. Sand production leads to many problems such as erosion of facility of well and surface equipment, environmental problems, reduction and interruption in production and Sometimes it causes the loss of wells. Therefore, controlling sand production from wells prone to sand production is very important. So far, various methods, including mechanical and chemical, have been proposed and performed to control sand production, which are consolidated in chemical methods by injecting polymer fluids such as resins, etc. to the sand formation. The main purpose of this study is to provide aqueous-based resin that, in addition to creating compressive strength and slightly reducing permeability, is environmentally friendly and effective in terms of health and safety in comparison with solvent-based resins. By combining different percentages of resin and its suitable hardener with the produced sand sample, different core samples were made with different percentages. The fabricated cores were tested for permeability and compressive strength. Experiments showed that the fluid used has the ability to chemically consolidate the sand and the compressive strength and permeability values also change with the amount of resin and hardener composition.

The oil industry is one of the most significant strategic industries in countries with oil reserves. For this reason, politicians desire to know how to choose a condition with maximum exploitation but minimum cost. In recent years, most of the experts have been paying attention to intelligent oil fields owing to their advantages. Intelligent oil fields and operational integrated systems can reduce the number of drilling operations and as a result, lower the costs of drilling. On the other hand, intelligent equipment will decrease water production from the field, improve the quality of the produced oil, and reduce the costs of water production. This paper focuses on generalizing production data values and exploitation costs of the oil field, from the conventional field to an intelligent one. To this end, a model of the system dynamic was developed in VENSIM software to assess the effective factors on intelligent oil fields, the value of reducing water production, and lowering drilling cost in the intelligent state. Eventually, it was found out that the costs of drilling and water production are dependent on the price variation of each oil barrel, the percentage of the lack of equipment, and the power of current suppliers. The variation of each factor has a remarkable effect on the costs of drilling and water production with oil.

In this study, stability of aqueous foam is increased by modified nanoparticles using surfactant. To better understand the behavior of stabilized foam with nanoparticles and surfactants, foam ability, stability, wettability changes of nanoparticle, and interfacial tension versus time were investigated. The results of contact angle of calcite/crude-oil/foam agent solution showed that adding CTAB surfactant to silica nanofluid changes the wettability of nanoparticles. At a concentration of critical micelle concentration of surfactant, the nanoparticle experiences the greatest change in wettability towards hydrophobicity, and contact angle increases from 20° at initial time to 57° after 24 hours. The results showed that at the mentioned concentration, the interfacial tension reaches its maximum value. This phenomenon was attributed to the reduction of free surfactants due to adsorption on the nanoparticles. Stability and foaming behaviors were investigated by Ross-Miles method. Foam stabilized with nanoparticles at low hydrophobic values at the beginning of life had a linear decay diagram similar to foam stabilized with surfactant alone. Therefore, the initial stability of the foam is controlled by the free surfactant. Later, the stability of the foam is controlled by the nanoparticles and increases substantially as the bridging mechanisms become more prominent, maximum capillary pressure increases, and viscosity of the liquid bulk increases. At high levels of nanoparticle hydrophobicity (close to CMC 1), the nanoparticles act as surfactants and no longer have the sharp linear drop observed in other samples with low adsorption values. Therefore, the beginning of the foam life is controlled by both nanoparticles and free surfactant. The results showed that the foaming behavior of foam generating solutions is similar to the interfacial tensile behavior. Also, the change in wettability of nanoparticles, which had a long equilibrium time, was proposed as a mechanism for high stability of nanoparticle-stabilized foam in the second half of its life.

Assessment of petroleum generation potential of the source rock as a function of total organic carbon content and kerogen type is of great importance in oil and gas exploration studies. The main aim of this research is to compare the performance of artificial neural networks trained by back propagation algorithm (ANN-BP) and metaheuristic methods including genetic algorithm (ANN-GA) and particle swarm optimization (ANN-PSO) for prediction of total organic carbon (TOC) content and remaining petroleum potential (S2) from the wireline data. For this purpose, Pabdeh Formation (Paleocene-Oligocene) in Mansuri oilfield is studied. Based on the results of linear regression on the test data, ANN-PSO method provides more accurate predictions of Rock-Eval derived TOC and S2 parameters with correlation coefficient (R2) values of 0.8548 and 0.9089, respectively. In addition, hydrogen index (HI) is appropriately predicted based on the relationship between TOC and S2 values obtained from the ANN-PSO method with R2 value of 0.6882, from which different types of kerogen can be distinguished with classification accuracy of 74 percent. Geochemical zonation of Pabdeh Formation based on organic richness and kerogen type reveals three distinctive parts, among which the middle part (Brown Shale Unit, BSU) demonstrates the greater petroleum generation potential with having the significant values of total organic carbon and hydrogen index. Therefore, the BSU can play an important role in hydrocarbon charging of the oilfield traps if it attains proper level of thermal maturity. Accordingly, precise determination of petroleum generation characteristics of Pabdeh Formation using the ANN-PSO model proposed in this study will lead to a reduction in uncertainty associated with petroleum system modeling, and therefore will considerably increase the exploration efficiency in the Mansuri oilfield.

In this study, solvent extraction during gas-liquid-liquid flow in a microchannel was investigated. Sodium hydroxide aqueous solution, acetic acid dissolved in n-hexane and nitrogen were employed as the aqueous, organic and gaseous phases, respectively. The microchannel was made of glass with a cross sectional dimension of 800×700 µm2. In the two-phase mode (without the gas phase), the flow regime was slug flow, while in the three-phase flow mode, the flow pattern was a double emulsion (gas in organic in water) flow. By increasing the total fluid flow from 0.005 to 0.020 mL/s, the overall volumetric mass transfer coefficient enhanced on average by 140%. Using the gas phase did not always improve the mass transfer coefficient in the microchannel. For example, at a constant liquids flow rate of 0.005 mL/s, increasing the gas flow rate from 0 to 0.1 mL/s, deteriorated the mass transfer coefficient, however, increasing the gas flow rate up to 0.2 mL/s led to augmentation of the mass transfer coefficient.

Injection of nanoparticle-stabilized foam has been considered by the oil industry due to its high stability. In this study, the interaction between nanoparticles and surfactants as well as the hysteresis of the foam injection sequence is investigated. For this purpose, secondary and tertiary core injection experiments were performed on synthetic glass core to investigate the oil recovery behavior of foam stabilized with calcium carbonate nanoparticles and SDS surfactant in sandstone reservoirs. According to the results, the secondary oil recovery by foam stabilized with a mixture of 0.04 wt.% of surfactant and 0.1 wt.%  of nanoparticles is significantly higher than the foam stabilized with counterpart nanoparticle and surfactant. In all cases, tertiary oil recovery was significantly lower than the tertiary mode. This phenomenon was attributed to the diffusion regime governing tertiary recovery compared to the convective regime in the secondary injection. In order to prove this hypothesis, the aging process performed in the core injection experiments was repeated in the contact angle device. In the diffusion regime, the nano fluid could not change the wettability of the glass to more water-wetness. The surfactant solution reduced the glass oil-wetness by only 5 degrees. The mixture of surfactant and nanoparticles brought this change in wettability to 16. The Nano fluid, surfactant solution, and mixture of surfactant and nanoparticles brought the initial wettability of about 150˚ to 76˚, 45˚, and 23, respectively, which it confirms the higher rate of convective regime in the change of wettability. Based on surface tension experiments, the superior behavior of the surfactant and nanoparticle mixture was attributed to the adsorption of surfactant molecules on the nanoparticles and the surface activation of the nanoparticles.