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Petroleum Science and Technology - Volume:4 Issue: 2, Autumn 2014

Journal of Petroleum Science and Technology
Volume:4 Issue: 2, Autumn 2014

  • تاریخ انتشار: 1393/08/01
  • تعداد عناوین: 8
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  • Maryam Jouyandeh, Mehdi Moayed Mohseni, Fariborz Rashidi Pages 1-9
    A theoretical solution is presented for the forced convection heat transfer of a viscoelastic fluid obeying the Giesekus constitutive equation in a concentric annulus under steady state, laminar, and purely tangential flow. A relative rotational motion exists between the inner and the outer cylinders, which induces the flow. A constant temperature was set in both cylinders, in this study. The fluid properties are taken as constants and axial conduction is negligible, but the effect of viscous dissipation is included. The dimensionless temperature profile, the normalized bulk temperature, and the inner and outer Nusselt numbers are derived from solving non-dimensional energy equation as a function of all relevant non-dimensional parameters. The effects of Deborah number (De), mobility factor (α), Brinkman number (Br) and velocity ratio (β) on the normalized temperature profile and Nusselt number are investigated. The results indicate the significant effects of these parameters on the dimensionless temperature distribution and Nusselt number.
    Keywords: Viscoelastic Fluid, Giesekus Model, Elasticity, Viscous Dissipation, Nusselt Number
  • Ali Ghajari, Hamid Soltanian, Seyyed Alireza Mortazavi Pages 10-19
    This study experimentally investigates the effect of multi-walled carbon nanotubes (MWNT’s), as a reinforcing material, on the physical properties of heavy-weight oil well cements. A candidate well is selected and the properties of the cement slurry used in a problematic section of the well are tested in the laboratory. Carbon nanotubes (CNT’s) are added as fibers to the cement slurry and the improvements in the cement slurry and stone properties are studied. This work discusses the problems associated with conventional heavy-weight oil well cement used in the candidate well and reports the detail of the improvements on cement properties obtained by adding CNT’s to cement slurry formulation. These properties include cement slurry rheological properties, free water, fluid loss, thickening time, cement stone elasticity, and compressive strength. When only 1 wt.% of CNT is added to the cement slurry, the yield point and plastic viscosity increase by eight and five times respectively, while the free water and fluid loss of cement slurry are reduced by 85% and 70% respectively. In addition, cement stone compressive strength increases by 73.8%. Moreover, the elastic properties of the cement stone are improved and higher values for the Young''s modulus and Poisson''s ratio are achieved; however, there is an optimum concentration of nano-additive at which the maximum yield point, plastic viscosity, compressive strength, Young''s modulus, and Poisson''s ratio are reached. The results of this study can be used to optimize the cement slurry design in any given set of conditions.
    Keywords: Carbon Nanotubes, Oil Well Cement, Thickening Time, Compressive Strength, Rheology, Young's Modulus, Poisson's Ratio
  • Akram Vahidi, Mohammad Ahmadi, Alireza Nourmohammad Pages 20-27
    Carbon dioxide flooding is considered to be one of the most effective enhanced oil recovery methods for the light oil reservoirs. Depending on the operating pressure, the process might be miscible or immiscible. Minimum miscibility pressure (MMP) is the most important parameter for assessing the applicability of any miscible gas flood for an oil reservoir. The miscibility condition is determined by conducting displacement tests at various pressures and the recovery is expected to improve as the displacement pressure increases, and then stays almost constant above the MMP. In this study, the MMP of pure carbon dioxide and an Iranian oil reservoir is estimated using slim-tube test. The experiment is performed under constant CO2 injection rate anddifferent displacement pressures above the bubble point pressure; input and output pressures are continually monitored during the test; the effluent liquid is flashed to atmospheric conditions and produced gases are passed through gas chromatography for compositional analysis. Volumetric oil recovery is measured, and oil recovery is plotted against the injection pressure at a 1.2 pore volume of the injected fluid. The results show that the oil recovery is more than 90% of original oil in place for all the pressures with a constant slope above the bubble point pressure. Therefore, MMP is considered to be equal to the bubble point pressure. In addition to the plot of oil recovery versus pressure, miscibility is also confirmed by the effluent gas composition, slim-tube pressure drop, and visual observations of phase behavior. The single phase high pressure fluid at the outlet of slim-tube, the small pressure drop across it, and no methane bank in the composition of effluent gas indicate that the miscibility is completely achieved. The experimental results are validated by modeling the test using a fully compositional simulator. The effect of varying CO2 mole fraction in the injected fluid is also investigated. The results show that an increase in CO2 mole fraction of the injected gas significantly decreases MMP.
    Keywords: CO2 Injection, Minimum Miscibility Pressure (MMP), Slim Tube Test, Compositional Simulation
  • Roghayyeh Lotfi, Alimorad Rashidi, Ehsaneh Fakhrmusavi, Mahmood Fatemi, Masoud Zare, Maryam Rashtchi Pages 28-34
    Single-walled carbon nanotubes (SWNTs) with high yield and quality were synthesized using chemical vapor deposition (CVD) over Co-Mo/ MgO nanocatalyst in a fluidized bed reactor. Different parameters such as temperature, the ratio of hydrocarbon source to hydrogen, the flow rate of gas, growth time, the size of catalyst particles, heating rate, and the kind of hydrocarbon source were examined to assess their effects on the SWNT synthesis. The influence of these parameters on the carbon nanotubes yield and quality is also reported. Single-walled carbon nanotubes were characterized by using different characterization techniques including thermo-gravimetric analysis (TGA), scanning electron microscopy (SEM), tunneling electron microscopy (TEM), Raman spectroscopy, and X-ray diffraction (XRD). Under the optimum operation conditions (900 °C, 30 min, rate of gas=1800 ml/min, heating rate of 7 °C/min, size of catalyst particle=212 μm, volumetric ratio of hydrocarbon source to hydrogen=1:1), single-walled carbon nanotubes with an average diameter of 0.9 nm and a yield of 300% (related to the catalyst) were produced.
    Keywords: Chemical Vapor Deposition, SWNT, Electron Microscopy, Raman Spectroscopy, Thermo, gravimetric Analysis
  • Baolun Niu, Ruijian Deng, Yiqing Lin, Xinrong Wu, Zhang Zhang, Changhua Yang, Weidong Yang, Zhaomin Li, Shaoran Ren Pages 35-42
    CO2 injection is an effective technique for improved oil recovery in light oil reservoirs, especially for water flooding abandoned reservoirs. In this study, the lower part of Es1 reservoirs in Pucheng oilfield was introduced as the target reservoir. By studying the minimum miscible pressure in CO2 flooding, the reservoir could achieve miscible flooding. Long core displacement experiments proved that water alternating CO2 flooding could significantly improve the recovery. For the reservoir characteristics, anti-corrosion technology in the process of injection was researched, and the H-20 inhibitor was screened. A channeling blocking agent in combination with the delayed expansion of gel particles and cross-linked copolymer was used to control the gas fluidity. The Pu 1-1 well groups were optimized to conduct a field trial. The cumulative injected liquid CO2 was 19219.95 ton, 0.248 PV and the cumulative increasing oil was 4520.9 t. The predicted recovery will increase by 8.3%. The successful implementation of the project can provide technical attempt for completion of energy to succeed and energy-saving emission reduction targets.
    Keywords: Gas Injection, IOR, Water Alternating CO2 Injection, CO2 Corrosion, CO2 Foam
  • Maryam Sadi, Jafar Sadeghzadeh Ahari, Saeed Zarrinpashne Pages 43-55
    The oxidative coupling of methane (OCM) performance over Na-W-Mn/SiO2 at elevated pressures has been simulated by adaptive neuro fuzzy inference system (ANFIS) using reaction data gathered in an isothermal fixed bed microreactor. In the designed neuro fuzzy models, three important parameters such as methane to oxygen ratio, gas hourly space velocity (GHSV), and reaction temperature were considered as inputs and methane conversion and the selectivity of product hydrocarbons (C2+) were chosen as outputs. Two five-layer neuro fuzzy models based on the partitioning algorithm were designed at each reaction pressure to predict the product hydrocarbons (C2+) selectivity and methane conversion separately as a linear combination of inputs by the optimal selection of number and type of the membership functions. Moreover, to evaluate the ability and accuracy of the developed neuro fuzzy models in the prediction of OCM reaction performance, the results of ANFIS models were compared with experimental data and artificial neural network outputs. The comparison was carried out by the calculation of some statistical parameters such as correlation coefficient (R2), mean squared error (MSE), and average relative deviation (ARD). The results show that there are excellent agreement between model predictions and experimental data and the proposed ANFIS model can predict the methane conversion and product hydrocarbons (C2+) selectivity under different operating conditions by high accuracy.
    Keywords: Oxidative Coupling of Methane, Neuro Fuzzy, Modeling, Conversion, Selectivity
  • Mohammad Saber Karambeigi, Ali Haghighi Asl, Masoud Nasiri Pages 56-66
    Treated sea water is the most significant source of water and surfactant floods. The various chemicals employed in treatment plants should be compatible with surfactant systems. Based on surface tension experiments, the activity of these chemicals is examined over a wide range of concentrations in different solutions, including distillated water, sea water by using three types of surfactant mixtures. For this purpose, the conventional chemicals of a typical water treatment plant, namely scale inhibitor, corrosion inhibitor, biocide, O2 scavenger, coagulant, and antifoam, were selected. The results show chemicals are completely compatible with the surfactant systems in concentrations utilized for an oilfield dosage. Scale inhibitor, O2 scavenger, and coagulant did not show any surface properties, but the positive effects of the other chemicals on the reduction of the surface tension were observed. The interaction of active chemicals was evaluated using response surface methodology. The results demonstrate that antifoam had more significant effects on the reduction of the surface tension than corrosion inhibitor and biocide.
    Keywords: Oilfield Chemicals, Surface Tension, Surfactant, Response Surface Methodology, Water Flooding
  • Alireza Shakeri, Somayeh Parham Pages 67-78
    Mauddud member with the age of late Albian to Cenomanian is equivalent to the lower Sarvak formation in the southern Persian Gulf and adjacent area. In this work, microfacies, depositional environment, and diagenetic processes affected the Mauddud member in a field in the Persian Gulf are investigated. Based on the studies of available cores and thin sections of 3 wells, five types of microfacies, namely MF1 to MF5, have been identified in the Mauddud member. These microfacies have been deposited in 2 facies belt including a vast lagoon and local bioclastic shoal. Based on the lack of great barrier reefs and calciturbidities and gradual change of microfacies into each other, it is concluded that the Mauddud member was deposited on a shallow marine homoclinal ramp. Several diagenetic processes such as bioturbation, micritization, dissolution, cementation, dolomitizetion, and compaction have influenced this member. Among all, dissolution increased porosity and thereby reservoir quality, while cementation and compaction decreased reservoir characteristics. Finally, it was found out that matrix porosity was the main type of porosity in the studied interval.
    Keywords: Mauddud Member, Microfacies, Depositional Environment, Diagenetic Processes, Reservoir Quality, The Persian Gulf