فهرست مطالب

Petroleum Science and Technology - Volume:6 Issue: 1, Winter 2016

Journal of Petroleum Science and Technology
Volume:6 Issue: 1, Winter 2016

  • 120 صفحه،
  • تاریخ انتشار: 1395/02/12
  • تعداد عناوین: 12
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  • Igor Rafael Ribeiro Aires*, Beethoven Gomes Dos Santos Costa, Renalle Cristina Alves De Medeiros Nascimento, Luciana Viana Amorim Pages 1-13
    The main objective of this work is to propose a mathematical model for the differential sticking coefficient of clayey drilling fluids with a lubricant as an additive and evaluate the influence of differential pressure and lubricant content on filter cake thickness and permeability. Tests were carried out on fluids composed of water and 4.86% of active bentonite clay prepared in Hamilton Beach agitators at a high rotation speed (17000 rpm) for 20 minutes. After a 24-hour time-out in a closed container, lubricants were added to the fluids at different levels. To obtain the differential sticking coefficient (DSC), and the filter cake, a differential sticking tester by Fann with a spherical torque plate was used, and the filter cake thickness was determined in an extensometer. The setting time, differential pressure, and lubricant content were defined as the input variables (independent variables) to the DSC mathematical model. The differential pressure and lubricant rate were the independent variables to the mathematical model of filter cake thickness (FCT) and permeability (K), which varied according to a factorial planning, was known as a second order model. The experimental data regression was performed utilizing Statistic software, version 7.0. The results clearly showed that it was possible to obtain a statistically meaningful and predictive mathematical model for DSC. It was also observed that the increase in the lubricant content was responsible for a DSC value reduction due to the fact that the lubricant was a dispersing agent reducing the filtrate volume and the filter cake thickness, and thereby decreasing the sticking risk due to differential pressure. Finally, from the analysis of point values and response surfaces for FCT and K, it was possible to observe tendencies that made clear that the differential pressure and lubricant content influenced filter cake properties.
    Keywords: Fluids, Differential Sticking, Modeling
  • Ali Karimi*, Ali Mohajeri, Ali Jebreili Jolodar, Ali Morad Rashidi, Khaled Forsat Pages 14-27
    In this study, the effect of preparation technique of carbon nanotube (CNT)-supported cobalt catalysts on the activity and selectivity of Fischer-Tropsch synthesis (FTS) was studied. Different concentrations of acetic acid were used for the pretreatment of the catalyst support to modify the surface properties of CNT. This modification improved the reduction degree and dispersion of supported cobalt simultaneously. The catalysts were prepared by incipient wetness impregnation of the cobalt precursor, and deionized water was used as the preparation medium. The obtained catalysts were characterized by XRD, TPR, TEM, and H2 chemisorption. The catalysts prepared under the optimum conditions exhibited significant stability and activity for FTS reaction in a CSTR reactor during 120 hr of experimental tests.
    Keywords: Carbon Nanotube, Cobalt Catalyst, Fischer–Tropsch Synthesis, Acetic Acid, Functional Groups
  • Faisal Alreshedan*, Apostolos Kantzas Pages 28-45
    Several methodologies published in the literature can be used to construct realistic pore networks for simple rocks, whereas in complex pore geometry formations, as formed in tight reservoirs, such a construction still remains a challenge. A basic understanding of pore structure and topology is essential to overcome the challenges associated with the pore scale modeling of tight porous media. A stochastic random generation algorithm was employed to assess the effects of certain pore structure and geometries on the estimation of petrophysical and electrical properties of tight media through physically realistic 3D random networks. A Weibull truncated equation was used to predict the distribution of network pores and throats. An equivalent 3D pore network of Berea Sandstone was generated based on published pore and throat size distributions. The estimated porosity, absolute permeability, and formation factor of the reconstructed pore network are in good agreement with published laboratory measurements. Moreover, the estimated drainage and imbibition relative permeability curves are in a good match with corresponding experimental relative permeability curves. Subsequently, the effect of pore structure on basic core properties is evaluated by varying the Berea network pore size, throat size, and coordination number (connectivity) distributions. Finally, the effect of pore and throat geometries on two phase flow properties is investigated. The study shows the importance of taking into consideration the internal pore structure for petrophysical and electrical properties estimation.
    Keywords: Tight Media, 3D Random Network, Weibull Truncated Equation, Berea Sandstone, Pore Structure, Geometries
  • Yahya Zamani*, Mohammad Rahimizadeh, Seyed Mohammad Seyedi Pages 46-52
    The iron-based catalyst was prepared by a microemulsion method. The composition of the final nanosized iron catalyst, in terms of the atomic ratio, contains 100Fe/4Cu/2K. The experimental techniques of XRD, BET, TEM, and TPR were used to study the phase, structure, and morphology of the catalyst. Fischer-Tropsch synthesis (FTS) reaction test was performed in a fixed bed reactor under pressure of 17 bar, temperature of 270-310 °C, H2 to CO ratio of 1, and a Gas Hourly Space Velocity (GHSV) of 3 nl.hr-1.gCat-1. The temperature of the system as a key parameter was changed and its effect on the selectivity and reaction rate was analyzed. The results show that the rates of both reactions including FTS and water-gas shift (WGS) raised by increasing temperature. For this condition, CO conversion was also increased up to 87.6%.
    Keywords: Nanoparticles, Iron Catalyst, Catalyst Characterization, Fischer, Tropsch Synthesis
  • Ali Sibevei, Zahra Naji Azimi, Saied Ahmadjo*, Mohammad Mahdi Mortazavi Pages 53-62
    This paper considers the problem of selecting the most appropriate ethylene propylene diene monomer (EPDM), which is a polyolefin with a variety of usages in different areas. The metallocene catalyst, bis(2-phenyl indenyl) zirconium dichloride ((2-PhInd)2ZrCl2) was synthesized by a modified method and applied to the terpolymerization of ethylene, propylene, and 5-ethylidiene-2-norbornene (ENB). The methylaluminoxane (MAO) was used as a cocatalyst. It showed an appropriate activity, a high incorporation ability of the comonomers, and good performance in terpolymerization. The compounded EPDM showed good thermal stability with time. Proper criteria were chosen for the selection of the best EPDM, and a hybrid of the analytical hierarchy process (AHP) and preference ranking organization method for enrichment evaluations (PROMETHEE) was used for prioritizing 15 different synthesized EPDM species. The sensitivity and Genetic Association Interaction Analysis (GAIA) analysis were also performed. Finally, one of the polymers, which had a very high quality and moderate yield, cost, and curing time was selected.
    Keywords: AHP, PROMETHEE, MCDM, EPDM, Catalyst, Metallocene
  • Ali Roostaie, Hassan Golghanddashti*, Saeed Abbasi, Abbas Shahrabadi Pages 63-72
    Scale formation and well plugging due to the incompatibility of injected waters is a critical field problem in oil recovery. A water injection process was successfully performed when the identification of the source of water, water quality considerations, and laboratory compatibility tests were considered. When different waters are mixed, it is necessary to evaluate their compatibility prior to the injection into oil wells. Jar test is conventionally performed in the laboratory to estimate formation damage by scale formation in the wellbore and facility. The individual waters may be quite stable under all system conditions and present no scale problems. However, once they are mixed, the reaction between ions dissolved in the individual waters may form insoluble products that cause permeability damage in the vicinity of the wellbore. The obtained results from the jar test for different mixtures of waters can be used to know the type of scale in the reservoir. This work was undertaken to experimentally identify the composition of mineral scales that occur in a raw water and different volume mixings. The formation of CaSO4, SrSO4, and CaCO3 during the sampling of production waters, including different reservoir layers and mixing of their different volumes with K sample have been proved by scanning electron microscopy micrographs and X-ray diffraction. The results of jar tests for the mixing of different waters indicated that the main constituents of the scale were strontium sulfate and calcium carbonate. The results showed that mixing ratio of 75 to 25% of K water to different produced waters were the most suitable ones.
    Keywords: Incompatibility, Formation Damage, Produced Water, Inorganic Scale, Water Injection, Jar Test
  • Zeai Wang*, Jianjun Tian, Xiaozhu Huang, Weiguo Gong, Pengfei Wang Pages 73-79
    Hydroprocessing has become the main technology for the production of API Group II and III base oils. One of the key properties is viscosity index for Group II and III base oils. The effect of wax content in hydrocracker unconverted oil on viscosity index and yield was studied in a 400 kton/year hydroisomerization dewaxing plant at a total pressure of 15 MPa, a feed rate of 38 ton/hour, and a gas to oil ratio of 710 Nm3(H2)/m3(feed). The contribution of wax hydroisomerization to the viscosity index of the main product 150N base oil increases with the wax content in the 11-19% range and reaches a constant value of 6 VI units rather than continuously rising with the wax content. The 150N yield decreases about 1.3%, when the wax content increases by 1%. This is related to a higher dewaxing temperature required at increased wax contents in order to keep the low pour point of 150N, which results in more multi-branched compounds with a low viscosity index in the base oils and more light hydrocracking products.
    Keywords: Mineral Base Stock Refining, Hydroisomerization Dewaxing, Base Oil, Viscosity Index
  • Jamal Aalaie* Pages 80-87
    In this work, nanocomposite (NC) hydrogels based on polyacrylamide/chromium triacetate were prepared at different reaction mixture (gelant) volumes and their crosslinking process and viscoelastic behaviors were studied. The X-ray diffraction (XRD) patterns taken from the NC hydrogels containing laponite nanoparticles did not show any distinct characteristic basal reflection for all of the NC hydrogels. Evaluating the crosslinking behavior of the gelants revealed that the torque value of the gelation increased with increasing the gelant volume. In addition, four successive steps in the gelation behavior were identified. According to the dynamic rheometry analysis of the prepared hydrogels, the storage modulus plateau range and its value decreased with increasing the gelant volume. Shear thinning behaviors were seen for all of the prepared gels. However, the gels prepared at larger gelant volumes showed a lower viscosity. The elastic properties of the NC gel were higher than that of the conventional gel. However, the addition of the laponite nanoparticles into the polyacrylamide gelling system slightly decreased the viscous energy dissipating and damping properties.
    Keywords: Polyacrylamide, Gelation, Nanocomposite Hydrogel, Viscoelastic Properties, Water Shut, off
  • Yusong Yuan*, Dongsheng Sun, Juanhua Lin Pages 88-97
    Weiyuan gas field, located in the Sichuan basin of south China, is a large marine gas field with the oldest reservoir (the Sinian sequences) in south China. The hydrocarbon origin of the gas field has long been debated by petroleum geologists. Recently, it was recognized that a paleo-oil pool maybe the significant contributor to the gas field. Consequently, when the paleo-oil pool had been cracked into gas has become an interesting topic. Actually, the time determination of oil cracking into gas is of significance to marine gas reservoir exploration in south China, because it is a pervasive hydrocarbon resource of marine gas reservoirs in south China. Characteristics of the gas composition, fluid inclusion, and bitumen in Sinian reservoir show that the present-day Weiyuan gas field originates from a paleo-oil pool cracked at high temperature. Data collected from the previous documents show that the temperature window of oil cracking into gas is around 160 to 210 °C on a geological time scale. On the basis of vitrinite reflectance, the heat flow history and erosion thickness in Weiyuan area were reconstructed. With the combination of heat flow history and burial history, the temperature history the paleo-oil pool experienced was reconstructed. The time of the paleo-oil cracking into gas is determined according to the oil cracking temperature window. The results show that the oil in the Weiyuan Sinian paleo-oil pool cracked into gas during the late Triassic to Eocene age.
    Keywords: Sichuan Basin, Weiyuan Paleo, oil Pool, Oil Cracking into Gas, Oil Cracking Temperature Window, Heat Flow History
  • Wanying Liu*, Ying Liu, Guisheng Huang, Jianhong Fu, Yong Pan, Ambrish Singh Pages 98-108
    A gas kick simulation model for deep-water horizontal well with diesel-based drilling fluid is presented in this paper. This model is mainly based on the mass, momentum, and energy conservation equations. The unique aspect of this model is the fluid-gas coupling and the change of mud properties after the gas influx from the formation. The simulation results show that the gas in an annulus dissolves first and it then escapes from the drilling fluid due to the gas solution in diesel. Therefore, it is possible to avoid existing gas hydrate by using oil-based drilling fluids. When gas kick occurred, it will be more dangerous, if the well has a longer horizontal section, a greater gas influx from the formation, and smaller displacement. The occurrence and development of overflow will be very quick in the condition of pumping; it will also be more dangerous, when diesel-based drilling fluid is used in the deep-water horizontal wells.
    Keywords: Deep, water Horizontal Well, Multi, phase Flow, Drilling Fluid, Diesel, based Drilling Fluid, Dynamic Simulation
  • Hamid Soltanian*, Ali Reza Mortazavi Pages 109-114
    It has long been known that temperature during circulation and after cement placement is one of the most important parameters for slurry design and the success in cement production. Conventional cements and low density cement slurries usually take a long time to set and cannot provide significant compressive strength. Therefore, it is important to design appropriate low density cement slurries for low temperature conditions during surface casing cementation. In well cementing procedures, the slurry must be fluid for a sufficient time to allow the task to be completed. One of the problems that frequently happens in cementing a low temperature formation is a long setting time, in which the cement is influenced by low temperatures and the thickening time increases. To solve this problem, a unique cement system, which contains nanosilica, hollow spherical material, and class-G oil well cement, was developed for the first time. For this purpose, some additives such as; dispersants and fluid loss control agents were used in the cement system. The laboratory tests show that this slurry has a low density, excellent fluid loss control, no free fluid, right-angle-set, and a short thickening time (47 minutes) at low temperatures. The experimental results presented herein can help resolving problems in surface casing cementing
    Keywords: Nanoaccelerator, Cement, Compressive Strength
  • Ghasem Khatinzadeh*, Mohammad Mahdyarfar, Amir Naser Ahmadi, Ali Mehdizadeh Pages 115-119
    In this work, the effects of permeate pressure and feed flow rate on the performance of a composite polyvinyl alcohol (PVA) membrane in the removal of benzene from gasoline by pervaporation (PV) were evaluated. The results indicate the remarkable effect of permeate pressure on membrane performance as reducing permeate pressure (higher vacuum) from 30 to 3 mmHg causes the total flux to increase from 6.6 to 51.7 g/hrm2 and from 12.2 to 79 g/hrm2 at 25 and 35 °C respectively. Furthermore, increasing feed flow rate enhances total flux and diminishes the amount of benzene in retentate (product) only below 1000 ml/min and has a negligible effect at higher flow rates.
    Keywords: Pervaporation, Benzene, Gasoline, Polyvinyl Alcohol, Flow Rate