PETROLEUM RESEARCH
Year:2013 | Volume:23 | Issue:73|Papers Count:13

A lumped kinetic model is proposed for i-butane cracking over an HZSM-5 zeolite catalyst (SiO2/Al2O3=484) and the experiments were carried out in a fixed bed reactor in the broad range of temperature of 470-530 oC and at a partial pressure of 20 kPa for i-butane and a total pressure of 104 kPa. Nitrogen was utilized in the experiments for adjusting the partial pressure of hydrocarbon feed and desired feed contact time. Due to the simple product distribution of i-butane cracking reaction, the proposed lumped kinetic model only consisted of 6 reaction steps and 5 lumped compounds including methane, i-butane, paraffins, olefins, and heavy components. The kinetic parameters of rate equations were obtained through the minimization of error objective function and the results indicated that the proposed model could predict the experimental data quite well. Finally, the statistical analysis of the kinetic model confirmed the validity of the model and the significance of the optimized values of the kinetic constants.

Nuclear magnetic resonance (NMR) is the response of atomic nucleus to external magnetic fields. In this work we have investigated the new method of MRIL, well logging by use of Nuclear magnetic resonance, to determine petrophysics parameters, such as porosity and pore size distribution to estimate hydrocarbon in the reservoir. Using the NMR data, we have calculated porosity and then compaired it with the neutron porosity. The results show good agreement between NMR porosity and the core porosity, but the neutron porosity is more than the core value.

The simulation of hydrodynamic and heat transfer phenomena in a catalytic reforming reactor is performed with the help of computational fluid dynamics. The governing equations of mass, momentum, and energy conservation are simultaneously solved together with turbulence equations through finite volume elements. The residence time distribution of each reactor is obtained using step tracer injection technique. Dispersion parameter for every reactor is evaluated and reported. By modifying geometry and reactor internals, we are successful to gain uniform flow distribution and to enhance the reactor capacity. It is found that capacity enhancement and an increase in the resistance of fluid distributors can improve uniformity. To take into account the amount of heat generated or consumed by the catalytic reactions, some volumetric heat sources are defined in the energy equation. The results show that the majority of temperature fall occurs through the first reactor because of endothermic rigorous reactions. It is also found out that heat dissipation decreases up to 35%, if the insulation thickness increases twofold.

A smart well is a well that is equipped with some devices improving the recovery of oil fields with the integration of the device performances. By using this technology the Capex, Opex, and interventional costs of oil fields will be decreased and more hydrocarbon can be produced as a result of the improved reservoir management. For these purposes and also for the added value of this technology, the smart well pilot has been designed. This setup, like other setups, needs to be designed according to our purpose. The design should simulate the real operating conditions of oil wells. These similarities are important in the aspects of hydrodynamics (such as pipe diameters, rate, etc.), operation (such as operational pressure and temperature) and thermodynamics similarity (such as operating fluid type). The pilot was designed with respect to the real oil reservoirs to support pressures up to 3, 000 psi, temperatures up to 200oF, and oil flow rates up to 2, 000 bbl per day. In addition, after designing and constructing the pilot, a computer package was programmed for the real-time demonstration of the data acquired from sensors including pressure, temperature, and flow rate. The main characteristic of this software is the ability to retrieve and save data, demonstrate data online, calculate the physical fluid properties, and also determine the flow regime. Furthermore, for testing the reliability and confidence of the package results, the results obtained were compared with those of a few different commercial packages and experimental data; acceptable results were obtained.

In order to evaluate the pore system of Jahrum Formation in coastal Fars, the microscopic examination and image analysis of thin sections have been done. Based on this investigation, 7 rock types have been identified and RCAL data and petrophysical logs are used. Finally, the results of the image analysis were compared with the experimental and petrophysical investigations. Image analysis is an easy and strong method in the evaluation of rock porosity; it is also cheaper and faster. In addition, this method provides valuable data on the type, shape, size, and distribution of pores. These data provide a thorough and accurate understanding of the reservoir rock quality.

In this study, an Oil-Water cylindrical cyclone separator is simulated by CFD techniques. The non-isotropic Reynolds stress turbulence model (RSM) and eulerian-eulerian (E-E) multiphase approach are applied. The semi-implicit pressure linked equations (SIMPLE) algorithm is used for the combination of continuity and pressure driven flow equation for two phases to gain the pressure distribution inside the cyclone. The CFD simulation results show good agreement with the reported experimental data. The results show that cyclone efficiency is decreased by increasing the split ratio (SR), and the vortex created on the top of the feed line is deformed. Additionally, the vortex length of the bottom of the feed line increases until SR is equal to 0.50, and then decreases. The optimum height of cyclone can be found according to the vortex length at each special split ratio.

The current study investigated the adsorption characteristics of phenanthroline and 2,2’-bipyridine from aqueous solutions on the new modified nanosorbent by the solid phase extraction method and UV spectroscopic technique. The selection of the appropriate extraction system is an important stage in the elaboration of the analytical procedure; also, the knowledge of the relations/interactions between isolated compounds, sorbent, and elution solvents is very important in the selection of the extraction system. In this work, CMK-1 mesoporous carbon molecular sieves were synthesized using mesoporous MCM-48 silica with various pore diameters as template and then modified by sodium dodecyl sulfate surfactant (SDS) and Fe+3 ions. This CMK-1 typed ordered nanoporous carbon was investigated as a novel solid phase extraction sorbent for the first time. The structural order and textural properties of the modified synthesized material were studied by XRD analysis, nitrogen adsorption-desorption analysis, SEM photograph, and FTIR technique. These PANH compounds were selectively adsorbed in a column which was filled up with this modified sorbent. Subsequently, the adsorbed analytes were eluted with dimethyl sulfoxide (DMSO) and their concentrations were measured by UV-vis instrument. The results showed that the limits of detection (based on 3σ) for phenanthroline and 2, 2’-bipyridine were 8.75 and 10.1 mg.l-1 respectively. Finally, the extraction and determination of phenanthroline and 2, 2’-bipyridine from real aqueous samples were successfully investigated.

The significance of preparing representative reservoir fluids in optimizing reservoir management is clearly obvious for experts, and it has always been tried to prepare a representative fluid at the early life of reservoir by standard methods. This will lead to the reduction of inaccuracy and causes an appropriate prediction of phase and flow behavior of reservoir. Methods of preparing an original reservoir fluid are mentioned in various standards like API-RP44 in details. These methods are on the basis of stabilizing reservoir and sampling conditions. In 1994, Fevang and Whitson presented a new method titled equilibrium contact mixing (ECM). They claimed that this method was operational for gas condensate reservoirs in any conditions. Their method reversed the dominant standards of sampling and had no time limitation in preparing representative fluid from the collected samples. This paper examines ECM techniques and checks the verity of this method in various conditions. For this purpose, a synthetic model consists of lean and rich gas condensate reservoirs in saturated and under saturated conditions and surface separator facilities are constructed. After production and sampling from models, ECM and recombination techniques are simulated and used for synthesizing original fluids from the collected samples. Evaluating the methods of synthesizing original reservoir fluids states that the new and non-familiar ECM techniques are remarkably more accurate than the conventional recombination method in any conditions, particularly in a depleted situation. The accurate obtained results suggest proposing this method to petroleum companies.

Wellbore instability is one of the important problems in drilling operations. Because this problem can delay drilling operation, increase drilling cost and in some cases can be the cause of the loose well. The cost of these problems is estimated to be more than two billion dollars in a year in the world. If proper physical and chemical mud properties are selected, more stable wells can be obtained. By using the rock mechanics sciences along with the complete cognition of the mechanical properties of the formation, the optimum well trajectory and mud weight window will be determined. Many ingredients are influential in well trajectory design; thus knowing and correctly using these ingredients can affect the design of the optimum mud pressure and well stability. The analytical methods are more usable than the numerical methods, because they are simple and usable without knowing some parameters of rock and formation, which are not usually available at the beginning of typical project. In this paper, we are trying to analyze the stability of the 2SK5 well in the Salman oil field by using three failure criteria, namely Mohr-coulomb, magi-coulomb, and drucker-prager, and to compare the usage of these criteria in wellbore stability analyses. Finally, some suggestions for drilling in this oil field are made.

Methane was directly converted to ethylene, acetylene, and synthesis gas using non-equilibrium plasma. The process was performed at room temperature and atmospheric pressure employing a quarts tube reactor with an outer diameter of 9 mm and an ac electrical discharge of 50 Hertz. Methane conversion was normally more than 50% with high selectivity to C2 hydrocarbons and synthesis gas. The experimental results show that, by applying higher voltages to the reactor, the conversion of methane and oxygen was increased. High selectivity to acetylene and synthesis gas was obtained at a higher level of voltage applied to the electrodes of the discharge zone. Introducing He to the feed stream enhanced the conversion of CH4 and O2; in this condition the yield of C2 hydrocarbons was as high as 27% with the energy efficiency of 0.26 mmol/kJ, which was the highest value obtained in this study. When CH4 partial pressure was increased in the feed it caused a decrease in the overall methane conversion while increased selectivity to acetylene productions. The energy efficiency was improved smoothly by increasing the CH4 partial pressure. Finally, the interactions of high energy electrons with various species available in non- thermal plasma were thoroughly discussed.

The wet cooling towers are one of the main consumers of water in oil and gas refineries as well as petrochemical companies for producing cooling water. If an optimum selection of cooling systems is considered in the design phase and retrofit operations in a factory, considerable water consumption savings will be achieved. For modifying existing systems to determine the best optimal option among all the alternatives available, the mathematical modeling and optimization of such plans can replace expensive laboratory or pilot plant methods previously used. In this study, using the mixed integer linear programming along with the operational experiences of the first superstructure plan, a network of cooling towers was created. In the next step, the most favorable model is regarded in two scenarios to reduce raw water consumption and cooling tower blowdown production with producing demine water (DM) required by the factory. The optimum scenario results in producing 200 m3h-1 DM water and reducing 480 m3h-1 cooling tower blowdown and 200m3h-1 raw water consumption. This scenario results are confirmed and it is now installed in ammonia plant (unit 1). The functions of NPV, IRR, and Payback are used to determine the economic criteria of the plan.

In this paper, an attempt was made to generally point out the role of drilling fluids in achieving hydrocarbon reservoirs and to investigate the experimental results of the effect of different environmental water flow rates in offshore area on the rate of influence of parameters like particle settlement on the seabed. Drilling fluids are pumped via drill string to the bottom hole and bit nozzles to carry suspending cuttings upward and are then thrown into the sea. This high volume of the removed cuttings will be dispersed in the sea levels and settled in the widespread deep waters. Also, due to limited space and using a platform for drilling several wells this can be even worse. This study investigates the effect of height and discharge rate on the dispersion-invasion of light weight drilling fluids. Considering discharging the fluids which are 45 lb.ft-3 in three conditions, namely top, surface, and subsurface of the sea level, with a respective flow rate of 0.4, 0.1, and 0.05 m.s-1, the results demonstrated that the rate of influence were (15, 10, 50), (15, 5, 5), and (20, 12, 10) respectively. With the dilution of drilling fluid in sea water, drilling fluids approach near sea level and disperse horizontally after 240 seconds. For a drilling fluid with a density of 65 lb.ft-3, the influential depth at flow rates 0.025, 0.05, 0.1, and 0.4 m.s-1 are 50, 45, 50, and 25 cm respectively. If fluids are discharged at the subsurface of sea, their depth influence will be 50 cm at these flow rates after 5, 30, 90 min, and over time according to different flow rates. In addition, it was observed that the slip velocity of drilling fluid particles at a water flow rate of 0.025 m.s-1 decreases; however, at a water flow rate of 0.05 m.s-1, the slip (falling) velocity was 7 cm.s-1.