Iranian Journal of Oil & Gas Science and Technology
Volume:2 Issue: 2, Spring 2013

Hydrocarbons are prone to bacterial and fungal contamination. Bacteria and fungi live and proliferate in water droplets within the fuels and on surfaces surrounding them. This can cause corrosion in oil exploration and production, clogging of fuel lines in aviation and higher emissions in diesel combustion engines to state few examples. State-of-the-art is the addition of biocides to fuels, which is associated with several disadvantages like costs and environmental burden. A novel technology to prevent biofouling in hydrocarbons is presented here. By applying an anti-microbial coating to the surfaces of hydrocarbon processing units, pipelines, and fuel containers, microbial growth can effectively be reduced. The coating can be a paint or varnish, for instance, epoxy resin as already used in aircraft fuel tanks to today. It contains transition metal oxides, thus an acidic surface is produced. This acidic surface was shown to eliminate up to 109 colony forming units per milliliter (CFU.ml-1) of bacteria of the species of agrobacterium tumefaciens and others in diesel, kerosene, and biodiesel, where other anti-microbial coatings based on silver did not perform. The technology has the potential to bring huge cost savings to the oil and gas industry, alongside an increase in safety and equipment reliability.

Reservoir characterization plays an important role in different parts of an industrial project. The results from a reservoir characterization study give insight into rock and fluid properties which can optimize the choice of drilling locations and reduce risk and uncertainty. Delineating hydrocarbon bearing zones within a reservoir is the main objective of any seismic reservoir characterization study. In the current study, using limited well control and seismic data, an attempt was made to predict the productive zones of a reservoir using elastic impedance inversion. Elastic impedance logs at near and far angles of incidence have been crossplotted to find the desired productive parts of the formation. Two partial angle stack seismic data have been inverted using a model-based post-stack seismic inversion. The crossplot of the two inverted volumes is interpreted based on the results from the well location. Finally, the hydrocarbon bearing zones of the reservoir was delineated according to the seismic crossplot analysis.

Thermal recovery involves well-known processes such as steam injection (cyclic steam stimulation, steam drive, and steam-assisted gravity drainage), in situ combustion, and a more recent technique that consists of heating the reservoir with electrical energy. When high frequency is used for heating, it is called electromagnetic (EM) heating. The applications of EM heating for heavy-oil reservoirs can be especially beneficial where conventional methods cannot be used because of large depth, reservoir heterogeneity, or excessive heat losses. This process can be modeled to determine temperature distribution in the porous reservoir rock during EM heating. In this paper, the homotopy perturbation method (HPM), a powerful series-based analytical tool, is used to approximate the temperature distribution, which has been modeled using a partial differential equation and special assumptions when high frequency currents are used. This method decomposes a complex partial differential equation to a series of simple ordinary differential equations which are easy to solve. According to the comparison of the solutions obtained by HPM with those of a numerical method (NM), good agreement is achieved. Moreover, a sensitivity study is done to determine the effect of initial temperature, oil rate, frequency and input power on the accuracy of HPM.

This work is a primary achievement in studying the CO2 and N2–oil systems. To predict gas-liquid relative permeability curves, a Shan-Chen type multicomponent multiphase lattice Boltzmann model for two-phase flow through 2D porous media is developed. Periodic and bounce back boundary conditions are applied to the model with the Guo scheme for the external body force (i.e., the pressure gradient). The influence of relationship between cohesion and adsorption parameters and the interfacial tension values in Young's equation, pore structure (micro scan image derived porous media response is compared with corresponding porosity and permeability ideal sphere pack structure), and saturation distribution on relative permeability curves are studied with the aim to achieve the realistic stable condition for the simulation of gas-liquid systems with a low viscosity ratio.

A computational fluid dynamic (CFD) study of methanol (MeOH) to dimethyl ether (DME) process in an adiabatic fixed-bed reactor is presented. One of the methods of industrial DME production is the catalytic dehydration of MeOH. Kinetic model was derived based on Bercic rate. The parameters of this equation for a specific catalyst were tuned by solving a one-dimensional homogenous model using MATLAB optimization module. A two-dimensional CFD simulation of the reaction is demonstrated and considered as numerical experiments. A sensitivity analysis was run in order to find the effect of temperature, pressure, and WHSV on the reactor performance. Good agreement was achieved between bench experimental data and the model. The results show that the maximum conversion of reaction (about 85.03%) is obtained at WHSV=10 h-1 and T=563.15 K, whereas the inlet temperature has a greater effect on methanol conversion. Moreover, the effect of water in inlet feed on methanol conversion is quantitatively studied. It was concluded that the results obtained from CFD analysis give precise guidelines for further studies on the optimization of reactor performance.

The current study assesses the root causes of hydrogen blisters on low strength carbon steel equipment. For this purpose, some experiments including hardness test, non-destructive test (NDT), metallography, and fractograpghy are conducted. The microstructure of two blisters is assessed by means of optical microscopy and scanning electron microscopy (SEM). The microstructural studies show that the steel plate has some inclusions and banded ferrite/pearlite structure. The energy dispersive x-ray spectroscopy (EDS) results indicate that these inclusions mainly contain Mn, S, Al, Ca, and Si. The results show that the inclusions and planar imperfections found in the NDT have been the nucleation locations for blisters in the plate. Remediation action plans are recommended to prevent further occurrence and growth of hydrogen blisters.