Mehdi Bahari - Academia.edu (original) (raw)

Papers by Mehdi Bahari

Arabian journal of geosciences, May 16, 2024

Journal of Molecular Liquids, Dec 31, 2023

Journal of Molecular Liquids, Oct 31, 2023

Fullerenes, Nanotubes and Carbon Nanostructures, 2017

Sodium Carboxymethyl Cellulose (NaCMC) is a water-soluble polymer which is widely used as a thick... more Sodium Carboxymethyl Cellulose (NaCMC) is a water-soluble polymer which is widely used as a thickener, stabilizer and viscosity modifier in different industries. As temperature increases, the length of the polymer chain of NaCMC decreases and viscosity of its solution drops sharply. In this paper, multilayer graphene sheets were produced by shear exfoliation of graphite in water/surfactant (Triton X-100) solution and NaCMC was dissolved in the obtained dispersion. The results show that shear exfoliated graphene (SEG) sheets do not affect the initial viscosity of NaCMC polymer solution, while they can dramatically prevent thermal degradation and reduction of after heat aging viscosity. This improved thermal stability not only occurs in low salinity solutions but also in saturated salt solutions. Also, results indicate that by increasing the duration of shear exfoliation process, after heat aging viscosity of NaCMC solutions increases. Finally, Alfalfa extract and Alkyl polyglycoside (APG0810), two eco-friendly surfactants were used instead of Triton X-100 in the shear exfoliation process. The results of this

Fullerenes Nanotubes and Carbon Nanostructures, Mar 30, 2017

Petroleum Science and Technology, Apr 17, 2016

ABSTRACT Microbial enhanced oil recovery (MEOR) is a useful technique to improve oil recovery fro... more ABSTRACT Microbial enhanced oil recovery (MEOR) is a useful technique to improve oil recovery from depleted oil reservoirs beyond primary and secondary recovery operations using bacteria and their metabolites. In the present study, the biosurfactant production potential of Bacillus licheniformis microorganisms that were isolated from oil samples of Zilaei reservoir in the southwest of Iran was explored under extreme conditions. Growth media with different temperatures of 40, 50, 60, and 70°C; salinities of 1, 3, 5, and 7 wt%; and yeast extract concentrations of 0.5, 1, 1.5, and 2 g/L were used to find the optimum growth conditions. The results demonstrated that bacteria grown in a mineral salt solution with temperature of 50°C, salinity of 1 wt% and yeast extract concentration of 1 g/L has the highest growth rate and therefore, these conditions are the optimum conditions for growing the introduced bacterium. This isolate was selected as the higher biosurfactant producer. The obtained biosurfactants by bacteria isolated in a medium with these conditions could reduce the interfacial tension of crude oil/water system from 36.8 to 0.93 mN/m and surface tension of water from 72 to 23.8 mN/m. The results of the core flooding tests showed that the tertiary oil recovery efficiency due to the injection of microorganisms was 13.7% of original oil in place and bacteria could reduce the oil viscosity by 41.242% at optimum conditions. Based on these results, the isolated microorganism is a promising candidate for the development of microbial oil recovery processes.

It has been proven that the common Arps empirical decline curve analysis (DCA) to be an extensive... more It has been proven that the common Arps empirical decline curve analysis (DCA) to be an extensively used tool for many years, however, it has much error in production forecasting. In the past, engineers forecasted the oil production rates without understanding of the reservoir engineering principals behind and without having the reservoir properties and operating conditions. These problems influences the quality of the production prediction by Arps model and decreases the validity of this technique. In addition, even by having those properties and conditions a reliable production prediction still cannot be promised without understanding of the theory that connects reservoir properties and operation to the production decline. Experience discovered that the production decline is completely complex that can’t be handled just by a simple mathematical model such as Arp, so the lack of an efficient tool for DCA is still essential. This paper presents the simultaneous use of the convention...

Spe Journal, Aug 27, 2014

Free-fall gravity drainage (FFGD) is the main production mechanism in the gas-invaded zone of fra... more Free-fall gravity drainage (FFGD) is the main production mechanism in the gas-invaded zone of fractured reservoirs. The gravity and capillary forces are two major forces that control the production performance of a fractured system under an FFGD mechanism. Gravity force acts as a driving force to remove oil from the matrix block whereas the resistive capillary force tends to keep oil inside the matrix. In this study, a series of experiments was performed to study the effects of the geometrical characteristics of the fracture and matrix on the oil-production rate under an FFGD mechanism by use of a glass micromodel. The oil-recovery factor (RF) was also obtained for a single matrix block by use of different patterns. Results from the experiments show that different flow regimes occur during the production life of a single matrix block under a FFGD mechanism. The fluid flow is controlled by the capillary-dominated regime at the early stage and late time of production life, whereas it shows a stabilized bulk flow under a gravity-dominated regime is exhibited at other times. Experimental results revealed that for a narrow fracture opening, fracture capillary pressure has a form similar to that of the matrix block. Also, it was observed that the oil-production rate and RF of the matrix block decreased as the permeability ratio between two media (matrix block and fracture) increased. Lower production rate is achieved in larger-fracture-spacing micromodels. In addition, wider vertical fractures lead to an early breakthrough of gas in bottom horizontal fracture that makes up the main portion of oil traps in the matrix block, and this reduces the RF. Results from this study show that in a heterogeneous layered matrix block, both the drainage rate and RF decrease in comparison with a homogeneous matrix block. Finally, a multiple linear-regression analysis was performed to understand the dimensionless groups affecting the RF of the FFGD process. It was found that the Bond number cannot truly describe the process and other parameters such as the fracture-/matrix-permeability ratio; fracture spacing and fracture opening should also be considered. (2004, 2006) investigated the behavior of the three-phase immiscible water-alternating-gas (WAG) injection in nonfractured micromodels. Rangel-German and Kovscek. (2006) studied the transfer mechanisms between matrix and fracture for a two-phase system by use of micromodels. They found that the rate of water uptake from a fracture into an unsaturated matrix and the porelevel pattern of water infiltration depend critically on the rate of water infiltration through fractures. Soudmand-asli et al. (2007) carried out experiments with etched-glass micromodels to investigate the microbial-improved-oil recovery process in fractured porous media. They showed that the microbial-oil-recovery efficiency with biosurfactant-producing bacteria in the fractured

Iranian Journal of Oil and Gas Science and Technology, 2020

Enhanced oil recovery (EOR) is a vital part of the process of oil production from sandstone and c... more Enhanced oil recovery (EOR) is a vital part of the process of oil production from sandstone and carbonate reservoirs. Maintaining and increasing oil production from many fields require proper selection, design, and implementation of EOR methods. The selection of EOR methods for specific reservoir conditions is one of the most difficult tasks for oil and gas companies. Screening of different EOR techniques considering previous experiences from the methods applied in other fields is a first step in the recommendation of any costly EOR operations. In this paper, EORgui software was utilized to screen eight enhanced oil recovery methods in one of Iran’s offshore sandstone oil fields. The reservoir is composed of two sections with different fluid properties, namely API, viscosity, and oil composition, but relatively homogeneous rock properties and high permeability (1500 mD). The results show that polymer flooding is technically the most suitable enhanced oil recovery method in the upper...

Journal of Petroleum Exploration and Production Technology, 2019

Smart water flooding as a developing technique utilizes modified water chemistry in terms of sali... more Smart water flooding as a developing technique utilizes modified water chemistry in terms of salinity and composition to prepare the best-suited brine composition for a specific brine/oil/rock system to obtain higher oil recovery efficiency. Huge amount of unrecovered oil is expected to be remained in carbonate reservoirs; however, few research works on incremental oil recovery during smart water injection in carbonate cores at reservoir condition are reported. Several core flooding tests using one of the Iranian carbonate reservoir rock are conducted to check the effectiveness of smart water injection for more oil recovery efficiency. The results reaffirm the positive effect of sulfate ions to play a key role for better smart water performance. Moreover, it was concluded that the calcium ion concentration is not as effective as magnesium ion for the tests performed at reservoir condition. Synthetic sea water (high-salinity) flooding was considered as the base scenario which results in almost 63% oil recovery efficiency for secondary recovery scenario. Formation of micro-emulsions was found to be the main reason of additional pressure drop during low-salinity water flooding. This clearly showed that the diluted smart water injecting increases the ultimate oil recovery up to 4-12% for already water-flooded carbonate reservoirs.

E3S Web of Conferences, 2019

SPE Journal, 2015

Summary Free-fall gravity drainage (FFGD) is the main production mechanism in the gas-invaded zon... more Summary Free-fall gravity drainage (FFGD) is the main production mechanism in the gas-invaded zone of fractured reservoirs. The gravity and capillary forces are two major forces that control the production performance of a fractured system under an FFGD mechanism. Gravity force acts as a driving force to remove oil from the matrix block whereas the resistive capillary force tends to keep oil inside the matrix. In this study, a series of experiments was performed to study the effects of the geometrical characteristics of the fracture and matrix on the oil-production rate under an FFGD mechanism by use of a glass micromodel. The oil-recovery factor (RF) was also obtained for a single matrix block by use of different patterns. Results from the experiments show that different flow regimes occur during the production life of a single matrix block under a FFGD mechanism. The fluid flow is controlled by the capillary-dominated regime at the early stage and late time of production life, whe...

E3S web of conferences, 2019

The Brooks-Corey power-law capillary pressure model is commonly imposed on core analysis data wit... more The Brooks-Corey power-law capillary pressure model is commonly imposed on core analysis data without verifying the validity of its underlying assumptions. The Brooks-Corey model, originally developed to model the pressure head during the drainage of soil, is only valid at low wetting phase saturations. However, such models are often applied in petroleum production simulations and may lead to erroneous recovery factors when the saturation range of interest is far from the end points. We demonstrate that exponential models work much better for capillary pressure compared to the Brooks-Corey model over a wide saturation range. Mercury injection porosimetry, petrographic image analysis, and magnetic resonance studies suggest that the pore and throat size distribution in many rocks are log-normally distributed. This fact was previously employed to calculate the capillary pressure function as a function of saturation for pore size distributions described by a truncated log-normal distribution. Employing a Taylor series expansion, we simplify the random fractal capillary pressure model of Hunt to , where is the wetting phase saturation, and and characteristic of the porous medium. An extensive dataset of seventeen centrifuge capillary pressure measurements were used in this research to demonstrate the merit of the new method. For both sandstones and carbonates, the logarithm of capillary pressure showed a linear relationship with saturation as observed by magnetic resonance imaging centrifuge capillary pressure measurements over a wide saturation range. This work demonstrates that: (a) in semi-log plots of capillary pressure as a function of saturation, capillary pressure will vary linearly over a wide saturation range, (b) such a plot as described in (a) will show the uni-or bimodal pore size distribution of the rock, (c) the exponential capillary pressure function simplifies analytical models that use the capillary pressure function, for example oil recovery models for fractured reservoirs.