As consequence of pressure drop in oil reservoirs, production of oil will be difficult and EOR methods are used to improve recovery. In many countries Polyacrylamide is used for polymer flooding in EOR processes, but the problem is that Polyacrylamide is expensive also Acrylamide needs to be handled using best laboratory practices (such as having safe systems of work and wearing appropriate gloves, lab coat etc.) to avoid poisonous exposure since it is a neurotoxin.

Formation damage due to asphaltene deposition in oil reservoir is an issue for many countries that can have strong effect on oil production during heavy oil recovery, miscible flooding, and even primary recovery. Many tests were performed by researchers to determine the amount of deposition and reduction of permeability but the boundaries in which the asphaltene deposited in oil or at the pore surface are not determined.In this paper, series of tests are performed in order to determine the effect of asphaltene deposition on sandstone rock. Assuming negligible change of viscosity due to various concentrations of asphaltene added, results of laboratory tests performed using pre-separated asphaltene contents from crude oil are showed, to be sure that the first stage (if we divide it into precipitation from liquid phase and deposition on pore surface) of depositing is passed, n-hexane used to flocculate asphaltene particles. To generate reliable data on formation permeability damage due to asphaltene deposition, several dynamic displacement experiments with oil asphaltene content were conducted in various rates and concentrations.These laboratory tests have shown evidence of core damage happening under dynamic flowing conditions. Data were plotted in order to determine the effect of permeability reduction with comparison to reference oil permeability. It shows a significant permeability reduction after flooding. The results have shown that removal and deposition processes occurred simultaneously and trends were similar to previous works where they follow a straight-line pattern except where removal occurs. The previous available models on CMG roughly matched the data.The test results and data can be used in formation damage due to asphaltene deposition models for matching and checking models available in literature and commercial softwares.

The deposition of asphaltene in porous media and their interaction with rock and fluids represent complex phenomena which needs to be investigated under dynamic flowing condition. It could occur by reducing mobility (λ=k/µ) in three probable mechanisms of asphaltene included damage: a) blocking pore throat, b) altering wettability, and c) increasing the reservoir fluid viscosity and can have strong effect on oil production through heavy oil recovery, miscible flooding, and even primary recovery. Many experiments were performed by researchers to determine the amount of deposition and permeability decline but the boundaries in which the asphaltene deposited in oil or at the pore surface was not determined, thus the models introduced have some difficulties using all parameters.In this paper, a mathematical model is developed constructing to simulate rock-fluid interactions describing permeability decline due to asphaltene deposition. The model considers the second stage (if separated into liquid phase precipitation and pore surface deposition) of asphaltene deposition in which n-hexane used to flocculate asphaltene particles in order to determine the effect of deposition on sandstone rock due to changing of pressure, temperature, and composition of reservoir oil. The influences of various injection rates and concentrations are considered carefully.This model simulation and corresponding analytical method is applied using laboratory data gained by performing various dynamic displacement experiments with pre-separated oil asphaltene content resulted a close agreement so it could predict the trend of permeability reduction due to deposition of asphaltene. So the procedure of matching the parameters is described here.This model can be used for analysis of laboratory core tests of formation damage due to flocculated asphaltene particles. Thus, the present study leads to a new insight into the mathematical explanation of flow behavior in porous media.

Formation damage due to asphaltene deposition could have bad consequences on oil production through heavy oil recovery, miscible flooding, and even primary recovery. Many tests were carried out by researchers to find the amount of permeability decline, but the limits in which the asphaltene deposited in oil or at the pore surface was not determined. In this paper, neural network is used to predict rock-fluid interactions describing permeability decline due to asphaltene deposition. The second stage of asphaltene deposition (if we separate it into precipitation from liquid phase, and deposition on pore surface) is considered in which n-hexane is used to flocculate asphaltene particles in order to determine the effect of deposition on sandstone rock due to changing of pressure, temperature, and composition of reservoir oil. An artificial neural network is trained using data gathered by performing various dynamic experiments with pre-separated oil asphaltene content, moreover, some of the experimental data used to test the network and resulted a good agreement so it could predict the trend of permeability reduction due to deposition of asphaltene. This network can be used to predict the trend of formation damage due to asphaltene deposition under various pressures and asphaltene concentrations. Thus, this study guides us to a novel explanation of flow behavior in porous media.

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