In this study, some experiments have been performed for determining parameters that affecting heavy oil recovery. In these experiments some hydrocarbon solvents such as Heptane, Octane and Decane have been used. In these experiments some parameters that are efficient in heavy oil recovery, like solvent type effect, hydrocarbon solvent injection rate, gravity segregation effect, injection orientation in uniform and oriented patterns, have been contemplated. A series of experiments performed whereby hydrocarbon solvents (Heptan, Octane and Decane) displaced heavy oil in micromodel pattern of different pore structure orientations. Successive images of invasion of solvents in heavy oil were taken at desired interval time during injection process. Image analysis technique is used to measure the oil recovery factor as a function of injected pore volume of solvents. The oil recovery factor versus pore volume of different injected solvents was plotted for different micromodel flow patterns, at different flow rates in both horizontal and vertical geometry. It has been found that the pore structure orientation have significant effect on oil recovery during solvent injection process this could be due to the enhancement or detraction of the longitudinal and transverse dispersion in the porous media. The results also indicated that gravity enhances the oil recovery in the case of vertical injection compared to the horizontal one. In addition solvents of lower molecular weight resulted in higher oil recovery.

The MISCIBLE DISPLACEMENT process appears to be an increasingly feasible method for the extraction of oil from depleted reservoirs. How­ever, there is a lack of fundamental understanding of how fracture geometrical characteristics impact the oil recovery efficiency in this type of enhanced oil recovery technique. In this work, a series of experimental tests were conducted whereby the n-Heptane as a solvent displaced n-Decane in the glass micro-models having different fracture geometries. It has been observed that the breakthrough time is decreased with increasing the fractures’ length. In contrast, breakthrough time is increased when increasing the fractures orientation angle related to flow direction. A correlation has been presented for the breakthrough time as a function of fracture length and its orientation.

This study investigates asphaltene precipitation and deposition due to MISCIBLE/imMISCIBLE gas injection as well as its impact on rock properties and gas injectivity in one of Iranian southwestern oilfields. DISPLACEMENT characteristics like GOR, breakthrough time and oil recovery are also studied.According to experiments, induced MISCIBLE/ imMISCIBLE gas injection permeability impairments are negligible. Therefore, gas injection has no negative impact on the formation regarding asphaltene precipitation and deposition.Ultimate oil recoveries are about 73% and 66% for MISCIBLE and imMISCIBLE gas injections respectively. These approximate oil recoveries are obtained in laboratory core scale representing microscopic sweep efficiencies then to convert it to field recoveries it should be multiplied by macroscopic ones to be experienced in the field application.

An important step in the modeling of two-phase gas and oil flow is to have the reliable relative permeability functions. None of the previous conventional methods can predict the consistent and accurate relative permeability values to show the effect of near miscibility on the qualitative and quantitative behavior of relative permeability functions under near MISCIBLE conditions. The main contribution of this work is to select the optimum approach to relative permeability determination based on the classification of the available relative permeability methods and comparing their results in order to extract more accurate relative permeability values under near MISCIBLE conditions. In this work, the unsteady state DISPLACEMENT experiments were performed on two different reservoir rock samples (i.e. a dolomite and a sandstone core plug sample from the west of Iran). In addition, CO2 and light oil samples as injection fluids were used to decrease the variance error. Also, by the selection of the best relative permeability methods, the bias errors are decreased. In this study, inverse modeling is used with the Civan and Donaldson method as the initial guess for 1-D, two-phase flow simulation. The results show that the history matching as the optimum method presents a reformed relation in order to generate the relative permeability values more consistent to laboratory data under near MISCIBLE conditions. Finally, this reformed relation can be embedded in fluid flow simulators to simulate the near MISCIBLE gas injection more precisely.

Stability analysis of MISCIBLE DISPLACEMENT has several applications in industries such as oil recovering and ground water tables. In this article an analytical solution is presented based on Tan and Homsy’s results for stability analysis in t=0. Moreover, a novel semi analytical solution is used, based on weighted residual method, to solve the Fourier space equations. The results are shown as  s (disturbance growth rate) - k (wave number); profiles for different values of mobility ratios and times. A comparison with the results of the other researches is also presented.

Carbon dioxide MISCIBLE DISPLACEMENT plays an important role in the field of MISCIBLE DISPLACEMENT for enhanced oil recovery. However, there is a very important relationship between the formation of MISCIBLE DISPLACEMENT and the minimum MISCIBLE pressure. The pendant drop method in the interfacial tension method was firstly used to predict the minimum MISCIBLE pressure of the supercritical carbon dioxide and the formation of oil in the test area oilfield. Under the condition of the simulated reservoir temperature 111. 5 ° C, the interfacial tension of the supercritical carbon dioxide and the formation oil system was tested experimentally by using formation oil samples of the test area oilfield. The range of test pressure was from 10. 06 MPa to 28. 57 MPa. Besides, the relation curve of the test pressure and the interfacial tension was drawn. The results show that under the reservoir temperature, the interfacial tension between the supercritical carbon dioxide and the formation oil shows an approximately linear downward trend with increasing the test pressure. The mathematical expression was obtained by the linear regression analysis. According to the extrapolation, the vanishing point of the interfacial tension was obtained. Then the minimum MISCIBLE pressure of the supercritical carbon dioxide and the formation oil system was determined. The actual test was carried out to verify the result by the pendant drop method. Finally, the minimum MISCIBLE pressure of the supercritical carbon dioxide and the formation oil system of the test area oilfield was determined to be 29. 4 MPa.