Recovery Of Heavy Oil Reservoirs Research Articles

The basic principle of enhancing oil recovery technology in heavy oil reservoirs

Due to the heterogeneity of heavy oil reservoirs and the high viscosity of heavy oil, the recovery rate of heavy oil reservoirs is much lower than that of conventional reservoirs. So increasing the recovery rate of heavy oil reservoirs is of great significance to the goal of improving the technical level of heavy oil development proposed by the National Energy Plan. This paper outlines several commonly used techniques for improving the recovery of heavy oil reservoirs, including steam flooding, hot water flooding, polymer flooding, surfactant flooding, microbial flooding, foam flooding, ultrasonic viscosity reduction technology, etc. And briefly explains the basic principles. The internal causes of the problem are analyzed, and several focal points for improving the recovery of heavy oil that should be paid attention to are put forward.

Formation mechanism and distribution characteristics of micro residual oil in ultra-high water cut reservoirs a case study of yangsanmu oilfield

The formation mechanism and distribution characteristics of microscopic remaining oil are the basis for efficient development and enhanced oil recovery of heavy oil reservoirs in ultra-high water cut stage. This paper takes Yangsanmu heavy oil reservoir in Huanghua depression as an example, micro-displacement simulation experiment based on microscopic pore structure analysis. Through parallel experiments, the remaining oil displacement effects of water flooding combined with polymer flooding, water flooding and surfactant polymer system combination, water flooding and poly-alkaline ternary composite flooding were compared. The formation mechanism and distribution pattern of remaining oil under different displacement medium conditions were studied to find a reasonable displacement medium system. The experimental results show that the formation of microscopic remaining oil in the study area is related to the stripping effect, the flow around, the pinch action occurs, the run through effect and the adherent flow. The distribution types of remaining oil are mainly angular type, pore wall oil film type, throat retention type, dispersed oil drop type and porphyritic remaining oil in macropores. The analysis of residual oil saturation under different displacement media shows that the combined flooding effect of water flooding and poly-alkaline ternary composite flooding are the best, followed by water flooding and surfactant polymer system combination flooding. This study provides guidance for the remaining oil exploration plan of the ultra-high water cut stage heavy oil reservoir in this area.

Viability of carbonated water injection (CWI) as a means of secondary oil recovery in heavy oil systems in presence and absence of wormholes: Microfluidic experiments

In this study, the performance of carbonated water injection (CWI) as a means of secondary oil recovery process was investigated. A series of flooding experiments were carefully designed and conducted in two state-of-the-art micromodels representing single and dual permeability porous media. The dual permeability micromodel is referring to a model with 17 high permeability channels mainly to mimic wormholes generated in unconsolidated sandstone reservoirs during sand production. Prior to CWI tests, waterflooding (WF) tests were carried out in both single and dual permeability micromodels saturated with two heavy crude oils (Type-I, °API = 20.44 and Type-II, °API = 15.49) to investigate the displacement performance of conventional and well known waterflooding technique. Next, through a series of flooding experiments performed at constant injection rate of qinj = 0.05 cm3/min and temperature of Texp = 21 °C, the effect of oil °API gravity on efficiency of CWI was examined. Results obtained for Type-I crude oil from a single permeability micromodel showed that the ultimate oil recovery of CWI can be increased by about 9% as compared to that of conventional WF. Furthermore, the analysis of the images taken during the displacement process of CWI showed wider distribution of frontal advancement compared to that of conventional WF when conducted in the same heavy oil saturated micromodel. It was also observed that for Type-II crude oil (°API = 15.49), the recovery factor was improved by 2.2% under the same conditions with that of conventional WF when performed in a single permeability micromodel. Therefore, the comparative evaluation of the performance of CWI conducted in two heavy oil systems to a single permeability micromodel showed 4.8% of improvement per one degree increase in oil °API gravity under the conditions of this study. Similarly, a series of experiments were conducted with both heavy oil samples in a dual-permeability micromodel where 17 high permeability channels representing dilated regions (or wormholes) were included in the model. The carbonated water injection implemented in the dual permeability micromodel saturated with heavy oil Type-II (°API = 15.49) resulted in 23.5% improvements in the recovery factor over single permeability case at nearly 1.6 PVs of injection at aforementioned experimental conditions and operations. Results of this study showed that CWI is a viable option for enhanced oil recovery in heavy oil reservoirs. Additionally, CWI has additional benefits through CO2 storage and carbon tax credits, though less than immiscible and miscible CO2 injection processes. Therefore, it is crucial to consider this relatively easier to implement alternate option prior to other costly enhanced oil recovery (EOR) methods.

Improving the Efficiency of the THAI-CAPRI Process by Nanocatalysts Originated from Rock Minerals

Toe-to-heel air injection method is a modified pattern in situ combustion which is applicable for the recovery of heavy oil reservoirs. A fixed bed of catalyst around the production well can improve performance and quality of the produced oil; however, pilot tests revealed rapid deactivation of the catalyst bed. Dispersion of fine catalyst particles (ideally nanoparticles) around the production well by carrier fluids may reduce the deactivation problem. In the first step of this study, three nanoparticles, namely calcite, montmorillonite (MMT), and Cloisite 20A, were dispersed in a heavy oil as candidate catalysts and subjected to simultaneous thermal analysis. Kinetic parameters of different reaction zones were obtained by the Coats and Redfern model, and it was observed that 0.5 wt % of the MMT more effectively catalyzed the combustion reactions. In the second step, selected sample was subjected to multiple heating rate experiments to study detailed kinetic effects. Results were analyzed by Vyazovkin is...

A novel optimization technique for Fast-SAGD process in a heterogeneous reservoir using discrete variables and repetition inhibitory algorithm

One of the most prevalent methods for enhanced oil recovery in heavy oil reservoirs is thermal techniques. Fast-SAGD process is an advance method of enhance oil recovery in which offset wells are drilled for cyclic steam injection and production. This leads to increasing the production efficiency. Optimization of this process was performed using various techniques including genetic algorithm (GA), imperialist competitive algorithm (ICA), and particle swarm optimization (PSO). Combination of recovery factor and cumulative steam to oil ratio was introduced as the objective function. This study represents a novel supplementary technique implemented in optimization algorithms to increase its speed, significantly. In this technique, effective parameters were defined using sensitivity analysis. Then they were converted to discrete variables. To discretize the selected parameters, three different functions including logarithmic, square, and linear were applied using Minitab 18. Moreover, repetition inhibitory algorithm (RIA) was implemented in optimization algorithms for the first time to prevent recalculation of duplicate states in optimization for the next generation, and to speed-up the optimization process. The results of sensitivity analysis indicated that maximum and minimum effective parameters were attributed to Fast-SAGD production well height and soak time, respectively. Results indicated that among various optimization algorithms, GA worked 6% better in comparison to other optimization techniques and linear discretization function resulted in better optimized point in a shorter time. Results indicated that optimization process using discrete variables and repetition inhibitory algorithm led to the optimized point 6.33 times faster than discrete optimization procedure without RIA. This was 16.46 times faster in comparison to continuous optimization algorithm. Moreover using RIA led to termination of optimization algorithm 9.67 times faster than continuous mode.

The study on classification methods for low production wells of thermal recovery and its applications

During the later period of steam injection, the oil production largely decreases to be a state of low production or low oil–steam ratio. In this article, a classification method of low production wells was established and some measures of improving oil production were researched for the low production wells during thermal recovery. Three visualization experiments were implemented to analyze the sweep efficiency and to measure the oil recovery factor during injecting different flooding agents. Then a novel diagram was introduced to guide us how to precisely choose the appropriate measures for the low production wells during thermal recovery in heavy oil reservoirs. According to the statistical results, the low production wells can be categorized into three types involving high degree of oil recovery, thermal disturbance (even steam channeling) among wells and dual factors. The results of visualization experiments showed that the injection of chemical agents can effectively increase the displacement efficiency in swept zone after steam injection. Temperature-resistant gel or foams can be used to decrease thermal disturbance and even steam channeling among wells during steam injection in heavy oil reservoir. The values of a new parameter can be employed to confirm the boundary of different improvement measures. Finally, a diagram was established to help choosing appropriate measures involving nitrogen injection, foam injection, gel injection and invalid measure.

Experimental study on blocking mechanism of nitrogen foam for enhancing oil recovery in heavy oil reservoirs

ABSTRACTFoam flooding is one of the effective techniques during thermal recovery process in heavy oil reservoir. Nitrogen is generally co-injection with the foaming agent for the generation of foam. However, the mechanism has not been totally understood, thereby requiring further discussion. In this study, a series of sand pack experiments for nitrogen foam steam flooding were designed and conducted. A comparison of influencing factors, including gas-liquid (foaming agent) ratio, permeability, injection scheme, and oil saturation was used to evaluate the stability and blocking mechanisms of foam. The results show that the blocking capacity of the gas-liquid ratio of 1:1 is the greatest in all cases under high-temperature condition. The blocking mechanism of foam is analyzed, which indicates that foam is selective to block larger pores and throats in porous media with high-permeability. And also, the stability of foam becomes worse while meeting oil. This characteristic is favorable for improving the sweep efficiency to enhance oil recovery in developing heavy oil reservoir.

Application of In-situ combustion for heavy oil production in China: A Review

In China, heavy oil reservoirs face several production challenges: most of the heavy oil reservoirs have already been in the middle or last stage of steam stimulation, and the throughput effect has deteriorated significantly; even though steam flooding has been widely applied in shallow reservoir, steam flooding technology suitable for medium-deep reservoir is still in the experimental stage; meanwhile, for ultra-heavy oil reservoir, a rapid decline in production is observed by utilizing conventional steam injection. Therefore, it is necessary to develop new technologies to replace steam floodingin order to enhance oil recovery of heavy oil reservoirs. In-situ combustion has been proved as a relatively effective technology for heavy oil production. In recent years, several field tests have been conducted in Shengli, Liaohe and Xinjiang oil regions, and the results proved that the feasibility of in-situ combustion technology for heavy oil reservoirs in China. This review paper introducesadvantages, adaptability, and developments of in-situ combustion technology for heavy oil reservoirs in China.

The macroscopic and microscopic analysis on the performance of steam foams during thermal recovery in heavy oil reservoirs

In heavy oil reservoirs, steam channeling and steam override seriously decrease oil production and the ultimate oil recovery during steam flooding. Aiming at the two problems, some experiments were carried out to analyze the EOR mechanisms through injecting foaming agents along with steam injection in heavy oil reservoirs. An orthogonal method was employed to analyze the multiple factors on foam’s properties to optimize foaming agent for steam injection. Then a novel 2D-visualization experiment was carried out to quantitatively study the characteristics of steam channeling and the variation of sweep efficiency during steam or steam foams flooding. Based on the experimental results, many bubble’s characteristics, such as migration, retention, regeneration and etc., were analyzed through the macroscopic and microscopic perspectives. The experimental results show that the Jamin effect increases the flow resistance of steam-phase in porous media to obviously enlarge the macro sweep efficiency and effectively increase micro oil displacement efficiency. On a macroscopic level, because of the unique structure, foams decrease steam override or steam channeling to improve sweep efficiency; on a microscopic level, due to the expansion effect of gas-phase, bubbles can desquamate the oil film on the pore wall and even the oil drop in the blind pore to decrease the residual oil saturation. In our experiments, the ultimate recovery of steam flooding can only reach 48.48%. However, the ultimate recovery of steam foams can reach 59.95%, which is 11.47% higher than steam flooding.

Anisotropy in Thermal Recovery of Oil Shale—Part 1: Thermal Conductivity, Wave Velocity and Crack Propagation

In this paper, the evolution of thermal conductivity, wave velocity and microscopic crack propagation both parallel and perpendicular to the bedding plane in anisotropic rock oil shale were studied at temperatures ranging from room temperature to 600 °C. The results show that the thermal conductivity of the perpendicular to bedding direction (KPER) (PER: perpendicular to beeding direction), wave velocity of perpendicular to bedding diretion (VPER), thermal conduction coefficient of parallel to beeding direction (KPAR) and wave velocity of parallel to beeding direction (VPAR) (PAR: parallel to bedding direction) decreased with the increase in temperature, but the rates are different. KPER and VPER linearly decreased with increasing temperature from room temperature to 350 °C, with an obvious decrease at 400 °C corresponding to a large number of cracks generated along the bedding direction. KPER, VPER, KPAR and VPAR generally maintained fixed values from 500 °C to 600 °C. 400 °C has been identified as the threshold temperature for anisotropic evolution of oil shale thermal physics. In addition, the relationship between the thermal conductivity and wave velocity based on the anisotropy of oil shale was fitted using linear regression. The research in this paper can provide reference for the efficient thermal recovery of oil shale, thermal recovery of heavy oil reservoirs and the thermodynamic engineering in other sedimentary rocks.

江37区蒸汽驱数值模拟开发规律研究

本文以大庆江37区为例，利用CMG软件内的STARS热采模块对浅薄层稠油油藏进行蒸汽吞吐数值模拟开发动态规律研究，对蒸汽驱转蒸汽吞吐参数优化，主要包括对转蒸汽驱时机、注汽井注汽速度、井底蒸汽温度与压力的优选，并得出转蒸汽驱推荐方案，对于提高稠油油藏的采收率具有一定的指导作用。 Taking Daqing Jiang 37 Block as an example, the study on the dynamic regularity of steam throughput in shallow heavy oil reservoirs with STARS heat mining module in CMG software is carried out. Meanwhile, parameter optimization for steam drive to steam soak is carried out, in-cluding the timing of steam flooding, the steam injection rate of steam injection well and the optimization of steam temperature and pressure at the bottom hole, and the recommendation scheme of turning to steam drive is obtained, which is significant to improve recovery of heavy oil reservoirs.

QUANTIFYING THE IMPACT OF GRID SIZE TO COMPARE WATER AND POLYMER FLOODING STRATEGIES IN A HIGHLY HETEROGENEOUS OFFSHORE FIELD

Polymer flooding can be a viable alternative to improve recovery of heavy oil reservoirs. The comparison of water and polymer flooding demands a detailed simulation results. The analysis of relevant data including uncertainties seeks to improve the decision process and requires a high number of simulation runs. Reservoir engineers usually bypass this problem using fast models to reduce computational time; however, it is important to maintain the reliability of heterogeneous reservoir models. This work presents an evaluation of fast models considering precision of results and simulation time in specific wells of interest. The fast model is required in this case because the simulation time of the entire reservoir would demand excessive computation effort for probabilistic approaches used in the decision analysis. Therefore, the main objective of the proposed work is to establish an innovative approach to evaluate and quantify how the grid size impacts the accuracy of results and both the time and computational resources. Based on the well location, three procedures are compared: (1) original grid size model (OTM), (2) selection of grid size based on streamlines to set a limited region defined by drainage area of wells of interest and a reliable results production index (DA), and (3) upscaling of the simulation model (UP). These two fast models are compared with the OTM model by evaluating water and polymer flooding production indicators. The results show an average simulation time reduction of 65% for the DA method and 34% for the UP method in comparison with OTM model (considering DA and UP cases with acceptable results). The DA method shows better accuracy than the UP method. In conclusion, the DA method offers a good alternative yielding a faster and reliable tool. This work presents a methodology used to build a fast model which can evaluate the impact of fast models in decision analysis comparing water and polymer flooding, especially when using EOR strategies and/or complex reservoirs.

Catalytic effect of zinc naphthenate on the heavy oil low-temperature oxidation in an air injection process

ABSTRACTAir-assisted steam flooding is a new effective technique for enhanced oil recovery in heavy oil reservoirs. The authors prepared zinc naphthenate as the catalyst in the laboratory and the investigated effects on low-temperature oxidation of heavy oil through the isothermal reactor. The results indicated that zinc naphthenate could accelerate the oxygen consumption rate and facilitate the cleavage reaction in the low-temperature oxidation process. The data shed more light on the mechanisms of low-temperature oxidation reactions of heavy oil and can provide a new way to enhance the recovery of heavy oil reservoir.

Novel Evaluation Method of Foam Agents for Thermal Recovery in Heavy Oil Reservoirs

Aiming at the influence of temperature on foaming ability and blocking characteristics during steam injection, a study is carried out to establish a new evaluation method of foaming agents at variable temperatures in a heavy oil reservoir. The method synthetically considers the influence of temperature variation on the foaming ability, foam stability, and resistance factor by introducing some important parameters, such as the average foam comprehensive index, the average foam resistance factor, the weighted factor, and the comprehensive value of foam performance. In the laboratory, five foaming agents are quantificationally evaluated according to the method introduced in this article. The experimental results indicate that agent A, ZWF-1, is the optimum foaming agent in terms of the order of the dimensionless evaluation parameters. Aiming at an actual well group of an oilfield from China, the pilot test of foam profile control is implemented. The practice results show that the cumulative incremental oil p...

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ABSTRACT Worldwide, new techniques to implement Enhanced Oil Recovery in heavy oil reservoirs have been studying, since as most of the global reserves are of this type of hydrocarbon. The Steam Assisted Gravity Drainage (SAGD) is a cutting age EOR method that have been applied in bitumen reservoirs gaining successful results, obtaining recoveryfactors up to 50%. The technique involves two horizontal wells, the first one located a few feet above the second one depending on the viscosity of the crude oil; by the upper well, the continuous vapor injection is made an for density differences this vapor tents to expand to the top of the formation heating the hydrocarbons which then, by gravity come down in the reservoir to be produce, with the condensed vapor, through the second horizontal well. The production mechanism evidenced in this technique is the gravity drainage because in its implementation, applied to bitumen, only the heated hydrocarbons will flow through the producer well by the effect of the gravity therefore a connectivity between the two wells must be necessary. However, in the majority of heavy oil reservoirs the crude have mobility i.e. the viscosity is not to high (<10.000 cP), at which the SAGD technique is not effective. This is because in this reservoirs no only the gravitational forces have influence, the viscous forces does to, whereby the injected vapor expands to the overburden, canalizing the vapor, generating energy losses and emulsions formation, causing that the vapor chamber, which is the physical principle of the SAGD, not to form. This paper presents a comparison of the behavior and develop of the vapor chamber in two different reservoirs with the same characteristics but different type of fluids, the first one is saturated with an extra heavy oil (254814 cP) and the other saturated with a heavy oil with mobility (4019.6 cP) in which the overriding of the vapor in the mobile oil by the effect of the gravitational forces is observed. Keywords: Heavy Oil, SAGD, Gravity Drainage, Steam Injection, Steam Chamber.

A New High-Temperature Gel for Profile Control in Heavy Oil Reservoirs

Controlling the phenomenon of steam channeling is a major challenge in enhancing oil recovery of heavy oil reservoirs developed by steam injection, and the profile control with gel is an effective method to solve this problem. The use of conventional gel in water flooding reservoirs also has poor heat stability, so this paper proposes a new high-temperature gel (HTG) plugging agent on the basis of a laboratory experimental investigation. The HTG is prepared with nonionic filler and unsaturated amide monomer (AM) by graft polymerization and crosslinking, and the optimal gel formula, which has strong gelling strength and controllable gelation time, is obtained by the optimization of the concentration of main agent, AM/FT ratio, crosslinker, and initiator. To test the adaptability of the new HTG to heavy oil reservoirs and the performance of plugging steam channeling path and enhancing oil recovery, performance evaluation experiments and three-dimensional steam flooding and gel profile control experiments are conducted. The performance evaluation experiments indicate that the HTG has strong salt resistance and heat stability and still maintains strong gelling strength after 72 hrs at 200 °C. The singular sand-pack flooding experiments suggest that the HTG has good injectability, which can ensure the on-site construction safety. Moreover, the HTG has a high plugging pressure and washing out resistance to the high-temperature steam after gel forming and keeps the plugging ratio above 99.8% when the following steam injected volume reaches 10 PV after gel breakthrough. The three-dimensional steam flooding and gel profile control experiments results show that the HTG has good plugging performance in the steam channeling path and effectively controls its expanding. This forces the following steam, which is the steam injected after the gelling of HTG in the model, to flow through the steam unswept area, which improves the steam injection profile. During the gel profile control period, the cumulative oil production increases by 294.4 ml and the oil recovery is enhanced by 8.4%. Thus, this new HTG has a good effect in improving the steam injection profile and enhancing oil recovery and can be used to control the steam channeling in heavy oil reservoirs.

Results of the Field Operation of a Distributed-Flux Burner in a Heater Treater in a Northern Canada Heavy Oil Field: Thermal Performance and Firetube Life

Summary Horizontal heater treaters are commonly used to separate oil/water emulsions from enhanced oil recovery in heavy oil reservoirs. Conventional burners used in these heaters can cause hot spots that result in coking of the viscous emulsion on the outer surface of the firetube. This coking layer acts as an insulator and results in high tube-wall temperatures, leading to an early failure of the firetube. The problem may be exacerbated when polymer injection is used in the recovery fluid because of the increased viscosity of the fluid and the thermal breakdown of the polymer, which create a thicker insulating layer along the firetube. To reduce the coking and the resulting firetube failures, a conventional burner can be replaced with a radiant distributed-flux burner that spreads the heat over a much larger area, with a very uniform flame shape. The distributed-flux burner consists of a porous-ceramic cylindrical surface that provides surface-stabilized premixed combustion, such that combustion characteristics at every point along the cylindrical burner surface are nearly identical. This reduces the peak heat flux within the combustion zone significantly, reducing the likelihood of hot spots and the potential for coking compared with conventional burners. At the same time, more heat is distributed farther down the length of the firetube, increasing heat transfer in the rear section of the heater and improving its overall efficiency and heater throughput. Firetube life is increased because of the lower peak temperatures of the tube wall, and because less heat may be needed to achieve the required process throughput and water cut. This paper presents data from both pilot tests and field tests of a recent burner retrofit of a horizontal heater treater at an oil sands field in northern Canada. The retrofit was completed in a 2-day effort. On the basis of recent field data, thermal analysis, and measurements made in laboratory tests, the distributed-flux burner is compared with a conventional burner with respect to thermal efficiency and tube-wall temperatures.

A laboratory study of enhancing heavy oil recovery with steam flooding by adding nitrogen foams

Abstract Two significant problems, steam override and steam channeling, decrease the sweep efficiency of steam to result in a lower oil recovery in heavy oil reservoirs. Thermal foam flooding, which is in fact steam flooding by adding non-condensate gas and foaming agent, presents a satisfactory effect in laboratory and field pilot. In this article, a new evaluation method was introduced to choose the optimum foaming agent for thermal foam flooding. The method considered the influence of temperature variation on the properties of foaming agent during steam flooding. Then the chosen surfactant and nitrogen were injected into the reservoir model in our experiments. The results showed that nitrogen foams effectively increased displacement efficiency of steam flooding from 43.30% to 81.24% in the single sand-pack experiment. Thermal foams can effectively improve injection profile to restrain steam injection from gravity override and steam channeling in reservoirs. Foaming agent is an important component in thermal foam flooding; on the one hand, it decreases oil–water interface tension to improve oil displacement efficiency, and on the other hand, it increases the stability of foams to improve sweep efficiency. Therefore, steam flooding by adding nitrogen foams is an effective EOR method to develop heavy oil reservoirs.

The Research and Application of Segregated Completion Technology in Horizontal Wells in the Heavy Oil Reservoirs

Liaohe oilfield is the biggest production base of the heavy oil in China. There are more than 800 horizontal wells with thermal recovery in the heavy oil reservoirs. Most of them adopt screen to complete the wells without packer outside of the casing, which results in packing off annulus space between screen and layer and only commingled steam or step steam can be injected inside the screen. Because of the areal and vertical anisotropy of the reservoirs, the horizontal sections are exploited unequally. According to the statistics, the horizontal wells with nonuniform exploitation accounts for 80 percent of all the horizontal wells with thermal recovery, and only 1/3 to 1/2 of the horizontal sections are comparatively well produced. The oil well productivity is seriously affected. So based on step steam injection inside the screen, we have developed the segregated completion and segregated steam injection technology applied to the horizontal wells with thermal recovery in heavy oil reservoirs. By means of the research on the segregated completion technology and development of high temperature ECP and casing thermal centralizer, which formed the corresponding technology applied in the horizontal wells with thermal recovery. Till now this technology has been applied in 8 wells, and average cyclic steam/oil ratio increased 0.1 plus, and the uniform development level of the horizontal section has been improved and the oilfield’s development effect has been advanced obviously.

Investigating Improved Oil Recovery in Heavy Oil Reservoirs

Primary production mechanisms do not recover an appreciable fraction of the hydrocarbon initially in place (HIIP). Practical knowledge has shown that, at the point when the natural energy in a heavy oil reservoir is nearly or altogether depleted, the recovery factor does not exceed about 20%. Some heavy oil reservoirs do not produce at all by natural drive mechanisms. This often necessitates adopting a production improvement strategy to augment recovery. Prior to implementing an improved oil recovery method (either secondary or tertiary) in the field, it is very important to investigate its potential for success. Reservoir simulation is a part of a continuous learning process used to gain insight into the feasibility and applicability of improved oil recovery methods. In this project, GEM compositional reservoir simulator has been used to study the efficiencies of different improved oil recovery strategies, ranging from waterflooding to solvent injection. The drainage volume investigated is a hypothetical box-shaped heavy oil reservoir composed of three distinct permeable layers.