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Collaborating Authors
Improved and Enhanced Recovery
A Comparative Study on WAS, SWAS, and Solvent-Soak Scenarios Applied to Heavy-Oil Reservoirs Using Five-Spot Glass Micromodels
Farzaneh, Seyed Amir (Heriot-Watt University) | Dehghan, Ali Akbar (Sharif University of Technology) | Ghazanfari, Mohammad H. (Sharif University of Technology) | Kharrat, Riyaz (Petroleum University of Technology)
Summary In this work, a series of solvent- and water-injection scenarios were conducted on horizontal five-spot glass micromodels that were saturated initially with heavy oil. Sandstone and limestone rock look-alike and network patterns with different pore structures were used in the experiments. The results show that the ultimate oil recovery of a water-alternating-solvent (WAS) scheme was greater than that of a simultaneously water-alternating-solvent (SWAS) scheme, and the efficiency of a solvent-soak scheme also offers a greater recovery. Likewise, the WAS scheme resulted in greater oil recovery when compared with continuous solvent injection (CSI), with the same amount of solvent consumption. Furthermore, some pore-scale phenomena, such as viscous fingering, diffusion of solvents into heavy oil, and localized entrapment of oil and solvent because of heterogeneity and/or water blockage, are also illustrated. The results of this work can be helpful for better understanding and verification of flow transport and pore-scale events during different solvent-based-injection scenarios in heavy-oil reservoirs.
- North America > United States (1.00)
- Asia > Middle East > Iran (0.69)
- Research Report > New Finding (0.48)
- Research Report > Experimental Study (0.34)
- Materials > Chemicals > Commodity Chemicals > Petrochemicals (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- Reservoir Description and Dynamics > Unconventional and Complex Reservoirs > Oil sand, oil shale, bitumen (1.00)
- Reservoir Description and Dynamics > Improved and Enhanced Recovery > Waterflooding (1.00)
A Review on Thermal Enhanced Heavy Oil Recovery from Fractured Carbonate Reservoirs
Ghoodjani, Eshragh (Sharif University of Technology) | Kharrat, Riyaz (Petroleum University of Technology) | Vossoughi, Manouchehr (Sharif University of Technology) | Bolouri, Seyed Hamed (U Of Shahid Bahonar Kerman)
Abstract Heavy oil in Middle East fractured carbonate reservoirs account for 25โ30% of the total oil in place in the region. Production of heavy oil from such reservoirs is thought to play an important role in the future of the ever-growing worldโs energy consumption in which Iranโs recoverable heavy oil is more than 85 billion barrels. The offshore Ferdows field in Iran is reportedly on the order of 30 billion barrels of oil and holds perhaps the greatest promise to add significant future carbonate heavy oil production within the region. With depletion of conventional petroleum reserves and increase of hydrocarbon fuel demand, there is no doubt that there will be a tremendous demand on the development of heavy oil reservoirs in the coming decades. Despite its strategic importance, recovery of heavy crude from fractured carbonate reservoirs has found limited applications due to the complexity of such reservoirs. As most of the oil is stored in matrix due to its higher storage capacity than fracture network, reservoir development plans will aim at maximizing the matrix oil recovery. For reservoirs with high recovery factor, minimizing matrix residual oil saturation is a critical issue to extend the life of the reservoir. For reservoirs with low recovery factor, accelerating the production rate is more vital. For each of these reservoir types, different Enhanced Oil Recovery (EOR) methods should be considered and implemented accordingly. In this study, a comprehensive review is conducted to figure out the feasibility of heavy oil recovery from fractured carbonate reservoirs by use of Cyclic Steam Stimulation (CSS), Steam injection, In-Situ Combustion (ISC), Steam Assisted Gravity Drainage (SAGD), Vapor Extraction (VAPEX) and Expanding Solvent-Steam Assisted Gravity Drainage (ES-SAGD).
- North America > United States > California (0.47)
- Asia > Middle East > Iran > Arabian Gulf (0.24)
- Reservoir Description and Dynamics > Unconventional and Complex Reservoirs > Oil sand, oil shale, bitumen (1.00)
- Reservoir Description and Dynamics > Unconventional and Complex Reservoirs > Naturally-fractured reservoirs (1.00)
- Reservoir Description and Dynamics > Unconventional and Complex Reservoirs > Carbonate reservoirs (1.00)
- Reservoir Description and Dynamics > Improved and Enhanced Recovery > Thermal methods (1.00)
A Comprehensive EOR Study of a Highly Fractured Matured Field-Case Study
Kharrat, R.. (Petroleum University of Technology) | Mahdavi, S.. (PUT Research Center) | Ghorbani, Davood (Denbury Resources)
Abstract Some of the Middle East fields are approaching their final stage of primary production. Most of these fields are highly fractured and carbonate in nature. One major problem is the creation of gas and water invaded zones during the history of production form such fields. Hence, the implementation of proper EOR process requires an extensive laboratory work and simulation studies. A mature field with more than six decades of production has been considered in this study to explore all possible EOR methods. Several EOR processes such as continuous gas injection (GI), WAG (water alternative gas flooding), SWAG (simultaneous WAG), FAWAG (Foam Assisted WAG), and GAGD (Gas Assisted Gravity Drainage) process were studied in laboratory scale and simulation work. The Gas injection and GAGD were found to be unfeasible due the high fracture frequency and early gas breakthrough even with low rate of injection. However, the WAG, SWAG and FWAG were found to be more feasible. This is possibly due to mobility modification by water phase. During SWAG method all pores displaced at the same time, so that a higher ultimate recovery factor achieved sooner in comparison with WAG process. In order to have better recovery for the residual oil, FAWAG method was applied to control the injectivity of injected gas and reduce the interfacial tension (IFT) between residual oil and rock. Surfactant was chosen in different concentration of 5000, 2000, 1000, and 500 ppm. All experiments were carried out under reservoir condition. The FAWAG process was found to be more suitable process for such reservoirs due to its high recovery. Finally the simulation study was conducted with different patterns of injection and production for all the mentioned EOR scenarios. It was found that the fractures density had an important role in the selection of the optimum pattern.
- Asia > Middle East (1.00)
- Europe (0.89)
- North America > United States > Alaska (0.28)
- North America > United States > Alaska > North Slope Basin > Kuparuk River Field (0.99)
- Asia > Middle East > Iran > Arabian Gulf > Arabian Basin > Arabian Gulf Basin > Sirri Field (0.99)
- Reservoir Description and Dynamics > Improved and Enhanced Recovery > Waterflooding (1.00)
- Reservoir Description and Dynamics > Improved and Enhanced Recovery > Gas-injection methods (1.00)
Macroscopic Recovery Mechanisms of In-Situ Combustion Process in Heavy Oil Fractured Systems: Effect of Fractures Geometrical Properties and Operational Parameters
Fatemi, S. Mobeen (Sharif University of Technology (now with Heriot-Watt University)) | Kharrat, Riyaz (Petroleum University of Technology) | Vossoughi, Shapour (University of Kansas) | Ghotbi, Cyrus (Sharif University of Technology)
Abstract The In-Situ Combustion (ISC) as a thermal EOR process has been studied deeply in heavy oil reservoirs and is a promising method for certain non-fractured sandstones. However, its feasibility in fractured carbonates remained questionable. The aim of the present work was to understand the recovery mechanisms of ISC in fractured models and to evaluate the effect of fractures geometrical properties such as orientation, density, location and networking on the ISC recovery performance. Combustion parameters of a fractured low permeable carbonate heavy oil reservoir in Middle East called KEM; applied to simulation study. Simulator has been validated with KEM combustion tube experimental data and validated model modified to 3D semi-scaled combustion cells. It was found that in fractured models oxygen first flows into the fractures and then diffuses from all sides into the matrix. Combustion of the oil in the fractures produces water ahead of fracture combustion front which prohibits oxygen from early breakthrough through fractures into producer. Water imbibes into matrix and causes further oil drainage. Part of this oil imbibes into downstream matrices and the other part produces into producer through fractures. The oxygen diffusion/water imbibition based recovery mechanism is slower in production rates compare to conventional model recovery mechanism, and also results in lower quality of produced oil. It was found that ISC recovery was higher in the presence of networked fractures (presence of both longitudinal and traversal fissures) compare to the case of presence of either longitudinal or traversal fracture systems. Results show that ISC is more feasible in the case of densely fractured reservoirs such as those in the Middle East. Further, sensitivity analysis on air injection rate, formation thickness, injection well depth of perforation and also feasibility of water alternating gas (air), WAG, process for fracture model have been studied.
- North America > United States (0.93)
- Asia > Middle East > Iran (0.29)
- Reservoir Description and Dynamics > Unconventional and Complex Reservoirs > Oil sand, oil shale, bitumen (1.00)
- Reservoir Description and Dynamics > Unconventional and Complex Reservoirs > Naturally-fractured reservoirs (1.00)
- Reservoir Description and Dynamics > Improved and Enhanced Recovery > Thermal methods (1.00)