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Results
Development And Application Of Steam Injection Simulators In Venezuela
Ferrer, Jose (University of Zulia) | Quintero, L. (University of Zulia) | Aquino, C. (University of Zulia) | Guevara, F. (University of Zulia) | Avila, A. (University of Zulia) | Perez, J. (University of Zulia) | Briceno, W. (University of Zulia) | Sanchez, L. (University of Zulia) | Rodriquez, E. (University of Zulia) | Finol, A. (Maraven S.A.) | Diaz-Munoz, J. (Maraven S.A.) | Ali, S.M. Farouq (University of Alberta)
Abstract Steam injection is a major oil recovery method in Venezuela, with some three trillion barrels of oil possibly recoverable by this technique. As a result, alongside the progress in steam injection technology, the development of a series of numerical simulators has been proceeding at an accelerated pace in Venezuela. This paper describes three of the steam injection simulators developed over the past five years, and their applicationto two major heavy oil reservoirs. These simulators describe three phase, non isothermal multi component flow, comprising four, three and two components, respectively, in three dimensions. The implicitness of the simulators increases in the order of decreasing number of components. It is shown, however, that for a variety of problems the less implicit but more efficientsimulators are adequate. The finite difference methods used for each simulator ere outlined. These, as well as the computational performance, are compared with the existing simulators. The application of the simulators to two major reservoirs in Venezuela-Morichal and M-6-is described and compared. Effects of such factors as spacing, injection rate, and gravity segregation are examined. It is shown that the oil recovery in the large M-6 steamflood would be 7 to 9% of the oil in place, well below the expected value, and considerably below the 15 – 26% recovery predicted for the Morichal Field by the simulators. Results also show that the oil-steam ratio is not always a reliable economic index. Introduction Steam injection is the most widely applied and promising enhanced oil recovery process for exploiting some of the vast deposits of heavy oil in Venezuela. The oil reservoirs in the Orinoco Petroleum Belt and the Bolivar Coast fields contain most of these heavy oils. The large M-6 and Morichal steam injection projects are representative of the future development of these oilfields. Several small field tests have been carried out in the Orinoco Petroleum Belt reservoirs. Waterflooding, gas injection, in situ combustion and cyclic steam injection have been tested on commercial scale. Several other processes have also been investigated in small pilot tests. In particular, cyclic steam injection has been extensively applied in the Bolivar Coast heavy oil reservoirs. A large scale steamflood is currently being conducted under the M-6 project. An in situ combustion pilot was also conducted in one of these reservoirs. Numerical simulation is a powerful tool in the management of reservoirs where steam injection is the recovery method. Efforts have been made to develop techniques for simulating steam injection into oil reservoirs, however, it was only in the last decade when definite advances in numerical models were realized. Shutler(1,2) rand Abdalla and Coats(3) described two-dimensional, three-phase flow numerical models for steam injection processes. Weinstein et al. (4) described a one-dimensional model that accounted for steam distillation of oil. Coats et al. (5) reported a three-dimensional steamflood model for a dead oil. Coats(6) presented a numerical model that included steam distillation of oil, release of solution gas, temperature dependence of relative permeability and a more implicit treatment of capillary pressure and transmissibilities in the fluid saturation calculations.
- North America > Canada > Alberta (0.30)
- South America > Venezuela > Zulian Region (0.25)
- South America > Venezuela > Morichal Field (0.99)
- South America > Venezuela > Zulia > Maracaibo Basin > Ayacucho Blocks > Tia Juana Field (0.94)
- South America > Venezuela > Zulia > Maracaibo Basin > Ayacucho Blocks > Lagunillas Field (0.94)
- (3 more...)
Numerical Simulation of Oil Production With Simultaneous Ground Subsidence
Finol, A. (U. of Zulia) | Ali, S.M. Farouq (Pennsylvania State U.)
Abstract A two-phase, two-dimensional black oil simulator was developed for simulating reservoir production behavior with simultaneously occurring reservoir formation compaction and ground subsidence at the surface.The flow equations were solved by both alternating direction implicit procedure and strongly implicit procedure. Reservoir compaction was described on the basis of the experimental data reported. The magnitude of areal subsidence at the surface was calculated using reservoir compaction, utilizing the recently developed theory of poroelasticity. poroelasticity. Computer runs were used to generate a variety of data, such as reservoir Pressure variation with oil production, for different reservoir compaction production, for different reservoir compaction coefficients. It was found that the average reservoir pressure increased with the Compaction coefficient pressure increased with the Compaction coefficient for a given cumulative oil production.The model was used for generating the reservoir formation profiles, as well as the ground subsidence bowls for a variety of conditions. It was found that the subsidence behavior strongly depends on the depth of burial. For example, with an increase in the depth, the reservoir bottom surface may actually uplift, while the top surface subsides.The model was also used for studying the effect of subsidence on pressure buildup behavior. The calculated reservoir pressure was higher in a compacting than in a noncompacting reservoir, taking into account the variation of permeability with compaction.Another phase studied was the effect of rebound on reservoir performance when gas is injected into the formation. Even though rebound is small in practice (on the order of 10 percent of subsidence), practice (on the order of 10 percent of subsidence), the effect was clearly evident in the reservoir pressure-production behavior. However, when there pressure-production behavior. However, when there was no rebound, gas injection simply inhibited compaction.Finally, the model was used for simulating the reported oil production and subsidence history of one of the Bolivar Coast oil fields in the Western Venezuela. Fair agreement was obtained between the observed and the predicted behavior. Introduction The phenomenon of ground subsidence associated with production of oil or gas from underground hydrocarbon reservoirs is not common; however, it does present environmental problems in a few oil-producing areas around the world. Notable examples are the Wilmington oil field, below Long Beach, Calif. where almost 30 ft of subsidence have been recorded, and the oil fields near and under Lake Maracaibo in Venezuela, where the surface has subsided as much as 10 ft. Other cases have been reported in Harris County, Tex., in the Niigata district of Japan, and in the Po Delta in Italy.Numerous causes may give rise to ground subsidence, either natural or as a result of man's activities. However, as far as the problem at hand is concerned, the observed land subsidence is considered to be a result of reservoir compaction, resulting from pore pressure decline in reservoirs that meet certain specific geometrical and structural conditions. The changes in the petrophysical properties of reservoir rocks caused by compaction properties of reservoir rocks caused by compaction have been studied to some extent, as well as the influence of such changes on the fluid production behavior of the reservoir. However, very little has been accomplished in relating the compaction of the underground reservoir with the subsidence occurring at the surface. Among the few studies conducted on this problem, the most realistic are those that consider subsidence above a disk-shaped reservoir, in which a uniform pressure reduction has occurred. These studies do not simulate the fluid production behavior of the compacting reservoir as such; this is considered to be known and is used to determine the compaction of the reservoir and the accompanying subsidence. SPEJ P. 411
- South America > Venezuela > Zulia (0.54)
- Asia > Japan > Chūbu > Niigata Prefecture > Niigata (0.24)
- North America > United States > California > Los Angeles County > Long Beach (0.24)
- Geology > Geological Subdiscipline > Geomechanics (1.00)
- Geology > Geological Subdiscipline > Economic Geology > Petroleum Geology (0.34)
- North America > United States > California > Los Angeles Basin > Wilmington Field (0.99)
- Oceania > Papua New Guinea > Papuan Peninsula > Central Province > National Capital District > Petroleum Retention License 15 > P’nyang Field (0.97)
- Oceania > Papua New Guinea > Papuan Peninsula > Central Province > National Capital District > Petroleum Retention License 15 > Elk-Antelope Field (0.97)
- (10 more...)