Gravity-Drainage and Oil-Reinfiltration Modeling in Naturally Fractured Reservoir Simulation
- Juan Ernesto Ladron de Guevara-Torres (PEMEX) | Fernando Rodriguez-de la Garza (PEMEX) | Agustin Galindo-Nava (PEMEX)
- Document ID
- Society of Petroleum Engineers
- SPE Reservoir Evaluation & Engineering
- Publication Date
- June 2009
- Document Type
- Journal Paper
- 380 - 389
- 2009. Society of Petroleum Engineers
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- 1,098 since 2007
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The gravity-drainage and oil-reinfiltration processes that occur in the gas-cap zone of naturally fractured reservoirs (NFRs) are studied through single porosity refined grid simulations. A stack of initially oil-saturated matrix blocks in the presence of connate water surrounded by gas-saturated fractures is considered; gas is provided at the top of the stack at a constant pressure under gravity-capillary dominated flow conditions. An in-house reservoir simulator, SIMPUMA-FRAC, and two other commercial simulators were used to run the numerical experiments; the three simulators gave basically the same results.
Gravity-drainage and oil-reinfiltration rates, along with average fluid saturations, were computed in the stack of matrix blocks through time. Pseudofunctions for oil reinfiltration and gravity drainage were developed and considered in a revised formulation of the dual-porosity flow equations used in the fractured reservoir simulation.
The modified dual-porosity equations were implemented in SIMPUMA-FRAC (Galindo-Nava 1998; Galindo-Nava et al. 1998), and solutions were verified with good results against those obtained from the equivalent single porosity refined grid simulations. The same simulations--considering gravity drainage and oil reinfiltration processes--were attempted to run in the two other commercial simulators, in their dual-porosity mode and using available options. Results obtained were different among them and significantly different from those obtained from SIMPUMA-FRAC.
One of the most important aspects in the numerical simulation of fractured reservoirs is the description of the processes that occur during the rock-matrix/fracture fluid exchange and the connection with the fractured network. This description was initially done in a simplified manner and therefore incomplete (Gilman and Kazemi 1988; Saidi and Sakthikumar 1993).
Experiments and theoretical and numerical studies (Saidi and Sakthikumar 1993; Horie et al. 1998; Tan and Firoozabadi 1990; Coats 1989) have allowed to understand that there are mechanisms and processes, such as oil reinfiltritation or oil imbibition and capillary continuity between matrix blocks, that were not taken into account with sufficient detail in the original dual-porosity formulations to model them properly and that modify significantly the oil-production forecast and the ultimate recovery in an NFR.
The main idea of this paper is to study in further detail the oil reinfiltration process that occurs in the gas invaded zone (gas cap zone) in an NFR and to evaluate its modeling to implement it in a dual-porosity numerical simulator.
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Barenblatt, G.I., Zheltov, Iu.P., and Kochina, I.N. 1960. Basic concepts in thetheory of seepage of homogeneous liquids in fissured rocks. J. ofApplied Mathematics and Mechanics 24 (5): 1286-1303.DOI:10.1016/0021-8928(60)90107-6.
Coats, K.H. 1989. ImplicitCompositional Simulation of Single-Porosity and Dual-Porosity Reservoirs.Paper SPE 18427 presented at the SPE Symposium on Reservoir Simulation,Houston, 6-8 February. DOI: 10.2118/18427-MS.
Vicencio-Fuentes, Omar A. 1998. Estudio de la Transferencia de FluidosMatriz-Fractura en Yacimientos Naturalmente Fracturados en la Zona Invadida porAgua. MS thesis, Universidad Nacional Autónoma de México, Mexico City,Mexico.
Ortega-Galindo, Ricardo. 2000. Modelado del Flujo de Fluidos Matriz-Fracturaen la Zona Invadida por Agua. MS thesis, Universidad Nacional Autónoma deMéxico, Mexico City, Mexico.
Gilman, J.R. and Kazemi, H. 1983. Improvements in Simulation ofNaturally Fractured Reservoirs. SPE J. 23 (4): 695-707.SPE-10511-PA. DOI: 10.2118/10511-PA.
Gilman, J.R. and Kazemi, H. 1988. Improved Calculations for Viscous andGravity Displacement in Matrix Blocks in Dual-Porosity Simulators. J.Pet Tech 40 (1): 60-70; Trans., AIME, 285.SPE-16010-PA. DOI: 10.2118/16010-PA.
Horie, T., Firoozabadi, A., and Ishimoto, K. 1990. Laboratory Studies ofCapillary Interaction in Fracture/Matrix Systems. SPE Res Eval & Eng5 (3): 353-360. SPE-18282-PA. DOI: 10.2118/18282-PA.
Kazemi, H., Merrill, J.R, Porterfield, K.L., and Zeman, P.R. 1976. Numerical Simulation of Water-Oil Flowin Naturally Fractured Reservoirs. SPE J. 16 (6): 317-326;Trans., AIME, 261. SPE-5719-PA. DOI: 10.2118/5719-PA.
Galindo-Nava, Agustín. 1998. Un simulador Numérico del Flujo MultifásicoTridimensional Hacia un Pozo Naturalmente Fracturado. MS thesis, UniversidadNacional Autónoma de México, Mexico City, Mexico.
Galindo-Nava, Agustín and Rodríguez-de la Garza, Fernando. 1998. SimuladorNumérico de Flujo de Fluidos en un Yacimiento Global o Hacia un Pozo en unYacimiento Naturalmente Fracturado o No Fracturado (Trifásico-Tridimensional)SIMPUMA-FRAC, Version 1.1. UNAM-IMP.
Rodríguez-de la Garza, Fernando. 1987. Un Simulador Numérico del FlujoMultifásico hacia Pozos Naturalmente Fracturados. Revista de IngenieríaPetrolera (June): 17-25.
Saidi, A.M. and Sakthikumar, S. 1993. Gas Gravity Drainage Under Secondaryand Tertiary Conditions in Fractured Reservoirs. Paper SPE 25614 presentedat the Middle East Oil Show, Bahrain, 3-6 April. DOI: 10.2118/25614-MS.
Tan, J.C.T. and Firoozabadi, A. 1995. Dual-Porosity SimulationIncorporating Reinfiltration and Capillary Continuity Concepts Part I: SingleGridcell. Paper SPE 29113 presented at the SPE Reservoir SimulationSymposium, San Antonio, Texas, USA, 12-15 February. DOI: 10.2118/29113-MS.
Thomas, L.K., Dixon, T.N., and Pierson, R.G. 1983. Fractured Reservoir Simulation.SPE J. 23 (1): 42-54. SPE-9305-PA. DOI:10.2118/9305-PA.
Ladrón de Guevara-Torres, J Ernesto. 2006. Modelado de La Reinfiltración deAceite en La Simulación Numérica de Yacimientos Fracturados. MS thesis,Universidad Nacional Autónoma de México, Mexico City, Mexico.
Warren, J.E. and Root, P.J. 1963. The Behavior of Naturally FracturedReservoirs. SPE J. 3 (3): 245-255; Trans., AIME,228. SPE-426-PA. DOI: 10.2118/426-PA.