A Rapid and Efficient Methodology to Convert Fractured Reservoir Images Into a Dual-Porosity Model

Abstract

MƒTHODOLOGIE RAPIDE ET EFFICACE POUR CONVERTIR LES IMAGES DE RƒSERVOIR A RAPID AND EFFICIENT METHODOLOGY TO CONVERT FRACTURED RESERVOIR IMAGES INTO A DUAL-POROSITY MODELBoth characterization and dynamic simulation of naturally-fractured reservoirs have benefited from major advances in recent years. However, the reservoir engineer is still faced with the difficulty of parameterizing the dual-porosity model used to represent such reservoirs. In particular, the equivalent fracture permeabilities and the equivalent matrix block dimensions of such a model cannot be easily derived from observation of the complex images of natural fracture networks. This paper describes a novel and systematic methodology to compute these equivalent parameters. copyright C 1998, Institut Français du Pétrole its validity and efficiency in dealing with field situations. A tensor of equivalent fracture permeability is derived from single-phase steady-state flow computations on the actual fracture network using a 3D resistor network method and specific boundary conditions. The equivalent block dimensions in each layer are derived from the rapid identification of a geometrical function based on capillary imbibition. The methodology was validated against fine-grid reference simulations with a conventional reservoir simulator. Then, a complex outcrop image of a sandstone formation was processed for demonstration purposes. This innovative tool enables the reservoir engineer to build a dualporosity model which best fits the hydraulic behavior of the actual fractured medium. METODOLOGêA RçPIDA Y EFICAZ PARA CONVERTIR LAS IMçGENES DE YACIMIENTOS FRACTURADOS EN MODELO DE DOBLE POROSIDADLa caracterizaci-n y la simulaci-n din ‡mica de los yacimientos naturalmente fracturados han aprovechado las ventajas derivadas de los importantes adelantos que han surgido durante estos oeltimos a-os. No obstante, el ingeniero de yacimientos sigue estando acuciado por la dificultad consistente en parametrar el modelo equivalente de doble porosidad utilizado para representar este gŽnero de yacimientos. B ‡sicamente, las permeabilidades de fractura equivalentes y las dimensiones del bloque matricial no se pueden deducir f ‡cilmente de la observaci-n de las im ‡genes complejas de redes naturales de fracturas. Se describe en el presente art'culo una tŽcnica, nueva y sistem ‡tica, para calcular estos par ‡metros equivalentes. Los resultados de su implementaci-n por medio de un software espec'fico demuestran su validez y su eficacia para el estudio de casos de campo. Un tensor de las permeabilidades de fractura se deduce de c ‡lculos de flujos estacionarios y monof ‡sicos en la red real de fracturas asimiladas a una red 3D de resistencia y sometido a condiciones l'mites espec'ficas. Las dimensiones del bloque equivalente en cada estrato se obtienen r ‡pidamente por identificaci-n de una funci-n geomŽtrica representativa de un desplazamiento capilar. La metodolog'a se ha validado por comparaci-n con las simulaciones de mallado fino, realizadas por medio de un simulador de ...

Connectivity‐consistent mapping method for 2‐D discrete fracture networks

“…Hybrid approaches have been developed to combine the advantages of the DFN and SC approaches. Most of them use a DFN approach at the onset for building equivalent heterogeneous continuous models mapping either the smallest fractures [Lee et al, 2001] or all fractures in the case of the fracture continuum model (FCM) [Botros et al, 2008;Bourbiaux et al, 1998;Jackson et al, 2000;Reeves et al, 2008;Svensson, 2001]. Fracture continuum models aim at benefiting both from the structure complexity of DFNs and from the simulation and computational simplicities of continuous media.…”

“…Fracture continuum models aim at benefiting both from the structure complexity of DFNs and from the simulation and computational simplicities of continuous media. The objective is often to use the FCM approximation as a basis for simulating more computationally demanding transient or multiphase flows [Bourbiaux et al, 1998;Karimi-Fard et al, 2006].…”

Joint Inversion of Fracture Model Properties for CO2Storage Monitoring or Oil Recovery History Matching

“…Stationary single phase flow is computed using varying boundary conditions. The results of these simulations are used to derive the equivalent permeability tensor [21,25].…”

Chemical Flooding in Naturally Fractured Reservoirs: Fundamental Aspects and Field-Scale Practices

“…Building a dual-porosity model that best fits the hydraulic behavior of the actual NFR is the first step in constructing a robust simulation model. This is achieved by parameterizing the dual-porosity model for which the equivalent fracture permeabilities and the equivalent matrix block dimensions should properly be identified (Bourbiaux et al, 1998).…”