Simulation of Waterflooding with Coarse-Scale Dual-Porosity Representation of Highly Heterogeneous Reservoirs

2013 ◽  
Author(s):  
Kristian Jessen ◽  
Mohammad Evazi Yadecuri
Keyword(s):  
Dual Porosity ◽  
Coarse Scale ◽  
Heterogeneous Reservoirs

Upscaling Technique for Highly Heterogeneous Reservoirs Based on Flow and Storage Capacity and the Lorenz Coefficient

SPE Journal ◽  
2020 ◽  
Vol 25 (04) ◽  
pp. 1981-1999 ◽  
Author(s):  
Victor S. Rios ◽  
Luiz O. S. Santos ◽  
Denis J. Schiozer
Keyword(s):  
Reservoir Simulation ◽  
Storage Capacity ◽  
Simulation Models ◽  
Scaling Up ◽  
Fine Scale ◽  
Coarse Scale ◽  
Heterogeneous Reservoirs ◽  
Upscaling Technique ◽  
Geological Models ◽  
And Storage

Summary Field-scale representation of highly heterogeneous reservoirs remains a challenge in numerical reservoir simulation. In such reservoirs, detailed geological models are important to properly represent key heterogeneities. However, high computational costs and long simulation run times make these detailed models unfeasible to use in dynamic evaluations. Therefore, the scaling up of geological models is a key step in reservoir-engineering studies to reduce computational time. Scaling up must be carefully performed to maintain integrity; both truncation errors and the smoothing of subgrid heterogeneities can cause significant errors. This work evaluates the latter—the effect of averaging small-scale heterogeneities in the upscaling process—and proposes a new upscaling technique to overcome the associated limitations. The technique is dependent on splitting the porous media into two levels guided by flow- and storage-capacity analysis and the Lorenz coefficient (LC), both calculated with static properties (permeability and porosity) from a fine-scale reference model. This technique allows the adaptation of a fine highly heterogeneous geological model to a coarse-scale simulation model in a dual-porosity/dual-permeability (DP/DP) approach and represents the main reservoir heterogeneities and possible preferential paths. The new upscaling technique is applied to different reservoir-simulation models with water injection and immiscible gas injection as recovery methods. In deterministic and probabilistic studies, we show that the resulting coarse-scale dual-permeability models are more accurate and can better reproduce the fine-scale results in different upscaling ratios (URs), without using any simulation results of the reference fine-scale simulation models, as some of the current alternative upscaling methods do.

Effects of fluid saturations on undrained poroelastic constants in layered media

2020 ◽  
Vol 223 (1) ◽  
pp. 366-378
Author(s):  
Shengjie Li
Keyword(s):  
Fluid Phase ◽  
Elastic Parameter ◽  
Pore Fluid ◽  
Fluid Distribution ◽  
Fluid Substitution ◽  
Coarse Scale ◽  
Vertical Stiffness ◽  
Heterogeneous Reservoirs ◽  
Stiffness Constant ◽  
Poroelastic Model

SUMMARY Understanding the fluid dependence of the poroelastic stiffness constants of a layered porous package is of great importance in subsurface exploration and development. While the effects of the pore-fluid distribution caused by coarse-scale heterogeneities within an isotropic medium have been studied for several decades, the role of these heterogeneities on the poroelastic constants of a finely layered package is still largely unexplored. In this study, we apply the poroelastic upscaling methods to estimate the fluid-dependent poroelastic stiffness constants of a layered package at the coarse scale. The numerical results show that the refined Gassmann's fluid substitution formulae presented in this paper is applicable if a single fluid phase is uniformly saturated within a layered package. The stiffness constants (${c_{11}}$ and ${c_{33}}$) of the layered package with patchy saturations are always higher than or equal to those obtained for the medium with homogeneous saturations, the stiffness constants predicted by the refined fluid substitution formulae for the package simultaneously saturated with different fluids fall between them. Experimental results confirm the relationship between the undrained vertical stiffness constant and the effective pore-fluid bulk modulus for the patch saturated package, indicating that a reasonable result can be achieved by properly choosing an effective poroelastic model that accounts both for the fluid hydraulic communication and the anisotropy of the medium. The results improve the understanding of the coarse-scale fluid dependence of the poroelastic stiffness constants of a layered package, and therefore, it can be used to interpret the seismically inverted elastic parameter for the petrophysical properties in heterogeneous reservoirs.

Coarse-scale resistivity for saturation estimation in heterogeneous reservoirs based on Archie’s formula

Geophysics ◽  
2011 ◽  
Vol 76 (2) ◽  
pp. E35-E43 ◽  
Author(s):  
Per Atle Olsen
Keyword(s):  
Water Saturation ◽  
Small Scale ◽  
Coarse Scale ◽  
Derived Relations ◽  
Analytical Expression ◽  
Resistivity Measurements ◽  
Heterogeneous Reservoirs ◽  
Geometric Average ◽  
Harmonic Average

Relations between porosity, saturation, and resistivity are essential when estimating in-place hydrocarbon volumes. The most common relation is the Archie formula. During the last decade, several new coarse-scale electromagnetic techniques for resistivity measurements have been developed. Applications of coarse-scale resistivity must consider the underlying geologic variability of porosity and saturation to be used in such relations. I have investigated the effect of small-scale (logging-scale) variability in porosity and water saturation on coarse-scale resistivity for Archie relations. An analytical expression for coarse-scale resistivity is derived based on the assumption of lognormal distributed porosity and saturation. Similarly, coarse-scale water saturation is derived assuming lognormal distributed porosity and resistivity. The results suggest that the coarse-scale equivalent Archie resistivity is normally less than the geometric average and larger than the harmonic average of the heterogeneous resistivity distribution. An important aspect of the analytical derived relations is the quantification of the effect of the variability (variance and covariance) on the coarse-scale results. Another coarse-scale average resistivity based on macroscopic anisotropy could be a practical approximation of the coarse-scale equivalent Archie resistivity in many cases.

Coarse Scale Capillary Pressure in Heterogeneous Reservoirs

2008 ◽  
Vol 75 (3) ◽  
pp. 275-294 ◽  
Author(s):  
George A. Virnovsky ◽  
Arild Lohne ◽  
Thomas R. Lerdahl
Keyword(s):  
Capillary Pressure ◽  
Coarse Scale ◽  
Heterogeneous Reservoirs
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