Analysis of Fracture Roughness Control on Permeability Using SfM and Fluid Flow Simulations: Implications for Carbonate Reservoir Characterization

Fluid flow through a single fracture is traditionally described by the cubic law, which is derived from the Navier-Stokes equation for the flow of an incompressible fluid between two smooth-parallel plates. Thus, the permeability of a single fracture depends only on the so-called hydraulic aperture which differs from the mechanical aperture (separation between the two fracture wall surfaces). This difference is mainly related to the roughness of the fracture walls, which has been evaluated in previous works by including a friction factor in the permeability equation or directly deriving the hydraulic aperture. However, these methodologies may lack adequate precision to provide valid results. This work presents a complete protocol for fracture surface mapping, roughness evaluation, fracture modeling, fluid flow simulation, and permeability estimation of individual fracture (open or sheared joint/pressure solution seam). The methodology includes laboratory-based high-resolution structure from motion (SfM) photogrammetry of fracture surfaces, power spectral density (PSD) surface evaluation, synthetic fracture modeling, and fluid flow simulation using the Lattice-Boltzmann method. This work evaluates the respective controls on permeability exerted by the fracture displacement (perpendicular and parallel to the fracture walls), surface roughness, and surface pair mismatch. The results may contribute to defining a more accurate equation of hydraulic aperture and permeability of single fractures, which represents a pillar for the modeling and upscaling of the hydraulic properties of a geofluid reservoir.

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Fault-related fracture modeling in a pre-salt lacustrine carbonate reservoir from Santos Basin, offshore Brazil: Predicting preferential fluid flow paths using 3D geological and flow simulation models

Marine and Petroleum Geology ◽

10.1016/j.marpetgeo.2021.105392 ◽

2021 ◽

pp. 105392

Author(s):

Ana Paula Burgoa Tanaka ◽

João Paulo Gomes Borges ◽

Gabriel Correa de Matos ◽

Maria Taryn Relvas Campos ◽

Bruno Miranda Cunha ◽

...

Keyword(s):

Fluid Flow ◽

Flow Simulation ◽

Simulation Models ◽

Carbonate Reservoir ◽

Flow Paths ◽

Fracture Modeling ◽

Lacustrine Carbonate

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FORWARD MODELING OF SEQUENCE STRATIGRAPHY AND DIAGENESIS: Application to Rapid, Cost-Effective Carbonate Reservoir Characterization

GeoArabia ◽

10.2113/geoarabia0303359 ◽

1998 ◽

Vol 3 (3) ◽

pp. 359-384 ◽

Cited By ~ 7

Author(s):

Robley K. Matthews ◽

Cliff Frohlich

Keyword(s):

Sequence Stratigraphy ◽

Reservoir Characterization ◽

Three Dimensional ◽

Flow Simulation ◽

Cost Effective ◽

Forward Modeling ◽

Carbonate Reservoir ◽

Sensitivity Testing ◽

Future Production ◽

Carbonate Reservoir Characterization

ABSTRACT Dynamic forward modeling of carbonate reservoir sequence stratigraphy and diagenetic overprint can yield rapid, cost-effective reservoir characterization. The common practice in reservoir characterization now relies heavily on massive data accumulation and geostatistics to produce the three-dimensional geocellular static model which is the basis for flow simulation. In dynamic forward modeling, reliance on understanding of geological process allows high resolution prediction of the geometry of permeable and impermeable units and horizons within the reservoir. Data requirements are reduced to state-of-the-art information on a relatively small number of control wells which constrain and calibrate the forward model. Sensitivity-testing among formally-stated competing concepts is encouraged. In the long-term, it is the accurate prediction of reservoir response to future production that will afford choice among competing static models and flow simulations. The goal should be to predict future problems and avoid them, rather than wait to observe problems and react to them.

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Evaluation of equivalent hydraulic aperture (EHA) for rough rock fractures

Canadian Geotechnical Journal ◽

10.1139/cgj-2018-0274 ◽

2019 ◽

Vol 56 (10) ◽

pp. 1486-1501 ◽

Cited By ~ 5

Author(s):

Fei Xiao ◽

Zhiye Zhao

Keyword(s):

Fluid Flow ◽

Rock Fracture ◽

Fluid Velocity ◽

Surrogate Models ◽

Rock Fractures ◽

Parallel Plates ◽

Characteristic Parameters ◽

Fracture Roughness ◽

Hydraulic Aperture ◽

The Impact

Most existing models for fluid transportation within a single rock fracture tend to use a channel with two smooth parallel plates, whereas real fracture surfaces are usually rough and tortuous, which can produce a flow field significantly different from the smooth plate model. For fluid flow in a rough fracture, there are surface concave areas (SCA), where the fluid velocity is extremely low, contributing little to the fluid transportation. It is of great significance to quantitatively evaluate the impact of rough surfaces on fluid flow. Therefore, a numerical model for simulating Newtonian fluid through rough fractures is proposed, where synthetic surfaces are generated according to statistical analysis of natural rock fractures and can be quantified by several characteristic parameters. Equivalent hydraulic aperture (EHA) is proposed as one quantitative indicator for evaluating the impact of fracture roughness. Systematic studies were conducted for evaluating EHAs of rough fractures, which, combined with characteristic parameters of fractures, are used to build surrogate models for EHA prediction. It is found that the EHA is directly correlated with the fracture roughness, the mean mechanical aperture, and the standard deviation of aperture distribution. The developed surrogate models were verified to have a high accuracy for EHA prediction.

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Shear-Thinning Fluid Flow in Variable-Aperture Channels

Proceedings ◽

10.3390/ecws-4-06426 ◽

2019 ◽

Vol 48 (1) ◽

pp. 28

Author(s):

Alessandro Lenci ◽

Vittorio Di Federico

Keyword(s):

Fluid Flow ◽

Pressure Gradient ◽

Flow Rate ◽

Geometric Model ◽

Shear Thinning ◽

Single Fracture ◽

Fracture Aperture ◽

Nonlinear Phenomenon ◽

Hydraulic Aperture ◽

Fluid Rheology

Non-Newtonian fluid flow in a single fracture is a 3D nonlinear phenomenon that is often averaged across the fracture aperture and described as 2D. To capture key interactions between fluid rheology and spatial heterogeneity, we adopted a simplified geometric model to describe aperture variability, consisting of adjacent one-dimensional channels with constant aperture, each drawn from assigned aperture distribution. The flow rate was then derived under the lubrication approximation for the two limiting cases of an external pressure gradient that was parallel/perpendicular to the channels; these two arrangements provided an upper/lower bound to fracture conductance. Fluid rheology was described via the Prandtl–Eyring shear-thinning model. Novel closed-form results for flow rate and hydraulic aperture were derived and are discussed; different combinations of parameters describing the fluid rheology and variability of the aperture field were considered. In general, flow rate depends, in a nonlinear fashion, on the dimensionless pressure gradient and distribution parameters.

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Petronius Project - Reservoir Characterization, Modelling, and Fluid-Flow Simulation

EAGE/AAPG 3rd Research Symposium - Developing and Managing Turbidite Reservoirs ◽

10.3997/2214-4609.201406571 ◽

1998 ◽

Author(s):

C. Randy Smith

Keyword(s):

Fluid Flow ◽

Reservoir Characterization ◽

Flow Simulation

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Shear-Thinning Fluid Flow in Variable-Aperture Channels

Water ◽

10.3390/w12041152 ◽

2020 ◽

Vol 12 (4) ◽

pp. 1152 ◽

Cited By ~ 1

Author(s):

Alessandro Lenci ◽

Sandro Longo ◽

Vittorio Di Federico

Keyword(s):

Fluid Flow ◽

Pressure Gradient ◽

Flow Rate ◽

Shear Thinning ◽

Skewed Distribution ◽

Upper And Lower Bounds ◽

Single Fracture ◽

Nonlinear Phenomenon ◽

Hydraulic Aperture ◽

Fluid Rheology

Non-Newtonian fluid flow in a single fracture is a 3-D nonlinear phenomenon that is often averaged across the fracture aperture and described as 2-D. To capture the key interactions between fluid rheology and spatial heterogeneity, we adopt a simplified geometric model to describe the aperture variability, consisting of adjacent one-dimensional channels with constant aperture, each drawn from an assigned aperture distribution. The flow rate is then derived under the lubrication approximation for the two limiting cases of an external pressure gradient that is parallel/perpendicular to the channels; these two arrangements provide upper and lower bounds to the fracture conductance. The fluid rheology is described by the Prandtl–Eyring shear-thinning model. Novel closed-form results for the flow rate and hydraulic aperture are derived and discussed; different combinations of the parameters that describe the fluid rheology and the variability of the aperture field are considered. The flow rate values are very sensitive to the applied pressure gradient and to the shape of the distribution; in particular, more skewed distribution entails larger values of a dimensionless flow rate. Results for practical applications are compared with those valid for a power-law fluid and show the effects on the fracture flow rate of a shear stress plateau.

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