Comparison of Domain Partitioning Algorithms in the Problem of Direct Flow Simulation in Rock Samples at the Pore Scale

2020 ◽  
Vol 12 (6) ◽  
pp. 990-995
Author(s):  
E. N. Golovchenko ◽  
M. V. Iakobovski ◽  
V. A. Balashov ◽  
E. B. Savenkov
Keyword(s):  
Flow Simulation ◽  
Pore Scale ◽  
Direct Flow ◽  
Rock Samples ◽  
Domain Partitioning ◽  
Partitioning Algorithms

Directional-Permeability Assessment in Formations With Complex Pore Geometry With a New Nuclear-Magnetic-Resonance-Based Permeability Model

SPE Journal ◽  
2016 ◽  
Vol 21 (04) ◽  
pp. 1436-1449 ◽  
Author(s):  
Lu Chi ◽  
Zoya Heidari
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Pore Geometry ◽  
Pore Scale ◽  
Rock Permeability ◽  
Permeability Model ◽  
Pore Connectivity ◽  
Anisotropic Permeability ◽  
Rock Samples ◽  
Directional Permeability

Summary This paper proposes a new method for directional-permeability assessment with nuclear-magnetic-resonance (NMR) measurements. Conventional techniques for permeability assessment from NMR measurements include empirical correlations such as SDR (Schlumberger-Doll-Research) and Coates models. However, carbonate rocks are known for lack of good correlations between pore-body-size and pore-throat-size, which makes it challenging and often unreliable to estimate permeability from NMR T2 (spin-spin relaxation time) distribution in carbonate formations with complex pore structure. It also was proposed that conventional permeability models can be improved by incorporating an estimated pore-connectivity factor. However, none of the previously introduced techniques reflects the anisotropic characteristics of rock permeability. The new NMR-based directional-permeability model, introduced in this paper, incorporates a directional pore-connectivity factor into a conventional NMR-based permeability model. We introduce two approaches to quantify the directional pore-network connectivity of rock samples with pore-scale images. The first approach calculates directional pore connectivity in 3D pore-scale images with a topological technique. The second approach combines image analysis and electrical formation factor. The new NMR-based permeability model enables assessment of rock permeability in any desired direction. We successfully calibrated and tested the introduced NMR-based permeability model on carbonate, sandstone, and sandpack samples with complex pore geometry or anisotropic permeability. The anisotropic permeability used for calibration and test purposes was obtained by the lattice Boltzmann method (LBM) simulations on microcomputed tomography (CT) images of rock samples. The comparison between the permeability estimates with our new NMR model and conventional NMR models (e.g., SDR and Coates models) demonstrated that the NMR-based directional-permeability model significantly improves assessment of rock permeability, by reflecting rock's anisotropic characteristics and minimizing calibration efforts. The outcomes of this research can significantly improve permeability assessment in complex carbonate reservoirs and anisotropic sandstone reservoirs, and can be extended further to organic-rich mudrock formations.

scholarly journals Study of Interactions between Induced and Natural Fracture Effects on Hydraulic Fracture Propagation Using a Discrete Approach

Lithosphere ◽  
2021 ◽  
Vol 2021 (Special 4) ◽  
Author(s):  
Yulong Zhang ◽  
Bei Han ◽  
Xin Zhang ◽  
Yun Jia ◽  
Chun Zhu
Keyword(s):  
Hydraulic Fracture ◽  
Fracture Propagation ◽  
Flow Simulation ◽  
Injection Pressure ◽  
Natural Fracture ◽  
Uniaxial Compression Test ◽  
Differential Stress ◽  
Rock Samples ◽  
Approach Angle ◽  
Hydraulic Fracture Propagation

Abstract The interaction mode of induced fracture and natural fracture plays an important role in prediction of hydraulic fracture propagation. In this paper, a two-dimensional hydromechanical coupled discrete element model is first introduced in the framework of particle flow simulation, which can well take into account mechanical and hydraulic properties of rock samples with natural fracture. The model’s parameters are strictly calibrated by conducting numerical simulations of uniaxial compression test and direct tensile and shear tests, as well as fluid flow test. The effectiveness of coupled model is also assessed by describing hydraulic fracture propagation in two representative cases, respectively, rock samples with and without preexisting fracture. With this model in hand, the effects of interaction between induced and natural fractures with different approach angles and differential stresses on fluid injection pressure and fracture propagation patterns are investigated and discussed. Results suggest that the interaction modes mainly involve three basic behaviors including the arrested, captured with offset, and directly crossing. For a given differential stress, the captured offset of hydraulic fracture by natural fracture gradually decreases with the approach angle increase, while for a fixed approach angle, that captured offset increases with differential stress decrease.

New Classification of Carbonate Rocks for Process-Based Pore-Scale Modeling

SPE Journal ◽  
2012 ◽  
Vol 18 (02) ◽  
pp. 243-263 ◽  
Author(s):  
Maryam Mousavi ◽  
Maša Prodanovic ◽  
David Jacobi
Keyword(s):  
Carbonate Rocks ◽  
Carbonate Rock ◽  
Flow Simulation ◽  
Pore Geometry ◽  
Carbonate Content ◽  
Pore Scale ◽  
Scale Modeling ◽  
New Concepts ◽  
Pore Scale Modeling

Summary Carbonate rocks are complex in structure and pore geometry and display heterogeneity on all length scales. In this paper, carbonate rocks are described on the basis of their contents and pore geometry for use in pore-scale modeling. Definitions of grains and porosities are based on other carbonate-rock classifications; we did not invent new concepts. On the basis of carbonate content (grain, mud, and cement), carbonate rocks were divided into three types: muddy, grainy, and mixed. Each type was divided into subtypes on the basis of pore geometries defined by other researchers. Pore-size distribution of Lønøy (2006) was used for each subtype. We review existing carbonate-rock models and suggest approaches, and show preliminary flow-simulation results, for pore-scale modeling of different grains, cement, and pore geometry in these complex rocks.

Pore-scale flow simulation in anisotropic porous material via fluid-structure coupling

2018 ◽  
Vol 95 ◽  
pp. 14-26
Author(s):  
Chen Li ◽  
Changbo Wang ◽  
Shenfan Zhang ◽  
Sheng Qiu ◽  
Hong Qin
Keyword(s):  
Porous Material ◽  
Flow Simulation ◽  
Pore Scale ◽  
Fluid Structure

INTERPRETATION OF MULTI-FREQUENCY DIELECTRIC PERMITTIVITY MEASUREMENTS FOR ASSESSMENT OF WATER SATURATION IN CARBONATE FORMATIONS WITH COMPLEX PORE STRUCTURE

2021 ◽  
Author(s):  
Zulkuf Azizoglu ◽  
◽  
Zoya Heidari ◽  
Keyword(s):  
Spatial Distribution ◽  
Dielectric Permittivity ◽  
Pore Structure ◽  
Carbonate Rock ◽  
Water Saturation ◽  
Dielectric Dispersion ◽  
Pore Scale ◽  
Rock Samples ◽  
Wide Range ◽  
Permittivity Measurements

Broadband relative dielectric dispersion measurements are considered interesting options for assessment of water-filled pore volume. Conventional models such as Complex Refractive Index Model (CRIM) and Maxwell Garnett (MG), often overlook or oversimplify the complexity of pore structure, geometrical distribution of the constituting fluids, and spatial distribution of minerals. This yields to significant errors in assessment of water saturation especially in rocks with complex pore structure. Therefore, it becomes important to quantify the impacts of pore structure and spatial distribution of minerals on broadband relative dielectric dispersion measurements to be able to make decisions about reliability of water saturation estimates from these measurements in a given formation. The objectives of this paper are (a) to quantify the impacts of pore structure and spatial distribution of minerals on relative dielectric permittivity measurements in a wide range of frequencies, (b) to propose a new simple and physically meaningful workflow, which honors pore geometry and spatial distribution of minerals to enhance fluid saturation assessment using relative dielectric permittivity measurements, (c) to verify the reliability of the introduced model in the pore-scale domain. First, we perform numerical simulations of relative dielectric dispersion measurements in the frequency range of 20 MHz to 1 GHz in the pore-scale domain. The input to the numerical simulator includes pore-scale images of actual complex carbonate rock samples. We use a physically meaningful model which honors spatial distribution of the rock constituents for the multi-frequency interpretation of relative dielectric response. To verify the reliability of the model in multiple frequencies, we apply the model to the results of relative dielectric simulations in the pore-scale domain on 3D computed tomography scan (CT-scan) images of carbonate rock samples, which are synthetically saturated to obtain a wide range of water saturation. We successfully verified the reliability of the introduced model in the pore-scale domain using carbonate rock samples with multi-modal pore-size distribution. Estimated water saturations from the results of simulations at 1 GHz resulted in an average relative error of less than 4%. We observed measurable improvements in fluid saturation estimates compared to the cases which CRIM or MG models are used. Results demonstrated that application of conventional models to estimate water saturation from relative dielectric response is not reliable in frequencies below 1 GHz.

Direct pore-scale flow simulation using quasi-hydrodynamic equations

2016 ◽  
Vol 61 (4) ◽  
pp. 192-194 ◽  
Author(s):  
V. A. Balashov ◽  
E. B. Savenkov
Keyword(s):  
Flow Simulation ◽  
Hydrodynamic Equations ◽  
Pore Scale

scholarly journals Three-Dimensional Pore-Scale Simulation of Flow and Thermal Non-Equilibrium for Premixed Gas Combustion in a Random Packed Bed Burner

Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6939
Author(s):  
Jinsheng Lv ◽  
Junrui Shi ◽  
Mingming Mao ◽  
Fang He
Keyword(s):  
Flow Simulation ◽  
Local Variation ◽  
Packed Bed ◽  
Surface Radiation ◽  
Discrete Ordinates ◽  
Layer By Layer ◽  
Pore Scale ◽  
Gas Temperature ◽  
Gas Combustion ◽  
Non Equilibrium

Pore-scale studies of premixed gas combustion in a packed bed is conducted to study the flow and thermal non-equilibrium phenomenon in packed bed. The 3D random packed bed is generated using the EDEM software and solid surface radiation is computed using Discrete Ordinates (DO) model. The simulations are carried out using a commercial software package based on the finite volume method. It is shown that the local variation of species mass fraction, reaction rate et al. in pores near the flame front is significant, the radiation heat flux is transferred layer-by-layer. Cold flow simulation without reaction reveals that flow non-equilibrium is one of the essential characteristics of packing bed and increase in flow velocity leads to intensify non-equilibrium phenomenon. The distributions for content of axial velocity and gas temperature are wave-like shape in the burner and vary with time.

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