The shale gas reservoirs are rich in organic and inorganic nano-sized pores. Generally, both adsorbed gas and free gas are considered to be exist in organic matrix pores, while there is no adsorbed gas in inorganic matrix pores. Therefore, gas transport mechanism is quite different in these two types of nanopores. Many researchers have provided the presence of water film on the inorganic pore...
The interest in viscoelastic surfactant solutions (VES) as enhanced oil recovery fluids has been increasing in recent years, due to their practical advantages over polymeric solutions. However, during their flow inside the porous medium, complex geometries (such as throats that connect pores) might cause high shear-extensional components, affecting the flow behavior, and therefore the...
The multi-stage fractured horizontal wells(MFHW) is the key technology for developing shale gas reservoirs. After the stimulated reservoir volume is fractured, the gas flowing in matrix is non-linear seepage controlled by the nano-scale pores, while the seepage in stimulated region is transformed into Darcy flow controlled by the micro-scale fracture network. In this paper, the steady-state...
X-ray Computed Tomography scanning is an innovative procedure that allows the internal structure of samples to be computed in 3D. It has completely revolutionized the way several measurements can be achieved in geoscience, including characterization of petrophysical properties of porous media. In order to provide accurate results, it is, of course, necessary to have high quality scan images,...
The current state-of-the-art modeling approaches for contaminant/heat transport in fractured rock include (1) discrete fracture-network (DFN) and discrete fracture-matrix (DFM) models with the fracture network and matrix blocks randomly generated, (2) numerical models based on conventional dual-continuum models, and (3) analytical models with simplified parallel fractures and slab-like matrix...
More complicated than polymer flooding, alkaline-surfactant-polymer (ASP) flooding is a chemical flooding technology with higher enhanced oil recovery. To better understand the flow dynamics in ASP floods, we designed and improved a physical model that is suitable for the pressure and oil saturation monitoring.
The basic model is a three-layer heterogeneous sandpack model. The optimization of...
The Digital Rocks (https://www.digitalrocksportal.org) is the first platform of its kind for data management of images of rock microstructure. It allows preservation, curation, visualization and basic analysis of images of porous materials (and experiments on them). Imaging modalities include X-ray (micro)tomography, (focused ion beam) scattered electron microscopy, optical microscopy,...
Core analysis for characterization of rock properties such as permeability involves laboratory flow experiments often performed at lower temperature and pressure than the conditions typically present in subsurface hydrocarbon reservoirs. For gas permeability in particular, slippage flow can occur at reservoir conditions, resulting in higher apparent permeabilities than would occur for Darcy...
The surface element integration technique was used to systematically study Derjaguin-Landau-Verwey-Overbeek (DLVO) interaction energies/forces between hollow spherical particles (HPs) and a planar surface or two intercepting half planes under different ionic strength conditions. The inner and outer spheres of HPs were concentric (CHP) or in point contact (PHP). In comparison to a solid...
Immobilization of transition metal oxides on a solid support by impregnation with solutions of metal salts is a common route in catalyst design. An inherent difficulty of such methods is that precipitation by solvent evaporation leads to undesirably large catalyst crystallites forming at the outer surface of the porous support. In this study we explore the potential of an alternative route,...
Models for multiphase flow in porous media account for several complex physical phenomena such as PVT behavior and interplay with the porous rock, which altogether make reservoir simulation a challenging task. High aspect ratios and strong petrophysical heterogeneity impose severe timestep (CFL) restrictions, and implicit discretizations are thus usually preferred over explicit ones. In a...
Nanoparticles are emerging as an important advancement in the petroleum industry, including in enhanced oil recovery. Nanoparticles have shown potential to mitigate some of the issues associated with enhanced oil recovery due to their impact on bulk and interfacial properties. However, before their application in any EOR operation, the study of nanoparticle transport behavior in porous media...
The platform carbonate reservoirs in the Mishrif Formation of the HF Oilfield in Iraq are highly heterogeneous and can easily lead to water injection breakthrough along the high permeable thin layer to reduce the water injection sweep efficiency. Therefore, it is of great significance to clarify the main controlling factors of heterogeneity and formulate a reasonable development...
The impact of fuel spills on the unsaturated zone are one of the main environmental issues when licensing new fuel stations or industrial facilities where Underground Storage Tanks (UST) are used. The development and use of fate and transport models of organic pollutants (BTEX) on the vadose zone can therefore be used to understand the behavior of these pollutants under different...
Profile control is one main effective measure to increase oil production and reduce water cut during the later period of oilfield development. The gel particle is a widely used profile control agent, but the research of migration performance in the pore throat is little, which limits its application. Based on the Hertz contact theory, the theoretical model of gel particle transport through...
Digital rock analysis and pore scale studies have become an essential tool in the oil and gas industry to understand and predict the petrophysical and multiphase flow properties for the assessment and exploitation of hydrocarbon reserves [1]. The fundamental problem in pore-scale imaging and modelling is how to represent and model the different range of scales encountered in porous media, from...
Advances in imaging technologies and high-performance computing are making it possible to perform Direct Numerical Simulation (DNS) of flow processes at the pore scale; nevertheless, the restrictions on the physical size of the sample (porous rock) that can be fully resolved using Navier-Stokes-based DNS are quite severe. For samples on the order of a cm 3 , the complexity of the spatial...
It is well established that acoustic emission is generated during hydraulic fracturing. Acoustic emission is used to find the volume effected by hydraulic fracturing, which is known as stimulated rock volume (SRV). Understanding the flow and transport properties of SRV is important as it effects the EUR of the oil reservoirs. In this study we analyze the change in permeability, an important...
In this study, polyvinylidene fluoride (PVDF) hollow fibers with different morphologies have been fabricated via a dry-jet wet spinning process and tested for membrane distillation (MD). The effects of PVDF content and solvents, dimethylacetamide (DMAc) and triethylphosphate (TEP), on the morphology, pore structure geometry and MD performance were investigated. Phase separation mechanism of...
Many tropic soils exhibit double- or even triple-porosity features as reflected by heterogeneous pore- and/or particle-size distributions. While the amount of clay in tropical soils is generally relatively high, cementation of the finer particles into larger grains make field soil often behave macroscopically more like coarse-textured media. Natural aggregation may further enhance preferential...
For the study of yield stress fluids flow in porous media, the complex pore-scale structure has been extensively idealized as bundles of capillaries. A bundle of rectilinear capillaries of circular cross-section has been used over the past decade for the development of a new method of pore-size distribution (PSD) characterization based on the injection of a yield stress fluid. The main idea of...
One of the longstanding challenges of the oil and gas industry is the problem of scale and hence, the term “upscaling” is used frequently in literature. In this work, we investigate the ways to represent connected regions with substantially different pore sizes. For this purpose, pore-scale simulations are combined with conventional continuum scale models. Our primary objective is to run...
Infiltration is the key hydrological process that affects a formation of runoff, floods generation, water erosion, and leaching of contaminants through soil. These processes are often most intensive in nearly saturated soils. An example of frequently highly saturated and intensively leached soils are the filter layers of the storm water infiltration swales, bioretention cells, and rain...
Concretes are materials of primary importance for the storage of nuclear waste in geological formation. They have a high specific surface area and a low hydraulic conductivity that confer them unique confining properties. Nevertheless, concretes may also be very reactive due to the high pH of their pore water. Therefore, understanding their chemical reactivity in situ is a key point. In this...
Development of unconventional shale gas reservoirs (SGRs) has been boosted by the advancements in two key technologies: horizontal drilling and multi-stage hydraulic fracturing. A large number of multi-stage fractured horizontal wells (MsFHW) have been drilled to enhance reservoir production performance. Gas flow in SGRs is a multi-mechanism process, including: desorption, diffusion, and...
Shale gas reservoirs generally develop micro fractures. During pressure-relief production, the change of micro-fracture width caused by stress-sensitivity is an important factor affecting shale gas transport. Based on the cubic grid model, the slippage flow model, the Knudsen diffusion model and the surface diffusion model, a gas mass transporting model considering the dynamic change of shale...
During the development of shale gas reservoir, large amount of hydraulic fracturing fluid are forcibly injected into the reservoir to create complex fracture networks. However, field data indicate that only a small fraction of the injected fluid can be recovered during the clean-up period. Except the mostly discussed reasons including capillary force, osmotic-force, and clay hydration, the...
Porous polymeric materials have a large variety of applications in many areas as highly selective membranes, selective adsorbents and filters, porous electrodes for fuel cells, sensors or insulators, etc. High crosslink density Cyanate Ester Resins (CERs) – also known as polycyanurates (PCNs) – are commonly used in aerospace applications and electronic devices as thermostable polymer...
Polymer flooding is one of the most commonly applied enhanced oil recovery technique. The main mechanism of polymer flooding is the increased sweep efficiency by increase injected water viscosity, which would reduce fingering, improve water injection profile and reduce the relative permeability of water flow. Meanwhile, viscoelasticity of polymer is suggested that it can improve displacement...
Viscous fingering--the fluid-mechanical instability that takes place when a low-viscosity fluid displaces a high-viscosity fluid--has traditionally been studied under either fully miscible or fully immiscible fluid systems. In practice, however, the miscibility between two fluids can change appreciably with temperature and pressure and often falls into the case of partial miscibility, where...
With the increasing application of nanomaterials for environmental remediation, modified nanoscale zero-valent iron (nZVI) particles have been extensively examined in terms of their enhanced mobility in porous media as compared to bare nZVI particles. However, the monitoring of nZVI particle transport processes in low permeability media is still a challenge. To quantify the particle transport...
The DECOVALEX project is an international research and model comparison collaboration for advancing the understanding and modeling of coupled thermo-hydro-mechanical (THM) processes in geological systems. Prediction of these coupled effects is an essential part of the safety assessment of geologic disposal systems for radioactive waste and spent nuclear fuel, but also for a range of other...
In this study, we analyze the filter cake formed due to mono and bi-dispersed spherical particles. The particle-particle, particle-filter interactions are simulated using Discrete Element Method (DEM) and the fluid flow is simulated using Finite Volume Method (FVM). The computation of the two-way particle-fluid interaction is the challenging part in the numerical studies mainly due to the...
As a mesoscopic kinetic approach, the lattice Boltzmann method (LBM) has been widely applied to characterize the flows in porous medium. However, for larger scale flow, upscaling microscale technique is the key and difficult point. Based on microtomographic images of an actual coal sample, numerical simulations were carried out using the LBM at the pore scale. The velocity/pressure...
Colloidal particles released by various chemical and industrial processes penetrate soils and groundwater, and transport themselves other contaminants like heavy metals or PCBs. Thus, an accurate description of the transport and retention of these particles is required to prevent and manage environmental contamination, like the pollution of drinking water supplies. Literature stands that...
We investigate the properties of the electrically conductive polymer Polypyrrole (PPy) in tubular pores of monolithic micro (pore diameter D < 2 nm)-, meso- (2 nm < D <20 nm) and macroporous (D > 50 nm) silicon. We successfully demonstrate a homogeneous filling via electro-polymerisation for the extremely anisotropic confinement of 12 nm pore diameter and 180 µm pore length. The kinetics of...
Mass transfer in field-scale discrete fracture networks (DFNs) is affected by the erratic internal structure and hydrogeological properties of the fractured media, which can result in non-Darcian flow due to channeling flow and non-Fickian transport due to matrix diffusion competing with fast displacement along fractures. This study explores flow and transport dynamics in various DFNs with a...
The orientational and translational order of a thermotropic ferroelectric liquid crystal (2MBOCBC) imbibed in self-organized, parallel, cylindrical pores with radii of 10, 15, or 20 nm in anodic aluminium oxide monoliths (AAO) are explored by high-resolution linear and circular optical birefringence as well as neutron diffraction texture analysis. The results are compared to experiments on the...
Permeability anisotropy is a common feature of hydrocarbon reservoirs. In practice, hydraulic fracturing has been an effective technique for enhancing the productivity of wells in low permeability reservoirs. However, most study about hydraulic fractures focuses on isotropic reservoirs and few literatures discussed the effect of permeability anisotropy and azimuth angle of fractures on the...
A new direct inverse method is developed that is capable of simultaneous estimation of hydraulic conductivity (K), boundary conditions, and flow field for both confined and unconfined aquifers. In this research, the direct inverse method is applied to the inversion of discrete fractured aquifers. By sampling synthetic aquifer problems with different fracture patterns, the inverse method is...
The design of a field-scale injection of engineered nanoparticle (NP) suspensions for the remediation of a polluted site requires the development of quantitative predictive models for the system design and implementation.
In general, micro- and nanoparticle transport in porous media is controlled by particle-particle and particle-porous media interactions, which are in turn affected by flow...
Pore network modeling is a technique that has been booming in recent years, and several authors have used it to obtain properties as absolute permeability, relative permeabilities and capillary pressures, which are common obtained from laboratory tests and/or experimental correlations. The scope of this work is to model flow and immiscible displacement and estimate fluid flow properties such...
Development in the dry unconventional gas-bearing Marcellus Shale in the Eastern United States has grown rapidly over the past decade. When a well is fractured in the Marcellus, only a small proportion of the slickwater fracturing fluid, typically <10%, is produced back following well completion. Most analyses also suggest that existing fracking and production practices only produce a...
The direct numerical simulations (DNS) experience of pore-scale flow is still relatively scarce and laborious due to the numerous practical challenges. They include typically huge model size and high computational expenses, some uncertainties in geometrical description related to resolution size and other factors remaining much in common for single and multiphase flow cases. Sometimes this...
Characterization of geologic heterogeneity is crucial for reliable and cost-effective subsurface management operations, especially in problems that involve complex physics such as deep aquifer storage of carbon dioxide. With recent advances in computational power and sensor technology, large-scale aquifer characterization using various types of measurements has been a promising approach to...
The densities of Minkowski functionals (volume, surface, mean curvature and total curvature) represent a complete set of independent global microstructural descriptors [1-3], as a consequence of Hadwiger’s characterization theorem [4]. Similar to correlation functions [5, 6] they offer a systematic and principally automatizable approach for the quantitative description of microstructures, but...
A standard approach to model diffusion in porous media is the assumption of the validity of Fick‘s Law. Although widely used, that description can only be employed for binary mixtures or low concentrations of the components as it neglects molecular interactions of the different species.
When looking e.g. at gas migration of an organic component in soil where higher concentrations of...
In-situ leaching of ores is considered as an economic and environmentally friendly production method. However, the leaching process is complicated by its dependence on the material’s heterogeneity and by retroactive effects over large scales. We developed an experimental procedure which is based on positron emission tomography (PET) during transport experiments with radiotracers (Kulenkampff...
The world is running out of fossil fuels and the products of their burning in air (mostly CO2) have already impacted global climate. Today it is clear that in near future we need to convert the global energy economy towards cleaner and renewable fuels (like hydrogen). However, to efficiently store hydrogen at ambient temperature and not too high pressures, we need to develop the hydrogen...
A new simulation model for solvent-aided thermal recovery of heavy oil and bitumen has been developed. The simulation model describes non-isothermal, multiphase, and multicomponent reservoir systems involving multiple kinetic reactions of heavy oil cracking. In the development of numerical simulator, we include 12 fluid-and-solid components in four phases of 1) aqueous, 2) liquid organic, 3)...
The numerical simulation of subsurface processes requires efficient and robust methods due to the large scales and the complex geometries involved. To resolve such complex geometries, corner-point grids are the industry standard to spatially discretize geological formations. Such grids include non-planar, non-matching and degenerated faces. The standard scheme used in industrial codes is the...
Permeability prediction of porous media is be of great significance for both petroleum and environment fields. The permeability of a porous medium can be directly calculated based on one 2D thin section. However, it is often doubtful. Therefore, a new technique of the permeability prediction from a 2D thin section is proposed. First 3D porous media is reconstructed from a 2D image using...
We present a simple single-pressure dynamic network simulator for two-phase flow in porous media with a focus on exploring the limits of a single-pressure network model.
Our work builds upon the work of Aker et al.[1] and Knudsen et al.[2], where we aim to more accurately describe and model the interactions of ganglia moving through the porous material. Whereas the previous models assumed...
The pore and throat size of the global unconventional oil and gas reservoir is mainly nano-scale, and the minimum radius is evenly about 1 nm. The characteristics of the unconventional oil reservoir depend greatly on the micro pore structure of the reservoir. Its main contents include the shape, size, quantity, connectivity and distribution characteristics of reservoir pores and throats. The...
In laboratory steady-state measurements of relative permeability, capillary discontinuities at sample ends give rise to capillary end-effects (CEE) and keep a higher water saturation toward the core end. The water saturation measured is higher than ideal saturation without CEE and result of erroneous relative permeability curves[1] finally. Especially in tight sand cores, high capillary force...
For further research on the effect of heavy oil viscosity on the fracture geometry, this paper establishes heavy oil fracturing model and conventional fracturing model based on thermal-hydraulic-mechanical (THM) coupled theory, Walther viscosity model and K-D-R temperature model. We take viscosity and density within heavy oil fracturing model as functions of pressure and temperature, while...
Pore network models have been applied for predicting petrophysical properties at pore scale. From a geometry point of view, basically a pore network and pore and throat size distributions are required for pore network modeling. Although different pore network models have been constructed using data extracted mainly from images, it is not always possible to count on the necessary information,...
The structure of nanopore in shale is complex, multiple gas migration mechanisms coexist. In this paper, we have used a bundle of tortuous capillary tubes with different diameters to represent porous structure of shale considering slippage effect and Knudsen diffusion and surface diffusion. Fractal theory is applied to mathematically express the capillary diameter distribution and their...
Characteristic of Coal Pore Structure and Its Relationship with Sedimentary Environment in Hegang Basin
Wang You-zhi1 , MaoCui2
（1.Exploration and Development Research Institute of Daqing Oilfield Company Ltd.，Heilongjiang, Daqing 163712, China
2.School of Geosciences, Northeast Petroleum University, Heilongjiang, Daqing 163318, China）
Abstract:Base on low temperature nitrogen adsorption...
Using the fresh oil⁃bearing core samples, this paper studied the remaining oil micro⁃distribution or occurrence and the influence of long⁃term waterflooding on the reservoir pore structures in major reservoir of Laojunmiao oilfleld in Yumen. The study indicates that the remaining oil occurrence in the reservoir is dominated by film or interstitial form, and the pore stucture is the key factor...
Accurate and efficient numerical simulation of fractured reservoirs is important and challenging. Conventional dual porosity and dual permeability(DP/DK) models are efficient but not accurate, especially when fracture-diagnostic tools make it easier to get the detail of the complex fracture networks. Discrete-fracture models(DFM) have been developed to use information of fracture networks,...
Multi-phase flow process in porous medium are generally simulated with in introduction of relative permeability, which is assumed to be a scalar function of phase saturation. Previous research have demonstrated this assumption might not be suitable for capillary force dominated heterogeneous porous medium. Similarly, in vugular porous medium, the free flow region in vugs would introduce...
Keywords:
Droplet flow regimes, Interfacial dynamics, Volume of Fluid method, Parasitic currents, Direct Numerical Simulations
Abstract:
Multiphase flow in microfluidic devices that produce identical droplets/ bubbles at a known frequency has gained attention due to its use in biomedical, chemical and engineering applications.
In this numerical study, we investigate the flow dynamics...
Heterogeneous carbonate rocks, especially coquinas, present several challenges regarding their morphological characterization, petrophysical parameterization, and obtained a more complete understanding of their fluid flow properties. Within this context, a workflow is proposed and analyzed for digital petrophysics using a combination of experimental data and numerical 3D fluid flow...
Hydraulic fracturing is one of the most effective treatment methods in development of low permeability reservoir which improve the conductivity of the formation such that the reservoir liquids seepage capacity is enhanced with flow friction reduced, which highly increase the withdrawal of underground liquid. However, with the existing of hydraulic fractures and due to the complication of their...
Carbon dioxide (CO2) diffusion in dual-porosity plays a great important role for effective flow in tight oil reservoir. The CO2 diffusion coefficient in matrix is different with the coefficient in fracture because of micro-scale effect. Matrix diffusion coefficient and fracture diffusion coefficient was introduced and respectively used into matrix flow model and fracture flow model. Using...
Aiming the heterogeneity of low permeability carbonate reservoir in M group of H oilfield, carried out the physical simulation experiment of multi-layer waterflooding, and based on the T2 relaxation spectrum technique, studied the micro distribution of residual oil and production degree of different permeability combination. Results show that to the different pore structure types, NMR tests...
Considering the sensitivity of microorganisms to the different environment, the microbial growth kinetics equation was improved, and a 3D two-phase five-component mathematical model which could fully reflect the microbial flooding process in the reservoir medium was established. The components of the model involve oil, water, microbe, nutrient and metabolite. The model integrates the effects...
In this paper, we studied the numerical simulation of shale gas reservoir with both hydraulic fractures and natural fractures using the embedded discrete fracture system. First, the 3D DFN (discrete fracture network) model was built according to the real geological state. Then, transmissibilities between the embedded fracture grid and the matrix grid are calculated using two different methods....
Abstract: The numerical simulation of pore scale seepage in porous media is of great significance for the development of new energy sources, such as shale gas and geothermal energy. In the past few years, many scholars have developed the numerical method including finite volume method (FVM), Lattice Boltzmann Method (LBM) and molecular dynamics to achieve this simulation in different levels....
Tight porous media have the characteristics of extremely low permeability and the permeability of it is sensitive to the effective stress. Stimulated reservoir volume (SRV) is usually performed to improve the production of well in tight porous media. The SRV zone is usually considered as a dual-porosity medium in well test or numerical simulation due to the computationally efficient. The shape...
Polymer flooding is an effective way to enhance the recovery rate of heavy oil reservoirs in high water-cut stage. To overcome the commonly existing defects of general polymer injection such as high costs and high transmissibility pathways. Multi-stage concentration polymer flooding and optimization methods are researched to clear out its influence on heterogeneous reservoir recovery...
Pore scale flow simulations in reservoir rocks heavily depend on characterizing and modeling of the pore space. Single scale and multiscale pore network extraction from micro-CT images are going through extensive development. However, the choice of pore network extractions method is sensitive to the rock nature (homogenous, complex or microporous). Additionally, the success of the pore network...
Different injected media huff and puff is a promising enhanced oil recovery approach in tight oil reservoirs, which can effectively supply formation energy and enhance the productivity of individual well. And there still exists many uncertainties of oil recovery mechanism in the process. In this study the experiment method of cyclic water injection and carbon dioxide huff and puff in tight...
Hydraulic fracture has become an essential well stimulation technique in tight oil reservoirs. Large-scale vertical well fracturing can generate longer vertically oriented fractures to increase drainage area and, therefore enhance production and recovery efficiency of single well while also save costs[1]. The aim of this study is to develop a more practical productivity forecast model that can...
In order to achieve gas kick early detection outside the riser, the ultrasonic propagation law in gas-liquid two-phase flow of riser annulus need to be analyzed. Therefore this paper aims to explore the ultrasonic propagation law in gas-liquid two-phase flow of riser annulus under different conditions and to establish a quantitative relationship between the ultrasonic signals and gas void...
Abstract: Low permeability carbonate reservoir generally contain multiple types pore structure as matrix pore, hole and crack, which lead to significant difference in water flooding seepage regularity and great perplex in oilfield production. In order to relate pore structure to seepage regularity of core samples preferably, micro-CT scanning and scanning electron microscope advanced...
We present a two-phase multicomponent reactive pore-scale model based on Direct Numerical Simulation of the Navier-Stokes equations using the Volume-Of-Fluid and the Continuous Species Transfer methods. In order to study wettability change during low-salinity flooding, simple upscaling rules from the nano-scale to the pore-scale are integrated to the model to describe (1) change of local...
Modeling nanoparticle (NP) transport in porous media is an important research topic in many subsurface engineering applications, such as enhanced oil recovery (EOR), fracture electromagnetic imaging and environmental remediation. An efficient field-scale simulation framework is critical for predicting NP performance and designing subsurface applications. In this work, an efficient...
