Papers by Farzam Javadpour
Gas-production decline in hydraulically fractured wells in shale formations necessitates refractu... more Gas-production decline in hydraulically fractured wells in shale formations necessitates refracturing. However, the vast number of wells in a field makes selection of the right well challenging. Additionally, the success of a refracturing job depends on the time to refracture a shale-gas well during its production life. In this paper we present a numerical simulation approach to development of a methodology for screening a well and to determine the optimal time of refracturing. We implemented our methodology for a well in the Barnett Shale, where we had access to data. The success of a refracturing job depends on reservoir characteristics and the initial induced fracture network. Systematic sensitivity analyses were performed so that the characteristics of a shale-gas horizontal well could be specified as to the possibility of its candidacy for a successful refracturing job. Different refracturing scenarios must be studied in detail so that the optimal design might be determined. Gi...
Microparticles transport and retention in porous media has received scientific attention due to i... more Microparticles transport and retention in porous media has received scientific attention due to its vast application in many disciplines like; transfusion medicine, environmental science, and petroleum reservoir engineering. At low Reynolds number flow, a balance between interactive surface forces and drag forces control particle movement and retention in porous media. Surface forces are electrostatic and van der Waals (vdW) forces. We used atomic force microscopy (AFM) to measure surface forces between particles and posts representing solid matrix of porous media in microfluidic models. We then for the first time combined the measured surface forces with the drag forces induced by the fluid flow on a moving or adhered particle to determine particle velocity or detachment criteria. We derived criteria formulation to determine particle adhesion, detachment, and rolling from force balances. We verified our theoretical formulations with extensive microparticle suspension flow experimen...
Liquid slippage on rough hydrophobic surfaces with and without entrapped bubbles
The process of liquid slip on rough-walled hydrophobic surfaces with and without entrapped gas bu... more The process of liquid slip on rough-walled hydrophobic surfaces with and without entrapped gas bubbles is modeled. Here, starting with the Navier–Stokes equations, a set of partial differential equations (PDE) and boundary conditions for the general effective slip tensor of a rough hydrophobic surface are constructed by an asymptotic analysis. The intrinsic slip and surface roughness are considered as the characteristics of the surface. The solution is based on a weak variation form that fully recovers the set of PDE and Navier slip boundary. For the surface with entrapped bubbles, a semi-analytical model based on eigenfunction expansion is developed. In addition to the surface characteristics, the size and contact angle of the bubbles are considered in the semi-analytical solution. Both models are validated with the published data as well as direct numerical simulation. Based on the model results, we present correlations of effective slip length with surface characteristics and ent...
One of the great challenges in modeling fluid flow in shale system is the existence of heterogene... more One of the great challenges in modeling fluid flow in shale system is the existence of heterogeneities at different scales. Heterogeneity is not new to researchers studying reservoir characterization. However, in shale strata heterogeneities exist at different scales, i.e., from molecular scale to multiwell scale. While the goal is to predict gas and oil production in a section of reservoir (single well or multiple wells), we learned that processes at very small scale control the production at well scale. We have started a comprehensive research to integrate porosity and permeability, hence fluid flow at different scales. The research includes numerous mathematical and numerical models along bench experiments to validate our models (Figure 1). Molecular scale. At the molecular scale we study the interaction of fluid molecules (gas and liquid, hydrocarbons and aqueous) with pore inner walls [1]. The molecular scale research provides slip coefficients for further implementation in flu...
Multiscale Modeling of Shale Apparent Permeability: An Integrated Study of Molecular Dynamics and Pore Network Model
SPE Annual Technical Conference and Exhibition
The physics of gas transport through shale systems is still ambiguous, even though several theore... more The physics of gas transport through shale systems is still ambiguous, even though several theoretical and experimental works have been reported. Most of the existing studies only concentrate on the permeability of shale kerogen. However, shales are composed of various amounts of organic matter and inorganic minerals (e.g., calcite, clay, and etc.). Inorganic pores could be larger than organic pores, hence, affect apparent permeability. To accurately predict shale apparent permeability, we couple molecular dynamics (MD) and a pore network model (PNM) to develop a multiscale framework for gas flow through shales. First, we use non-equilibrium MD to study the pressure-driven flow behavior of methane through organic, calcite, and clay (montmorillonite) nanopores under subsurface conditions, from which we build modified Hagen-Poiseuille equations to characterize the overall conductivity of each pore. Then we incorporate these formulations into a shale pore network model, in which the im...
Optimization of multistage fractured horizontal well in tight oil based on embedded discrete fracture model
Computers & Chemical Engineering
Abstract Optimizing multistage fractured horizontal wells (MFHW) can tap the full potential of ti... more Abstract Optimizing multistage fractured horizontal wells (MFHW) can tap the full potential of tight oil reservoirs. Although recent studies have introduced various frameworks, most of the significant parameters for MFHW are not optimized simultaneously, which may lead to actual performance that is far below expected performance, especially in heterogeneous reservoirs. Here, we present an efficient optimization framework that couples embedded discrete fracture model (EDFM) and intelligent algorithms to maximize net present value. We also examined the performance of four optimization algorithms in our model: genetic algorithm (GA), multilevel coordinate search (MCS), covariance matrix adaptation evolution strategy (CMA-ES), and generalized pattern search (GPS). Our results suggest that because CMA-ES handles MFHW optimization robustly and effectively, it may be utilized in future applications. Our framework serves as an efficient tool to optimize MFHW design, which plays an increasingly significant role in the enhancement of tight oil recovery.
Journal of Geophysical Research: Solid Earth
Upscaling pore pressure dependence of shale gas permeability is of great importance and interest ... more Upscaling pore pressure dependence of shale gas permeability is of great importance and interest in the investigation of gas production in unconventional reservoirs. In this study, we apply the Effective Medium Approximation, an upscaling technique from statistical physics, and modify the Doyen model for unconventional rocks. We develop an upscaling model to estimate the pore pressure-dependent gas permeability from pore throat size distribution, pore connectivity, tortuosity, porosity, and gas characteristics. We compare our adapted model with six data sets: three experiments, one pore-network model, and two lattice-Boltzmann simulations. Results showed that the proposed model estimated the gas permeability within a factor of 3 of the measurements/simulations in all data sets except the Eagle Ford experiment for which we discuss plausible sources of discrepancies.
The Journal of Physical Chemistry C, 2016
Pore-Scale Perspective of Gas/Water Two-Phase Flow in Shale
SPE Journal
Summary The transport behaviors of both single-phase gas and single-phase water at nanoscale devi... more Summary The transport behaviors of both single-phase gas and single-phase water at nanoscale deviate from the predictions of continuum flow theory. The deviation is greater and more complex when both gas and liquid flow simultaneously in a pore or network of pores. We developed a pseudopotential-based lattice Boltzmann (LB) method (LBM) to simulate gas/water two-phase flow at pore scale. A key element of this LBM is the incorporation of fluid/fluid and fluid/solid interactions that successfully capture the microscopic interactions among phases. To calibrate the model, we simulated a series of simple and static nanoscale two-phase systems, including phase separation, a Laplace bubble, contact angle, and a static nanoconfined bubble. In this work, we demonstrate the use of our proposed LBM to model gas/water two-phase flow in systems like a single nanopore, two parallel nanopores, and nanoporous media. Our LBM simulations of static water-film and gas-film scenarios in nanopores agree ...
A framework for predicting the production performance of unconventional resources using deep learning
Applied Energy
Gas Flow Models of Shale: A Review
Energy & Fuels
New Slip Coefficient Model Considering Adsorbed Gas Diffusion in Shale Gas Reservoirs
Energy & Fuels
Physical Review E
Molecular dynamics (MD) simulations is currently the most popular and credible tool to model wate... more Molecular dynamics (MD) simulations is currently the most popular and credible tool to model water flow in nanoscale where the conventional continuum equations break down due to the dominance of fluid-surface interactions. However, current MD simulations are computationally challenging for the water flow in complex tube geometries or a network of nanopores, e.g., membrane, shale matrix, and aquaporins. We present a novel mesoscopic lattice Boltzmann method (LBM) for capturing fluctuated density distribution and a nonparabolic velocity profile of water flow through nanochannels. We incorporated molecular interactions between water and the solid inner wall into LBM formulations. Details of the molecular interactions were translated into true and apparent slippage, which were both correlated to the surface wettability, e.g., contact angle. Our proposed LBM was tested against 47 published cases of water flow through infinite-length nanochannels made of different materials and dimensions-flow rates as high as seven orders of magnitude when compared with predictions of the classical no-slip Hagen-Poiseuille (HP) flow. Using the developed LBM model, we also studied water flow through finite-length nanochannels with tube entrance and exit effects. Results were found to be in good agreement with 44 published finite-length cases in the literature. The proposed LBM model is nearly as accurate as MD simulations for a nanochannel, while being computationally efficient enough to allow implications for much larger and more complex geometrical nanostructures.
Transport in Porous Media
In this study, a novel triple pore network model (T-PNM) is introduced which is composed of a sin... more In this study, a novel triple pore network model (T-PNM) is introduced which is composed of a single pore network model (PNM) coupled to fractures and micro-porosities. We use two stages of the watershed segmentation algorithm to extract the required data from semi-real micro-tomography images of porous material and build a structural network composed of three conductive elements: meso-pores, micro-pores, and fractures. Gas and liquid flow are simulated on the extracted networks and the calculated permeabilities are compared with dual pore network models (D-PNM) as well as the analytical solutions. It is found that the processes which are more sensitive to the surface features of material, should be simulated using a T-PNM that considers the effect of micro-porosities on overall process of flow in tight pores. We found that, for gas flow in tight pores where the close contact of gas with the surface of solid walls makes Knudsen diffusion and gas slippage significant, T-PNM provides ...
Digital Rock Techniques to Study Shale Permeability: A Mini-Review
Energy & Fuels
On the Inference of Gas Diffusion Coefficient in Organic Matter of Shale Gas Reservoirs
SPE Annual Technical Conference and Exhibition
Gas production from shale-gas reservoirs constitutes the largest portion of total gas production.... more Gas production from shale-gas reservoirs constitutes the largest portion of total gas production. The US shale reservoirs are tight and inherently heterogeneous with abundant presence of kerogenic material. Modeling fluid flow in shale reservoirs is complex and still an active field of research. The complexity arises from different flow physics such as pressure flow and diffusion. Many of the field performance forecasts constantly underestimate production from these reservoirs because most of the current models ignore important governing physics. This study provides new insights on diffusion in organic matter, in an effort to correct a main source of underestimation of gas production in shale gas models. In an earlier study, we developed for the first time a detailed diffusion model and showed how pore size distribution and specific surface area of the pores in organic matter can significantly influence gas production. An important parameter controlling the rate of gas release is th...
Javadpour Upscaling Water Flow in Composite Nanoporous Shale Matrix Using Lattice Boltzmann Method
Water Resources Research
SPE Journal
Summary Geologic modeling of mudrock reservoirs is complicated by the presence of multiscale hete... more Summary Geologic modeling of mudrock reservoirs is complicated by the presence of multiscale heterogeneities and lithofacies lateral discontinuity. The resolution of wireline logs is also too low to capture many small-scale heterogeneities that affect fluid flow. In addition, the large distance between logged wells results in uncertain long-range correlations. Supplementary to wireline log data, high-resolution outcrop images offer a direct representation of detailed heterogeneities and lithofacies connectivity. We used high-resolution panoramic outcrop images to collect data on lithofacies heterogeneity and the role that depositional processes play in this heterogeneity. We then used these data in different classes of reservoir algorithms—two-point-based, object-based, and higher-order statistics—to build a geologic model. To present our methodology, we used data collected from Eagle Ford outcrops in west Texas. We found the higher-order-statistics method to be especially efficient...
Determination of Nanoparticle Macrotransport Coefficients from Pore Scale Processes
Transport in Porous Media
Dynamic porosity and apparent permeability in porous organic matter of shale gas reservoirs
Fuel
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Papers by Farzam Javadpour