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Embedded Discrete Fracture Modeling and Application in Reservoir Simulation

Embedded Discrete Fracture Modeling and Application in Reservoir Simulation
A Book

by Kamy Sepehrnoori,Yifei Xu,Wei Yu

  • Publisher : Elsevier
  • Release : 2020-08-27
  • Pages : 304
  • ISBN : 0128196882
  • Language : En, Es, Fr & De
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The development of naturally fractured reservoirs, especially shale gas and tight oil reservoirs, exploded in recent years due to advanced drilling and fracturing techniques. However, complex fracture geometries such as irregular fracture networks and non-planar fractures are often generated, especially in the presence of natural fractures. Accurate modelling of production from reservoirs with such geometries is challenging. Therefore, Embedded Discrete Fracture Modeling and Application in Reservoir Simulation demonstrates how production from reservoirs with complex fracture geometries can be modelled efficiently and effectively. This volume presents a conventional numerical model to handle simple and complex fractures using local grid refinement (LGR) and unstructured gridding. Moreover, it introduces an Embedded Discrete Fracture Model (EDFM) to efficiently deal with complex fractures by dividing the fractures into segments using matrix cell boundaries and creating non-neighboring connections (NNCs). A basic EDFM approach using Cartesian grids and advanced EDFM approach using Corner point and unstructured grids will be covered. Embedded Discrete Fracture Modeling and Application in Reservoir Simulation is an essential reference for anyone interested in performing reservoir simulation of conventional and unconventional fractured reservoirs. Highlights the current state-of-the-art in reservoir simulation of unconventional reservoirs Offers understanding of the impacts of key reservoir properties and complex fractures on well performance Provides case studies to show how to use the EDFM method for different needs

Implementation and Application of the Embedded Discrete Fracture Model (EDFM) for Reservoir Simulation in Fractured Reservoirs

Implementation and Application of the Embedded Discrete Fracture Model (EDFM) for Reservoir Simulation in Fractured Reservoirs
A Book

by Yifei Xu

  • Publisher : Unknown Publisher
  • Release : 2015
  • Pages : 246
  • ISBN : 9876543210XXX
  • Language : En, Es, Fr & De
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Fractured reservoirs have gained continuous attention from oil and gas industry. A huge amount of hydrocarbon are trapped in naturally fractured carbonate reservoirs. Besides, the advanced technology of multi-stage hydraulic fracturing have gained a great success in economic development of unconventional oil and gas reservoirs. Fractures add complexity into reservoir flow and significantly impact the ultimate recovery. Therefore, it is important yet challenging to accurately and effectively predict the recovery from fractured reservoirs. Conventional dual-continuum approaches, although effective in the simulation of naturally fractured reservoirs, may fail in some cases due to the highly idealized reservoir model. The unstructured-grid discrete fracture models, although flexible in representing complex fracture geometries, are restricted by the high complexity in gridding and high computational cost. An Embedded Discrete Fracture Model (EDFM) was recently developed to honor the accuracy of discrete fracture models while keeping the efficiency offered by structured gridding. By dividing the fractures into segments using matrix cell boundaries and creating non-neighboring connections (NNCs), the flow influence of fractures can be efficiently modeled through transport indices. In this work, the EDFM was implemented in UTCHEM, a chemical flooding in-house reservoir simulator developed at The University of Texas, to study complex recovery processes in fractured reservoirs. In addition, the model was applied in commercial simulators by making use of the non-intrusive property of the EDFM and the NNC functionality offered by the simulators. The accuracy of the EDFM in the modeling of orthogonal, non-orthogonal, and inclined fractures was verified against fine-grid explicit fracture simulations. Furthermore, case studies were performed to investigate the influence of hydraulic fracture orientations on primary depletion and the impact of large-scale natural fractures on water flooding processes. The influence of matrix grid size and fracture relative permeability was also studied. Finally, with modifications in NNC transmissibility calculation, the EDFM was applied to the modeling of a multi-lateral well stimulation technology. The accuracy of the modified formulations was verified through comparison with a multi-branch well method. The simulations carried out in this work confirmed the flexibility, applicability, and extensiveness of the EDFM.

Shale Gas and Tight Oil Reservoir Simulation

Shale Gas and Tight Oil Reservoir Simulation
A Book

by Wei Yu,Kamy Sepehrnoori

  • Publisher : Gulf Professional Publishing
  • Release : 2018-08-10
  • Pages : 430
  • ISBN : 0128138696
  • Language : En, Es, Fr & De
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Shale Gas and Tight Oil Reservoir Simulation delivers the latest research and applications used to better manage and interpret simulating production from shale gas and tight oil reservoirs. Starting with basic fundamentals, the book then includes real field data that will not only generate reliable reserve estimation, but also predict the effective range of reservoir and fracture properties through multiple history matching solutions. Also included are new insights into the numerical modelling of CO2 injection for enhanced oil recovery in tight oil reservoirs. This information is critical for a better understanding of the impacts of key reservoir properties and complex fractures. Models the well performance of shale gas and tight oil reservoirs with complex fracture geometries Teaches how to perform sensitivity studies, history matching, production forecasts, and economic optimization for shale-gas and tight-oil reservoirs Helps readers investigate data mining techniques, including the introduction of nonparametric smoothing models

Modeling and Simulation of Fluid Flow in Naturally and Hydraulically Fractured Reservoirs Using Embedded Discrete Fracture Model (EDFM)

Modeling and Simulation of Fluid Flow in Naturally and Hydraulically Fractured Reservoirs Using Embedded Discrete Fracture Model (EDFM)
A Book

by Mahmood Shakiba

  • Publisher : Unknown Publisher
  • Release : 2014
  • Pages : 314
  • ISBN : 9876543210XXX
  • Language : En, Es, Fr & De
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Modeling and simulation of fluid flow in subsurface fractured systems has been steadily a popular topic in petroleum industry. The huge potential hydrocarbon reserve in naturally and hydraulically fractured reservoirs has been a major stimulant for developments in this field. Although several models have found limited applications in studying fractured reservoirs, still more comprehensive models are required to be applied for practical purposes. A recently developed Embedded Discrete Fracture Model (EDFM) incorporates the advantages of two of the well-known approaches, the dual continuum and the discrete fracture models, to investigate more complex fracture geometries. In EDFM, each fracture is embedded inside the matrix grid and is discretized by the cell boundaries. This approach introduces a robust methodology to represent the fracture planes explicitly in the computational domain. As part of this research, the EDFM was implemented in two of The University of Texas in-house reservoir simulators, UTCOMP and UTGEL. The modified reservoir simulators are capable of modeling and simulation of a broad range of reservoir engineering applications in naturally and hydraulically fractured reservoirs. To validate this work, comparisons were made against a fine-grid simulation and a semi-analytical solution. Also, the results were compared for more complicated fracture geometries with the results obtained from EDFM implementation in the GPAS reservoir simulator. In all the examples, good agreements were observed. To further illustrate the application and capabilities of UTCOMP- and UTGEL-EDFM, a few case studies were presented. First, a synthetic reservoir model with a network of fractures was considered to study the impact of well placement. It was shown that considering the configuration of background fracture networks can significantly improve the well placement design and also maximize the oil recovery. Then, the capillary imbibition effect was investigated for the same reservoir models to display its effect on incremental oil recovery. Furthermore, UTCOMP-EDFM was applied for hydraulic fracturing design where the performances of a simple and a complex fracture networks were evaluated in reservoirs with different rock matrix permeabilities. Accordingly, it was shown that a complex network is an ideal design for a very low permeability reservoir, while a simple network results in higher recovery when the reservoir permeability is moderate. Finally, UTGEL-EDFM was employed to optimize a conformance control process. Different injection timings and different gel concentrations were selected for water-flooding processes and their impact on oil recovery was evaluated henceforth.

Development of an Efficient Embedded Discrete Fracture Model for 3D Compositional Reservoir Simulation in Fractured Reservoirs

Development of an Efficient Embedded Discrete Fracture Model for 3D Compositional Reservoir Simulation in Fractured Reservoirs
A Book

by Ali Moinfar

  • Publisher : Unknown Publisher
  • Release : 2013
  • Pages : 464
  • ISBN : 9876543210XXX
  • Language : En, Es, Fr & De
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Naturally fractured reservoirs (NFRs) hold a significant amount of the world's hydrocarbon reserves. Compared to conventional reservoirs, NFRs exhibit a higher degree of heterogeneity and complexity created by fractures. The importance of fractures in production of oil and gas is not limited to naturally fractured reservoirs. The economic exploitation of unconventional reservoirs, which is increasingly a major source of short- and long-term energy in the United States, hinges in part on effective stimulation of low-permeability rock through multi-stage hydraulic fracturing of horizontal wells. Accurate modeling and simulation of fractured media is still challenging owing to permeability anisotropies and contrasts. Non-physical abstractions inherent in conventional dual porosity and dual permeability models make these methods inadequate for solving different fluid-flow problems in fractured reservoirs. Also, recent approaches for discrete fracture modeling may require large computational times and hence the oil industry has not widely used such approaches, even though they give more accurate representations of fractured reservoirs than dual continuum models. We developed an embedded discrete fracture model (EDFM) for an in-house fully-implicit compositional reservoir simulator. EDFM borrows the dual-medium concept from conventional dual continuum models and also incorporates the effect of each fracture explicitly. In contrast to dual continuum models, fractures have arbitrary orientations and can be oblique or vertical, honoring the complexity and heterogeneity of a typical fractured reservoir. EDFM employs a structured grid to remediate challenges associated with unstructured gridding required for other discrete fracture models. Also, the EDFM approach can be easily incorporated in existing finite difference reservoir simulators. The accuracy of the EDFM approach was confirmed by comparing the results with analytical solutions and fine-grid, explicit-fracture simulations. Comparison of our results using the EDFM approach with fine-grid simulations showed that accurate results can be achieved using moderate grid refinements. This was further verified in a mesh sensitivity study that the EDFM approach with moderate grid refinement can obtain a converged solution. Hence, EDFM offers a computationally-efficient approach for simulating fluid flow in NFRs. Furthermore, several case studies presented in this study demonstrate the applicability, robustness, and efficiency of the EDFM approach for modeling fluid flow in fractured porous media. Another advantage of EDFM is its extensibility for various applications by incorporating different physics in the model. In order to examine the effect of pressure-dependent fracture properties on production, we incorporated the dynamic behavior of fractures into EDFM by employing empirical fracture deformation models. Our simulations showed that fracture deformation, caused by effective stress changes, substantially affects pressure depletion and hydrocarbon recovery. Based on the examples presented in this study, implementation of fracture geomechanical effects in EDFM did not degrade the computational performance of EDFM. Many unconventional reservoirs comprise well-developed natural fracture networks with multiple orientations and complex hydraulic fracture patterns suggested by microseismic data. We developed a coupled dual continuum and discrete fracture model to efficiently simulate production from these reservoirs. Large-scale hydraulic fractures were modeled explicitly using the EDFM approach and numerous small-scale natural fractures were modeled using a dual continuum approach. The transport parameters for dual continuum modeling of numerous natural fractures were derived by upscaling the EDFM equations. Comparison of the results using the coupled model with that of using the EDFM approach to represent all natural and hydraulic fractures explicitly showed that reasonably accurate results can be obtained at much lower computational cost by using the coupled approach with moderate grid refinements.

Assisted History Matching for Unconventional Reservoirs

Assisted History Matching for Unconventional Reservoirs
A Book

by Sutthaporn Tripoppoom,Wei Yu,Kamy Sepehrnoori,Jijun Miao

  • Publisher : Gulf Professional Publishing
  • Release : 2021-08-01
  • Pages : 330
  • ISBN : 0128222433
  • Language : En, Es, Fr & De
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As unconventional reservoir activity grows in demand, reservoir engineers relying on history matching are challenged with this time-consuming task in order to characterize hydraulic fracture and reservoir properties, which are expensive and difficult to obtain. Assisted History Matching for Unconventional Reservoirs delivers a critical tool for today’s engineers proposing an Assisted History Matching (AHM) workflow. The AHM workflow has benefits of quantifying uncertainty without bias or being trapped in any local minima and this reference helps the engineer integrate an efficient and non-intrusive model for fractures that work with any commercial simulator. Additional benefits include various applications of field case studies such as the Marcellus shale play and visuals on the advantages and disadvantages of alternative models. Rounding out with additional references for deeper learning, Assisted History Matching for Unconventional Reservoirs gives reservoir engineers a holistic view on how to model today’s fractures and unconventional reservoirs. Provides understanding on simulations for hydraulic fractures, natural fractures, and shale reservoirs using embedded discrete fracture model (EDFM) Reviews automatic and assisted history matching algorithms including visuals on advantages and limitations of each model Captures data on uncertainties of fractures and reservoir properties for better probabilistic production forecasting and well placement

Assisted History Matching for Unconventional Reservoirs

Assisted History Matching for Unconventional Reservoirs
A Book

by Sutthaporn Tripoppoom,Wei Yu,Kamy Sepehrnoori,Jijun Miao

  • Publisher : Gulf Professional Publishing
  • Release : 2021-08-15
  • Pages : 330
  • ISBN : 9780128222423
  • Language : En, Es, Fr & De
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As unconventional reservoir activity grows in demand, reservoir engineers relying on history matching are challenged with this time-consuming task in order to characterize hydraulic fracture and reservoir properties, which are expensive and difficult to obtain. Assisted History Matching for Unconventional Reservoirs delivers a critical tool for today's engineers proposing an Assisted History Matching (AHM) workflow. The AHM workflow has benefits of quantifying uncertainty without bias or being trapped in any local minima and this reference helps the engineer integrate an efficient and non-intrusive model for fractures that work with any commercial simulator. Additional benefits include various applications of field case studies such as the Marcellus shale play and visuals on the advantages and disadvantages of alternative models. Rounding out with additional references for deeper learning, Assisted History Matching for Unconventional Reservoirs gives reservoir engineers a holistic view on how to model today's fractures and unconventional reservoirs. Provides understanding on simulations for hydraulic fractures, natural fractures, and shale reservoirs using embedded discrete fracture model (EDFM) Reviews automatic and assisted history matching algorithms including visuals on advantages and limitations of each model Captures data on uncertainties of fractures and reservoir properties for better probabilistic production forecasting and well placement

Low Salinity and Engineered Water Injection for Sandstone and Carbonate Reservoirs

Low Salinity and Engineered Water Injection for Sandstone and Carbonate Reservoirs
A Book

by Emad Walid Al Shalabi,Kamy Sepehrnoori

  • Publisher : Gulf Professional Publishing
  • Release : 2017-06-14
  • Pages : 178
  • ISBN : 0128136057
  • Language : En, Es, Fr & De
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Low Salinity and Engineered Water Injection for Sandstones and Carbonate Reservoirs provides a first of its kind review of the low salinity and engineered water injection (LSWI/EWI) techniques for today’s more complex enhanced oil recovery methods. Reservoir engineers today are challenged in the design and physical mechanisms behind low salinity injection projects, and to date, the research is currently only located in numerous journal locations. This reference helps readers overcome these challenging issues with explanations on models, experiments, mechanism analysis, and field applications involved in low salinity and engineered water. Covering significant laboratory, numerical, and field studies, lessons learned are also highlighted along with key areas for future research in this fast-growing area of the oil and gas industry. After an introduction to its techniques, the initial chapters review the main experimental findings and explore the mechanisms behind the impact of LSWI/EWI on oil recovery. The book then moves on to the critical area of modeling and simulation, discusses the geochemistry of LSWI/EWI processes, and applications of LSWI/EWI techniques in the field, including the authors’ own recommendations based on their extensive experience. It is an essential reference for professional reservoir and field engineers, researchers and students working on LSWI/EWI and seeking to apply these methods for increased oil recovery. Teaches users how to understand the various mechanisms contributing to incremental oil recovery using low salinity and engineering water injection (LSWI/EWI) in sandstones and carbonates Balances guidance between designing laboratory experiments, to applying the LSWI/EWI techniques at both pilot-scale and full-field-scale for real-world operations Presents state-of-the-art approaches to simulation and modeling of LSWI/EWI

Fractured Vuggy Carbonate Reservoir Simulation

Fractured Vuggy Carbonate Reservoir Simulation
A Book

by Jun Yao,Zhao-Qin Huang

  • Publisher : Springer
  • Release : 2017-08-08
  • Pages : 245
  • ISBN : 3662550326
  • Language : En, Es, Fr & De
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This book solves the open problems in fluid flow modeling through the fractured vuggy carbonate reservoirs. Fractured vuggy carbonate reservoirs usually have complex pore structures, which contain not only matrix and fractures but also the vugs and cavities. Since the vugs and cavities are irregular in shape and vary in diameter from millimeters to meters, modeling fluid flow through fractured vuggy porous media is still a challenge. The existing modeling theory and methods are not suitable for such reservoir. It starts from the concept of discrete fracture and fracture-vug networks model, and then develops the corresponding mathematical models and numerical methods, including discrete fracture model, discrete fracture-vug model, hybrid model and multiscale models. Based on these discrete porous media models, some equivalent medium models and methods are also discussed. All the modeling and methods shared in this book offer the key recent solutions into this area.

A History Matching Workflow Using Proxy-based MCMC Applied in Tight Reservoir Simulation Studies

A History Matching Workflow Using Proxy-based MCMC Applied in Tight Reservoir Simulation Studies
A Book

by Silpakorn Dachanuwattana

  • Publisher : Unknown Publisher
  • Release : 2017
  • Pages : 220
  • ISBN : 9876543210XXX
  • Language : En, Es, Fr & De
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Reservoir simulation for tight reservoirs often requires characterization of hydraulic and natural fracture networks in the reservoir model. Microseismic data reveals approximate boundary of the fracture networks but its direct application of stimulated rock volume (SRV) fails short to capture fracture connectivity and fracture conductivity, which significantly dominate well performance. Embedding discrete fractures in reservoir simulation is thus required to attain more realistic reservoir behavior. However, using local grid refinement (LGR) to model discrete fractures is computationally expensive. Even more challenging is generating multiple realizations of the fracture-embedded reservoir models during history-matching. Not only one simulation but extensive series of simulations are required to deal with complex geometry of fractures as well as other uncertain parameters. However, recent developments in a methodology called Embedded Discrete Fracture Model (EDFM) have overcome the computational complexity using discrete fractures in reservoir simulations. In this thesis, we develop an efficient assisted history matching (AHM) workflow using proxy-based Markov chain Monte Carlo (MCMC) algorithm and integrate the workflow with the EDFM preprocessor. To improve the efficiency, the optimal proxy is studied by comparing the performance of four types of proxies: quadratic polynomial, cubic polynomial, k-nearest neighboring (KNN), and kriging under various contexts such as different measurement errors. The results show that kriging proxy is more accurate than KNN proxy and cubic proxy. The quadratic proxy was the least accurate in our evaluations. However, if larger measurement error is introduced, the distinction between accuracy of the four proxies becomes less clear in spite of their different computational costs. Incorporating these findings, the proxy-based MCMC workflow is developed and implemented in conjunction with the EDFM to history match a shale oil well in Vaca Muerta formation to demonstrate the application of the workflow. The microseismic data are accounted to constrain the uncertain geometries of the fractures. The integrated workflow can successfully and efficiently history match the actual shale-oil well with complex fractures. Not only the uncertainties of reservoir properties are narrowed down but the posterior likelihood of fracture geometry scenario is also attained after history matching. We also compare the proxy-based MCMC workflow with the direct MCMC and a commercial history matching software in terms of accuracy and efficiency. It is found that the direct MCMC cannot find enough solutions to construct the posterior probability density (PPD) in an efficient manner. For the commercial software, it can find solutions faster than the proxy-based MCMC. However, the former is stuck in the local minima, thus resulting in an invalid PPD. Ultimately, the proxy-based MCMC workflow provides the most accurate history matching results with efficient manner for this tight oil reservoir.

Modeling Interwell Fracture Interference and Huff-n-Puff Pressure Containment in Eagle Ford Using EDFM

Modeling Interwell Fracture Interference and Huff-n-Puff Pressure Containment in Eagle Ford Using EDFM
A Book

by Mauricio Xavier Fiallos Torres

  • Publisher : Unknown Publisher
  • Release : 2019
  • Pages : 278
  • ISBN : 9876543210XXX
  • Language : En, Es, Fr & De
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Shale field operators have vested a tremendous interest in optimal spacing of infill wells and further fracture optimization, which ideally should have as little interference with the existing wells as possible. Although proper modeling has been employed to show the existence of well interference, few models have forecasted the impact of multiple inter-well fractures on child wells production and also implemented Huff-n-Puff and injection containment methods. These prognoses of the reservoir simulations abet to optimize further hydraulic fracture designs and improve the efficiency of Enhanced Oil Recovery (EOR) in unconventional reservoirs. This thesis presented a rigorous workflow for estimating the impacts of spatial variations in fracture conductivity and complexity on fracture geometries of inter-well interference when modeling EOR Huff-n-Puff. Furthermore, we applied a non-intrusive embedded discrete fracture modeling (EDFM) method in conjunction with a commercial reservoir simulator to investigate the impact of well interference through connecting fractures by multi-well history matching, to propose profitable opportunities for Huff-n-Puff application. In this sense, the value of our workflow relies on a robust understanding of fracture properties, real production data validation, and the add-on feature of multi-pad wellbore image logging interpretation in the process. First, according to updated production data from Eagle Ford, the model was constructed to perform four (parent) wells history matching including five inner (child) wells. Later, fracture diagnostic results from well image logging were employed to perform sensitivity analysis on properties of long interwell connecting fractures such as number, conductivity, geometry, and explore their impacts on history matching. However, the estimation of these inter-well connecting fractures which were employed for enhanced history matching varied significantly from unmeasured fracture sensitivities. Finally, optimal cluster spacing was recommended considering interwell interference. The obtained results lead our study to the implementation of Huff-n-Puff models that capture inter-well interference seen in the field and their affordable impact sensitivities focused on variable injection rates/locations and multi-point water injection to mimic pressure barriers. The simulation results strengthen the understanding of modeling complex fracture geometries with robust history matching and support the need to incorporate containment strategies when EOR Huff-n-Puff is implemented. Moreover, the simulation outcomes show that well interference is present and reduces effectiveness of the fracture hits when connecting natural fractures. As a result of the inter-well long fractures, the bottom hole pressure behavior of the parent wells tends to equalize, and the pressure does not recover fast enough. Furthermore, the EDFM application is strongly supported by complex fracture propagation interpretation from image logs through the child wells in the reservoir. Through this study, multiple containment scenarios were proposed to contain the pressure in the area of interest, considering more than 2000 hydraulic fractures. The model became a valuable stencil to inform the impacts on well location and spacing, the completion staging, initial huff-n-puff decisions, and subsequent containment strategies (e.g. to improve cycle timing and efficiency), so that it can be expanded to other areas of the field. The simulation results and understandings afforded have been applied to the field satisfactorily to support significant reductions in offset fracture interference by up to 50% and reduce completion costs up to 23% while improving new well capital efficiency. Consequently, these outcomes support pressure containment benefits that lead to increased pressure build, reduced gas communication, reduced offset shut-in volumes, and ultimately, improvements in net utilization and capital efficiency

Transport in Shale Reservoirs

Transport in Shale Reservoirs
A Book

by Kun Sang Lee,Tae Hong Kim

  • Publisher : Gulf Professional Publishing
  • Release : 2019-02-20
  • Pages : 150
  • ISBN : 0128178612
  • Language : En, Es, Fr & De
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Transport in Shale Reservoirs fills the need for a necessary, integrative approach on shale reservoirs. It delivers both the fundamental theories of transport in shale reservoirs and the most recent advancements in the recovery of shale oil and gas in one convenient reference. Shale reservoirs have distinctive features dissimilar to those of conventional reservoirs, thus an accurate evaluation on the behavior of shale gas reservoirs requires an integrated understanding on their characteristics and the transport of reservoir and fluids. Updates on the various transport mechanisms in shale, such as molecular diffusion and phase behavior in nano-pores Applies theory to practice through simulation in both shale oil and gas Presents an up-to-date reference on remaining challenges, such as organic material in the shale simulation and multicomponent transport in CO2 injection processes

Development of a Multi-mechanistic Triple-porosity, Triple-permeability Compositional Model for Unconventional Reservoirs

Development of a Multi-mechanistic Triple-porosity, Triple-permeability Compositional Model for Unconventional Reservoirs
A Book

by Nithiwat Siripatrachai

  • Publisher : Unknown Publisher
  • Release : 2016
  • Pages : 329
  • ISBN : 9876543210XXX
  • Language : En, Es, Fr & De
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Most existing compositional reservoir simulators often model fractures using local grid refinement, unstructured-grid, or fine-grid models. Modeling different scales of fractures requires a large number of grid blocks to capture the heterogeneity of the formation. Using a large number of grid blocks presents computational challenges, even with todays powerful processors. An enhanced matrix permeability on the grid block that hosts short-scale fractures is commonly used to eliminate natural fractures and simplify the model. Additionally, several existing multi-porosity models may not be able to capture heterogeneity and flow behavior in different porosity domains. Sequential flow assumption is frequently made in their models. Flows between different porosity types are not fully coupled, and in some model, a simplified inter-porosity transmissibility function is used for any porosity pairs. The oil and gas reserves and flow of reservoir fluids are strongly dependent on phase behavior. Large capillary pressure values are encountered in tight formations such as tight-rocks and shales. The tiny pore throats in these formations result in large capillary pressure. The effect of capillary pressure in tight formations can significantly impact the fluid phase behaviors in the reservoir during production and enhanced oil recovery (EOR) processes. Not incorporating this effect into the simulation can result in an inaccurate estimation of ultimate recovery as well as inefficient design and implementation of EOR techniques. In spite of this, the effect of capillary pressure on phase behavior in tight reservoirs has not been well studied using compositional simulation, especially for hydraulically fractured reservoirs.In this research, a fully implicit, multi-mechanistic, fully coupled, triple-porosity, triple-permeability compositional model has been developed for unconventional reservoirs. The hydraulically fractured tight rock and shale reservoir is treated as a triple-porosity system consisting of matrix blocks, natural fractures (micro fractures), and hydraulic fractures (macro fractures). Small-scale fractures are handled by a dual-continuum model. An embedded discrete fracture model is used to effectively and efficiently capture the flow dynamics of hydraulic fractures at any orientations, honoring the complexity and heterogeneity of the fracture networks. The triple-porosity model enables us to assign reservoir properties corresponding to the porosity type. The flows in three porosity types are fully coupled without making the assumption of sequential flow. The inter-porosity fluid transfer honors the geometry of the intersecting porosity pair. The development of the proposed numerical model incorporates the effect of capillary pressure on phase behavior. The transport of hydrocarbon follows a multi-mechanistic flow mechanism that is driven by pressure and concentration fields. The simulator has been validated with analytical solutions and a commercial reservoir simulator for a single-porosity model and a dual-porosity, dual-permeability model, both with and without grid refinement. With the proposed model, we can accurately capture major physics of transport phenomena that have been done to date and have the most realistic modeling of fluid flow in hydraulically fractured tight rock and shale reservoirs. The simulator is used in parametric studies to investigate the production performance from hydraulically fractured reservoirs under different modeling techniques and the effect of capillary pressure on phase behavior on reserves and ultimate recovery. The simulator is used to study the impact of inter-porosity transport on the recovery and fluid transport and phase behavior in hydraulically fractured tight rocks and shale formations under high capillary pressure. The outcomes of this project are an improved understanding of phase behavior and fluid flow in hydraulically fractured shale and tight rocks and an increased accuracy of the production prediction and ultimate recovery.

Improved Reservoir Models and Production Forecasting Techniques for Multi-Stage Fractured Hydrocarbon Wells

Improved Reservoir Models and Production Forecasting Techniques for Multi-Stage Fractured Hydrocarbon Wells
A Book

by Ruud Weijermars,Wei Yu,Aadi Khanal

  • Publisher : MDPI
  • Release : 2019-12-12
  • Pages : 238
  • ISBN : 3039218921
  • Language : En, Es, Fr & De
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The massive increase in energy demand and the related rapid development of unconventional reservoirs has opened up exciting new energy supply opportunities along with new, seemingly intractable engineering and research challenges. The energy industry has primarily depended on a heuristic approach—rather than a systematic approach—to optimize and tackle the various challenges when developing new and improving the performance of existing unconventional reservoirs. Industry needs accurate estimations of well production performance and of the cumulative estimated ultimate reserves, accounting for uncertainty. This Special Issue presents 10 original and high-quality research articles related to the modeling of unconventional reservoirs, which showcase advanced methods for fractured reservoir simulation, and improved production forecasting techniques.

Mobility Control of Gas Injection in Highly Heterogeneous and Naturally Fractured Reservoirs

Mobility Control of Gas Injection in Highly Heterogeneous and Naturally Fractured Reservoirs
A Book

by Jose Sergio de Araujo Cavalcante Filho

  • Publisher : Unknown Publisher
  • Release : 2016
  • Pages : 574
  • ISBN : 9876543210XXX
  • Language : En, Es, Fr & De
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Since a significant portion of the world’s oil reserves resides in naturally fractured reservoirs (NFR), it is important to maximize oil production from these reservoirs. Mobility control EOR techniques, such as water alternating gas (WAG) and foam injection, may be used in NFRs to improve oil recovery. Foam injection may be modeled by empirical or mechanistic models, the latter being capable of representing foam generation and coalescence effects. Numerical models are needed to evaluate EOR techniques in NFR. The Embedded Discrete Fracture Model (EDFM) is capable of representing conductive faults or fractures and describing NFR and unconventional reservoirs as a triple porosity medium (hydraulic fractures, natural fractures, and matrix). This work aims at developing a general EDFM framework to allow the evaluation of different mobility control EOR methods in NFR. The mobility control EOR methods evaluated were the WAG and continuous foam injection. The formulation used to evaluate mobility control by foam injection in NFR was the population balance assuming local equilibrium and the P*c models. Nanoparticle transport models (Two Site and Two Rate models) were implemented and validated to allow simulation of nanoparticle stabilized foam injection. An EDFM preprocessor was further developed and validated against the in-house fully implicit simulator, unstructured grid models from the literature and fine-grid models using a commercial simulator. Simulation run time was reduced by applying a porosity cut-off in the fracture cells assuming constant fracture conductivity. Validation case studies included multi-fractured wells producing through depletion and a 2D quarter five-spot production scheme (water and miscible gas injection) in NFR. We obtained a good agreement between EDFM, unstructured grid, and fine-grid models. Application case studies included 3D models under water, miscible gas and WAG injection, which confirmed the efficiency of the EDFM in modeling complex fracture networks. We used the EDFM to simulate multilateral well stimulation and we performed an automated history matching of the production data of a field test. The foam model and the nanoparticle transport models were validated against experimental data from the literature. It is concluded that the effect of fractures on hydrocarbon production depends on fracture network connectivity, which may be modeled using the EDFM preprocessor. Simulation results using mobility control EOR methods show considerable improvements in oil recovery due to a postponement in gas breakthrough.

CO2 Injection in the Network of Carbonate Fractures

CO2 Injection in the Network of Carbonate Fractures
A Book

by J. Carlos de Dios,Srikanta Mishra,Flavio Poletto,Alberto Ramos

  • Publisher : Springer Nature
  • Release : 2020-12-17
  • Pages : 243
  • ISBN : 3030629864
  • Language : En, Es, Fr & De
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This book presents guidelines for the design, operation and monitoring of CO2 injection in fractured carbonates, with low permeability in the rock matrix, for geological storage in permanent trapping. CO2 migration is dominated by fractures in formations where the hydrodynamic and geochemical effects induced by the injection play a key role influencing the reservoir behavior. CO2 injection in these rocks shows specific characteristics that are different to injection in porous media, as the results from several research studies worldwide reveal. All aspects of a project of this type are discussed in this text, from the drilling to the injection, as well as support works like well logging, laboratory and field tests, modeling, and risk assessment. Examples are provided, lesson learned is detailed, and conclusions are drawn. This work is derived from the experience of international research teams and particularly from that gained during the design, construction and operation of Hontomín Technology Development Plant. Hontomín research pilot is currently the only active onshore injection site in the European Union, operated by Fundación Ciudad de la Energía-CIUDEN F.S.P. and recognized by the European Parliament as a key test facility. The authors provide guidelines and tools to enable readers to find solutions to their problems. The book covers activities relevant to a wide range of practitioners involved in reservoir exploration, modeling, site operation and monitoring. Fluid injection in fractured media shows specific features that are different than injection in porous media, influencing the reservoir behavior and defining conditions for safe and efficient operation. Therefore, this book is also useful to professionals working on oil & gas, hydrogeology and geothermal projects, and in general for those whose work is related to activities using fluid injection in the ground.

Multiphase Fluid Flow in Porous and Fractured Reservoirs

Multiphase Fluid Flow in Porous and Fractured Reservoirs
A Book

by Yu-Shu Wu

  • Publisher : Gulf Professional Publishing
  • Release : 2015-09-23
  • Pages : 418
  • ISBN : 0128039116
  • Language : En, Es, Fr & De
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Multiphase Fluid Flow in Porous and Fractured Reservoirs discusses the process of modeling fluid flow in petroleum and natural gas reservoirs, a practice that has become increasingly complex thanks to multiple fractures in horizontal drilling and the discovery of more unconventional reservoirs and resources. The book updates the reservoir engineer of today with the latest developments in reservoir simulation by combining a powerhouse of theory, analytical, and numerical methods to create stronger verification and validation modeling methods, ultimately improving recovery in stagnant and complex reservoirs. Going beyond the standard topics in past literature, coverage includes well treatment, Non-Newtonian fluids and rheological models, multiphase fluid coupled with geomechanics in reservoirs, and modeling applications for unconventional petroleum resources. The book equips today’s reservoir engineer and modeler with the most relevant tools and knowledge to establish and solidify stronger oil and gas recovery. Delivers updates on recent developments in reservoir simulation such as modeling approaches for multiphase flow simulation of fractured media and unconventional reservoirs Explains analytical solutions and approaches as well as applications to modeling verification for today’s reservoir problems, such as evaluating saturation and pressure profiles and recovery factors or displacement efficiency Utilize practical codes and programs featured from online companion website

Well Production Performance Analysis for Shale Gas Reservoirs

Well Production Performance Analysis for Shale Gas Reservoirs
A Book

by Liehui Zhang,Zhangxin Chen,Yu-long Zhao

  • Publisher : Elsevier
  • Release : 2019-05-16
  • Pages : 388
  • ISBN : 0444643168
  • Language : En, Es, Fr & De
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Well Production Performance Analysis for Shale Gas Reservoirs, Volume 66 presents tactics and discussions that are urgently needed by the petroleum community regarding unconventional oil and gas resources development and production. The book breaks down the mechanics of shale gas reservoirs and the use of mathematical models to analyze their performance. Features an in-depth analysis of shale gas horizontal fractured wells and how they differ from their conventional counterparts Includes detailed information on the testing of fractured horizontal wells before and after fracturing Offers in-depth analysis of numerical simulation and the importance of this tool for the development of shale gas reservoirs

Simulation Study of Preformed Particle Gel for Conformance Control

Simulation Study of Preformed Particle Gel for Conformance Control
A Book

by Pongpak Taksaudom

  • Publisher : Unknown Publisher
  • Release : 2014
  • Pages : 574
  • ISBN : 9876543210XXX
  • Language : En, Es, Fr & De
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Conformance control has long been a compelling subject in improving waterflood oil recovery. By blocking the areas previously swept by water, subsequently injected water is allowed to sweep the remaining unswept portions of the reservoir and thereby increase the ultimate oil recovery. One technique that has received a great deal of attention recently in achieving this in-depth water shut-off is crosslinked gel injection. However, processing and predicting the performance of these gels in complex petroleum reservoirs is known to be extremely challenging. A model that accurately represents the reservoir features, chemical properties, and displacement mechanisms is, therefore, required. In this study, we further developed the UT in-house numerical reservoir simulator, branded as UTGEL. Our first focus was to enable UTGEL to simulate a new type of temperature-resistant and salt-tolerant pre-crosslinked swellable particle gel, known as Preformed Particle Gel or PPG. A series of numerical simulations have been conducted to match with experimental data and generate parameters for full field scale simulation. Five laboratory experimental matching attempts were successfully performed using the UTGEL simulator in this study. The matched experiments included a fracture model, two sandpack models, a sandstone coreflood experiment, and a parallel sandpack model. The second focus of this study was to investigate the applications of PPG in blocking high-permeability layers, fractures, and conduits. A number of synthetic and actual field cases were generated to study the performance of PPG in (1) reservoirs with various layered permeability contrasts, from extremely low to extremely high permeability contrasts, (2) reservoirs containing extensive conduits or channels, and (3) real field cases where heterogeneity had been identified unfavorable to the waterflood efficiency. The simulation outcomes indicated significant incremental oil recovery from PPG treatment ranging from less than 5% to almost 30%. A number of sensitivity analyses were also conducted to provide some insights on the optimal PPG treatment design. Lastly, to enhance the capability of UTGEL in simulating gel transport in diverse scenarios, a novel Embedded Discrete Fracture Modeling (EDFM) concept was implemented into UTGEL in this study, allowing multiple sets of fracture planes and conduits with dip angles and orientations to be modeled and simulated with gel treatments for the first time with a rather computationally inexpensive method. Although the developed simulator requires further improvement and validation against wider reservoir and fluid conditions, the representative results from a number of generated models in this study have suggested another step forward towards achieving realistic reservoir modeling and advanced gel transport simulation.

SPE Reservoir Engineering

SPE Reservoir Engineering
An Official Publication of the Society of Petroleum Engineers

by Anonim

  • Publisher : Unknown Publisher
  • Release : 1997
  • Pages : 329
  • ISBN : 9876543210XXX
  • Language : En, Es, Fr & De
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