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Efficient Geomechanical Simulations Of Large Scale Naturally Fractured Reservoirs Using The Fast Multipole Displacement Discontinuity Method Fm Ddm
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Book Synopsis Efficient Geomechanical Simulations of Large-Scale Naturally Fractured Reservoirs Using the Fast Multipole-Displacement Discontinuity Method (FM-DDM) by : Alexander José Verde Salas
Download or read book Efficient Geomechanical Simulations of Large-Scale Naturally Fractured Reservoirs Using the Fast Multipole-Displacement Discontinuity Method (FM-DDM) written by Alexander José Verde Salas and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Geothermal and unconventional reservoirs play an important role in supplying fuel for a growing energy demand in the United States. The development of such reservoirs relies on creating a fracture network to provide flow and transport conduits during injection and production operations. The Displacement Discontinuity Method (DDM) is frequently used for modeling the behavior of fractures embedded in elastic and poroelastic rocks. However, DDM requires the calculation of the influence among all fractures being computationally inefficient for large systems of cracks. It demands quadratic and cubic complexity of memory and solution time by direct methods, respectively, limiting its application to only small-scale situations. Recent fast summation techniques such as the Fast Multipole Method (FMM) have been used to speed up the solution of several boundary element problems using modest computational resources. FMM relies in accelerating matrix-vector products in iterative methods by splitting the computation of the influences among elements into near and far-field interactions. While the former are calculated similarly to the conventional DDM, the latter, where most of the interactions are found, are efficiently approximated by the FMM using analytical multipole and local expansions. However, in spite of its immediately apparent application in the geomechanic context, FMM has been limited to only certain fracture problems because those analytical expansions are only available for selected fundamental solutions and the development for new ones requires complex mathematical derivations even for those kernels of simple form. This work presents a new method called Fast Multipole-Displacement Discontinuity Method (FM-DDM) for an efficient flow-geomechanical simulation of large-scale naturally fractured reservoirs undergoing fluid injection and extraction. The approach combines both DDM and FMM using for the latter a kernel-independent version where multipole and local expansions are not required opening a range of potential applications within the geothermal and oil industries. Several case studies involving fracture networks with up to one hundred thousands of boundary elements were presented to evaluate accuracy, computational efficiency and applications of the FMM approach. From the results, FM-DDM showed an excellent agreement with well-known benchmark solutions outperforming DDM with linear complexity in both memory and execution time. In addition, a variety of large-scale geomechanical applications were efficiently evaluated with FM-DDM involving interactions between transverse hydraulic fractures and a fracture network, fast visualization of high-resolution stress distribution, and the design of exploitation strategies in elastic and poroelastic fractured reservoirs. The electronic version of this dissertation is accessible from http://hdl.handle.net/1969.1/152448
Book Synopsis Coupled Geomechanics and Multiphase Flow Modeling in Naturally and Hydraulically Fractured Reservoirs by : Yanli Pei
Download or read book Coupled Geomechanics and Multiphase Flow Modeling in Naturally and Hydraulically Fractured Reservoirs written by Yanli Pei and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fluid injection and production in highly fractured unconventional reservoirs could induce complex stress reorientation and redistribution. The strong stress sensitivity of fractured formations may also lead to non-negligible fracture opening or closure under the reservoir loading or unloading process. Hence, a coupled flow and geomechanics model is in high demand to assist with stress prediction and production forecast in unconventional reservoirs. In this dissertation, an enhanced geomechanics model is developed for fractured reservoirs and integrated with the in-house compositional reservoir simulator – UTCOMP for coupled flow and geomechanics modeling. The multiphase flow model is solved using the finite volume method (FVM) with an embedded discrete fracture model (EDFM) to represent flow through complex fractures. Based on static fracture assumption, the finite element method (FEM) is applied to solve the geomechanics model by incorporating fracture effects on rock deformation through pore pressure changes. An iterative coupling procedure is implemented between fluid flow and geomechanics, and the 3D coupled model is applied to predict spatiotemporal stress evolution in single-layer and multilayer unconventional reservoirs. To consider dynamic fracture properties, the geomechanics model is further enhanced by the extended finite element method (XFEM) with a modified linear elastic proppant model. The fracture surface is under the coeffects of pore pressure and proppant particles, and various enrichment functions are introduced to reproduce the discontinuous fields over fracture paths. The enhanced geomechanics model is validated against classical Sneddon and Elliot’s problem and presents a first-order spatial convergence rate. Numerical studies indicate that modeling fracture closure is necessary for poorly propped, highly stressed, or fast depleted reservoirs, and fracture opening can be significant under high permeability and low stiffness conditions. The coupled flow and geomechanics model is finally combined with a displacement discontinuity method (DDM) hydraulic fracture model to establish an integrated reservoir-geomechanics-fracture model for the end-to-end optimization of secondary stimulations. It is applied to Permian Basin and Sichuan Basin tight formations to optimize parent-child well spacing at different infill times. The integrated model provides hands-on guidelines for refracturing and infill drilling in multilayer unconventional reservoirs and can be easily adapted to other basins under their unique data
Book Synopsis Development of an Efficient Embedded Discrete Fracture Model for 3D Compositional Reservoir Simulation in Fractured Reservoirs by : Ali Moinfar
Download or read book Development of an Efficient Embedded Discrete Fracture Model for 3D Compositional Reservoir Simulation in Fractured Reservoirs written by Ali Moinfar and published by . This book was released on 2013 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Book Synopsis Geomechanics, Fluid Dynamics and Well Testing, Applied to Naturally Fractured Carbonate Reservoirs by : Nelson Enrique Barros Galvis
Download or read book Geomechanics, Fluid Dynamics and Well Testing, Applied to Naturally Fractured Carbonate Reservoirs written by Nelson Enrique Barros Galvis and published by Springer. This book was released on 2018-05-02 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents an important step towards a deeper understanding of naturally fractured carbonate reservoirs (NFCRs). It demonstrates the various kinds of discontinuities using geological evidence, mathematical kinematics model and computed tomography and uses this as a basis for proposing a new classification for NFCRs. Additionally, this study takes advantage of rock mechanics theory to illustrate how natural fractures can collapse due to fluid flow and pressure changes in the fractured media. The explanations and mathematical modeling developed in this dissertation can be used as diagnostic tools to predict fluid velocity, fluid flow, tectonic fracture collapse, pressure behavior during reservoir depleting, considering stress-sensitive and non-stress-sensitive, with nonlinear terms in the diffusivity equation applied to NFCRs. Furthermore, the book presents the description of real reservoirs with their field data as the principal goal in the mathematical description of the realistic phenomenology of NFCRs.
Book Synopsis Thermo-Hydro-Mechanical Behavior of Conductive Fractures Using a Hybrid Finite Difference - Displacement Discontinuity Method by : Mohammadreza Jalali
Download or read book Thermo-Hydro-Mechanical Behavior of Conductive Fractures Using a Hybrid Finite Difference - Displacement Discontinuity Method written by Mohammadreza Jalali and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Large amounts of hydrocarbon reserves are trapped in fractured reservoirs where fluid flux is far more rapid along fractures than through the porous matrix, even though the volume of the pore space may be a hundred times greater than the volume of the fractures. These are considered extremely challenging in terms of accurate recovery prediction because of their complexity and heterogeneity. Conventional reservoir simulators are generally not suited to naturally fractured reservoirs' production history simulation, especially when production processes are associated with large pressure and temperature changes that lead to large redistribution of effective stresses, causing natural fracture aperture alterations. In this case, all the effective processes, i.e. hydraulic, thermal and geomechanical, should be considered simultaneously to explain and evaluate the behavior of stress-sensitive reservoirs over the production period. This is called thermo-hydro-mechanical (THM) coupling. In this study, a fully coupled thermo-hydro-mechanical approach is developed to simulate the physical behavior of fractures in a plane strain thermo-poroelastic medium. A hybrid numerical method, which implements both the finite difference method (FDM) and the displacement discontinuity method (DDM), is established to study the pressure, temperature, deformation and stress variations of fractures and surrounding rocks during production processes. This method is straightforward and can be implemented in conventional reservoir simulators to update fracture conductivity as it uses the same grid block as the reservoir grids and requires only discretization of fractures. The hybrid model is then verified with couple of analytical solutions for the fracture aperture variation under different conditions. This model is implemented for some examples to present the behavior of fracture network as well as its surrounding rock under thermal injection and production. The results of this work clearly show the importance of rate, aspect ratio (i.e. geometry) and the coupling effects among fracture flow rate and aperture changes arising from coupled stress, pressure and temperature changes. The outcomes of this approach can be used to study the behavior of hydraulic injection for induced fracturing and promoting of shearing such as hydraulic fracturing of shale gas or shale oil reservoirs as well as massive waste disposal in the porous carbonate rocks. Furthermore, implementation of this technique should be able to lead to a better understanding of induced seismicity in injection projects of all kinds, whether it is for waste water disposal, or for the extraction of geothermal energy.
Book Synopsis Numerical Modeling of Fracture Permeability Change in Naturally Fractured Reservoirs Using a Fully Coupled Displacement Discontinuity Method by : Qingfeng Tao
Download or read book Numerical Modeling of Fracture Permeability Change in Naturally Fractured Reservoirs Using a Fully Coupled Displacement Discontinuity Method written by Qingfeng Tao and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Fractures are the main flow channels in naturally fractured reservoirs. Therefore the fracture permeability is a critical parameter to production optimization and reservoir management. Fluid pressure reduction caused by production induces an increase in effective stress in naturally fractured reservoirs. The change of effective stress induces fracture deformation and changes fracture aperture and permeability, which in turn influences the production. Coupled interactions exist in the fractured reservoir: (i) fluid pressure change induces matrix deformation and stress change; (ii) matrix deformation induces fluid volume change and fluid pressure change; (iii) fracture deformation induces the change of pore pressure and stress in the whole field (the influence disappears at infinity); (iv) the change of pore pressure and stress at any point has an influence on the fracture and induces fracture deformation. To model accurately the influence of pressure reduction on the fracture permeability change in naturally fractured reservoirs, all of these coupled processes need to be considered. Therefore, in this dissertation a fully coupled approach is developed to model the influence of production on fracture aperture and permeability by combining a finite difference method to solve the fluid flow in fractures, a fully coupled displacement discontinuity method to build the global relation of fracture deformation, and the Barton-Bandis model of fracture deformation to build the local relation of fracture deformation. The fully coupled approach is applied to simulate the fracture permeability change in naturally fracture reservoir under isotropic in situ stress conditions and high anisotropic in situ stress conditions, respectively. Under isotropic stress conditions, the fracture aperture and permeability decrease with pressure reduction caused by production, and the magnitude of the decrease is dependent on the initial effective in situ stress. Under highly anisotropic stress, the fracture permeability can be enhanced by production because of shear dilation. The enhancement of fracture permeability will benefit to the production of oil and gas.
Book Synopsis Hydraulic Fracture Modeling in Naturally Fractured Reservoirs by : Kaustubh Shrivastava
Download or read book Hydraulic Fracture Modeling in Naturally Fractured Reservoirs written by Kaustubh Shrivastava and published by . This book was released on 2019 with total page 239 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hydraulic fracturing of horizontal wells is one of the key technological breakthroughs that has led to the shale revolution. Hydraulic fracturing models are used to engineer hydraulic fracture design and optimize production. Typically, hydraulic fracturing models treat hydraulic fractures as planar, bi-wing fractures. However, recent core-through investigations have suggested that during hydraulic fracturing in naturally fractured reservoirs, complex hydraulic fracture geometries can be created due to the interaction of the growing hydraulic fracture with natural fractures. This limits the application of planar fracture models for optimizing hydraulic fracturing design in naturally fractured reservoirs. In this research, we present a novel three-dimensional displacement discontinuity method based hydraulic fracturing simulator that allows us to model hydraulic fracture growth in the presence of natural fractures along with proppant transport in an efficient manner. The model developed in this dissertation is used to investigate the interaction of a hydraulic fracture with natural fractures and study the transport of proppant in the resulting complex fracture networks. This investigation gives us novel insight into the influence of fracture geometry and stress interference on the final distribution of proppant in fracture networks. Based on this investigation, suggestions are made to improve proppant transport in complex fracture networks. In order to correctly capture the effect of natural fractures on fracture growth, knowledge about the distribution of natural fractures in the reservoir is imperative. Typically, little is known about the in-situ natural fracture distribution, as direct observation of the reservoir is not possible. A novel technique of synthetic coring is developed to create a discrete fracture network (DFN) from core data, and it is used to create a DFN based on the Hydraulic Fracturing Test Site #1 data. Hydraulic fracture propagation is modeled in the created DFN, and the results are compared with field observations. As the reservoir may contain thousands of natural fractures, simulations in a realistic DFN can be computationally very expensive. In order to reduce the computational requirements of the simulator, we present a novel predictor step based on the local linearization method that provides a better initial guess for solving the fluid-solid interaction problem. This is shown to reduce computational time significantly. A novel technique, Extended Adaptive Integral Method, to speed up the simulator is developed. The method uses an effective medium to represent the interaction between displacement discontinuity elements and reduces the order of complexity of solving the geomechanical system of equations from O(N2) to O(NlogN). The novel formulation of this method is presented, and sensitivity studies are conducted to show the improvement in computational efficiency
Book Synopsis Static Conceptual Fracture Modeling by : Ronald A. Nelson
Download or read book Static Conceptual Fracture Modeling written by Ronald A. Nelson and published by John Wiley & Sons. This book was released on 2019-10-07 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt: Modelling of flow in naturally fractured reservoirs is quickly becoming mandatory in all phases of oil and gas exploration and production. Creation of a Static Conceptual Fracture Model (SCFM) is needed as input to create flow simulations for today and for prediction of flow into the future. Unfortunately, the computer modelers tasked with constructing the gridded fracture model are often not well versed in natural fracture characterization and are often forced to make quick decisions as to the input required by the software used to create these models. Static Conceptual Fracture Modelling: Preparing for Simulation and Development describes all the fracture and reservoir parameters needed to create the fracture database for effective modelling and how to generate the data and parameter distributions. The material covered in this volume highlights not only natural fracture system quantification and formatting, but also describes best practices for managing technical teams charged with creating the SCFM. This book will become a must on the shelf for all reservoir modelers.
Book Synopsis Numerical Modeling of Complex Hydraulic Fracture Propagation in Layered Reservoirs with Auto-optimization by : Jiacheng Wang (Ph. D.)
Download or read book Numerical Modeling of Complex Hydraulic Fracture Propagation in Layered Reservoirs with Auto-optimization written by Jiacheng Wang (Ph. D.) and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hydraulic fracturing brings economic unconventional reservoir developments, and multi-cluster completion designs result in complex hydraulic fracture geometries. Therefore, accurate yet efficient modeling of the propagation of multiple non-planar hydraulic fractures is desired to study the mechanisms of hydraulic fracture propagation and optimize field completion designs. In this research, a novel hydraulic fracture model is developed to simulate the propagation of multiple hydraulic fractures with proppant transport in layered and naturally fractured reservoirs. The simplified three-dimensional displacement discontinuity method (S3D DDM) is enhanced to compute the hydraulic fracture deformation and propagation with analytical fracture height growth and vertical width variation. Using a single row of DDM elements, the enhanced S3D DDM hydraulic fracture model computes the fully 3D geometries with a similar computational intensity to a 2D model. Then an Eulerian-Lagrangian proppant transport model is developed, where the slurry flow rate and pressure are solved within the Eulerian regime, and the movement of solid proppant particles is solved within the Lagrangian regime. The adaptive proppant gridding scheme in the model allows a smaller grid size at the earlier fracturing stage for higher resolution and a larger grid size at the later fracturing stage for higher efficiency. Besides the physical model, an optimization module that utilizes advanced optimization algorithms such as genetic algorithm (GA) and pattern search algorithm (PSA) is proposed to automatically optimize the completion designs according to the preset targets. Numerical results show that hydraulic fracture propagation is under the combined influence of the in-situ stress, pumping schedule, natural fractures, and cluster placement. Hence, numerical simulation is needed to predict complex hydraulic fracture geometries under various geologic and completion settings. The complex hydraulic fracture geometries, together with fracturing fluid and proppant properties, also affect proppant placement. Moreover, the stress contrast at layer interfaces can cause proppant bridging and form barriers on the proppant transport path. The optimized completion designs increase effective hydraulic and propped areas, but they vary depending on the optimization targets. The developed hydraulic fracture model provides insights into the hydraulic fracturing process and benefits unconventional reservoir development
Book Synopsis Embedded Discrete Fracture Modeling and Application in Reservoir Simulation by : Kamy Sepehrnoori
Download or read book Embedded Discrete Fracture Modeling and Application in Reservoir Simulation written by Kamy Sepehrnoori and published by Elsevier. This book was released on 2020-08-27 with total page 306 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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
Book Synopsis Implementation and Application of the Embedded Discrete Fracture Model (EDFM) for Reservoir Simulation in Fractured Reservoirs by : Yifei Xu
Download or read book Implementation and Application of the Embedded Discrete Fracture Model (EDFM) for Reservoir Simulation in Fractured Reservoirs written by Yifei Xu and published by . This book was released on 2015 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Book Synopsis An Effective Method of Stochastic Simulation of Complex Large-scale Transport Processes in Naturally Fractured Reservoirs by : Yujie Hu
Download or read book An Effective Method of Stochastic Simulation of Complex Large-scale Transport Processes in Naturally Fractured Reservoirs written by Yujie Hu and published by . This book was released on 2002 with total page 362 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Discrete Fracture Network Modeling of Hydraulic Stimulation by : Mark W. McClure
Download or read book Discrete Fracture Network Modeling of Hydraulic Stimulation written by Mark W. McClure and published by Springer Science & Business Media. This book was released on 2013-06-15 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt: Discrete Fracture Network Modeling of Hydraulic Stimulation describes the development and testing of a model that couples fluid-flow, deformation, friction weakening, and permeability evolution in large, complex two-dimensional discrete fracture networks. The model can be used to explore the behavior of hydraulic stimulation in settings where matrix permeability is low and preexisting fractures play an important role, such as Enhanced Geothermal Systems and gas shale. Used also to describe pure shear stimulation, mixed-mechanism stimulation, or pure opening-mode stimulation. A variety of novel techniques to ensure efficiency and realistic model behavior are implemented, and tested. The simulation methodology can also be used as an efficient method for directly solving quasistatic fracture contact problems. Results show how stresses induced by fracture deformation during stimulation directly impact the mechanism of propagation and the resulting fracture network.
Book Synopsis Application of Displacement Discontinuity Method to Hydraulic Fracture Propagation in Heterogeneous Rocks by : Sho Hirose
Download or read book Application of Displacement Discontinuity Method to Hydraulic Fracture Propagation in Heterogeneous Rocks written by Sho Hirose and published by . This book was released on 2019 with total page 418 pages. Available in PDF, EPUB and Kindle. Book excerpt: The development of multi-stage hydraulic fracturing technique in horizontal wells enables us to produce oil and gas at economic rate from shale formations, leading to the shale revolution in the United States. Field observations including production history, microseismic mapping, and coring in fractured zones have revealed that the heterogeneity of shale rocks such as natural fractures is likely to have a large impact on oil and gas production from shale reservoirs. In this dissertation, a new hydraulic fracturing model based on the displacement discontinuity method (DDM) was developed. The major achievements in this research include the extension of DDM to multilayered media, the modeling of the interaction with natural fractures in three dimensions, and the development of a DDM-based hydraulic fracturing simulator. The formulation of DDM was revisited, and the equivalence of DDM and BEM was mathematically demonstrated. DDM was extended to multilayered media by using the method of images. The new DDM was applied to a three-layered medium in plain strain containing vertical and horizontal cracks. A sensitivity study suggests that bi-material solutions are sufficient for three-layered media under plain strain conditions. A DDM-based hydraulic fracturing model was developed. The discretized DDM and flow equations were solved in a segregated or fully coupled manner. A new splitting scheme was proposed to improve the convergence speed of the segregated method. The interaction between hydraulic and natural fractures was modeled for both intersecting and remotely interacting cases in our simulator. Poroelastic effects were partially incorporated into DDM by assuming an undrained condition. It was found that poroelastic effects under the undrained condition were limited to the vicinity of hydraulic fractures. Hydraulic fracturing simulations were performed in the presence of synthetic natural fracture networks. Synthetic microseismic events were generated, and inversion analyses of the synthetic microseismic data were performed. It was suggested that the density of microseismic events was affected by both the areal density and length distribution of natural fractures
Book Synopsis Drilling Geomechanics in Naturally Fractured Reservoirs Near Salt Structures by : Juan Pedro Morales Salazar
Download or read book Drilling Geomechanics in Naturally Fractured Reservoirs Near Salt Structures written by Juan Pedro Morales Salazar and published by Springer Nature. This book was released on with total page 169 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Fractured Vuggy Carbonate Reservoir Simulation by : Jun Yao
Download or read book Fractured Vuggy Carbonate Reservoir Simulation written by Jun Yao and published by Springer. This book was released on 2017-08-08 with total page 253 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Book Synopsis Hierarchical Modeling of Fractures for Naturally Fractured Reservoirs by : Ankesh Anupam
Download or read book Hierarchical Modeling of Fractures for Naturally Fractured Reservoirs written by Ankesh Anupam and published by . This book was released on 2010 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt: Discrete Fracture Networks (DFN) models have long been used to represent heterogeneity associated with fracture networks but all previous approaches have been either in 2D (assuming vertical fractures) or for simple models within a small domain. Realistic representation of DFN on field scale models have been impossible due to two reasons - first because the representation of extremely large number of fractures requires significant computational capability and second, because of the inability to represent fractures on a simulation grid, due to extreme aspect ratio between fracture length and aperture. This thesis presents a hierarchal approach for fracture modeling and a novel random walker simulation to upscale the fracture permeability. The modeling approach entails developing effective flow characteristics of discrete fractures at micro and macrofracture scales without explicitly representing the fractures on a grid. Separate models were made for micro scale and macro scale fracture distribution with inputs from the seismic data and field observations. A random walker simulation is used that moves walkers along implicit fractures honoring the intersection characteristics of the fracture network. The random walker simulation results are then calibrated against high-resolution flow simulation for some simple fracture representations. The calibration enables us to get an equivalent permeability for a complex fracture network knowing the statistics of the random walkers. These permeabilities are then used as base matrix permeabilities for random walker simulation of flow characteristics of the macro fractures. These are again validated with the simulator to get equivalent upscaled permeability. Several superimposed realizations of micro and macrofracture networks enable us to capture the uncertainty in the network and corresponding uncertainty in permeability field. The advantage of this methodology is that the upscaling process is extremely fast and works on the actual fractures with realistic apertures and yields both the effective permeability of the network as well as the matrix-fracture transfer characteristics.
