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Author: Dong Chen Publisher: ISBN: Category : Coalbed methane Languages : en Pages : 151
Book Description
A reservoir simulation model is usually required to represent the combined effects of gas transport, water flow, and coal swelling/shrinking on the extraction of coalbed methane (CBM). Although a number of models have been developed in recent years, most of them are based on coal permeability models under the assumptions of uniaxial strain and constant overburden load. Under these assumptions, coal permeability is defined as a function of pore pressure only. This allows the gas transport and water flow to be decoupled from coal deformation. In this study, these two assumptions are relaxed: a general porosity and effective permeability model is developed to represent the behavior of both the primary medium (coal matrix) and the secondary medium (fractures) under conditions of variable stress. The effective permeability model is defined as a function of effective stress, and can be applied to the full spectrum of mechanical conditions spanning prescribed in-situ stresses through constrained displacement. Moreover the effect of matrix moisture is often ignored in previous simulation studies, but some experimental results showed that the presence of moisture in the coal matrix had profound influences on the gas storage and transport in coal seams by reducing the gas adsorption capacity of the coal, decreasing the gas effective diffusivity through the coal matrix, and varying the coal swelling strain. In order to investigate the magnitude and interplay the moisture effects on CBM production, approximate relationships have been built to quantify the moisture effect on the gas adsorption capacity, the gas effective diffusivity and the coal swelling strain. These relationships have been calibrated by comparison with a selection of literature data. Both the permeability model and the moisture effect correlations are implemented into a fully coupled model of coal deformation, gas transport in the matrix system, and gas-water flow in the fracture system. The FE model has been verified through the history matching of the gas and water production profiles in the Powder River Basin. The verified FE model is applied to conduct a series of parametric studies. These parametric studies illustrate important non-linear responses due to the effective stress that cannot be recovered where mechanical influences are not rigorously coupled with the two-phase flow system.
Author: Dong Chen Publisher: ISBN: Category : Coalbed methane Languages : en Pages : 151
Book Description
A reservoir simulation model is usually required to represent the combined effects of gas transport, water flow, and coal swelling/shrinking on the extraction of coalbed methane (CBM). Although a number of models have been developed in recent years, most of them are based on coal permeability models under the assumptions of uniaxial strain and constant overburden load. Under these assumptions, coal permeability is defined as a function of pore pressure only. This allows the gas transport and water flow to be decoupled from coal deformation. In this study, these two assumptions are relaxed: a general porosity and effective permeability model is developed to represent the behavior of both the primary medium (coal matrix) and the secondary medium (fractures) under conditions of variable stress. The effective permeability model is defined as a function of effective stress, and can be applied to the full spectrum of mechanical conditions spanning prescribed in-situ stresses through constrained displacement. Moreover the effect of matrix moisture is often ignored in previous simulation studies, but some experimental results showed that the presence of moisture in the coal matrix had profound influences on the gas storage and transport in coal seams by reducing the gas adsorption capacity of the coal, decreasing the gas effective diffusivity through the coal matrix, and varying the coal swelling strain. In order to investigate the magnitude and interplay the moisture effects on CBM production, approximate relationships have been built to quantify the moisture effect on the gas adsorption capacity, the gas effective diffusivity and the coal swelling strain. These relationships have been calibrated by comparison with a selection of literature data. Both the permeability model and the moisture effect correlations are implemented into a fully coupled model of coal deformation, gas transport in the matrix system, and gas-water flow in the fracture system. The FE model has been verified through the history matching of the gas and water production profiles in the Powder River Basin. The verified FE model is applied to conduct a series of parametric studies. These parametric studies illustrate important non-linear responses due to the effective stress that cannot be recovered where mechanical influences are not rigorously coupled with the two-phase flow system.
Author: Yuanping Cheng Publisher: Springer Nature ISBN: 9811638950 Category : Technology & Engineering Languages : en Pages : 535
Book Description
This book focuses on the mechanical properties and permeability of coal, and the gas flow in coal seams. Based on coal permeability models, it establishes different models for coal seam gas, from the linear flow model to the gas–solid coupling flow model. It also provides the theoretical basis for the exploitation and safe production of coal as well as coal seam gas resources. As such, it is a valuable reference for researchers, advanced students and practitioners working in mining engineering and coalbed methane engineering.
Author: Ferdinando Salata Publisher: MDPI ISBN: 3039366823 Category : Technology & Engineering Languages : en Pages : 422
Book Description
The paradigm in the design of all human activity that requires energy for its development must change from the past. We must change the processes of product manufacturing and functional services. This is necessary in order to mitigate the ecological footprint of man on the Earth, which cannot be considered as a resource with infinite capacities. To do this, every single process must be analyzed and modified, with the aim of decarbonising each production sector. This collection of articles has been assembled to provide ideas and new broad-spectrum contributions for these purposes.
Author: Kai Velten Publisher: John Wiley & Sons ISBN: 3527627618 Category : Science Languages : en Pages : 362
Book Description
This concise and clear introduction to the topic requires only basic knowledge of calculus and linear algebra - all other concepts and ideas are developed in the course of the book. Lucidly written so as to appeal to undergraduates and practitioners alike, it enables readers to set up simple mathematical models on their own and to interpret their results and those of others critically. To achieve this, many examples have been chosen from various fields, such as biology, ecology, economics, medicine, agricultural, chemical, electrical, mechanical and process engineering, which are subsequently discussed in detail. Based on the author`s modeling and simulation experience in science and engineering and as a consultant, the book answers such basic questions as: What is a mathematical model? What types of models do exist? Which model is appropriate for a particular problem? What are simulation, parameter estimation, and validation? The book relies exclusively upon open-source software which is available to everybody free of charge. The entire book software - including 3D CFD and structural mechanics simulation software - can be used based on a free CAELinux-Live-DVD that is available in the Internet (works on most machines and operating systems).
Author: David Wood Publisher: Gulf Professional Publishing ISBN: 0323859569 Category : Science Languages : en Pages : 412
Book Description
Sustainable Natural Gas Reservoir and Production Engineering, the latest release in The Fundamentals and Sustainable Advances in Natural Gas Science and Engineering series, delivers many of the scientific fundamentals needed in the natural gas industry, including improving gas recovery, simulation processes for fracturing methods, and methods for optimizing production strategies. Advanced research covered includes machine learning applications, gas fracturing mechanics aimed at reducing environmental impact, and enhanced oil recovery technologies aimed at capturing carbon dioxide. Supported by corporate and academic contributors along with two well-distinguished editors, this book provides today’s natural gas engineers the fundamentals and advances in a convenient resource Helps readers advance from basic equations used in conventional gas reservoirs Presents structured case studies to illustrate how new principles can be applied in practical situations Covers advanced topics, including machine learning applications to optimize predictions, controls and improve knowledge-based applications Helps accelerate emission reductions by teaching gas fracturing mechanics with an aim of reducing environmental impacts and developing enhanced oil recovery technologies that capture carbon dioxide
Author: Publisher: ISBN: Category : Languages : en Pages :
Book Description
Salient features of technical progress for the first quarter are the following: (I) computer-assisted literature searches have been completed for several strategies designed to cover different aspects of the model development and evaluation program. Some strategy refinement and additional searches are required. Ultimately a comprehensive bibliography will have been compiled and evaluated; (II) basic mathematical components that are sufficient for the development of a first numerical model for water and methane flows to coal mines have been identified. This initial set of components is a basis for the collection and analysis of refinements to provide more realistic accounts of the complex factors affecting coal-bed methane during mining and degasification; (III) a set of basic partial differential equations for flow of water and gas in a horizontal, homogeneous coal seam has been formulated in terms of pressure, pore saturation, and adsorbed gas variables and presented in normalized form for numerical solution. Equation sets corresponding to alternative choices of dependent variables will be formulated and compared with this initial set and (IV) computer subroutines have been modified and assembled to implement one-dimensional, nonsteady, two-phase flow models. These programs implement numerical, finite-difference, method-of-lines algorithms in a format that facilitates substitution of mathematical components and equation sets. Initial runs with this software package have illustrated the superiority of a particular space-discretization scheme and provide data for comparison of grid and permeability weighting schemes.
Author: Dong Chen
Author: Dong Chen
Author: Fred N. Kissell
Author: Yuanping Cheng
Author: Zhenhan Yao
Author: Ferdinando Salata
Author: 
Author: Simon Emmert
Author: Kai Velten
Author: David Wood
Author: