Download or read book CT measurements of two phase flow in fractured porous media written by Richard Gary Hughes and published by . This book was released on 1995 with total page 114 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book CT Measurements of Two phase Flow in Fractured Porous Media written by and published by . This book was released on 1997 with total page 67 pages. Available in PDF, EPUB and Kindle. Book excerpt: The simulation of flow in naturally fractured reservoirs commonly divides the reservoir into two continua - the matrix system and the fracture system. Flow equations are written presuming that the primary flow between grid blocks occurs through the fracture system and that the primary fluid storage is in the matrix system. The dual porosity formulation of the equations assumes that there is no flow between matrix blocks while the dual permeability formulation allows fluid movement between matrix blocks. Since most of the fluid storage is contained in the matrix, recovery is dominated by the transfer of fluid from the matrix to the high conductivity fractures. The physical mechanisms influencing this transfer have been evaluated primarily through numerical studies. Relatively few experimental studies have investigated the transfer mechanisms. Early studies focused on the prediction of reservoir recoveries from the results of scaled experiments on single reservoir blocks. Recent experiments have investigated some of the mechanisms that are dominant in gravity drainage situations and in small block imbibition displacements. The mechanisms active in multiphase flow in fractured media need to be further illuminated, since some of the experimental results appear to be contradictory. This report describes the design, construction, and preliminary results of an experiment that studies imbibition displacement in two fracture blocks. Multiphase (oil/water) displacements will be conducted at the same rate on three core configurations. The configurations are a compact core, a two-block system with a 1 mm spacer between the blocks, and a two-block system with no spacer. The blocks are sealed in epoxy so that saturation measurements can be made throughout the displacement experiments using a Computed Tomography (CT) scanner.

Download or read book CT Measurements of Two phase Flow in Fractured Porous Media written by Richard G. Hughes and published by . This book was released on 1997 with total page 57 pages. Available in PDF, EPUB and Kindle. Book excerpt: The simulation of flow in naturally fractured reservoirs commonly divides the reservoir into two continua - the matrix system and the fracture system. Flow equations are written presuming that the primary flow between grid blocks occurs through the fracture system and that the primary fluid storage is in the matrix system. The dual porosity formulation of the equations assumes that there is no flow between matrix blocks while the dual permeability formulation allows fluid movement between matrix blocks. Since most of the fluid storage is contained in the matrix, recovery is dominated by the transfer of fluid from the matrix to the high conductivity fractures. The physical mechanisms influencing this transfer have been evaluated primarily through numerical studies. Relatively few experimental studies have investigated the transfer mechanisms. Early studies focused on the prediction of reservoir recoveries from the results of scaled experiments on single reservoir blocks. Recent experiments have investigated some of the mechanisms that are dominant in gravity drainage situations and in small block imbibition displacements. The mechanisms active in multiphase flow in fractured media need to be further illuminated, since some of the experimental results appear to be contradictory. This report describes the design, construction, and preliminary results of an experiment that studies imbibition displacement in two fracture blocks. Multiphase (oil/water) displacements will be conducted at the same rate on three core configurations. The configurations are a compact core, a two-block system with a 1 mm spacer between the blocks, and a two-block system with no spacer. The blocks are sealed in epoxy so that saturation measurements can be made throughout the displacement experiments using a Computed Tomography (CT) scanner.

Download or read book Design and Construction of an Experiment for Two phase Flow in Fractured Porou i e Porous Media written by Rafael E. G. Ayala and published by . This book was released on 1993 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book CT Imaging of Two Phase Flow in Fractured Porous Media written by and published by . This book was released on 1996 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper describes the design, construction, and preliminary results of an experiment that studies imbibition displacement in two fracture blocks. Three core configurations were constructed. The configurations are a compact core, a two-block system with a 1 mm spacer between the blocks, and a two-block system with no spacer. The blocks are sealed in epoxy so that saturation measurements can be made throughout the displacement experiments using a Computed Tomography (CT) scanner. Preliminary results are presented from a water/air experiment. These results suggest that it is incorrect to assume negligible capillary continuity between matrix blocks as is often done.

Download or read book Design and Construction of an Experiment for Two phase Flow in Fractured Porous Media written by and published by . This book was released on 1993 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt: In numerical reservoir simulation naturally fractured reservoirs are commonly divided into matrix and fracture systems. The high permeability fractures are usually entirely responsible for flow between blocks and flow to the wells. The flow in these fractures is modeled using Darcy's law and its extension to multiphase flow by means of relative permeabilities. The influence and measurement of fracture relative permeability for two-phase flow in fractured porous media have not been studied extensively, and the few works presented in the literature are contradictory. Experimental and numerical work on two-phase flow in fractured porous media has been initiated. An apparatus for monitoring this type of flow was designed and constructed. It consists of an artificially fractured core inside an epoxy core holder, detailed pressure and effluent monitoring, saturation measurements by means of a CT-scanner and a computerized data acquisition system. The complete apparatus was assembled and tested at conditions similar to the conditions expected for the two-phase flow experiments. Fine grid simulations of the experimental setup-were performed in order to establish experimental conditions and to study the effects of several key variables. These variables include fracture relative permeability and fracture capillary pressure. The numerical computations show that the flow is dominated by capillary imbibition, and that fracture relative permeabilities have only a minor influence. High oil recoveries without water production are achieved due to effective water imbibition from the fracture to the matrix. When imbibition is absent, fracture relative permeabilities affect the flow behavior at early production times.

Download or read book Computational Methods for Multiphase Flows in Porous Media written by Zhangxin Chen and published by SIAM. This book was released on 2006-04-01 with total page 551 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book offers a fundamental and practical introduction to the use of computational methods. A thorough discussion of practical aspects of the subject is presented in a consistent manner, and the level of treatment is rigorous without being unnecessarily abstract. Each chapter ends with bibliographic information and exercises.

Download or read book Three phase Flow in Fractured Porous Media written by Mohammad J. Sabti and published by . This book was released on 2018 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this work, we used a high-resolution micro-CT scanner integrated with a three-phase core-flooding apparatus to perform two- and three-phase flow experiments on fractured sandstone and carbonate rock samples. The study aimed at investigating how the fluids in the matrix interact with those in the fracture conduit when oil spreadability plays a key role. In-situ fluid distribution maps are compared under spreading and nonspreading conditions during secondary and tertiary gas injection processes. In the case of spreading fluid system and secondary gas injection process, the oil phase in the matrix is not trapped. The injected gas invades large oil-filled pores in the matrix and displaces oil into the fracture while leaving relatively thick spreading layers of the defending fluid in the crevices. These layers play a pivotal role in maintaining the hydraulic connectivity of oil and ultimately lower remaining oil saturation significantly. In case where the initial oil saturation in the matrix is hydraulically trapped due to a preceding waterflood, gas first displaces brine before accessing oil. When gas reaches trapped oil globules, the oil spreads between brine in the corners and gas in the center of the elements and becomes reconnected. In both scenarios, the oil phase maintains its hydraulic conductivity through spreading layers and drains into the fracture. This phenomenon has a significant impact on oil production from matrix in fractured oil reservoirs. However, infrequent oil layers observed under nonspreading condition are not stable and collapse easily as gas/oil capillary pressure is increased during gas injection. This means that oil has poor connectivity that hinders its movement from the matrix to the fracture. In another group of experiments, the effect of wettability on matrix-fracture interactions is investigated by performing tertiary gas injection on an oil-wet fractured limestone sample. The distribution of the measured in-situ contact angles indicated that the wettability alteration in the matrix surrounding the fracture was relatively less uniform and lower than that in the intact matrix. This was attributed to the presence of fracture, which reduced the invasion of crude oil into the neighboring matrix during drainage. The insight developed in this work using different rock types, wettability conditions, and three-phase saturation histories may have direct implications for the design of EOR schemes involving gas injection.

Download or read book Two phase Flow in Porous Media and Fractures written by Dustin Crandall and published by . This book was released on 2007 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Handbook of Porous Media written by Kambiz Vafai and published by CRC Press. This book was released on 2015-06-23 with total page 946 pages. Available in PDF, EPUB and Kindle. Book excerpt: Handbook of Porous Media, Third Edition offers a comprehensive overview of the latest theories on flow, transport, and heat-exchange processes in porous media. It also details sophisticated porous media models which can be used to improve the accuracy of modeling in a variety of practical applications. Featuring contributions from leading experts i

Download or read book Fluid Flow in Fractured Porous Media written by Yujing Jiang and published by MDPI. This book was released on 2019-09-30 with total page 492 pages. Available in PDF, EPUB and Kindle. Book excerpt: The fluid flow in fracture porous media plays a significant role in the assessment of deep underground reservoirs, such as through CO2 sequestration, enhanced oil recovery, and geothermal energy development. Many methods have been employed—from laboratory experimentation to theoretical analysis and numerical simulations—and allowed for many useful conclusions. This Special Issue aims to report on the current advances related to this topic. This collection of 58 papers represents a wide variety of topics, including on granite permeability investigation, grouting, coal mining, roadway, and concrete, to name but a few. We sincerely hope that the papers published in this Special Issue will be an invaluable resource for our readers.

Download or read book Workshop Report written by and published by . This book was released on 1997 with total page 552 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Rock Mechanics Meeting Society s Challenges and Demands Two Volume Set written by Erik Eberhardt and published by CRC Press. This book was released on 2007-05-17 with total page 1772 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ore extraction through surface and underground mining continues to involve deeper excavations in more complex rock mass conditions. Communities and infrastructure are increasingly exposed to rock slope hazards as they expand further into rugged mountainous terrains. Energy needs are accelerating the development of new hydroelectric dams and exploit

Download or read book Flow and Transport in Porous Media and Fractured Rock written by Muhammad Sahimi and published by John Wiley & Sons. This book was released on 2011-05-09 with total page 635 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this standard reference of the field, theoretical and experimental approaches to flow, hydrodynamic dispersion, and miscible displacements in porous media and fractured rock are considered. Two different approaches are discussed and contrasted with each other. The first approach is based on the classical equations of flow and transport, called 'continuum models'. The second approach is based on modern methods of statistical physics of disordered media; that is, on 'discrete models', which have become increasingly popular over the past 15 years. The book is unique in its scope, since (1) there is currently no book that compares the two approaches, and covers all important aspects of porous media problems; and (2) includes discussion of fractured rocks, which so far has been treated as a separate subject. Portions of the book would be suitable for an advanced undergraduate course. The book will be ideal for graduate courses on the subject, and can be used by chemical, petroleum, civil, environmental engineers, and geologists, as well as physicists, applied physicist and allied scientists that deal with various porous media problems.

Download or read book Multiphase Flow in Fractured Porous Media written by and published by . This book was released on 1995 with total page 466 pages. Available in PDF, EPUB and Kindle. Book excerpt: The major goal of this research project was to improve the understanding of the gas-oil two-phase flow in fractured porous media. In addition, miscible displacement was studied to evaluate its promise for enhanced recovery.

Download or read book Measuring Fracture Aperture and Water Saturation Distributions Using Computed Tomography and Its Application to Modeling Geomechanical Impact on Fluid Flow in Fractures written by Da Huo and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding multiphase fluid flow behavior in fractured porous media is crucial for developing fractured hydrocarbon reservoirs, implementing hydraulic fracturing, and predicting potential leakage in gas and CO2 storage. Since fracture aperture distributions are stress-dependent, the flow behaviors are also stress-dependent. The goal of this research is to investigate stress-dependent fluid flow properties in rock fractures. To carry out this work, fast and accurate methods to measure the stress-dependent fracture aperture and water saturation during the core-flooding experiments are needed. X-ray CT imaging is attractive for measuring fracture apertures and water saturations because it can be combined with dynamic flow experiments. In this dissertation we develop a set of methods for measuring fracture aperture and water saturation distributions and quantify the errors associated with these methods. Furthermore, we investigate the stress-dependency of fluid flow in fractures using the methods. In the first part of this dissertation, we develop a full set of methods for calculating fracture aperture and water saturation distributions using X-ray CT scanning. For fracture aperture measurements, the method relates fracture aperture with missing CT attenuation, scanner voxel size, and CT numbers of the rock matrix. The validity of the model is established by comparing apertures calculated with the conventional calibration-based method, evaluating model predictability at different scanner voxel sizes, comparing with calibration coefficients in the literature from a number of experiments with different rocks and X-ray scanners and comparing aperture measurements for air-filled and water-filled fractures. The results suggest that the method provides reliable aperture measurements. The method also avoids the need for time-consuming calibration and accounts for rock property heterogeneities. The missing CT attenuation concept is then applied to multiphase scans (scans where the fracture is partially filled with water and gas) to develop a method for measuring the water saturation in rock fractures surrounded by porous rocks. We analyze the new method by comparing water saturation measurements with two previously developed methods. The new method includes the missing CT attenuation changes for different matrix porosities and water saturations and thus it is more broadly applicable to a wide range of conditions. Finally, we quantify the systematic and random errors related to the fracture aperture and water saturation measurements. Error analysis shows the method provides an aperture measurement error of 22 microns with 5 repeated scans, which is less than one-twentieth of the voxel size. The analysis demonstrates that averaging of replicate scans highly improves the detection accuracy. Comparisons between aperture measurements made in air and water-filled fractures show that the dry scan is the most recommended method due to its lower errors. Water saturation measurements for individual pixel exhibit a high degree of error (40%). However, the average water saturation in the fracture can be measured with an accuracy of around 10% by averaging 5 repeated scans. The fracture aperture and water saturation measurement methods are particularly valuable for combining dynamic core flooding experiments with simultaneous fracture aperture and water saturation measurements. Using concurrent CT scanning and core flooding, we improve understanding of stress-dependent fluid flow in fractures. The stress-dependent permeability, capillary pressure and relative permeability in rock fractures are separately explored. From the stress-dependent permeability data, changes in permeability are attributed to three factors: changes in mean aperture, changes in roughness, and changes in contact area. We find that stress-dependent permeability and hysteretic behavior is influenced by both aperture and roughness changes. For a small aperture fracture tested here, changes in roughness dominate the permeability response to stress changes. The Modified Cubic Law (Witherspoon et al., 1980), Walsh (1981), Zimmerman et al. (1992) and Sisavath et al. (2003) models are compared with the experimental data and results show that all four models do not result in sufficiently large permeability variation. Additionally none of the previous models quantifies the relative contribution of aperture and roughness to permeability change. A new empirical model is proposed based on the Modified Cubic Law (Witherspoon et al., 1980) that provides a better match to the experimental data and accounts for both stress-dependent aperture and roughness. Using laboratory measurements of fracture aperture distributions under various conditions of effective stress, invasion percolation simulations are employed to model the capillary pressure curves as a function of the effective stress. The stress-dependent aperture distribution data demonstrates that increasing stress has two effects: (1) the mean aperture will decrease; (2) the variance of aperture distribution will increase. The mean aperture decrease will increase entry pressure. As the variance of aperture distribution increases with stress, the plateau area of the capillary pressure curve tends to grow steeper, indicating that capillary behavior changes from more fracture-like to more porous media-like. For the stress-dependency of relative permeability in rock fractures, previous studies provide contradictory evidence of the influence of increasing stress on the relative permeability of fractures. Some studies suggest that irreducible water saturation increases, while others show the reverse. In an attempt to resolve these differences, laboratory core flooding experiments are applied to measure the relative permeability of nitrogen-water mixtures in a fracture under various states of effective stress. Simultaneous X-ray CT measurements are made of aperture and water saturation distributions in the fracture. Two effective stress levels, 2.07 MPa and 5.52 MPa, are applied to investigate the stress-dependency. For both states of stress, the measurements show that the relative permeability to gas is very low until a critical saturation is reached. As gas saturation increases beyond the critical value, relative permeability to gas increases quickly while water becomes essentially immobile. Results also demonstrate that increasing stress lowers the irreducible water saturation and the end-point non-wetting phase relative permeability when the experiments are conducted at the same flow rate. Using invasion percolation theory with the fracture aperture maps made at the two different effective stresses, capillary pressure curves are calculated and used to explain changes in phase interference at different stress levels. Finally, the preferential flow paths are analyzed at both stress levels. We use this analysis to reconcile flow regimes observed in earlier studies, and conclude that the differences between them can be explained by the relative importance of viscous and capillary forces. Specifically, if the experiments are designed to keep the capillary number constant, the irreducible water saturation increases with increasing confining stress. If the experiments are conducted at the same flow rate, higher confining stress decreases the irreducible water saturation, as was observed in these experiments. The analysis and data presented here also suggest that small increases in the water saturation of a fracture may dramatically reduce gas flow rates. This may present an additional and unexplored explanation for rapid production decline of gas wells in fractured reservoirs.

Download or read book Unsaturated Soils Research Applications written by Nasser Khalili and published by CRC Press. This book was released on 2014-06-05 with total page 1850 pages. Available in PDF, EPUB and Kindle. Book excerpt: Unsaturated Soils: Research and Applications contains 247 papers presented at 6th International Conference on Unsaturated Soils (UNSAT2014, Sydney, Australia, 2-4 July 2014). The two volumes provide an overview of recent experimental and theoretical advances in a wide variety of topics related to unsaturated soil mechanics: - Unsaturated Soil Behavior - Experimentation - Modelling - Case Histories - Geotechnical Engineering Problems - Multidisciplinary and New Areas Unsaturated Soils: Research and Applications presents a wealth of information, and is of interest to researchers and practising engineers in soil mechanics and geotechnical engineering. These proceedings are dedicated to Professor Geoffrey E. Blight (1934-2013), who passed in November 2013.