He has served as senior technical consultant and manager for marathon oil company in. Gilman, page 4 of 35 with all these issues, there may appear to. Field examples and case studies demonstrate the importance of integrated geologic and. Naturally fractured reservoirs 2nd edition free ebook download as pdf file. Pdf advances in the study of naturally fractured hydrocarbon. Characterization of naturally fractured reservoirs digital.
Recognizing naturally fractured reservoirs petrowiki. This course covers geologic and engineering concepts, methodology, and technology used to characterize, evaluate, and manage naturally fractured reservoirs. There are many logging tools and many methods that can be used for detection and evaluation of naturally fractured reservoirs see aquilera. Naturally fractured reservoirs nfrs are defined as reservoirs where fractures created by geological processes have a significant impact on the migration, storage, and extraction of hydrocarbons table 5. Spe member price usd 45 naturally fractured reservoirs present unique and specialized challenges to hydrocarbon extraction. Aguilera5 classified the naturally fractured reservoirs in types a, b and c. The problem is reduced to solving an integral equation.
Directional permeability has important applications to drawdown andor injection with regard to well placement, and eor. The focus is on understanding fractures in a reservoir how to. Well test analysis for naturally fractured reservoirs. Get pdf abstract an idealized model has been developed for the purpose of studying the characteristic behavior of a permeable medium which contains regions which contribute significantly to the pore volume of the system hut contribute negligibly to the flow capacity. Spe 84590 presented at the spe technical conference and exhibition held in colorado, 5 to 8 october.
Pdf though matrix and secondary porosity permeabilities of a naturally fractured reservoir are. This publication deals exclusively with naturally fractured reservoirs, and includes many subjects usually treated in separate volumes. Naturally fractured reservoirs pdf free download epdf. Calculate porosity partitioning coefficient of a naturally fractured reservoir calculate storage capacity and interporosity flow factor analyze well tests in naturally fractured reservoirs assess reservoir performance of horizontal wells in nfr use mbe to analyze impact of pressure depletion on recovery dr. Naturally fractured reservoirs present a production paradox. The pressure buiidup performance has been examined insomedetait. Castagna1 1university of houston 2schlumberger and 3delta geophysics received march 2012, revision accepted september 2012 abstract. Formation evaluation of naturally fractured reservoirs author roberto aguilera link web page. Geologists, engineers, and petrophysicists concerned with hydrocarbon production from naturally fractured reservoirs will find this book a valuable tool for obtaining pertinent rock data to evaluate reserves and optimize well location and performance. Petrophysical characterization of carbonate naturally. He held the title of senior research consultant for chevron energy technology company where he worked for 27 years on an array of international projects that included reservoir structural geology studies, consulting, technology development, training, and exploration. It is important to establish some basic criteria for recognizing when fractures are an important element in reservoir performance and to recognize the nature and performance characteristics of a naturally fractured reservoir.
Reservoir characterization for naturally fractured reservoirs. For these reservoir characteristics it is difficult to place a reasonable certainty of volumetric estimates of original hydrocarbonsinplace and reserves. The production of fluids from naturally fractured reservoirs has. Numerical results show that d, the ratio of matrix system permeability to. In naturally fractured reservoirs, the derivative tends to show several stabilizations at different levels. Naturally fractured reservoirs nfrs are defined as reservoirs where. Because they must be incorporate into the numerical model of simulation the results of the petrophysical characterization, it is conceptualized like a model of double porosity. The most difficult problem after finding basement rock reservoirs is to evaluate. Carbonate naturally fractured reservoir is a multiporous system that contain microfractures, fractures, vugs, macrovugs, matrix, type of fractures network. Recovery efficiency in fractured reservoirs according to j. Formation evaluation of naturally fractured reservoirs. This behavior is observed particularly in reservoir where matrix porosity is. Geologic and engineering aspects of naturally fractured. A naturally fractured reservoir nfr has two different porosities and permeability.
A reservoir simulation approach for modeling of naturally. Problems related to naturally fractured reservoirs by adel. Well test analysis for fractured reservoir evaluation. The high permeabilities of the fractures effectively short circuits the matrix blocks, making it difficult to establish sufficiently high pressure gradients to allow effective viscous displacement of the oil in the matrix a new important effect comes into play imbibition. They are also notorious for early gas or water breakthrough.
How dual porosity reservoirs are modeled with modern numerical simulators and simulation exercises will. Behaviour of naturally fractured reservoirs re17 stephan k. Fracture porosity of naturally fractured reservoirs onepetro. Purchase well test analysis for fractured reservoir evaluation, volume 27 1st edition. Well production heterogeneity is a characteristic of most naturally fractured reservoirs. It is written for students, reservoir geologists, log analysts and petroleum engineers. Hydraulic fracturing in naturally fractured reservoirs and. The original idealized model assumes that the fracture is the primary conduit for flow, whereas the matrix acts. In fractured reservoirs viscous displacement often fails. The behavior of naturally fractured reservoirs including. Naturally fractured reservoirs training course petroskills fr. Fractures and open ings of large size form vugs and interconnected channels, whereas the fine cracks form blocksy5. Oil recovery in fractured reservoirs arne graue, robert w.
Aguilera, r naturally fractured reservoirs, pennwell. Therefore, naturally fractured reservoirs are termed as dual. The focus is on understanding fractures in a reservoir how to determine whether fractures are important to hydrocarbon producibility, and if so. The solution is straightforward, and involves only ordinary bessel functions. Introduction conventional reservoir engineering techniques and naturally fractured reservoirs do not mix well.
Characterization of naturally fractured reservoirs article pdf available in spe reprint series spe 69538 march 2001 with 1,474 reads how we measure reads. Simulation of naturally fractured reservoirs with simbestii. Jim has also been involved in training, consultation, and project work in reservoir engineering, reservoir simulation, naturally fractured reservoirs, horizontal wells and production uncertainty analysis. Naturally fractured reservoirs constitute a substantial percentage of remaining hydrocarbon resources. Naturally fractured reservoir an overview sciencedirect topics. Textbook series natural fractured reservoir engineering. A new method to estimate reserve in naturally fractured. The purpose of this collection of 15 papers is to introduce the subject of naturally fractured reservoir characterization to engineers interested in gaining a basic overview of the technology and its applications. However, there are no panaceas, and tools and methods that work well in one reservoir can.
Pdf naturally fractured reservoirs, within which porosity, permeability pathways andor impermeable. Pressure response in a naturally fractured reservoir showing ideal dual porosity behavior. Fractured basement reservoir characterization for fracture. Fractured basement reservoirs differ from other types of naturally fractured reservoirs in that they are generally considered to have no primary porosity le van hung et al. The behavior of naturally fractured reservoirs joi%warren p, j, rqot members aime abstract. The same conclusion was reached earlier by odeh 1965 who studied several fractured reservoirs. Naturally fractured reservoirs have been classified according to the relative contribution of the matrix and fractures to the total fluid production. Naturally fractured reservoirs aguilera, roberto on.
So talking about fractured reservoirs in general is not good enough. Naturally fractured reservoirs nfrs have been studied intensively for several decades in the geologic and engineering fields and recently, two new approaches have been proposed to address the problem of transient pressure testing in naturally fractured reservoirs. In naturally fractured reservoirs, the matrix pore volume, therefore the matrix porosity is reduced as a result of large reservoir pressure drop due to oil production. Chapter 1 deals with geologic aspects of naturally fractured reservoirs, reasons for generations of fractures including tectonic, regional, contractio nal and surfacerelated fra ctures, migration and accumulation of petr61eum, direct and indirect sources of information. The porosity of the matrix is the primary porosity, whereas secondary porosity is represented by fractures channels. They include reservoirs with low hydrocarbon recovery. Coauthor of fractured reservoir analysis, an aapg school. Naturally fractured reservoir characterization seeks to confront many of these challenges by providing an introduction to the engineering and geological character of naturally fractured reservoirs. Determining how the fractures originated provides us with important clues for the areal and vertical distribution of fractures as well as a likely reservoir recovery. Natural fractures exist practically in all reservoirs, dividing the reservoir rock in pieces, called matrix blocks.
Recovery the rate of pressure decline per unit of oil produced the absence of transition zones in a fractured reservoir pressure drop around a producing wellbore in a fractured reservoir is very low. Practical aspects of simulation of fractured reservoirs 08012003 2003, james r. Reservoir characterization of fractured reservoirs in. Get pdf abstract an idealized model has been developed for the purpose of studying the characteristic behavior of a permeable medium which contains regions which contribute significantly to the pore volume of the system hut contribute negligibly to the flow. The behavior of naturally fractured reservoirs onepetro. Naturally fractured reservoirs exist throughout the world and represent. The use of the dualporosity approach for the modeling of naturally fractured reservoirs has become widely accepted in the oil industry.
They found that water coning takes place in fractured porous medium with permeability up to 10 darcys in both good and poorly cemented wells. It is written for students, reservoir geologists, log. A good development strategy for such reservoirs requires accurate information on reserve in place. Evaluation of water coning phenomenon in naturally. Because they must be incorporate into the numerical model of simulation the results of the petrophysical characterization, it is conceptualized like a. Fractured reservoirs are not isotropic, and models of fluid movement must account for. However, traditional rate transient analysis, a reserve estimation technique, is not suited for naturally fractured reservoirs. Seismic characterization of naturally fractured reservoirs using amplitude versus offset and azimuth analysis mehdi e. Fractured reservoirs the reservoir gasoil ratio, gor us.
Hydraulic fracturing in tight gas and shale gas reservoirs is an essential stimulation technique for production enhancement. Studies in naturally fractured reservoirs for improved eor scott p. Natural fractures, which are part of the secondary porosity, can be classified as tectonic, regional, and diagenetic aguilera, 1988. Seismic characterization of naturally fractured reservoirs. In naturallyfractured reservoirs, the derivative tends to show several stabilizations at different levels. On the other hand, they represent some of the largest, most productive reservoirs on earth. An alternative analytical solution to the system of equations for fluid flow through a doubleporosity medium with a boundary condition of an equipotential surface is given in this paper.
Depending on the selection of the radial flow regime, different well and reservoir models may be possible. Roberto aguilera, 1995, naturally fractured reservoirs 2nd edition. Abstract due to complexity associated to petrophysical characterization of the porosity in naturally fractured reservoirs, a methodology to discretize it in four main systems was developed. Characterization of naturally fractured reservoirs.
Fractured reservoirs are not isotropic, and models of fluid movement must account for such heterogeneity. Castagna1 1university of houston 2schlumberger and 3delta geophysics received march 2012, revision accepted september 2012. Recovery factors and reserves in naturally fractured reservoirs. Often, hydraulic fracturing induces fracture patterns that are more complex than the planar geometry that has been assumed in the past models. The best known attempts at simple continuum models are the dual porosity approaches for naturally fractured reservoirs aguilera, 1980. Studies in naturally fractured reservoirs for improved eor. The behavior of naturally fractured reservoirs joi%warren p, j, rqot members aime abstract an idealized model has been developed for the purpose of studying the characteristic behavioroja permeable medium which contains regions which contribute sigizificantly to tbe pore volume o. The purpose of this collection of 15 papers is to introduce the subject of naturally fractured reservoir characterization to engineers interested in gaining a basic overview of the technology and its. They often comprise high permeable, low storage volume fractures, and tight, high storage volume matrix blocks. Pdf permeabilities and skins in naturally fractured reservoirs.
This large pressure drop causes the fracture pore volume, therefore fracture porosity, to increase. Most naturally fractured reservoirs i am familiar with are characterized by low matrix porosities less than 10% and low matrix permeabilities less than 1 md. Controls on recovery factor in fractured reservoirs. Applications and limitations of geologic and engineering procedures and tools are discussed. This course covers geologic and engineering concepts, methodology, and technology used to characterize, evaluate, and manage naturallyfractured reservoirs. Pdf characterization of naturally fractured reservoirs. Naturally fractured reservoirs fluid flow in petroleum. Evaluation of water coning phenomenon in naturally fractured. Fracture propagation in naturally fractured reservoirs. The challenge of estimating recovery from naturally fractured. The challenge of estimating recovery from naturally. Naturally fractured reservoirs are elusive systems to characterize and difficult to engineer and predict. Wayne narr is a structural geologist with interest in characterization and modeling of naturally fractured reservoirs. Geologic analysis of naturally fractured reservoirs.
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