Geologic analysis of naturally fractured reservoirs 2nd. For anisotropic reservoirs in general, and fractured reservoirs in particular, several philosophical changes are required to be made. It discusses practical aspects of largescale numerical simulation of naturally fractured reservoirs nfr and highlights some experiences in forecasting performance of nfr. 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. On the other hand, they represent some of the largest, most productive reservoirs on earth. A common scenario is low porosity and low permeability matrix blocks surrounded by a tortuous, highly permeable fracture network. Pdf the behavior of naturally fractured reservoirs. Field examples and case studies demonstrate the importance of integrated geologic and. Recognizing naturally fractured reservoirs petrowiki. Rock properties advanced rock properties naturally fractured reservoirs. Naturally fractured reservoirs have been classified according to the relative contribution of the matrix and fractures to the total fluid production. Natural fractures are important conduits for oil or gas flow to producing wells. Naturally fractured reservoir an overview sciencedirect. Closure of these fractures seriously impairs well productivity.
This fiveday course covers reservoir engineering, well testing, and simulation aspects of naturally fractured reservoirs. An idealized model has been developed for the purpose of studying the characteristic behavior of a permeable medium which contains. For these reservoir characteristics it is difficult to place a reasonable certainty of volumetric estimates of original hydrocarbonsinplace and reserves. If, however, a plot of the deviation from the asymptotic solution behaves in the prescribed manner, it is safe to con clude that the reservoir can be considered to be. Such permeability is affected by the host rocks geological history and not only a function of the matrix or primary permeability but also the natural fracture and. In the past halfcentury, the study of fluid flow and transport processes in fractured porous media has received great attention and has. In the past halfcentury, the study of fluid flow and transport processes in fractured porous media has received great attention and has been one of the most active areas in. Carbonate naturally fractured reservoir is a multiporous system that contain microfractures, fractures, vugs, macrovugs, matrix, type of fractures network. Manual typecurve analysis for well in naturally fractured reservoirs is tedious, and the interpretation involved is difficult. Reserves estimates in naturally fractured reservoirs present a unique challenge to the reservoir engineer. Textbook series natural fractured reservoir engineering. We model a twodimensional fractured reservoir in which the matrix is. In naturally fractured reservoirs, the derivative tends to show several stabilizations at different levels. 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.
Most of these reservoirs have carbonate rock type which is naturally fractured. The challenge of estimating recovery from naturally. The effect of vugs on permeability depends on their connectivity. The more successful developments of naturally fractured reservoirs are often those that have been approached cautiously with a phased development plan. Article recovery factors and reserves in naturally fractured reservoirs. Surfactant enhanced oil recovery from naturally fractured. State of the art part 1 physical mechanisms and simulator formulation the physics, alternative approaches in fractured reservoir simulation, simulation of specific phenomena in fractures, simulation of conductive faults and the different issues of well modeling. Naturally fractured reservoirs petroleum reservoir.
Naturally fractured reservoirs training course petroskills fr. Naturally fractured reservoirs are elusive systems to characterize and difficult to engineer and predict. Type 2 vs type 1 tectonic fractured reservoirs cenozoic asmari fields, zagros dual porosity reservoirs type 2 hydrocarbon storage capacity is given by micro and vuggy matrix porosity systems, whilst deliverability is provided by networks of fissures. This course covers geologic and engineering concepts, methodology, and technology used to characterize, evaluate, and manage naturally fractured reservoirs. Hydraulic fracturing of naturally fractured reservoirs. Naturally fractured reservoirs present unique and specialized challenges to hydrocarbon extraction. 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. 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. Pdf the nature of naturally fractured reservoirs researchgate. Yushu wu, in multiphase fluid flow in porous and fractured reservoirs, 2016. In fractured reservoirs viscous displacement often fails.
Naturally fractured reservoirs aguilera, roberto on. Geologic and engineering aspects of naturally fractured. The focus is on understanding fractures in a reservoir how to determine whether fractures are important to hydrocarbon producibility, and if so. Some of the most prolific fields produce from naturally fractured vuggy reservoirs nfvrs. To describe flow in naturally fractured reservoirs, double pomsity model has been widely used. The uncertainties relating to the size of the physical structure and the fluid content of the reservoir make understanding fluid flow unpredictable. Natural fractures exist practically in all reservoirs, dividing the reservoir rock in pieces, called matrix blocks. Naturally fractured reservoirs 2nd edition free ebook download as pdf file. Fracture network connectivity and aperture or conductivity distribution are two crucial features controlling flow behavior of naturally fractured reservoirs. Schlumberger uses a unique combination of modeling and visualization techniques to simulate fracture properties. This course covers geologic and engineering concepts, methodology, and technology used to characterize, evaluate, and manage naturallyfractured reservoirs.
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. 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. Applications and limitations of geologic and engineering procedures and tools are discussed. Ideally, we should consider different reservoir concepts encapsulated in a large ensemble of reservoir models to quantify the impact of these and other geological uncertainties. Pdf the use of the dualporosity approach for the modeling of naturally fractured reservoirs has become widely accepted in the oil industry. The behavior of naturally fractured reservoirs abstract j. Reliable production forecasting for fractured carbonate reservoirs is a challenge. A number of the selected manuscripts focus on outcrop analogues. Geologic analysis of naturally fractured reservoirs. Pdf naturally fractured reservoirs present a production paradox.
Fluid flow in naturally fractured reservoirs petrowiki. When properly analyzed and integrated with novel approachesthesestudiesoften revealkeyinformationto understand the architecture and geoplumbing of fractured reservoirs in the subsurface. Most naturally fractured reservoirs i am familiar with are char acterized by low matrix porosities less than 10% and low matrix permeabilities less than 1 md. In this paper, however, we focus here on the influence of fracture aperture distribution. Fracture porosity of naturally fractured reservoirs onepetro. 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. Reserve estimates for naturally fractured reservoirs onepetro. Pdf use of fractured reservoir simulators can help reservoir engineers in the understanding of the main physical mechanisms and in the choice of the. In naturallyfractured reservoirs, the derivative tends to show several stabilizations at different levels. Root members aime 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. Petrophysical characterization of carbonate naturally. In other words, a cell is a discretized element of volume including both fracture and matrix blocks. A simulation approach for screening of eor scenarios in.
Naturally fractured reservoir an overview sciencedirect topics. Depending on the selection of the radial flow regime, different well and reservoir models may be possible. Van golfracht t 1982 fundamentals of fractured reservoir engineeringdevelopments in petroleum science, no. Flow diagnostics for naturally fractured reservoirs. This behavior is observed particularly in reservoir where matrix porosity is. Fluids are stored in the matrix, fractures and vugs. They are also notorious for early gas or water breakthrough. These include quantification in reservoir descriptions, interpretive evaluation of production history or history matching, reservoir modeling to understand the scaling of various geological and engineering data. Determination of fracture conductivity and porosity versus closure stress are important for characterizing naturally fractured. Part 2 matrixfracture transfers and typical features of numerical studies fracture cell found at the grid location under consideration. View notes chapter 8 wta naturally fractured reservoirs. Dec 17, 2016 fracture network connectivity and aperture or conductivity distribution are two crucial features controlling flow behavior of naturally fractured reservoirs. Controls on recovery factor in fractured reservoirs. This large pressure drop causes the fracture pore volume, therefore fracture porosity, to increase.
Purchase geologic analysis of naturally fractured reservoirs 2nd edition. 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. The effect of connectivity on flow properties is well documented. Well production heterogeneity is a characteristic of most naturally fractured reservoirs.
Gravity drainage mechanism in naturally fractured carbonate. P lemonnier and b bourbiaux simulation of naturally fractured reservoirs. The applied study of naturally fractured reservoirs seeks to constrain this uncertainty by developing new understanding, and is necessarily a broad, integrated, interdisciplinary topic. Geologic analysis of naturally fractured reservoirs 2nd edition. Because they must be incorporate into the numerical model of simulation the results of the petrophysical characterization, it is conceptualized like a. Spe 84590 presented at the spe technical conference and exhibition held in colorado, 5 to 8 october. 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. Surfactant enhanced oil recovery from naturally fractured reservoirs. Pdf characterization of naturally fractured reservoirs.
The challenge of estimating recovery from naturally fractured. Naturally fractured reservoirs present a production paradox. 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. This chapter presents the critical attributes that must be evaluated to quantify fractured reservoirs in a logical, workable sequence. The behavior of naturally fractured reservoirs onepetro. In this case, the overall flui d flow in the reservoir strongly depends. They include reservoirs with low hydrocarbon recovery. Natural fractures, adverse wettability and complex matrix heterogeneity are all uncertain and can all negatively impact upon recovery. Introduction the development of reservoir modeling and reservoir characterization for naturally fractured reservoirs nfrs has lagged behind simpler matrix flow dominated rock. Pdf article recovery factors and reserves in naturally. 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.
Naturally fractured carbonate reservoirs are geological formations characterized by a heterogeneous distribution of porosity and permeability. This book addresses some of the challenges and advances in knowledge, approaches, concepts, and methods used to characterize the interplay of rock matrix and. It is expected for naturally occurring formations that the transition period of flow from fissures to matrix takes place during the radial flow regime. Bunger csiro earth science and resource engineering ian wark laboratory melbourne, victoria, 3168, australia, rob.
A major premise of the presentation is that there is value in incorporating fractures separate from the matrix. Reservoir characterization for naturally fractured reservoirs. Most of these hydrocarbon volumes have been left behind because of the poor. Naturally fractured reservoirs exist throughout the world and represent significant amounts of oil and gas reserves, water, and other natural resources on earth. 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.
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