Transfers and typical features of numerical studies naturally fractured reservoirs contain a significant amount of the. 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. The geological society of london the geology of fractured. An idealized model has been developed for the purpose of studying the characteristic. A reservoir simulation approach for modeling of naturally. Pressure response in a naturally fractured reservoir showing ideal dual porosity behavior. Seismic characterization of naturally fractured reservoirs using amplitude versus offset and azimuth analysis mehdi e. The behavior of naturally fractured reservoirs onepetro. This conference will explore the many ways in which the geology of fractures is fundamental to the understanding of fluid flow in the subsurface, and hence to predicting and monitoring reservoir performance.
Geologic and engineering aspects of naturally fractured. Discretization and gridding in reservoir simulation 2. In reasonable non fractured reservoirs, it is usually possible to estimate permeability, and hence productivity, but this is not always possible in fractured reservoirs. Reservoir fluid characterisation supplementary scripts used at the montanuniversitat up to the retirement. All petroleum reservoirs contain natural or manmade fractures. Geologic analysis of naturally fractured reservoirs 2nd edition. Recognizing naturally fractured reservoirs petrowiki. Gilman, page 5 of 35 however, fracture flow could be used to ones advantage as in gasinduced gravity drainage of. 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. Wayne narr is a structural geologist with interest in characterization and modeling of naturally fractured reservoirs. This large pressure drop causes the fracture pore volume, therefore fracture porosity, to increase. Well test analysis for naturallyfractured reservoirs stanfords. The 2020 book covers the understanding, evaluation, and effects of fractures on reservoirs.
Van golfracht introduction a carbonate reservoir is defined as being fractured only if a continuous network of various degrees of fracturing is distributed throughout the reservoir. 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. 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. Pdf the nature of naturally fractured reservoirs researchgate. Such fractures formed naturally during the specific geological circumstances of reservoir history. The regional water quality of groundwater s\, reservoirs \, and stream waters surrounding the study area was determin ed with a total of 100 samples in pre and postmonsoon seasons of april t o may and september to october in 2018 by analyzing the major cationanion and radon contents. This course covers geologic and engineering concepts, methodology, and technology used to characterize, evaluate, and manage naturally fractured reservoirs. Fracaflow is the only package available on the market to provide all the necessary tools to assess fractured reservoirs, from secondary porosity assessment to permeability computation. Petrophysical characterization of carbonate naturally fractured reservoirs for use in dual porosity simulators hector pulido1,2, fernando samaniego1, guadalupe galiciamunoz1, jesus rivera r.
Well test analysis for naturally fractured reservoirs. Geologic analysis of naturally fractured reservoirs nelson, ronald on. 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. Pdf reservoir characterization for naturally fractured reservoirs. Fracture studies, natural fractures, john lorenz, fracture. A fractured reservoir is one in which naturally occurring fractures either have or are predicted to have a significant effect on reservoir fluid flow in the form of 1 increased reservoir permeability, 2 increased porosity, andor 3 increased permeability anisotropy. A large proportion of the worlds oil and gas is produced from fractured reservoirs, with new discoveries continuing to be made and put into development. Most of these hydrocarbon volumes have been left behind because of the poor.
It is expected for naturally occurring formations that the transition period of flow from fissures to matrix takes place during the radial flow regime. Naturally fractured reservoirs exist throughout the world and represent significant amounts of oil and gas reserves, water, and other natural resources on earth. In fractured reservoirs viscous displacement often fails. With a few exceptions, the rock matrix is generally responsible for the storage capacity of a reservoir whilst existing layerbound and crosslayer fracture sets.
Castagna1 1university of houston 2schlumberger and 3delta geophysics received march 2012, revision accepted september 2012 abstract. The focus is on understanding fractures in a reservoir how to determine whether fractures are important to hydrocarbon producibility, and if so. It offers a comprehensive, practical discussion and description of natural fractures, their origins, characteristics, and effects on reservoir permeability. Sun spe 84590 data obtained on the 100 fractured reservoirs examined in this study indicate that overall, their ultimate recoveries are somewhat lower than those of many conventional reservoirs, but they still compare favorably with some conventional reservoir types. Drilling and completion strategies in naturally fractured reservoirs, paper spe 59057, presented at the spe international. Pemex, tomatla 25 colonia santo domingo delegacion coyoacan c. Reservoir characterization for naturally fractured reservoirs. 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 capacity. They include reservoirs with low hydrocarbon recovery. Chapter 7 naturally fractured carbonate reservoirs t. A naturally fractured reservoir is comprised of complicated rock structure surrounded by irregular vug and natural fracture systems.
For these reservoir characteristics it is difficult to place a reasonable certainty of volumetric estimates of original hydrocarbonsinplace and reserves. Practical aspects of simulation of fractured reservoirs 08012003 2003, james r. Naturally fractured reservoirs training course petroskills fr. Pdf naturally fractured reservoirs present a production paradox. Evaluation of water coning phenomenon in naturally fractured oil reservoirs reda abdel azim1 received. Textbook series natural fractured reservoir engineering. Seismic characterization of naturally fractured reservoirs.
Pdf introduction to naturally fractured reservoirs researchgate. Crains petrophysical handbook fractured reservoir basics. Naturally fractured reservoirs aguilera, roberto on. Type 1 tectonic fractured reservoir, ain zalah field aqrawi et al. Geologic analysis of naturally fractured reservoirs. Controls on recovery factor in fractured reservoirs. 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. Reservoir characterization and simulation modeling of naturally fractured reservoirs nfrs presents unique challenges that differentiate it from conventional. Natural fractures result from the interaction of earth stresses while manmade fractures result from drilling activities, increase in pore pressure in injection operations, reservoir cooling during water flooding, redistribution of earth stresses in the field as a result of injection and. It allows geologists and reservoir engineers to pragmatically understand the impact of fractures and their associated uncertainties.
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. Purchase geologic analysis of naturally fractured reservoirs 2nd edition. Naturally fractured reservoirs are elusive systems to characterize and difficult to engineer and predict. Fractures and open ings of large size form vugs and interconnected channels, whereas the fine cracks form blocksy5. Naturally fractured reservoirs 2nd edition free ebook download as pdf file.
Naturally fractured reservoirs have been classified according to the relative contribution of the matrix and fractures to the total fluid production. 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. Moe and thomas bogno department of physics, university of bergen, norway abstract visualization of the effects of various wettability conditions on oil recovery in fractured reservoirs is demonstrated in twodimensional insitu imaging experiments in large blocks of. Prediction of naturally fractured reservoir performance using. To simplify this actual reservoir system, warren and root 1963 first presented the idealized system with an orthogonal set of cubic matrix blocks with intersecting fractures as shown in fig. This chapter presents the critical attributes that must be evaluated to quantify fractured reservoirs in a logical, workable sequence. Pdf characterization of naturally fractured reservoirs. Gravity drainage mechanism in naturally fractured carbonate.
Recovery efficiency in fractured reservoirs according to j. Naturally fractured reservoir an overview sciencedirect topics. Evaluation of water coning phenomenon in naturally fractured. The challenge of estimating recovery from naturally.
Fracture frequency is variable, up to 2040 per metre of core. Surfactant enhanced oil recovery from naturally fractured reservoirs. Naturally fractured reservoir characterization digital edition. 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. Characterization of naturally fractured reservoirs article pdf available in spe reprint series spe 69538 march 2001 with 1,495 reads how we measure reads.
This article is published with open access at abstract water coning is a complex phenomenon observed in conventional and unconventional. Pdf this presentation is an introduction to naturally fractured reservoirs for subsurface students and professionals in the hydrocarbon industry. 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. Well production heterogeneity is a characteristic of most naturally fractured reservoirs. Although decline curve analysis is widely used, methods specific to naturally fractured reservoirs do not appear to be. Ehligeconomides ca, taha m, marin hd, novoa e and sanchez o. Petrophysical characterization of carbonate naturally.
Natural fractured reservoir engineering phdg textbooks in preparation, intended to be issued during 2015. Although both the presence of fractures and the presence of a reservoir can be determined from logs, a production test will be needed to determine whether economic production. Surfactant enhanced oil recovery from naturally fractured. The reservoir represents a gasoil system and has four. Fracture porosity of naturally fractured reservoirs onepetro. Purchase fundamentals of fractured reservoir engineering, volume 12 1st edition. Fundamentals of fractured reservoir engineering, volume 12.
Pdf use of fractured reservoir simulators can help reservoir engineers in the understanding of the main physical mechanisms and in the choice of the. 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. Oil recovery in fractured reservoirs arne graue, robert w. Analysis of groundwater drought propagation in temperate climates using a water balance.