Download or read book Simulation of Enhanced Oil Recovery in Naturally Fractured Reservoirs Using Dual porosity Models written by Ali Mohammed Hmood Al-Rudaini and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Simulation of Naturally Fractured Reservoirs Using Empirical Transfer Function written by Prasanna Kumar Tellapaneni and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This research utilizes the imbibition experiments and X-ray tomography results for modeling fluid flow in naturally fractured reservoirs. Conventional dual porosity simulation requires large number of runs to quantify transfer function parameters for history matching purposes. In this study empirical transfer functions (ETF) are derived from imbibition experiments and this allows reduction in the uncertainness in modeling of transfer of fluids from the matrix to the fracture. The application of the ETF approach is applied in two phases. In the first phase, imbibition experiments are numerically solved using the diffusivity equation with different boundary conditions. Usually only the oil recovery in imbibition experiments is matched. But with the advent of X-ray CT, the spatial variation of the saturation can also be computed. The matching of this variation can lead to accurate reservoir characterization. In the second phase, the imbibition derived empirical transfer functions are used in developing a dual porosity reservoir simulator. The results from this study are compared with published results. The study reveals the impact of uncertainty in the transfer function parameters on the flow performance and reduces the computations to obtain transfer function required for dual porosity simulation.

Download or read book Oil Recovery from Naturally Fractured Reservoirs by Steam Injection Methods Final Report written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Oil recovery by steam injection is a proven, successful technology for nonfractured reservoirs, but has received only limited study for fractured reservoirs. Preliminary studies suggest recovery efficiencies in fractured reservoirs may be increased by as much as 50% with the application of steam relative to that of low temperature processes. The key mechanisms enhancing oil production at high temperature are the differential thermal expansion between oil and the pore volume, and the generation of gases within matrix blocks. Other mechanisms may also contribute to increased production. These mechanisms are relatively independent of oil gravity, making steam injection into naturally fractured reservoirs equally attractive to light and heavy oil deposits. The objectives of this research program are to quantify the amount of oil expelled by these recovery mechanisms and to develop a numerical model for predicting oil recovery in naturally fractured reservoirs during steam injection. The experimental study consists of constructing and operating several apparatuses to isolate each of these mechanisms. The first measures thermal expansion and capillary imbibition rates at relatively low temperature, but for various lithologies and matrix block shapes. The second apparatus measures the same parameters, but at high temperatures and for only one shape. A third experimental apparatus measures the maximum gas saturations that could build up within a matrix block. A fourth apparatus measures thermal conductivity and diffusivity of porous media. The numerical study consists of developing transfer functions for oil expulsion from matrix blocks to fractures at high temperatures and incorporating them, along with the energy equation, into a dual porosity thermal reservoir simulator. This simulator can be utilized to make predictions for steam injection processes in naturally-fractured reservoirs. Analytical models for capillary imbibition have also been developed.

Download or read book Embedded Discrete Fracture Modeling and Application in Reservoir Simulation written by Kamy Sepehrnoori and published by Elsevier. This book was released on 2020-08-27 with total page 306 pages. Available in PDF, EPUB and Kindle. Book excerpt: The development of naturally fractured reservoirs, especially shale gas and tight oil reservoirs, exploded in recent years due to advanced drilling and fracturing techniques. However, complex fracture geometries such as irregular fracture networks and non-planar fractures are often generated, especially in the presence of natural fractures. Accurate modelling of production from reservoirs with such geometries is challenging. Therefore, Embedded Discrete Fracture Modeling and Application in Reservoir Simulation demonstrates how production from reservoirs with complex fracture geometries can be modelled efficiently and effectively. This volume presents a conventional numerical model to handle simple and complex fractures using local grid refinement (LGR) and unstructured gridding. Moreover, it introduces an Embedded Discrete Fracture Model (EDFM) to efficiently deal with complex fractures by dividing the fractures into segments using matrix cell boundaries and creating non-neighboring connections (NNCs). A basic EDFM approach using Cartesian grids and advanced EDFM approach using Corner point and unstructured grids will be covered. Embedded Discrete Fracture Modeling and Application in Reservoir Simulation is an essential reference for anyone interested in performing reservoir simulation of conventional and unconventional fractured reservoirs. Highlights the current state-of-the-art in reservoir simulation of unconventional reservoirs Offers understanding of the impacts of key reservoir properties and complex fractures on well performance Provides case studies to show how to use the EDFM method for different needs

Download or read book Continuous CO2 Injection Design in Naturally Fractured Reservoirs Using Neural Network Based Proxy Models written by Hassan Hamam and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: More than 60% of the original oil in place (OOIP) is left in the ground after the primary and secondary recovery processes. With the introduction of enhanced oil recovery (EOR), that number goes down to about 40% of the OOIP. Carbon dioxide (CO2) injection is one of the most effective EOR methods in naturally fractured reservoirs. The fracture network provides a faster means for fluid flow due to its high conductivity but it is also the cause of premature breakthrough of the injected fluids. However, if employed efficiently, fractures can help push the injected CO2 to the reservoir boundaries so that a large portion of the reservoir fluid interacts with the injected CO2. Zones swept by miscible CO2 reported the lowest residual oil saturation.Continuous CO2 injection is becoming more and more preferred to the popular cyclic pressure pulsing. Continuous CO2 injection has no down time and could potentially provide better CO2 interaction with the reservoir fluid which provides a higher recovery. In this research, artificial neural networks (ANNs) are used to construct robust proxy models with highly predictive capabilities for naturally fractured reservoirs undergoing continuous CO2 injection. The main purpose of this research is to shed more light and understanding on continuous CO2 injection in naturally fractured reservoirs and provide a tool that empowers engineers to make decisions on the fly while evaluating uncertainty and mitigating risk rather than wait months or years to do so. In light of the above, various ANN designs and configurations undergo development and evolution to ultimately be able to provide valuable insights regarding reservoir performance, history matching, and injection design for naturally fractured reservoirs undergoing CO2 injection. Initial ANN designs targeted specific reservoirs using specific fluid compositions from the literature. The designed ANNs were able to provide predictions with a low degree of error. ANN designs went over many complex adjustments, variations, and enhancements until final configurations were reached. The final ANN designs developed in this research surpass previously developed ANNs in similar projects with its capability to handle a huge range of reservoir properties, relative permeability, capillary pressure, and fluid compositions under uncertainty.The reservoir simulation model used in this research is a two-well, two-layer, miscible compositional simulation model working in a dual-porosity system. Critical parameters affected the accuracy and predictability of the ANN designs and they were an essential part of the final ANN configurations. The parameters that a major effect on continuous CO2 injection are reservoir fluid composition, fracture permeability, well spacing, bottomhole flowing pressure (BHFP), thickness, and CO2 injection amount under miscible conditions had the highest impact on recovered oil.The final ANN designs were encompassed inside a graphical user interface that equipped the ANN with uncertainty evaluation capabilities. The ease to use nature of the GUI allows anyone to use the developed ANNs in this research, as well as provide a simple intuitive interface to manipulate input data, run simultaneous sensitivity and uncertainty analysis. The developed ANNs in this research bring us a step closer to achieving real-time simulation for naturally fractured reservoirs undergoing CO2 injection. The correlations embedded in the ANNs were able to overcome reservoir fluid, relative permeability, and capillary pressure limitations that existed in the previous ANN studies.

Download or read book Lectures written by and published by . This book was released on 1990 with total page 456 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Naturally Fractured Reservoirs written by Roberto Aguilera and published by Pennwell Corporation. This book was released on 1995 with total page 521 pages. Available in PDF, EPUB and Kindle. Book excerpt: This publication deals exclusively with naturally fractured reservoirs, and includes many subjects usually treated in separate volumes. It is written for students, reservoir geologists, log analysts and petroleum engineers.

Download or read book Improved Upscaling and Reservoir Simulation of Enhanced Oil Recovery Processes in Naturally Fractured Reservoirs written by Mohamed Ahmed Elfeel and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fundamentals of Fractured Reservoir Engineering written by T.D. van Golf-Racht and published by Elsevier. This book was released on 1982-04-01 with total page 729 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the modem language of reservoir engineering by reservoir description is understood the totality of basic local information concerning the reservoir rock and fluids which by various procedures are extrapolated over the entire reservoir. Fracture detection, evaluation and processing is another essential step in the process of fractured reservoir description. In chapter 2, all parameters related to fracture density and fracture intensity, together with various procedures of data processing are discussed in detail. After a number of field examples, developed in Chap. 3, the main objective remains the quantitative evaluation of physical properties. This is done in Chap. 4, where the evaluation of fractures porosity and permeability, their correlation and the equivalent ideal geometrical models versus those parameters are discussed in great detail. Special rock properties such as capillary pressure and relative permeability are reexamined in the light of a double-porosity reservoir rock. In order to complete the results obtained by direct measurements on rock samples, Chap. 5 examines fracturing through indirect measurements from various logging results. The entire material contained in these five chapters defines the basic physical parameters and indicates procedures for their evaluation which may be used further in the description of fractured reservoirs.

Download or read book Improved Simulation of Naturally Fractured Reservoirs Using Unstructured Grids and Multi rate Dual porosity Models written by Christine Maier and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Simulation Studies to Evaluate the Effect of Fracture Closure on the Performance of Naturally Fractured Reservoirs Annual Report written by and published by . This book was released on 1992 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt: The second year of this three-year research program to evaluate the effect of fracture closure on the recovery of oil and gas from naturally fractured reservoirs has been completed. The overall objectives of the study are to: (1) evaluate the reservoir conditions where fracture closure is significant, and (2) evaluate innovative fluid injection techniques capable of maintaining pressure within the reservoir. Simulation studies have been conducted with a dual porosity simulator capable of simulating the performance of vertical and horizontal wells. Each simulation model has been initialized with properties typical of the Austin Chalk reservoir in Pearsall Field, Texas. During year one, simulations of both vertical and horizontal well performance were made assuming that fracture permeability was insensitive to pressure charge. The results confirmed that horizontal wells could increase both rate of oil recovery and total oil recovery from naturally fractured reservoirs. During the second year the performances of the same vertical and horizontal wells were evaluated with the assumption that fracture permeability was a function of reservoir pressure. This required repetition of most of the natural depletion cases simulated in year one while invoking the pressure-sensitive fracture permeability option. To investigate sensitivity to in situ stress, two stress conditions were simulated for each primary variable. The water injection cases, begun in year one, were extended to include most of the reservoir parameters investigated for natural depletion, including fracture permeability as a function of net stress and the use of horizontal wells. The results thus far confirm that pressure-sensitive fractures degrade well performance and that the degradation is reduced by water injection pressure maintenance. Furthermore, oil recovery can be significantly increased by water injection pressure maintenance.

Download or read book Streamline based Simulation of Water Injection in Naturally Fractured Reservoirs written by Ahmed Al Huthali and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The current streamline formulation is limited to single-porosity systems and is then not suitable for application to naturally fractured reservoirs. Describing the fluid transport in naturally fractured reservoirs has been recognized as a main challenge for simulation engineers due to the complicated physics involved. In this work, we generalized the streamline-based simulation to describe the fluid transport in naturally fractured reservoirs. We implemented three types of transfer function: the conventional transfer function (CTF), the diffusion transfer function (DTF), and the empirical transfer function (ETF). We showed that these transfer functions can be implemented easily in the current single-porosity streamline codes. These transfer functions have been added as a source term to the transport equation that describes the saturation evolution along the streamlines. We solved this equation numerically for all types of transfer functions. The numerical solution of the continuity equation with DTF and ETF requires discretizing a convolution term. We derived an analytical solution to the saturation equation with ETF in terms of streamline TOF to validate the numerical solution. We obtain an excellent match between the numerical and the analytical solution. The final stage of our study was to validate our work by comparing our dual-porosity streamline simulator (DPSS) to the commercial dual-porosity simulator, ECLIPSE. The dual-porosity ECLIPSE uses the CTF to describe the interaction between the matrix-blocks and the fracture system. The dual-porosity streamline simulator with CTF showed an excellent match with the dual-porosity ECLIPSE. On the other hand, dual-porosity streamline simulation with DTF and ETF showed a lower recovery than the recovery obtained from the dual-porosity ECLIPSE and the DPSS with CTF. This difference in oil recovery is not due to our formulation, but is related to the theoretical basis on which CTF, DTF, and ETF were derived in the literature. It was beyond the scope of this study to investigate the relative accuracy of each transfer function. We demonstrate that the DPSS is computationally efficient and ideal for large-scale field application. Also, we showed that the DPSS minimizes numerical smearing and grid orientation effects compared to the dual-porosity ECLIPSE.

Download or read book Shale Gas and Tight Oil Reservoir Simulation written by Wei Yu and published by Gulf Professional Publishing. This book was released on 2018-08-10 with total page 430 pages. Available in PDF, EPUB and Kindle. Book excerpt: Shale Gas and Tight Oil Reservoir Simulation delivers the latest research and applications used to better manage and interpret simulating production from shale gas and tight oil reservoirs. Starting with basic fundamentals, the book then includes real field data that will not only generate reliable reserve estimation, but also predict the effective range of reservoir and fracture properties through multiple history matching solutions. Also included are new insights into the numerical modelling of CO2 injection for enhanced oil recovery in tight oil reservoirs. This information is critical for a better understanding of the impacts of key reservoir properties and complex fractures. Models the well performance of shale gas and tight oil reservoirs with complex fracture geometries Teaches how to perform sensitivity studies, history matching, production forecasts, and economic optimization for shale-gas and tight-oil reservoirs Helps readers investigate data mining techniques, including the introduction of nonparametric smoothing models

Download or read book Compositional Modelling of Imbibition Oil Recovery Processes in Naturally fractured Reservoirs written by Shamsuddin H. Shenawi and published by . This book was released on 1994 with total page 334 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Projects Investigating Oil Recovery from Naturally Fractured Reservoirs written by United States. National Petroleum Technology Office and published by . This book was released on 1999 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Development of an Implicit Full tensor Dual Porosity Compositional Reservoir Simulator written by Farhad Tarahhom and published by . This book was released on 2008 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: A large percentage of oil and gas reservoirs in the most productive regions such as the Middle East, South America, and Southeast Asia are naturally fractured reservoirs (NFR). The major difference between conventional reservoirs and naturally fractured reservoirs is the discontinuity in media in fractured reservoir due to tectonic activities. These discontinuities cause remarkable difficulties in describing the petrophysical structures and the flow of fluids in the fractured reservoirs. Predicting fluid flow behavior in naturally fractured reservoirs is a challenging area in petroleum engineering. Two classes of models used to describe flow and transport phenomena in fracture reservoirs are discrete and continuum (i.e. dual porosity) models. The discrete model is appealing from a modeling point of view, but the huge computational demand and burden of porting the fractures into the computational grid are its shortcomings. The affect of natural fractures on the permeability anisotropy can be determined by considering distribution and orientation of fractures. Representative fracture permeability, which is a crucial step in the reservoir simulation study, must be calculated based on fracture characteristics. The diagonal representation of permeability, which is customarily used in a dual porosity model, is valid only for the cases where fractures are parallel to one of the principal axes. This assumption cannot adequately describe flow characteristics where there is variation in fracture spacing, length, and orientation. To overcome this shortcoming, the principle of the full permeability tensor in the discrete fracture network can be incorporated into the dual porosity model. Hence, the dual porosity model can retain the real fracture system characteristics. This study was designed to develop a novel approach to integrate dual porosity model and full permeability tensor representation in fractures. A fully implicit, parallel, compositional chemical dual porosity simulator for modeling naturally fractured reservoirs has been developed. The model is capable of simulating large-scale chemical flooding processes. Accurate representation of the fluid exchange between the matrix and fracture and precise representation of the fracture system as an equivalent porous media are the key parameters in utilizing of dual porosity models. The matrix blocks are discretized into both rectangular rings and vertical layers to offer a better resolution of transient flow. The developed model was successfully verified against a chemical flooding simulator called UTCHEM. Results show excellent agreements for a variety of flooding processes. The developed dual porosity model has further been improved by implementing a full permeability tensor representation of fractures. The full permeability feature in the fracture system of a dual porosity model adequately captures the system directionality and heterogeneity. At the same time, the powerful dual porosity concept is inherited. The implementation has been verified by studying water and chemical flooding in cylindrical and spherical reservoirs. It has also been verified against ECLIPSE and FracMan commercial simulators. This study leads to a conclusion that the full permeability tensor representation is essential to accurately simulate fluid flow in heterogeneous and anisotropic fracture systems.

Download or read book Implementation of Full Permeability Tensor Representation in a Dual Porosity Reservoir Simulator written by Bowei Li and published by . This book was released on 2001 with total page 306 pages. Available in PDF, EPUB and Kindle. Book excerpt: Transport and flow phenomena in porous media and fractured rock arise in many fields of science and engineering, including petroleum and groundwater engineering. Over the past few decades, there are two classes of models that have been developed for describing flow and transport phenomena in porous media and fractured rock. They are the continuum and discrete models. Continuum models include single porosity and dual porosity models. The latter is popularly applied in simulating flow in naturally fractured systems. Discrete feature models explicitly recognize the fracture system's geometrical properties, such as orientation and intensity. But shortcomings have been experienced for such discrete models in that large computational efforts are required for a realistic treatment of a heavily fractured system. Such a large fractured system may contain millions of fracture features. The huge demand of computational resources may seriously undermine the application of discrete models for such systems. Moreover, the discrete feature model is more difficult to use for multiphase flow and complex recovery mechanisms for oil recovery process. The dual porosity model, a subclass of the continuum model, is a favorable approach to study flow in naturally fractured systems. In the dual porosity approach, it is assumed that the fissured porous media can be represented by two colocated continua called the matrix and the fracture system. High conductivity but low storativity typically characterizes the fracture system, whereas the matrix is usually characterized as low conductivity but high storativity. The matrix generally acts as a source that transfers its mass to the surrounding fractures; then fluid is transported to production wells. There are two main reasons for the acceptance of dual porosity model. The first reason is its ability to handle the length scale inconsistency between matrix and fractures. It is impractical to simulate a fractured system by a single porosity approach if a matrix block is gridded to the fracture's length scale. But the dual porosity approach may divide the physical problem into two interactive problems. Therefore the dual porosity model captures the length scales of the physical problem, and is much easier to handle computationally. The second advantage of the dual porosity model is its capacity to address complex local phenomena at the matrix boundary surrounded by fractures. Conventional dual porosity models generally use a diagonal permeability tensor to formulate and discretize the flow equations for the fracture system. However, such practice does not always adequately reflect the characteristics of natural fractures characterized by heterogeneity and anisotropy ascribed to the fracture's varied orientation, apertures, and intensity. Therefore, conventional dual porosity models may overlook the naturally fractured system's directionality and heterogeneity. This study is designed to develop a novel approach to model fluid flow in natural fractured systems with a dual porosity approach. In the study, a full permeability tensor representation of fracture flow is implemented in the UTCHEM dual porosity chemical flood simulator. The full permeability tensor feature in the fracture system adequately captures the system's characteristics, i.e., directionality and heterogeneity. At the same time, the powerful dual porosity concept is inherited. The capability of modeling the local complex physical phenomena is maintained in the simulator. The implementation has been verified through studying waterflooding in a cylindrical reservoir, and waterflooding in a spherical reservoir. As an application of the implementation, a study on a naturally fractured system was conducted. Simulation results were compared with that generated by the Fracman simulator (Golder Associates, 2000) a discrete feature model. Another application is waterflooding through a fractured system using dual porosity approach. A conclusion can be drawn from all these studies that for a heterogeneous and anisotropic system, full permeability tensor representation of flow is necessary to accurately simulate flow in such system.