Download or read book The Analysis and Prediction of Well Performance for Hydraulically Fractured Wells Using Reservoir Modelling Techniques written by Gas Research Institute and published by . This book was released on 1990 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since 1983, numerous cooperative research wells and Staged Field Experiments have been conducted in the Travis Peak formation in east Texas by the Gas Research Institute (GRI). Many of the wells analyzed have exhibited slow fracture fluid cleanup. In these cases, several days or weeks of flow were required after the treatment before significant gas flow was measured. For these same wells, post-fracture pressure buildup data were often difficult to analyze with confidence using conventional analysis methods. As such, a research project was undertaken to better understand post-fracture production and pressure transient behavior. The objective of the research project was to investigate fractures that affected fracture fluid injection, fracture fluid inhibition and fracture fluid cleanup in wells that are completed in low permeability gas reservoirs. It was also important to determine which of the factors most affected the analysis of post-fracture pressure transient data and the ultimate gas recovery. Before these items could be studied in detail, however, it was also necessary to learn how to model correctly these effects by taking into account factors such as formation damage, fracture conductivity damage, non-Darcy flow, relative permeability hysteresis and capillary pressure effects. The result of this research showed that fracture conductivity must be high enough to allow proper fracture fluid cleanup prior to running a pressure transient test. If the fracture has not cleaned up sufficiently, the incorrect result will be obtained from conventional pressure transient test methods. Even if most of the fluid has been cleaned up, the results obtained from conventional methods should only be considered first order approximations. The engineer must then take these estimates and use reservoir simulation methods to history match the production and pressure transient data in order to better analyze the formation and fracture properties. The research also demonstrated that producing a well on a small choke after a fracture treament will maximize ultimate gas recovery. If severe crushing of the proppant occurs due to rapid pressure drawdown, then fracture fluid can be trapped in and around the fracture which will tend to suppress gas production and reduce ultimate gas recovery. In summary, the reservoir engineering research has led to the conclusion that multilayered, multiphase reservoir systems such as are normally encountered in low permeability rocks are difficult to evaluate with accuracy unless multiphase, multilayered reservoir models are used to history match all of the available data.

Download or read book Performance Prediction from Hydraulically Fractured Wells in Tight Oil Reservoir written by Harish Yerramsetty and published by . This book was released on 2011 with total page 238 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Novel Integrated and Revolutionary Well Test Interpretation and Analysis written by Freddy Escobar and published by BoD – Books on Demand. This book was released on 2019-01-30 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt: The TDS technique is a practical, easy, and powerful tool for well test interpretation. It uses characteristic features and points found on the pressure derivative versus time plot, so that reservoir parameters can be easily calculated by using several analytic expressions. Most calculations can be verified more than once and applied to systems where the conventional straight-line method has no applications. This book deals with well tests run in elongated systems, partially completed/penetrated wells, multirate tests, hydraulically fractured wells, interference tests, and naturally fractured reservoirs. This technique is used in all commercial well-testing software. Its use is the panacea for well test interpretation and can also be extended to rate-transient analysis, although not shown here.

Download or read book Improved Reservoir Models and Production Forecasting Techniques for Multi Stage Fractured Hydrocarbon Wells written by Ruud Weijermars and published by MDPI. This book was released on 2019-12-12 with total page 238 pages. Available in PDF, EPUB and Kindle. Book excerpt: The massive increase in energy demand and the related rapid development of unconventional reservoirs has opened up exciting new energy supply opportunities along with new, seemingly intractable engineering and research challenges. The energy industry has primarily depended on a heuristic approach—rather than a systematic approach—to optimize and tackle the various challenges when developing new and improving the performance of existing unconventional reservoirs. Industry needs accurate estimations of well production performance and of the cumulative estimated ultimate reserves, accounting for uncertainty. This Special Issue presents 10 original and high-quality research articles related to the modeling of unconventional reservoirs, which showcase advanced methods for fractured reservoir simulation, and improved production forecasting techniques.

Download or read book Hybrid Semi mechanistic Well Performance Modeling and Prediction written by Chigozie C. Aniemena and published by . This book was released on 2014 with total page 287 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Performance of Fractured Horizontal Well in Tight Gas Reservoir written by Jiajing Lin and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Horizontal wells have been used to increase reservoir recovery, especially in unconventional reservoirs, and hydraulic fracturing has been applied to further extend the contact with the reservoir to increase the efficiency of development. In the past, many models, analytical or numerical, were developed to describe the flow behavior in horizontal wells with fractures. Source solution is one of the analytical/semi-analytical approaches. To solve fractured well problems, source methods were advanced from point sources to volumetric source, and pressure change inside fractures was considered in the volumetric source method. This study aims at developing a method that can predict horizontal well performance and the model can also be applied to horizontal wells with multiple fractures in complex natural fracture networks. The method solves the problem by superposing a series of slab sources under transient or pseudosteady-state flow conditions. The principle of the method comprises the calculation of semi-analytical response of a rectilinear reservoir with closed outer boundaries. A statistically assigned fracture network is used in the study to represent natural fractures based on the spacing between fractures and fracture geometry. The multiple dominating hydraulic fractures are then added to the natural fracture system to build the physical model of the problem. Each of the hydraulic fractures is connected to the horizontal wellbore, and the natural fractures are connected to the hydraulic fractures through the network description. Each fracture, natural or hydraulically induced, is treated as a series of slab sources. The analytical solution of superposed slab sources provides the base of the approach, and the overall flow from each fracture and the effect between the fractures are modeled by applying superposition principle to all of the fractures. It is assumed that hydraulic fractures are the main fractures that connect with the wellbore and the natural fractures are branching fractures which only connect with the main fractures. The fluid inside of the branch fractures flows into the main fractures, and the fluid of the main fracture from both the reservoir and the branch fractures flows to the wellbore. Predicting well performance in a complex fracture network system is extremely challenged. The statistical nature of natural fracture networks changes the flow characteristic from that of a single linear fracture. Simply using the single fracture model for individual fracture, and then adding the flow from each fracture for the network could introduce significant error. This study provides a semi-analytical approach to estimate well performance in a complex fracture network system.

Download or read book A New Method for History Matching and Forecasting Shale Gas oil Reservoir Production Performance with Dual and Triple Porosity Models written by Orkhan Samandarli and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Different methods have been proposed for history matching production of shale gas/oil wells which are drilled horizontally and usually hydraulically fractured with multiple stages. These methods are simulation, analytical models, and empirical equations. It has been well known that among the methods listed above, analytical models are more favorable in application to field data for two reasons. First, analytical solutions are faster than simulation, and second, they are more rigorous than empirical equations. Production behavior of horizontally drilled shale gas/oil wells has never been completely matched with the models which are described in this thesis. For shale gas wells, correction due to adsorption is explained with derived equations. The algorithm which is used for history matching and forecasting is explained in detail with a computer program as an implementation of it that is written in Excel's VBA. As an objective of this research, robust method is presented with a computer program which is applied to field data. The method presented in this thesis is applied to analyze the production performance of gas wells from Barnett, Woodford, and Fayetteville shales. It is shown that the method works well to understand reservoir description and predict future performance of shale gas wells. Moreover, synthetic shale oil well also was used to validate application of the method to oil wells. Given the huge unconventional resource potential and increasing energy demand in the world, the method described in this thesis will be the "game changing" technology to understand the reservoir properties and make future predictions in short period of time.

Download or read book Well Test Analysis for Fractured Reservoir Evaluation written by G. Da Prat and published by Elsevier. This book was released on 1990-11-19 with total page 221 pages. Available in PDF, EPUB and Kindle. Book excerpt: The main purpose of this book is to provide the reader with a basic understanding of the behaviour of fractured reservoirs, using evaluation techniques based on processing pressure and flow-rate data resulting from production testing.It covers the fundamental reservoir engineering principles involved in the analysis of fluid flow through fractured reservoirs, the application of existing models to field cases, and the evaluation and description of reservoirs, based on processed data from pressure and production tests. The author also discusses production decline analysis, the understanding of which is a key factor influencing completion or abandonment of a well or even a field.The theoretical concepts are presented as clearly and simply as possible in order to aid comprehension. The book is thus suitable for training and educational purposes, and will help the reader who is unfamiliar with the subject acquire the necessary skills for successful interpretation and analysis of field data.One of the most important features of the book is that it fills the gap between field operations and research, in regard to proper management of reservoirs. The book also contains a computer program (FORTRAN language) which can be incorporated in existing software designed for reservoir evaluation; type curves generation, test design and interpretation, can be achieved by using this program.Petroleum engineers, reservoir engineers, petroleum geologists, research engineers and students in these fields, will be interested in this book as a reference source. It can also be used as a text book for training production and reservoir engineering professionals. It should be available in university and oil company libraries.

Download or read book Using Rate Transient Analysis and Bayesian Algorithms for Reservoir Characterization in Hydraulically Fractured Horizontal Gas Wells During Linear Flow written by Pirayu Yuhun and published by . This book was released on 2019 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt: Multi-stage hydraulically fractured horizontal wells (MFHWs) are currently a popular method of developing shale gas and oil reservoirs. The performance of MFHWs can be analyzed by an approach called Rate transient analysis (RTA). However, the predicted outcomes are often inaccurate and provide non-unique results. Therefore, the main objective of this thesis is to couple Bayesian Algorithms with a current production analysis method, that is, rate transient analysis, to generate probabilistic credible interval ranges for key reservoir and completion variables. To show the legitimacy of the RTA-Bayesian method, synthetic production data from a multistage hydraulically fractured horizontal completion in a reservoir modeled after Marcellus shale reservoir was generated using a reservoir (CMG) model. The synthetic production data was analyzed using a combination of rate transient analysis with Bayesian techniques. Firstly, the traditional log-log plot was produced to identify the linear flow production regime, which is usually the dominant regime in shale reservoirs. Using the linear flow production data and traditional rate transient analysis equations, Bayesian inversion was carried out using likelihood-based and likelihood-free Bayesian methods. The rjags and EasyABC packages in statistical software R were used for the likelihood-based and likelihood-free inversion respectively. Model priors were based (1) on information available about the Marcellus shale from technical literature and (2) hydraulic fracture design parameters. Posterior distributions and prediction intervals were developed for the fracture length, matrix permeability, and skin factor. These predicted credible intervals were then compared with actual synthetic reservoir and hydraulic fracture data. The methodology was also repeated for an actual case in the Barnett shale for a validation. The most substantial finding was that for all the investigated cases, including complicated scenarios (such as finite fracture conductivity, fracturing fluid flowback, heterogeneity of fracture length, and pressure-dependent reservoir), the combined RTA-Bayesian model provided a reasonable prediction interval that encompassed the actual/observed values of the reservoir/hydraulic fracture variables. The R-squared value of predicted values over true values was more than 0.5 in all cases. For the base case in this study, the choice of the prior distribution did not affect the posterior distribution/prediction interval in a significant manner in as much as the prior distribution was partially informative. However, the use of noninformative priors resulted in a loss of precision. Also, a comparison of the Approximate Bayesian Computation (ABC) and the traditional Bayesian algorithms showed that the ABC algorithm reduced computational time with minimal loss of accuracy by at least an order of magnitude by bypassing the complicated step of having to compute the likelihood function. In addition, the production time, number of iterations and tolerance of fitting had a minimal impact on the posterior distribution after an optimum point--which was at least one-year production, 10,000 iterations and 0.001 respectively. In summary, the RTA-Bayesian production analysis method implemented in relatively easy computational platforms, like R and Excel, provided good characterization of all key variables such as matrix permeability, fracture length and skin when compared to results obtained from analytical methods. This probabilistic characterization has the potential to enable better understanding of well performance, improved identification of optimization opportunities and ultimately improved ultimate recovery from shale gas resources.

Download or read book Long term Well Performance Prediction in Unconventionaltight Gas And Shale Gas Reservoirs written by Pichit Vardcharragosad and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Unconventional tight gas and shale gas are the largest and fastest growing natural gas supply in the US. Natural gas produced from tight gas and shale gas reservoirs accounts for 60% of U.S. natural gas production in 2011. This number is expected to increase to 73% in 2040 (EIA, 2013). The lack of understanding and the lack of tools that can be applied to these unconventional plays are the major challenges. In unconventional tight gas and shale gas, the conventional reservoir engineering tools have been proven to be unsuccessful because they fail to capture the large differences in physical properties which heavily impact the production behaviors. The main differences include the ultra-low permeability of the formation, presence of adsorbed phase, and the need for multi-stage hydraulically fractured horizontal well completion to create massive flow area.This study aims to develop new reservoir engineering analysis techniques which fully apply for unconventional tight gas and shale gas reservoirs. The new techniques should be able to capture the reservoir responses that are characterized by the transient flow regime and the multi-mechanistic flow in ultra-low permeability formations, the complex flow pattern from hydraulic fracture completion, and the natural gas desorption. We focus on formulating the fundamental, physics-based governing equation for these tight gas and shale gas reservoirs, as well as the long-term analysis and prediction tools that can capture their physical properties. The research applies new promising tools, a density approach, which was proposed to the industry by our research group. In the density method, gas diffusivity equation will be solved in a density-based form, and effects of reservoir depletion on fluid properties are captured through dimensionless variable, [lambda]-[beta]. The density method has been proven to be a reliable production data analysis tool applicable to conventional gas reservoirs produced under constant flowing pressure, constant flow rate, variable pressure/rate constraint as well as in reservoirs with significant rock compressibility. In this thesis, we prove that density-based technique can be further extended to analyze production data from i) gas linear and fractal flow under boundary dominating condition, ii) gas radial, linear, and fractal flow with significant transient flow period, and iii) gas flow under slippage and desorption effects. We demonstrate that [lambda]-[beta] can effectively quantify effects of depletion on gas properties in reservoirs with linear, radial, and fractal flow. We also show how to incorporate slippage and desorption effects as well as transient flow effect by properly modified definitions of [lambda]-[beta]. Based on these results, we are able to show that the density-based production analysis tools, originally developed for conventional gas reservoirs under boundary dominated radial flow, can be applied to predict and analyze production from unconventional gas reservoirs. In addition, we are able to use these density-based tools to analyze the impact of flow geometries on production decline behavior of gas wells.

Download or read book Prediction of Effects of Hydraulic Fracturing Using Reservoir and Well Flow Simulation written by and published by . This book was released on 1992 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper presents a method to predict and evaluate effects of hydraulic fracturing jobs by using reservoir and well flow numerical simulation. The concept of the method i5 that steam production rate at the operating well head pressure is predicted with different fracture conditions which would be attained by the hydraulic fracturing jobs. Then, the effects of the hydraulic fracturing is evaluated by comparing the predicted steam production rate and that before the hydraulic fracturing. This course of analysis will suggest how large fracture should be created by the fracturing job to attain large enough increase in steam production at the operating condition and the best scheme of the hydraulic fracturing job.

Download or read book Investigation of Analytical Models Incorporating Geomechanical Effects on Production Performance of Hydraulically and Naturally Fractured Unconventional Reservoirs written by Umut Aybar and published by . This book was released on 2014 with total page 354 pages. Available in PDF, EPUB and Kindle. Book excerpt: Production from unconventional reservoirs became popular in the last decade in the U.S. Promising production results and predictions, as well as improvements in hydraulic fracturing and horizontal drilling technology made unconventional reservoirs economically feasible. Therefore, an effective and efficient reservoir model for unconventional resources became a must. In order to model production from such resources, analytical, semi-analytical, and numerical models have been developed, but analytical models are frequently used due to their practicality, relative simplicity, and also due to limited availability of field data. This research project has been accomplished in two main parts. In the first part, two analytical models for unconventional reservoirs, one with infinite hydraulic fracture conductivity assumption proposed by Patzek et al. (2013), while the other one with finite hydraulic fracture conductivity assumption developed by Ozkan et al. (2011) are compared. Additionally, a commercial reservoir simulator (CMG, IMEX, 2012) is employed to compare the results with the analytical models. Sensitivity study is then performed to identify the critical parameters controlling the production performance of unconventional reservoirs. In the second part, naturally and hydraulically fractured unconventional reservoir is considered. In addition, geomechanical effects on natural and hydraulic fractures are examined. A simple analytical dual porosity model, which represents the natural fractures in unconventional reservoirs, is improved to handle the constant bottom-hole pressure production scenario to identify the production performance differences between the cases with and without geomechanical effects. Finally, geomechanical effects are considered for combined natural and hydraulic fractures, and an evaluation of the circumstances in which the geomechanical effects cause a significant production loss is carried out.

Download or read book Well Production Performance Analysis for Shale Gas Reservoirs written by Liehui Zhang and published by Elsevier. This book was released on 2019-05-16 with total page 390 pages. Available in PDF, EPUB and Kindle. Book excerpt: Well Production Performance Analysis for Shale Gas Reservoirs, Volume 66 presents tactics and discussions that are urgently needed by the petroleum community regarding unconventional oil and gas resources development and production. The book breaks down the mechanics of shale gas reservoirs and the use of mathematical models to analyze their performance. - Features an in-depth analysis of shale gas horizontal fractured wells and how they differ from their conventional counterparts - Includes detailed information on the testing of fractured horizontal wells before and after fracturing - Offers in-depth analysis of numerical simulation and the importance of this tool for the development of shale gas reservoirs

Download or read book Hydraulic Fracture Modeling written by Yu-Shu Wu and published by Gulf Professional Publishing. This book was released on 2017-11-30 with total page 568 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hydraulic Fracture Modeling delivers all the pertinent technology and solutions in one product to become the go-to source for petroleum and reservoir engineers. Providing tools and approaches, this multi-contributed reference presents current and upcoming developments for modeling rock fracturing including their limitations and problem-solving applications. Fractures are common in oil and gas reservoir formations, and with the ongoing increase in development of unconventional reservoirs, more petroleum engineers today need to know the latest technology surrounding hydraulic fracturing technology such as fracture rock modeling. There is tremendous research in the area but not all located in one place. Covering two types of modeling technologies, various effective fracturing approaches and model applications for fracturing, the book equips today's petroleum engineer with an all-inclusive product to characterize and optimize today's more complex reservoirs. - Offers understanding of the details surrounding fracturing and fracture modeling technology, including theories and quantitative methods - Provides academic and practical perspective from multiple contributors at the forefront of hydraulic fracturing and rock mechanics - Provides today's petroleum engineer with model validation tools backed by real-world case studies

Download or read book Well Production Performance and Well Test Analysis for Hydraulically Fractured Wells written by Yizhu Liao and published by . This book was released on 1993 with total page 654 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Geologic Analysis of Naturally Fractured Reservoirs written by Ronald Nelson and published by Elsevier. This book was released on 2001-08-24 with total page 353 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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. Nelson emphasizes geological, petrophysical, and rock mechanics to complement other studies of the subject that use well logging and classical engineering approaches. This well organized, updated edition contains a wealth of field and laboratory data, case histories, and practical advice. - A great how-to-guide for anyone working with fractured or highly anisotropic reservoirs - Provides real-life illustrations through case histories and field and laboratory data

Download or read book Multiscale Reservoir Simulation written by Song Du and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In the past decades, considerable effort has been put into developing high resolution geological models for oil and gas reservoirs. Although the growth of computational power is rapid, the static model size still exceeds the model size for routine reservoir simulation. We develop and apply a variety of grid coarsening and refinement algorithms and single and multiphase upscaling approaches, applied to tight gas and conventional reservoir models. The proposed research is organized into three areas. First the upgridding of detailed three dimensional geologic models is studied. We propose an improved layer design algorithm with considerations of accuracy and efficiency. This involves developing measures of reservoir heterogeneity and using these measures to design an optimal grouping of geologic model layers for flow simulation. The optimal design is shown to be a tradeoff between the desire to preserve the reservoir heterogeneity and a desire to minimize the simulation time. The statistical analysis is validated by comparison with flow simulation results. Accurate upgridding/upscaling of single-phase parameters is necessary. However, it does not always satisfy the accuracy requirements, especially for the model which is aggressively coarsened. We introduce a pseudoization method with total mobility and effective fractional flow as the major targets. This pseudoization method helps to push upgridding/coarsening degree to the limit but still be able to reproduce the fine scale field performance. In practice, it is common to not use a different set of pseudos for every coarse cell; only a limited number of pseudo functions should be generated for different "rock types" or geological zones. For similar well patterns and well control conditions, applying pseudo is able to reproduce the fine scale performance for different simulation runs. This is the second proposed research area. Finally, it is necessary to increase flow resolution for precise field history matching and forecasting. This has received increasing attention, especially when studying hydraulically fractured wells in unconventional reservoirs. We propose a multiscale reservoir simulation model combining local grid refinement (LGR) and pillar-based upscaling for tight gas reservoir performance prediction. Pillar-based coarsening away from the wells is designed for tight gas reservoirs. It compensates for the extra computational cost from LGR, which is used to represent hydraulic fractures. Overall reservoir performances, including the accuracy and efficiency, are evaluated. The electronic version of this dissertation is accessible from http://hdl.handle.net/1969.1/148248