Incorporating Rigorous Height Determination Into Unified Fracture Design

Incorporating Rigorous Height Determination Into Unified Fracture Design PDF

Author: Termpan Pitakbunkate

Publisher:

Published: 2010

Total Pages:

ISBN-13:

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Hydraulic fracturing plays an important role in increasing production rate in tight reservoirs. The performance of the reservoir after fracturing can be observed from the productivity index. This parameter is dependent on the fracture geometry; height, length and width. Unified fracture design (UFD) offers a method to determine the fracture dimensions providing the maximum productivity index for a specific proppant amount. Then, in order to achieve the maximum productivity index, the treatment schedules including the amount of liquid and proppant used for each stage must be determined according to the fracture dimensions obtained from the UFD. The proppant number is necessary for determining the fracture geometry using the UFD. This number is used to find the maximum productivity index for a given proppant amount. Then, the dimensionless fracture conductivity index corresponding to the maximum productivity index can be computed. The penetration ration, the fracture length, and the propped fracture width can be computed from the dimensionless fracture conductivity. However, calculating the proppant number used in UFD requires the fracture height as an input. The most convenient way to estimate fracture height to input to the UFD is to assume that the fracture height is restricted by stress contrast between the pay zone and over and under-lying layers. In other words, the fracture height is assumed to be constant, independent of net pressure and equal to the thickness of the layer which has the least minimum principal stress. However, in reality, the fracture may grow out from the target formation and the height of fracture is dependent on the net pressure during the treatment. Therefore, it is necessary to couple determination of the fracture height with determination of the other fracture parameters. In this research, equilibrium height theory is applied to rigorously determine the height of fracture. Solving the problem iteratively, it is possible to incorporate the rigorous fracture height determination into the unified fracture design.

Physical Optimization of Acid Fracturing with Unified Fracture Design

Physical Optimization of Acid Fracturing with Unified Fracture Design PDF

Author: Arjun Ravikumar

Publisher:

Published: 2014

Total Pages:

ISBN-13:

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Acid fracturing is a reservoir stimulation technique where a fracture is created by injection of acid into the reservoir instead of conventional proppant slurry. The acid causes differential etching on the fracture walls, creating asperities. These asperities hold up the fracture wall, thus contributing to fracture conductivity. Acid fracturing is used mainly to stimulate carbonate rock. This technique has certain advantages over conventional fracturing. There is no proppant used, therefore the risk of screenout is nullified. There are also logistic reasons such as transport of proppant, which might make acid fracturing a viable choice. Theoretically, acid fractures have infinite conductivity in these conduits. This is not always true in practice. In this work, a physical optimization of acid fracturing is performed by utilizing the Unified Fracture Design methodology (UFD, hereforth). Parametric studies are performed to study the dependency of productivity on various factors.

Methodologies and New User Interfaces to Optimize Hydraulic Fracturing Design and Evaluate Fracturing Performance for Gas Wells

Methodologies and New User Interfaces to Optimize Hydraulic Fracturing Design and Evaluate Fracturing Performance for Gas Wells PDF

Author: Wenxin Wang

Publisher:

Published: 2006

Total Pages:

ISBN-13:

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This thesis presents and develops efficient and effective methodologies for optimal hydraulic fracture design and fracture performance evaluation. These methods incorporate algorithms that simultaneously optimize all of the treatment parameters while accounting for required constraints. Damage effects, such as closure stress, gel damage and non-Darcy flow, are also considered in the optimal design and evaluation algorithms. Two user-friendly program modules, which are active server page (ASP) based, were developed to implement the utility of the methodologies. Case analysis was executed to demonstrate the workflow of the two modules. Finally, to validate the results from the two modules, results were compared to those from a 3D simulation program. The main contributions of this work are: An optimal fracture design methodology called unified fracture design (UFD)is presented and damage effects are considered in the optimal design calculation. As a by-product of UFD, a fracture evaluation methodology is proposed to conduct well stimulation performance evaluation. The approach is based on calculating and comparing the actual dimensionless productivity index of fractured wells with the benchmark which has been developed for optimized production. To implement the fracture design and evaluation methods, two web ASP based user interfaces were developed; one is called Frac Design (Screening), and the other is Frac Evaluation. Both modules are built to hold the following features. Friendly web ASP based user interface Minimum user inputo Proppant type and mesh size selection- Damage effects consideration options- Convenient on-line help.

Unconventional Oil and Gas Resources Handbook

Unconventional Oil and Gas Resources Handbook PDF

Author: Y Zee Ma

Publisher: Gulf Professional Publishing

Published: 2015-10-06

Total Pages: 552

ISBN-13: 0128025360

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Unconventional Oil and Gas Resources Handbook: Evaluation and Development is a must-have, helpful handbook that brings a wealth of information to engineers and geoscientists. Bridging between subsurface and production, the handbook provides engineers and geoscientists with effective methodology to better define resources and reservoirs. Better reservoir knowledge and innovative technologies are making unconventional resources economically possible, and multidisciplinary approaches in evaluating these resources are critical to successful development. Unconventional Oil and Gas Resources Handbook takes this approach, covering a wide range of topics for developing these resources including exploration, evaluation, drilling, completion, and production. Topics include theory, methodology, and case histories and will help to improve the understanding,integrated evaluation, and effective development of unconventional resources. Presents methods for a full development cycle of unconventional resources, from exploration through production Explores multidisciplinary integrations for evaluation and development of unconventional resources and covers a broad range of reservoir characterization methods and development scenarios Delivers balanced information with multiple contributors from both academia and industry Provides case histories involving geological analysis, geomechanical analysis, reservoir modeling, hydraulic fracturing treatment, microseismic monitoring, well performance and refracturing for development of unconventional reservoirs

Hydraulic Fracture Optimization with a Pseudo-3D Model in Multi-layered Lithology

Hydraulic Fracture Optimization with a Pseudo-3D Model in Multi-layered Lithology PDF

Author: Mei Yang

Publisher:

Published: 2011

Total Pages:

ISBN-13:

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Hydraulic Fracturing is a technique to accelerate production and enhance ultimate recovery of oil and gas while fracture geometry is an important aspect in hydraulic fracturing design and optimization. Systematic design procedures are available based on the so-called two-dimensional models (2D) focus on the optimization of fracture length and width, assuming one can estimate a value for fracture height, while so-called pseudo three dimensional (p-3D) models suitable for multi-layered reservoirs aim to maximize well production by optimizing fracture geometry, including fracture height, half-length and width at the end of the stimulation treatment. The proposed p-3D approach to design integrates four parts: 1) containment layers discretization to allow for a range of plausible fracture heights, 2) the Unified Fracture Design (UFD) model to calculate the fracture half-length and width, 3) the PKN or KGD models to predict hydraulic fracture geometry and the associated net pressure and other treatment parameters, and, finally, 4) Linear Elastic Fracture Mechanics (LEFM) to calculate fracture height. The aim is to find convergence of fracture height and net pressure. Net pressure distribution plays an important role when the fracture is propagating in the reservoir. In multi-layered reservoirs, the net pressure of each layer varies as a result of different rock properties. This study considers the contributions of all layers to the stress intensity factor at the fracture tips to find the final equilibrium height defined by the condition where the fracture toughness equals the calculated stress intensity factor based on LEFM. Other than maximizing production, another obvious application of this research is to prevent the fracture from propagating into unintended layers (i.e. gas cap and/or aquifer). Therefore, this study can aid fracture design by pointing out: (1) Treating pressure needed to optimize fracture geometry, (2) The containment top and bottom layers of a multi-layered reservoir, (3) The upwards and downwards growth of the fracture tip from the crack center.

A Unified Statistical Methodology for Modeling Fatigue Damage

A Unified Statistical Methodology for Modeling Fatigue Damage PDF

Author: Enrique Castillo

Publisher: Springer Science & Business Media

Published: 2009-02-27

Total Pages: 232

ISBN-13: 1402091826

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This book is an attempt to provide a uni?ed methodology to derive models for fatigue life. This includes S-N, ?-N and crack propagation models. This is not a conventional book aimed at describing the fatigue fundamentals, but rather a book in which the basic models of the three main fatigue approaches, the stress-based, the strain-based and the fracture mechanics approaches, are contemplated from a novel and integrated point of view. On the other hand, as an alternative to the preferential attention paid to deterministic models based on the physical, phenomenological and empirical description of fatigue, their probabilistic nature is emphasized in this book, in which stochastic fatigue and crack growth models are presented. This book is the result of a long period of close collaborationbetween its two authors who, although of di?erent backgrounds, mathematical and mechanical, both have a strong sense of engineering with respect to the fatigue problem. When the authors of this book ?rst approached the fatigue ?eld in 1982 (twenty six years ago), they found the following scenario: 1. Linear, bilinear or trilinear models were frequently proposed by relevant laboratoriesandacademiccenterstoreproducetheW ̈ ohler?eld. Thiswas the case of well known institutions, which justi?ed these models based on clientrequirementsorpreferences. Thisledtotheinclusionofsuchmodels and methods as, for example, the up-and-down, in standards and o?cial practical directives (ASTM, Euronorm, etc.), which have proved to be unfortunate.

CIGOS 2019, Innovation for Sustainable Infrastructure

CIGOS 2019, Innovation for Sustainable Infrastructure PDF

Author: Cuong Ha-Minh

Publisher: Springer Nature

Published: 2019-10-10

Total Pages: 1264

ISBN-13: 981150802X

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This book presents selected articles from the 5th International Conference on Geotechnics, Civil Engineering Works and Structures, held in Ha Noi, focusing on the theme “Innovation for Sustainable Infrastructure”, aiming to not only raise awareness of the vital importance of sustainability in infrastructure development but to also highlight the essential roles of innovation and technology in planning and building sustainable infrastructure. It provides an international platform for researchers, practitioners, policymakers and entrepreneurs to present their recent advances and to exchange knowledge and experience on various topics related to the theme of “Innovation for Sustainable Infrastructure”.

Unified Constitutive Laws of Plastic Deformation

Unified Constitutive Laws of Plastic Deformation PDF

Author: A. S. Krausz

Publisher: Elsevier

Published: 1996-05-31

Total Pages: 479

ISBN-13: 008054343X

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High-technology industries using plastic deformation demand soundly-based economical decisions in manufacturing design and product testing, and the unified constitutive laws of plastic deformation give researchers aguideline to use in making these decisions. This book provides extensive guidance in low cost manufacturing without the loss of product quality. Each highly detailed chapter of Unified Constitutive Laws of Plastic Deformation focuses on a distinct set of defining equations. Topics covered include anisotropic and viscoplastic flow, and the overall kinetics and thermodynamics of deformation. This important book deals with a prime topic in materials science and engineering, and will be of great use toboth researchers and graduate students. Describes the theory and applications of the constitutive law of plastic deformation for materials testing Examines the constitutive law of plastic deformation as it applies to process and product design Includes a program on disk for the determination and development of the constitutive law of plastic deformation Considers economical design and testing methods