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fracture-parameter
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Designing an Optimal Pumping Program for Multi-stage Hydraulic Fracturing Operation and Investigating the Effect of Different Parameters
, M.Sc. Thesis Sharif University of Technology ; Jamshidi, Saeed (Supervisor)
Abstract
With the production from the reservoirs, the amount of in-situ oil storage has decreased and there is a need to increase oil recovery (EOR) from the reservoir. Increased oil recovery (EOR) includes operations such as acidizing and hydraulic fracturing. Considering the economic and high operational costs and geomechanical complexities, as well as the technical progress of hydraulic fracturing and its future; It is necessary to manage hydraulic fracturing operations optimally. This research is about hydraulic fracturing and its main goal is to optimize the parameters of the fracture or the geometry of the fracture. The research study was carried out on the Bangistan Reservoir located in the...
Effect of coarse aggregate volume on fracture behavior of self compacting concrete
, Article Construction and Building Materials ; Volume 52 , 15 February , 2014 , Pages 137-145 ; ISSN: 09500618 ; Beygi, M. H. A ; Kazemi, M. T ; Vaseghi Amiri, J ; Rahmani, E ; Rabbanifar, S ; Eslami, M ; Sharif University of Technology
Abstract
This paper presents the effect of volume of coarse aggregate on fracture characteristics of self- compacting concrete (SCC). Based on an experimental programme, a series of three point bending tests were carried out on 58 notched beams. SCC was prepared with coarse aggregate in varying percentages of 30%, 40%, 50% and 60% (as the percentage of the total aggregate volume). For all mixes, the fracture parameters were analyzed by the work-of- fracture method (WFM) and by the size effect method (SEM) to obtain a suitable correlation between these methods which is used to calibrate fracture numerical models. The results showed that with decrease of volume of coarse aggregate from 60% to 30% in...
The effect of water to cement ratio on fracture parameters and brittleness of self-compacting concrete
, Article Materials and Design ; Volume 50 , 2013 , Pages 267-276 ; 02613069 (ISSN) ; Kazemi, M. T ; Nikbin, I. M ; Amiri, J. V ; Sharif University of Technology
Elsevier Ltd
2013
Abstract
The paper describes an experimental research on fracture characteristics of self-compacting concrete (SCC). Three point bending tests conducted on 154 notched beams with different water to cement (w/c) ratios. The specimens were made from mixes with various w/c ratios from 0.7 to 0.35. For all mixes, common fracture parameters were determined using two different methods, the work-of-fracture method (WFM) and the size effect method (SEM). Test results showed that with decrease of w/c ratio from 0.7 to 0.35 in SCC: (a) the fracture toughness increases linearly: (b) the brittleness number is approximately doubled: (c) the effective size of the process zone cf in SEM and the characteristic...
Determination of the fracture parameters of concrete with improved wedge-splitting testing
, Article Engineering Fracture Mechanics ; Volume 276 , 2022 ; 00137944 (ISSN) ; Du, C ; Ghaemian, M ; Zhao, W ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
Considering the quasi-brittle mechanical properties of concrete, wedge-splitting tests are employed and improved in this paper to study the fracture behaviour of concrete. A novel wedge-splitting device is designed by fixing ten springs on the force transmission component. The adaptive spring force can be imposed on top of a concrete specimen to retard the brittle fracture process. With the proposed wedge-splitting test design for notched cuboid specimens, the complete load–strain/CMOD curves of concrete can be generated directly. The fracture toughness and the fracture energy can be calculated easily without numerical fitting using the double-K fracture model. The descending branch of the...
Crack growth modeling via 3D automatic adaptive mesh refinement based on modified-SPR technique
, Article Applied Mathematical Modelling ; Volume 37, Issue 1-2 , 2013 , Pages 357-383 ; 0307904X (ISSN) ; Eghbalian, M ; Moslemi, H ; Azadi, H ; Sharif University of Technology
2013
Abstract
In this paper, the three-dimensional automatic adaptive mesh refinement is presented in modeling the crack propagation based on the modified superconvergent patch recovery technique. The technique is developed for the mixed mode fracture analysis of different fracture specimens. The stress intensity factors are calculated at the crack tip region and the crack propagation is determined by applying a proper crack growth criterion. An automatic adaptive mesh refinement is employed on the basis of modified superconvergent patch recovery (MSPR) technique to simulate the crack growth by applying the asymptotic crack tip solution and using the collapsed quarter-point singular tetrahedral elements...
Fracture properties of steel fiber reinforced high strength concrete using work of fracture and size effect methods
, Article Construction and Building Materials ; Volume 142 , 2017 , Pages 482-489 ; 09500618 (ISSN) ; Golsorkhtabar, H ; Beygi, M. H. A ; Gholamitabar, M ; Sharif University of Technology
Elsevier Ltd
2017
Abstract
This paper deals with investigation of fracture behavior of steel fiber reinforced high strength concrete (SFRHSC) and compare it to plain high strength concrete (HSC). Based on an experimental program, a series of three point bending tests were carried out on 54 notched beams, as recommended by RILEM. The fracture parameters were measured by two methods: work of fracture method (WFM) and size effect method (SEM). Then the fracture parameters obtained from these two methods were compared. The results showed that with increase of steel fibers, fracture energy of GF in WFM and Gf in SEM increase but this increase in work of fracture method is more significant. The effective size of the process...
Characterization of fracture dynamic parameters to simulate naturally fractured reservoirs
, Article International Petroleum Technology Conference, IPTC 2008, Kuala Lumpur, 3 December 2008 through 5 December 2008 ; Volume 1 , 2008 , Pages 473-485 ; 9781605609546 (ISBN) ; Siavoshi, J ; Parvizi, H ; Esmaili, S ; Karimi, M. H ; Nasiri, A ; Sharif University of Technology
2008
Abstract
Fractures identification is essential during exploration, drilling and well completion of naturally fractured reservoirs since they have a significant impact on flow contribution. There are different methods to characterize these systems based on formation properties and fluid flow behaviour such as logging and testing. Pressure-transient testing has long been recognized as a reservoir characterization tool. Although welltest analysis is a recommended technique for fracture evaluation, but its use is still not well understood. Analysis of pressure transient data provides dynamic reservoir properties such as average permeability, fracture storativity and fracture conductivity.An infusion of...