scholarly journals Continuum Damage Modeling of Hydraulic Fracture from Perforations in Horizontal Wells

2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Feng Sun ◽  
Peng Jia ◽  
Shifeng Xue
Keyword(s):  
Hydraulic Fracture ◽  
Damage Mechanics ◽  
Damage Model ◽  
Horizontal Wells ◽  
Element Model ◽  
Fracture Plane ◽  
Continuum Damage ◽  
Fracture Geometry ◽  
Initial Fracture ◽  
The Impact

The perforations play an important role in determining the near-wellbore fracture geometry during the stimulation phase. To address the impact of perforations on fracture geometry in horizontal wells, a 3D coupled hydromechanical finite element model is developed and employed. Based on the theory of continuum damage mechanics, scalar damage variable governs the degradation of the stiffness of the solid. Damage affects the crack element modeling that is used to consider crack behavior and construct a crack-tracking algorithm to simulate propagation. The model was validated against the analytical solutions and perforation fracture experiments. The results indicate that perforation can be used to control the fracturing pressure and propagation behavior of the initial fracture, which has a further effect on the fracture geometry of near-wellbore region in horizontal wells. Optimizing perforation parameters can direct the propagation of the initial fracture toward the preferred fracture plane. The results demonstrate an improved capability to depict the 3D near-wellbore fracture geometry and fracture propagation with a continuum damage model. The model enables the optimization of orientations and perforation parameters, so that most efficient perforating completions can be designed for hydraulic fracture stimulation.

scholarly journals Failure Analysis of Composite Pinned Joints Based on Continuum Damage Mechanics

2018 ◽  
Vol 36 (5) ◽  
pp. 848-855
Author(s):  
Hongliang Tuo ◽  
Xiaoping Ma ◽  
Zhixian Lu
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Damage Mechanics ◽  
Continuum Damage Mechanics ◽  
Element Model ◽  
Fracture Plane ◽  
Continuum Damage ◽  
Bearing Strength ◽  
Matrix Damage ◽  
Pinned Joints

The paper conducted bearing tests on composite pinned joints with four different stacking sequences. The bearing strength and bearing chord stiffness were obtained. The influence of stacking sequences on failure modes, bearing strength and bearing chord stiffness was discussed. Based on continuum damage mechanics, a three-dimensional finite element model of composite pinned joint under bearing load was built, where the maximum strain criterion was employed for initiation and bi-liner damage constitutive relation for revolution of fiber damage, while the physical-based Puck criterion was used for matrix damage initiation, and matrix damage revolution depended on the effective strain on the fracture plane. The failure mode, bearing strength and bearing chord stiffness of composite pinned joint were discussed with this model under which the non-linear shear behavior and in-situ strength effects were considered. Good agreements between test results and numerical simulations validates the accuracy and applicability of the finite element model.

Can We Engineer Better Multistage Horizontal Completions? Evidence of the Importance of Near-wellbore Fracture Geometry from Theory, Lab and Field Experiments

2015 ◽  
Author(s):  
B.. Lecampion ◽  
J.. Desroches ◽  
X.. Weng ◽  
J.. Burghardt ◽  
J.E.. E. Brown
Keyword(s):  
Pressure Drop ◽  
Field Experiments ◽  
Horizontal Wells ◽  
Fracture Plane ◽  
Hydraulic Fractures ◽  
Multiple Fractures ◽  
Fracture Geometry ◽  
Complex Fracture ◽  
Limited Entry ◽  
The Impact

Abstract There is accepted evidence that multistage fracturing of horizontal wells in shale reservoirs results in significant production variation from perforation cluster to perforation cluster. Typically, between 30 and 40% of the clusters do not significantly contribute to production while the majority of the production comes from only 20 to 30% of the clusters. Based on numerical modeling, laboratory and field experiments, we investigate the process of simultaneously initiating and propagating several hydraulic fractures. In particular, we clarify the interplay between the impact of perforation friction and stress shadow on the stability of the propagation of multiple fractures. We show that a sufficiently large perforation pressure drop (limited entry) can counteract the stress interference between different growing fractures. We also discuss the robustness of the current design practices (cluster location, limited entry) in the presence of characterized stress heterogeneities. Laboratory experiments highlight the complexity of the fracture geometry in the near-wellbore region. Such complex fracture path results from local stress perturbations around the well and the perforations, as well as the rock fabric. The fracture complexity (i.e., the merging of multiple fractures and the reorientation towards the preferred far-field fracture plane) induces a strong nonlinear pressure drop on a scale of a few meters. Single entry field experiments in horizontal wells show that this near-wellbore effect is larger in magnitude than perforation friction and is highly variable between clusters, without being predictable. Through a combination of field measurements and modeling, we show that such variability results in a very heterogeneous slurry rate distribution; and therefore, proppant intake between clusters during a stage, even in the presence of limited entry techniques. We also note that the estimated distribution of proppant intake between clusters appears similar to published production log data. We conclude that understanding and accounting for the complex fracture geometry in the near-wellbore is an important missing link to better engineer horizontal well multistage completions.

Modelling the asymmetric tension–compression properties of additively manufactured alloys using continuum damage mechanics

2021 ◽  
pp. 146442072110134
Author(s):  
A Nayebi ◽  
H Rokhgireh ◽  
M Araghi ◽  
M Mohammadi
Keyword(s):  
Damage Mechanics ◽  
Continuum Damage Mechanics ◽  
Element Model ◽  
Continuum Damage ◽  
Compression Tests ◽  
Compression Properties ◽  
Mechanics Model ◽  
Stress Components ◽  
Tension And Compression ◽  
Closure Effect

Additively manufactured parts often comprise internal porosities due to the manufacturing process, which needs to be considered in modelling their mechanical behaviour. It was experimentally shown that additively manufactured parts’ tensile and compressive mechanical properties are different for various metallic alloys. In this study, isotropic continuum damage mechanics is used to model additively manufactured alloys’ tension and compression behaviours. Compressive stress components can shrink discontinuities present in additively manufactured alloys. Therefore, the crack closure effect was employed to describe different behaviours during uniaxial tension and compression tests. A finite element model embedded in an ABAQUS’s UMAT format was developed to account for the isotropic continuum damage mechanics model. The numerical results of tension and compression tests were compared with experimental observations for additively manufactured maraging steel, AlSi10Mg and Ti-6Al-4V. Stress–strain curves in tension and compression of these alloys were obtained using the continuum damage mechanics model and compared well with the experimental results.

Cross-Ply Laminates under Static Three-Point Bending: A Numerical Development Model

2012 ◽  
Vol 498 ◽  
pp. 42-54 ◽  
Author(s):  
S. Benbelaid ◽  
B. Bezzazi ◽  
A. Bezazi
Keyword(s):  
Numerical Model ◽  
Damage Mechanics ◽  
Progressive Failure ◽  
Damage Model ◽  
Continuum Damage Mechanics ◽  
Failure Criteria ◽  
Continuum Damage ◽  
Damage Development ◽  
Element Analysis ◽  
Progressive Failure Analysis

This paper considers damage development mechanisms in cross-ply laminates using an accurate numerical model. Under static three points bending, two modes of damage progression in cross-ply laminates are predominated: transverse cracking and delamination. However, this second mode of damage is not accounted in our numerical model. After a general review of experimental approaches of observed behavior of laminates, the focus is laid on predicting laminate behavior based on continuum damage mechanics. In this study, a continuum damage model based on ply failure criteria is presented, which is initially proposed by Ladevèze. To reveal the effect of different stacking sequence of the laminate; such as thickness and the interior or exterior disposition of the 0° and 90° oriented layers in the laminate, an equivalent damage accumulation which cover all ply failure mechanisms has been predicted. However, the solution algorithm using finite element analysis which implements progressive failure analysis is summarized. The results of the numerical computation have been justified by the previous published experimental observations of the authors.

Investigation of Production-Induced Stress Changes for Infill-Well Stimulation in Eagle Ford Shale

SPE Journal ◽  
2018 ◽  
Vol 23 (04) ◽  
pp. 1372-1388 ◽  
Author(s):  
Xuyang Guo ◽  
Kan Wu ◽  
John Killough
Keyword(s):  
Horizontal Wells ◽  
Eagle Ford Shale ◽  
Eagle Ford ◽  
Fracture Geometry ◽  
Complex Fracture ◽  
Study Results ◽  
Stress Changes ◽  
Sensitivity Studies ◽  
Stress States ◽  
The Impact

Summary Heterogeneous stress has a great effect on fracture propagation and perforation-cluster efficiency of infill wells. Principal-stress reorientation induced by depletion of parent wells has been investigated by previous numerical studies assuming uniform biwing fracture geometry along the horizontal wells. However, recent field diagnostics indicate that fractures along the horizontal wells are generally nonuniformly developed. In this study, we investigated the impact of depletion of parent wells with complex fracture geometry on stress states, and analyzed stimulation efficiency of infill wells by using an in-house reservoir geomechanical model for Eagle Ford Shale. The model fully couples multiphase flow and rock deformation in three dimensions based on the finite-element method, incorporating complex fracture geometry and heterogeneity. We used this model to accurately characterize pressure distribution and to update stress states through history matching production data of parent wells in Eagle Ford Shale. Depletion of parent wells with nonuniform fracture geometries, which has not been researched thoroughly in the literature, is incorporated in the study. Results show that magnitude and orientation of principal stresses are greatly altered by depletion, and the alteration is uneven because of nonuniform fracture geometries. Stress reversal monitored at the center of the infill location starts after 1 year of production, and it takes another 8 months to be totally reversed for 90°. We also performed sensitivity studies to examine effects of parameters on changes of magnitude and orientation of stress at the infill location, and found that effects of bottomhole pressure (BHP), differential stress (DS), and fracture geometry of parent wells are all significant, whereas effects of the reservoir elastic property are limited. Effects of production time of parent wells are also noticeable in all sensitivity studies. This work analyzes stress-state change induced by depletion of parent wells in Eagle Ford Shale, and provides critical insights into the optimization for stimulation of infill wells.

Continuum damage mechanics-based analysis of creep–fatigue interaction behavior in a turbine rotor

2018 ◽  
Vol 28 (3) ◽  
pp. 455-477 ◽  
Author(s):  
WZ Wang ◽  
YZ Liu
Keyword(s):  
Damage Mechanics ◽  
Maximum Stress ◽  
Continuum Damage Mechanics ◽  
Turbine Rotor ◽  
Von Mises Stress ◽  
Temperature Phase ◽  
Continuum Damage ◽  
Interaction Behavior ◽  
Creep Fatigue ◽  
The Impact

The aim of this study is to analyze the creep–fatigue interaction behavior of a steam turbine rotor under idealized cyclic thermomechanical loading conditions. A Chaboche model-based material constitutive model is applied to simulate the multiaxial stress–strain behavior in the rotor. Influence of accumulated damage during the whole iterations on the creep–fatigue interaction behavior is described by continuum damage mechanics. Analysis of the temperature and stress variations during the startup phase reveals that the startup phase can be divided into a condensation phase, a high steam flux phase, and an elevated temperature phase and that thermal stress reaches its maximum value in the condensation phase. In addition, creep–fatigue interaction in the rotor leads to a gradual decrease in the maximum stress; furthermore, comparison of the von Mises stress displays that the impact of damage accumulation results in the shift of the location with the maximum stress. Investigation of creep–fatigue damage discloses that the total damage is concentrated on the steam inlet notch zone and the blade groove of the first and third stages.

scholarly journals Modeling hydraulic fracture of glaciers using continuum damage mechanics

2016 ◽  
Vol 62 (234) ◽  
pp. 794-804 ◽  
Author(s):  
MOSTAFA E. MOBASHER ◽  
RAVINDRA DUDDU ◽  
JEREMY N. BASSIS ◽  
HAIM WAISMAN
Keyword(s):  
Hydraulic Fracture ◽  
Damage Mechanics ◽  
Water Pressure ◽  
Continuum Damage Mechanics ◽  
Positive Influence ◽  
Continuum Damage ◽  
Iceberg Calving ◽  
Isotropic Damage ◽  
Plausible Mechanism ◽  
Viscoelastic Constitutive Model

ABSTRACTThe presence of water-filled crevasses is known to increase the penetration depth of crevasses and this has been hypothesized to play an important role controlling iceberg calving rate. Here, we develop a continuum-damage-based poro-mechanics formulation that enables the simulation of water-filled basal and surface crevasse propagation. The formulation incorporates a scalar isotropic damage variable into a Maxwell-type viscoelastic constitutive model for glacial ice, and the effect of the water pressure on fracture propagation using the concept of effective solid stress. We illustrate the model by simulating quasi-static hydrofracture in idealized rectangular slabs of ice in contact with the ocean. Our results indicate that water-filled basal crevasses only propagate when the water pressure is sufficiently large, and that the interaction between simultaneously propagating water-filled surface and basal crevasses can have a mutually positive influence leading to deeper crevasse propagation, which can critically affect glacial stability. Therefore, this study supports the hypothesis that hydraulic fracture is a plausible mechanism for the accelerated breakdown of glaciers.

Prediction of Rupture in Gas Forming Process Using Continuum Damage Mechanic

2012 ◽  
Vol 463-464 ◽  
pp. 1047-1051
Author(s):  
M. Rahafrooz ◽  
M. Sanjari ◽  
M. Moradi ◽  
Danial Ghodsiyeh
Keyword(s):  
Metal Forming ◽  
Damage Mechanics ◽  
Damage Model ◽  
Simulation Software ◽  
Ductile Damage ◽  
Continuum Damage ◽  
Forming Process ◽  
Continuum Damage Mechanic ◽  
Damage Mechanic ◽  
Metal Forming Process

The Continuum Damage Mechanics is a branch of applied mechanics that used to predict the initiation of cracks in metal forming process. In this article, damage definition and ductile damage model are explained, and also ductile damage model is applied to predict initiation of fracture in gas metal forming process with ABAQUS/EXPLICIT simulation. In this method instead of punch, the force is applied by air pressure. In this study, first the ductile damage criterion and its relations are taken into account and, subsequently, the process of gas-aid formation process is put into consideration and ductile damage model for prediction of rupture area is simulated using ABAQUS simulation software. Eventually, the process of formation via gas on the aluminum with total thickness of 0.24 [mm] was experimentally investigated and the results acquired from experiment were compared with relating simulations. The effect of various parameters such as radius of edge matrix, gas pressure and blank temperature has been evaluated. Simulation was compared with experimental results and good agreement was observed.

Prediction of Impact Damage of Composite Laminates Using a Mixed Damage Model

2014 ◽  
Vol 513-517 ◽  
pp. 235-237
Author(s):  
Shi Yang Zhao ◽  
Pu Xue
Keyword(s):  
Composite Laminates ◽  
Damage Mechanics ◽  
Failure Modes ◽  
Impact Damage ◽  
Damage Model ◽  
Material Model ◽  
Element Model ◽  
Fiber Damage ◽  
Damage Process ◽  
Matrix Damage

In order to effectively describe the damage process of composite laminates and reduce the complexity of material model, a mixed damage model based on Linde Criteria and Hashin Criteria is proposed for prediction of impact damage in the study. The mixed damage model can predict baisc failure modes, including fiber fracture, matrix tensile damage, matrix compressive damage. Fiber damage and matrix damage in compression are described based on the progressive damage mechanics; and matrix damage in tension is described based on Continuous Damage Mechanics (CDM). Meanwhile, for interlaminar delamination, damage is described by cohesive model. A finite element model is established to analyze the damage process of composite laminate. A good agreement is got between damage predictions and experimental results.

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