Experimental Study of Proppant Bridging in a Model of a Hydraulic Fracture

SPE Journal ◽  
2022 ◽  
pp. 1-12
Author(s):  
Sergey Golovin ◽  
Alexey Besov ◽  
Aleksey Chebotnikov ◽  
Evgeny Ermanyuk
Keyword(s):  
Experimental Study ◽  
Numerical Simulations ◽  
Hydraulic Fracture ◽  
Threshold Value ◽  
Channel Width ◽  
Qualitative Description ◽  
Experimental Facility ◽  
Proppant Transport ◽  
Fracturing Fluids ◽  
Slurry Rheology

Summary In this article, we investigate formation of the local clogging (bridging) of proppant in a channel with gradually narrowing walls. The experimental facility allows us to simulate the process of the proppant transport in a hydraulic fracture by reproduction of the characteristic channel width, velocity of slurry, rheology of fracturing fluids, and typical concentrations of proppant. The goal of the study is to give qualitative description of the dynamics of the congestion of the proppant up to the complete blockage of the flow. In contrast to common practice of imposing bridging criteria by postulating certain threshold value of the width to proppant size ratio, we demonstrate that the bridging process involves several stages: clogging of two to three particles, growth of stable “islands,” connection of the islands by arches, and, finally, the total sandout of the cell by the bridged proppant. The observations of the paper gives better understanding of the bridging process giving the directions for more precise numerical simulations.

Numerical Simulation of Proppant Transport in Hydraulically Fractured Reservoirs

2021 ◽  
Author(s):  
Seyhan Emre Gorucu ◽  
Vijay Shrivastava ◽  
Long X. Nghiem
Keyword(s):  
Hydraulic Fracturing ◽  
Hydraulic Fracture ◽  
Fractured Reservoirs ◽  
Injection Timing ◽  
Fracture Permeability ◽  
Step Size ◽  
Time Step ◽  
Time Step Size ◽  
Proppant Transport ◽  
Fracture Closure

Abstract An existing equation-of-state compositional simulator is extended to include proppant transport. The simulator determines the final location of the proppant after fracture closure, which allows the computation of the permeability along the hydraulic fracture. The simulation then continues until the end of the production. During hydraulic fracturing, proppant is injected in the reservoir along with water and additives like polymers. Hydraulic fracture gets created due to change in stress caused by the high injection pressure. Once the fracture opens, the bulk slurry moves along the hydraulic fracture. Proppant moves at a different speed than the bulk slurry and sinks down by gravity. While the proppant flows along the fracture, some of the slurry leaks off into the matrix. As the fracture closes after injection stops, the proppant becomes immobile. The immobilized proppant prevents the fracture from closing and thus keeps the permeability of the fracture high. All the above phenomena are modelled effectively in this new implementation. Coupled geomechanics simulation is used to model opening and closure of the fracture following geomechanics criteria. Proppant retardation, gravitational settling and fluid leak-off are modeled with the appropriate equations. The propped fracture permeability is a function of the concentration of immobilized proppant. The developed proppant simulation feature is computationally stable and efficient. The time step size during the settling adapts to the settling velocity of the proppants. It is found that the final location of the proppants is highly dependent on its volumetric concentration and slurry viscosity due to retardation and settling effects. As the location and the concentration of the proppants determine the final fracture permeability, the additional feature is expected to correctly identify the stimulated region. In this paper, the theory and the model formulation are presented along with a few key examples. The simulation can be used to design and optimize the amount of proppant and additives, injection timing, pressure, and well parameters required for successful hydraulic fracturing.

Effect of Ramp Angle on the Anti-Loosening Ability of Wedge Self-Locking Nuts Under Vibration

2018 ◽  
Vol 140 (7) ◽  
Author(s):  
Jianhua Liu ◽  
Hao Gong ◽  
Xiaoyu Ding
Keyword(s):  
Finite Element ◽  
Numerical Simulations ◽  
Production Technology ◽  
Material Properties ◽  
Threshold Value ◽  
Commercial Production ◽  
Experimental Results ◽  
Fe Method ◽  
Transversal Vibration

Recently, the wedge self-locking nut, a special anti-loosening product, is receiving more attention because of its excellent reliability in preventing loosening failure under vibration conditions. The key characteristic of a wedge self-locking nut is the special wedge ramp at the root of the thread. In this work, the effect of ramp angle on the anti-loosening ability of wedge self-locking nuts was studied systematically based on numerical simulations and experiments. Wedge self-locking nuts with nine ramp angles (10 deg, 15 deg, 20 deg, 25 deg, 30 deg, 35 deg, 40 deg, 45 deg, and 50 deg) were modeled using a finite element (FE) method, and manufactured using commercial production technology. Their anti-loosening abilities under transversal vibration conditions were analyzed based on numerical and experimental results. It was found that there is a threshold value of the initial preload below which the wedge self-locking nuts would lose their anti-loosening ability. This threshold value of initial preload was then proposed for use as a criterion to evaluate the anti-loosening ability of wedge self-locking nuts quantitatively and to determine the optimal ramp angle. Based on this criterion, it was demonstrated, numerically and experimentally, that a 30 deg wedge ramp resulted in the best anti-loosening ability among nine ramp angles studied. The significance of this study is that it provides an effective method to evaluate the anti-loosening ability of wedge self-locking nuts quantitatively, and determined the optimal ramp angle in terms of anti-loosening ability. The proposed method can also be used to optimize other parameters, such as the material properties and other dimensions, to guarantee the best anti-loosening ability of wedge self-locking nuts.

Assessment of Possible Thermal Damage of Tissue due to Atherectomy by Means of a Mechanical Debulking Device

2008 ◽  
Author(s):  
Ryang D. Lovik ◽  
John P. Abraham ◽  
Eph M. Sparrow
Keyword(s):  
Numerical Simulations ◽  
Thermal Injury ◽  
Thermal Damage ◽  
Threshold Value ◽  
Posterior Tibial Artery ◽  
Artery Wall ◽  
Flow Rates ◽  
Injury Index ◽  
Orbital Atherectomy

In vitro and cadaver experiments, coupled with numerical simulations, were performed to assess the possibility that orbital atherectomy might cause thermal damage of tissue. The experiments involved debulking operations on a surrogate artery and on the plaque-lined posterior tibial artery of a cadaver. Temperatures and coolant flow rates measured during these experiments enabled a numerical simulation of the debulking of a plaque-lined artery in a living human. The temperature variations from the numerical simulations were used to evaluate a thermal injury index. The resulting values of the index were found to be several orders of magnitude below the threshold value for thermal injury. It is concluded that it is extremely unlikely that the use of an orbital debulking device, the Diamondback 360°™ (Cardiovascular Systems, Inc.), can lead to thermal injury of the artery wall.

A visualization study of proppant transport in foam fracturing fluids

2018 ◽  
Vol 52 ◽  
pp. 235-247 ◽  
Author(s):  
Songyang Tong ◽  
Robin Singh ◽  
Kishore K. Mohanty
Keyword(s):  
Proppant Transport ◽  
Fracturing Fluids

scholarly journals Nonlinear Analysis of the Dynamics of Criminality and Victimisation: A Mathematical Model with Case Generation and Forwarding

2019 ◽  
Vol 2019 ◽  
pp. 1-17
Author(s):  
Chikodili Helen Ugwuishiwu ◽  
D. S. Sarki ◽  
G. C. E. Mbah
Keyword(s):  
Mathematical Model ◽  
Numerical Simulations ◽  
Nonlinear Analysis ◽  
Deterministic Model ◽  
Positive Impact ◽  
Threshold Value ◽  
Dynamical Analysis ◽  
Viable Option ◽  
Effective Implementation ◽  
The Impact

In this paper, a system of deterministic model is presented for the dynamical analysis of the interactional consequence of criminals and criminality on victimisation under two distinguishable forms of rehabilitation—the behavioural reformation of criminals and the emotional psychotherapy of victims. A threshold value, R0=maxRK,RV, responsible for the persistence of crime/criminality and victimisation, is obtained and, using it, stability analyses on the model performed. The impact of an effective implementation of the two forms of rehabilitation was found to be substantial on crime and criminality, while an ineffective implementation of same was observed to have a detrimental consequence. The prevention of repeat victimisation was seen to present a more viable option for containing crime than the noncriminalisation of victims. Further, the removal of criminals, either through quitting or death, among others, was also found to have a huge positive impact. Numerical simulations were performed for a variety of mixing criminal scenarios to verify the analytical results obtained.

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