scholarly journals An approximate solution for a penny-shaped hydraulic fracture that accounts for fracture toughness, fluid viscosity and leak-off

2016 ◽  
Vol 3 (12) ◽  
pp. 160737 ◽  
Author(s):  
E. V. Dontsov

This paper develops a closed-form approximate solution for a penny-shaped hydraulic fracture whose behaviour is determined by an interplay of three competing physical processes that are associated with fluid viscosity, fracture toughness and fluid leak-off. The primary assumption that permits one to construct the solution is that the fracture behaviour is mainly determined by the three-process multiscale tip asymptotics and the global fluid volume balance. First, the developed approximation is compared with the existing solutions for all limiting regimes of propagation. Then, a solution map, which indicates applicability regions of the limiting solutions, is constructed. It is also shown that the constructed approximation accurately captures the scaling that is associated with the transition from any one limiting solution to another. The developed approximation is tested against a reference numerical solution, showing that accuracy of the fracture width and radius predictions lie within a fraction of a per cent for a wide range of parameters. As a result, the constructed approximation provides a rapid solution for a penny-shaped hydraulic fracture, which can be used for quick fracture design calculations or as a reference solution to evaluate accuracy of various hydraulic fracture simulators.

2016 ◽  
Vol 797 ◽  
pp. 1-28 ◽  
Author(s):  
E. V. Dontsov

This study investigates the propagation of a semi-infinite buoyancy-driven hydraulic fracture in situations when the fluid is able to solidify along the crack walls. Such problems occur when hot magma ascends from a chamber due to buoyancy forces and solidifies by interacting with colder rock. In the model, the solidification rate is calculated assuming a one-dimensional heat transfer problem, in which case it becomes mathematically equivalent to Carter’s leak-off model, which is commonly used to describe the fluid leak-off from a hydraulic fracture into a porous rock formation. In order to construct a mathematical model for a buoyancy-driven hydraulic fracture with solidification, the aforementioned thermal problem is combined with (i) linear plane-strain elasticity to ensure equilibrium of the rock surrounding the fracture, (ii) linear elastic fracture mechanics to determine the fracture propagation, (iii) lubrication theory to capture the viscous fluid flow inside the crack and to account for the effect of buoyancy, and (iv) volume balance of the magma. To address the problem, the governing equations are first rewritten in terms of one integral equation with a non-singular kernel, which significantly simplifies the analysis and the procedure for obtaining a numerical solution. The latter solution is shown to obey a multiscale behaviour near the fracture tip that is fully resolved by the numerical scheme. In order to understand the structure of the solution and to quantify the regimes of propagation (and the associated transitions), a thorough analysis of the problem has been performed. Finally, the developments are applied to investigate the non-steady propagation of a buoyancy-driven fracture that is fed by a constant flux.


1983 ◽  
Vol 105 (2) ◽  
pp. 116-124 ◽  
Author(s):  
M. B. Rubin

A laboratory experiment was conducted to study hydraulic fracturing in an impermeable material (PMMA). Quantitative experimental data were obtained to compare with numerical predictions for a simple hydraulic fracture treatment that is not complicated by the effects of fluid leak-off and proppant transport. The borehole pressure, the pressure in the fracture at three locations, the fracture width at one location, and the fracture length were measured as functions of time during propagation of a vertically contained hydraulic fracture. The experimental data are compared with the predictions of simple solutions and the results indicate that when the finite width of the laboratory model is included in the analysis, the comparison between theory and experiment is quite good. The results also indicate that the assumption of a uniform pressure distribution in the fracture is adequate to accurately predict the critical parameters (fracture width and length) even when the fracturing fluid is very viscous.


2021 ◽  
Author(s):  
Jiacheng Wang ◽  
Jon Olson

Abstract We propose an adaptive Eulerian-Lagrangian (E-L) proppant module and couple it with our simplified three-dimensional displacement discontinuity method (S3D DDM) hydraulic fracture model. The integrated model efficiently calculates proppant transport during three-dimensional (3D) hydraulic fracture propagation in multi-layer formations. The results demonstrate that hydraulic fracture height growth mitigates the form of proppant bed, so the proppant placement is more uniform in the hydraulic fracture under a smaller stress contrast. A higher fracturing fluid viscosity improves the suspension of proppant particles and generates a fracture larger in height and width but shorter in length. Lower proppant density and particle size reduce the proppant settling and create more uniform proppant placements, while they do not affect the hydraulic fracture geometry. Moreover, a larger proppant particle size limits the accessibility of the hydraulic fracture to the proppant, so the larger proppant particles do not fill the fracture tip and edge where the fracture width is small.


Alloy Digest ◽  
1987 ◽  
Vol 36 (2) ◽  

Abstract SAE 1020 is a low-carbon steel combining good machinability, workability and weldability. It is carburized for use in case-hardened components and it is used for a wide range of applications in the hot-worked, cold-worked, normalized or quenched-and-tempered conditions. Its many uses include bolts, rods, plate applications, machinery components, case-hardened parts, spinning tools and trimming dies. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on low temperature performance and corrosion resistance as well as heat treating, machining, joining, and surface treatment. Filing Code: CS-113. Producer or source: Carbon steel mills.


Alloy Digest ◽  
1991 ◽  
Vol 40 (10) ◽  

Abstract ZYMAXX provides outstanding compressive creep resistance, toughness and chemical inertness at high temperatures and pressures and under adverse conditions. They have a wide range of uses beyond chemical processing, including aerospace and automotive applications, general industrial equipment, home appliances, farm and construction equipment. This datasheet provides information on physical properties, hardness, tensile properties, and compressive strength as well as fracture toughness and creep. It also includes information on corrosion resistance. Filing Code: Cp-18. Producer or source: E. I. Dupont de Nemours & Company Inc..


Alloy Digest ◽  
1993 ◽  
Vol 42 (2) ◽  

Abstract Durcomet 100 is an improved version of Alloy CD-4 MCu with better corrosion and wear resistance. The alloy is used in the annealed condition and possesses excellent corrosion resistance over a wide range of corrosion environments. Mechanical strength is also very high. This datasheet provides information on composition, physical properties, hardness, and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as heat treating and joining. Filing Code: SS-540. Producer or source: Duriron Company Inc.


Alloy Digest ◽  
1956 ◽  
Vol 5 (4) ◽  

Abstract VDC is an air-hardening 5% chromium die steel recommended for a wide range of hot work applications requiring resistance to heat and abrasion, and is particularly useful for white metal die casting and extrusion applications. It is equivalent to AISI TYPE H13. This datasheet provides information on composition and hardness as well as fracture toughness. It also includes information on heat treating, machining, and joining. Filing Code: TS-45. Producer or source: Latrobe Steel Company.


2007 ◽  
Vol 580 ◽  
pp. 359-380 ◽  
Author(s):  
S. M. ROPER ◽  
J. R. LISTER

We study steady vertical propagation of a crack filled with buoyant viscous fluid through an elastic solid with large effective fracture toughness. For a crack fed by a constant flux Q, a non-dimensional fracture toughness K=Kc/(3μQm3/2)1/4 describes the relative magnitudes of resistance to fracture and resistance to viscous flow, where Kc is the dimensional fracture toughness, μ the fluid viscosity and m the elastic modulus. Even in the limit K ≫ 1, the rate of propagation is determined by viscous effects. In this limit the large fracture toughness requires the fluid behind the crack tip to form a large teardrop-shaped head of length O(K2/3) and width O(K4/3), which is fed by a much narrower tail. In the head, buoyancy is balanced by a hydrostatic pressure gradient with the viscous pressure gradient negligible except at the tip; in the tail, buoyancy is balanced by viscosity with elasticity also playing a role in a region within O(K2/3) of the head. A narrow matching region of length O(K−2/5) and width O(K−4/15), termed the neck, connects the head and the tail. Scalings and asymptotic solutions for the three regions are derived and compared with full numerical solutions for K ≤ 3600 by analysing the integro-differential equation that couples lubrication flow in the crack to the elastic pressure gradient. Time-dependent numerical solutions for buoyancy-driven propagation of a constant-volume crack show a quasi-steady head and neck structure with a propagation rate that decreases like t−2/3 due to the dynamics of viscous flow in the draining tail.


2019 ◽  
Vol 827 ◽  
pp. 312-317
Author(s):  
Vitalijs Pavelko

The theoretical model of quasi-static crack growth in the elastic-plastic material under load variation in a wide range. Small-scale yielding is principal assumption and main restriction of proposed theory. The model of crack growth provides for continues and interrelated both the crack propagation and plastic deformation development. The nonlinear first-order differential equation describes the quasi-static process of crack growth. In dimensionless form this equation invariant in respect to geometrical configuration and material. The critical size of the plastic zone is proposed as the characteristics of material resistance which is directly connected with the fracture toughness, but more convenient in practical applications of invariant equation. The demonstration of solution is performed for the double cantilever beam that widely used as the standard (DCB) sample for measurement of the mode-I interlaminar fracture toughness. he short analysis of some properties of solution of the invariant equation and its application is done.


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