Three-Dimensional Hydraulic Fracture Simulation Using Fixed Grid Finite Element Algorithms

1994 ◽  
Vol 116 (1) ◽  
pp. 2-9 ◽  
Author(s):  
T. S. Lee ◽  
S. H. Advani ◽  
C. K. Pak
Keyword(s):  
Finite Element ◽  
Hydraulic Fracture ◽  
Fluid Pressure ◽  
Three Dimensional ◽  
Fracture Width ◽  
Coupled Equations ◽  
Fixed Grid ◽  
Fracture Simulation ◽  
Fracture Fluid ◽  
Novel Algorithms

A three-dimensional hydraulic fracture simulator (HYFFIX) is reformulated using finite element methodology and a newly adapted fixed grid. The numerical procedures for the coupled equations governing the fracture width, fluid pressure, and evolution of equilibrium planar crack in layered media are summarized. Fixed grid mesh control algorithms for the efficient tracking of the moving crack/fracture fluid front are detailed. The introduction of these novel algorithms in the simulator makes it numerically efficient and stable, in comparison to previously reported models which utilize migrating mesh techniques. Due to the enhanced numerical efficiency and compactness of the refined code, the model can also be readily implemented on a workstation or microcomputer.

Active monitoring of hydraulic fracture propagation: an experimental and numerical study

2011 ◽  
Vol 51 (1) ◽  
pp. 479 ◽  
Author(s):  
Amin Nabipour ◽  
Brian Evans ◽  
Mohammad Sarmadivaleh
Keyword(s):  
Hydraulic Fracturing ◽  
Real Time ◽  
Hydraulic Fracture ◽  
Numerical Study ◽  
Fluid Pressure ◽  
Active Monitoring ◽  
Fracture Width ◽  
True Triaxial ◽  
Transmitted Waves ◽  
Triaxial Cell

Hydraulic fracturing is known as one of the most common stimulation techniques performed in oil and gas wells for maximising hydrocarbon production. It is a complex procedure due to numerous influencing factors associated with it. As a result, hydraulic fracturing monitoring techniques are used to determine the real-time extent of the induced fracture and to prevent unwanted events. Although the well-known method of monitoring is the microseismic method, active monitoring of a hydraulic fracture has shown capable of providing useful information about the fracture properties in both laboratory conditions and field operations. In this study, the focus is on laboratory experiment of hydraulic fracturing using a true-triaxial cell capable of simulating field conditions required for hydraulic fracturing. By injecting high-pressure fluid, a hydraulic fracture was induced inside a 20 cm cube of cement. Using a pair of ultrasonic transducers, transmission data were recorded before and during the test. Both cases of an open and closed hydraulic fracture were investigated. Then, using a discrete particle scheme, seismic monitoring of the hydraulic fracture was numerically modelled for a hexagonally packed sample and compared with the lab results. The results show good agreements with data in the literature. As the hydraulic fracture crosses the transducers line, signal dispersion was observed in the compressional wave data. A decrease was observed in both the amplitude and velocity of the waves. This can be used as an indicator of the hydraulic fracture width. As the fracture closes by reducing fluid pressure, a sensible increase occurred in the amplitude of the transmitted waves while the travel time showed no detectable variations. The numerical model produced similar results. As the modelled hydraulic fracture reached the source-receiver line, both amplitude and velocity of the transmitted waves decreased. This provides hope for the future real-time ability to monitor the growth of induced fractures during the fraccing operation. At present, however, it still needs improvements to be calibrated with experimental results.

Finite Element Analyses of a Butterfly Valve Assembly

1989 ◽  
Vol 111 (2) ◽  
pp. 197-202
Author(s):  
B. Goksel ◽  
J. J. Rencis ◽  
M. Noori
Keyword(s):  
Finite Element ◽  
Fluid Pressure ◽  
Three Dimensional ◽  
Finite Element Analyses ◽  
Butterfly Valve ◽  
Commercial Code ◽  
Valve Assembly ◽  
Dimensional Finite Element ◽  
Static Fluid ◽  
Three Dimensional Finite Element

Two and three-dimensional finite element analyses of a butterfly valve assembly subjected to static fluid pressure were carried out using commercial code ANSYS. Good agreement between the experimental and finite element results were obtained. Sensitivity of results to various boundary and loading conditions was also investigated.

Finite Element Model Simulations Associated With Hydraulic Fracturing

1982 ◽  
Vol 22 (02) ◽  
pp. 209-218 ◽  
Author(s):  
Sunder H. Advani ◽  
J.K. Lee
Keyword(s):  
Finite Element ◽  
Hydraulic Fracturing ◽  
Finite Element Model ◽  
Hydraulic Fracture ◽  
Element Model ◽  
In Situ Stress ◽  
Fracture System ◽  
Model Simulations ◽  
Fracture Fluid

Abstract Recently emphasis has been placed on the development and testing of innovative well stimulation techniques for the recovery of unconventional gas resources. The design of optimal hydraulic fracturing treatments for specified reservoir conditions requires sophisticated models for predicting the induced fracture geometry and interpreting governing mechanisms. This paper presents methodology and results pertinent to hydraulic fracture modeling for the U.S. DOE's Eastern Gas Shales Program (EGSP). The presented finite-element model simulations extend available modeling efforts and provide a unified framework for evaluation of fracture dimensions and associated responses. Examples illustrating the role of multilayering, in-situ stress, joint interaction, and branched cracks are given. Selected comparisons and applications also are discussed. Introduction Selection and design of stimulation treatments for Devonian shale wells has received considerable attention in recent years1-3. The production of natural gas from such tight eastern petroliferous basins is dependent on the vertical thickness of the organically rich shale matrix, its inherent fracture system density, anisotropy, and extent, and the communication-link characteristics of the induced fracture system(s). The investigation of stimulation techniques based on resource characterization, reservoir property evaluation, theoretical and laboratory model simulations, and field testing is a logical step toward the development of commercial technology for optimizing gas production and related costs. This paper reports formulations, methodology, and results associated with analytical simulations of hydraulic fracturing for EGSP. The presented model extends work reported by Perkins and Kern,4 Nordgren,5 Geertsma and DeKlerk,6 and Geertsma and Haafkens.7 The simulations provide a finite-element model framework for studying vertically induced fracture responses with the effects of multilayering and in-situ stress considered. In this context, Brechtel et al.,8 Daneshy,9 Cleary,10 and Anderson et al.11 have done recent studies addressing specific aspects of this problem. The use of finite-element model techniques for studying mixed-mode fracture problems encountered in dendritic fracturing and vertical fracture/joint interaction also is illustrated along with application of suitable failure criteria. Vertical Hydraulic Fracture Model Formulations Coupled structural fracture mechanics and fracture fluid response models for predicting hydraulically induced fracture responses have been reported previously.12,13 These simulations incorporate specified reservoir properties, in-situ stress conditions, and stimulation treatment parameters. One shortcoming of this modeling effort is that finite-element techniques are used for the structural and stress intensity simulations, while a finite-difference approach is used to evaluate the leakoff and fracture-fluid response in the vertical crack. A consistent framework for conducting all simulations using finite-element modeling is formulated here.

Modeling of Hydraulic Fracture Propagation in Shale Gas Reservoirs: A Three-Dimensional, Two-Phase Model

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
Chong Hyun Ahn ◽  
Robert Dilmore ◽  
John Yilin Wang
Keyword(s):  
Hydraulic Fracture ◽  
Three Dimensional ◽  
Fracture Network ◽  
Gas Reservoirs ◽  
Two Phase ◽  
Coupled Equations ◽  
Detailed Method ◽  
Network Propagation ◽  
Hydraulic Fracture Propagation ◽  
Fracture Height

A three-dimensional, two-phase, dual-continuum hydraulic fracture (HF) propagation simulator was developed and implemented. This paper presents a detailed method for efficient and effective modeling of the fluid flow within fracture and matrix as well as fluid leakoff, fracture height growth, and the fracture network propagation. Both a method for solving the system of coupled equations, and a verification of the developed model are presented herein.

Developing a Tool for 3D Reservoir Simulation of Hydraulically Fractured Wells

2007 ◽  
Vol 10 (01) ◽  
pp. 50-59 ◽  
Author(s):  
Josef R. Shaoul ◽  
Aron Behr ◽  
George Mtchedlishvili
Keyword(s):  
Simulation Model ◽  
Reservoir Simulation ◽  
Hydraulic Fracture ◽  
Fracture Plane ◽  
Tight Gas ◽  
Fracture Conductivity ◽  
Fracture Width ◽  
Fracture Simulation ◽  
Reservoir Simulator ◽  
Actual Fracture

Summary This paper describes the development and capabilities of a novel and unique tool that interfaces a hydraulic fracture model and a reservoir simulator. This new tool is another step in improving both the efficiency and consistency of connecting hydraulic fracture engineering and reservoir engineering. The typical way to model hydraulically fractured wells in 3D reservoir simulators is to approximate the fracture behavior with a modified skin or productivity index (PI). Neither method captures all the important physics of flow into and through the fracture. This becomes even more critical in cases of multiphase flow and multilayered reservoirs. Modeling the cleanup phase following hydraulic fracture treatments can be very important in tight gas reservoirs, and this also requires a more detailed simulation of the fracture. Realistic modeling of horizontal wells with multiple hydraulic fractures is another capability that is needed in the industry. This capability requires more than an approximate description of the fracture(s) in the reservoir-simulation model. To achieve all the capabilities mentioned above, a new tool was developed within a commercial lumped 3D fracture-simulation model. This new tool enables significantly more accurate prediction of post-fracture performance with a commercial reservoir simulator. The automatically generated reservoir simulator input files represent the geometry and hydraulic properties of the reservoir, the fracture, the damaged zone around the fracture, and the initial pressure and filtrate fluid distribution in the reservoir. Consistency with the fracture-simulation inputs and outputs is assured because the software automatically transfers the information. High-permeability gridblocks that capture the 2D variation of the fracture conductivity within the reservoir simulator input files represent the fracture. If the fracture width used in the reservoir model is larger than the actual fracture width, the permeability and porosity of the fracture blocks are reduced to maintain the transmissibility and porous volume of the actual fracture. Both proppant and acid fracturing are handled with this approach. To capture the changes in fracture conductivity over time as the bottomhole flowing pressure (BHFP) changes, the pressure-dependent behavior of the fracture is passed to the reservoir simulator. Local grid refinement (LGR) is used in the region of the wellbore and the fracture tip, as well as in the blocks adjacent to the fracture plane. Using small gridblocks adjacent to the fracture plane is needed for an adequate representation of the filtrate-invaded zone using the leakoff depth distribution provided by the fracture simulator. The reservoir simulator input can be created for multiphase fluid systems with multiple layers and different permeabilities. In addition, different capillary pressure and relative permeability saturation functions for each layer are allowed. Introduction Historically, there have been three basic approaches commonly used for predicting the production from hydraulically fractured wells. First, analytic solutions were most commonly used, based on an infinite-conductivity or, later, a finite-conductivity fracture with a given half-length. This approach also was extended to cover horizontal multiple fractured wells (Basquet et al. 1999). With the development of reservoir simulators, two other approaches were developed. For complicated multiwell, multilayer, multiphase simulations (i.e., full-field models), the fracture stimulation was usually approximated as a negative skin. This is the same as increasing the effective wellbore radius in the simulation model. An alternate approach, developed initially for tight gas applications, was to develop a special-purpose numeric reservoir simulator that could explicitly model the flow in the fracture and take into account the special properties of the proppant, such as the stress-dependent permeability or the possibility of non-Darcy flow. Such models typically were limited to a single-layer, single-phase (oil or gas) situation.

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