A 3-D Hydraulic Fracture Propagation Model Applied for Multiple-Layered Formation

2019 ◽  
Author(s):  
Jizhou Tang ◽  
Lihua Zuo ◽  
Lizhi Xiao ◽  
Kan Wu ◽  
Bin Qian ◽  
...  
Keyword(s):  
Hydraulic Fracture ◽  
Fracture Propagation ◽  
Propagation Model ◽  
Layered Formation ◽  
Hydraulic Fracture Propagation

Investigation of Rupture and Slip Mechanisms of Hydraulic Fractures in Multiple-Layered Formations

SPE Journal ◽  
2019 ◽  
Vol 24 (05) ◽  
pp. 2292-2307 ◽  
Author(s):  
Jizhou Tang ◽  
Kan Wu ◽  
Lihua Zuo ◽  
Lizhi Xiao ◽  
Sijie Sun ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Hydraulic Fracture ◽  
Fracture Propagation ◽  
Propagation Model ◽  
Rock Deformation ◽  
Hydraulic Fractures ◽  
Fracture Geometry ◽  
Fracture Width ◽  
Hydraulic Fracture Propagation ◽  
Fracture Height

Summary Weak bedding planes (BPs) that exist in many tight oil formations and shale–gas formations might strongly affect fracture–height growth during hydraulic–fracturing treatment. Few of the hydraulic–fracture–propagation models developed for unconventional reservoirs are capable of quantitatively estimating the fracture–height containment or predicting the fracture geometry under the influence of multiple BPs. In this paper, we introduce a coupled 3D hydraulic–fracture–propagation model considering the effects of BPs. In this model, a fully 3D displacement–discontinuity method (3D DDM) is used to model the rock deformation. The advantage of this approach is that it addresses both the mechanical interaction between hydraulic fractures and weak BPs in 3D space and the physical mechanism of slippage along weak BPs. Fluid flow governed by a finite–difference methodology considers the flow in both vertical fractures and opening BPs. An iterative algorithm is used to couple fluid flow and rock deformation. Comparison between the developed model and the Perkins–Kern–Nordgren (PKN) model showed good agreement. I–shaped fracture geometry and crossing–shaped fracture geometry were analyzed in this paper. From numerical investigations, we found that BPs cannot be opened if the difference between overburden stress and minimum horizontal stress is large and only shear displacements exist along the BPs, which damage the planes and thus greatly amplify their hydraulic conductivity. Moreover, sensitivity studies investigate the impact on fracture propagation of parameters such as pumping rate (PR), fluid viscosity, and Young's modulus (YM). We investigated the fracture width near the junction between a vertical fracture and the BPs, the latter including the tensile opening of BPs and shear–displacement discontinuities (SDDs) along them. SDDs along BPs increase at the beginning and then decrease at a distance from the junction. The width near the junctions, the opening of BPs, and SDDs along the planes are directly proportional to PR. Because viscosity increases, the width at a junction increases as do the SDDs. YM greatly influences the opening of BPs at a junction and the SDDs along the BPs. This model estimates the fracture–width distribution and the SDDs along the BPs near junctions between the fracture tip and BPs and enables the assessment of the PR required to ensure that the fracture width at junctions and along intersected BPs is sufficient for proppant transport.

scholarly journals Analysis of Hydraulic Fracture Propagation Using a Mixed Mode and a Uniaxial Strain Model considering Geomechanical Properties in a Naturally Fractured Shale Reservoir

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Youngho Jang ◽  
Gayoung Park ◽  
Seoyoon Kwon ◽  
Baehyun Min
Keyword(s):  
Shale Gas ◽  
Hydraulic Fracture ◽  
Mixed Mode ◽  
Fracture Propagation ◽  
Fracture Network ◽  
Uniaxial Strain ◽  
Propagation Model ◽  
Geomechanical Properties ◽  
Hydraulic Fracture Propagation ◽  
Strain Model

This study proposes a hydraulic fracture propagation model with a mixed mode comprising opening and sliding modes to describe a complex fracture network in a naturally fractured shale gas formation. We combine the fracture propagation model with the mixed mode and the uniaxial strain model with tectonic impacts to calculate the stress distribution using geomechanical properties. A discrete fracture network is employed to realize the fracture network composed of natural and hydraulic fractures. We compare the fracture propagation behaviours of three cases representing the Barnett, Marcellus, and Eagle Ford shale gas formations. Sensitivity analysis is performed to investigate the effects of the geomechanical properties of the reservoir on the sliding mode’s contribution to the mixed mode. The numerical results highlight the significance of the mixed mode for the accurate assessment of fracture propagation behaviours in shale gas formations with high brittleness.

scholarly journals Numerical Investigation of Hydraulic Fracture Extension Based on the Meshless Method

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Chaoneng Zhao ◽  
Yongquan Hu ◽  
Jinzhou Zhao ◽  
Qiang Wang ◽  
Pei He ◽  
...  
Keyword(s):  
Hydraulic Fracture ◽  
Fracture Propagation ◽  
Propagation Model ◽  
Propagation Path ◽  
Hydraulic Fractures ◽  
Stress Inversion ◽  
Stress Shadow ◽  
Single Well ◽  
Hydraulic Fracture Propagation ◽  
Element Free

The fracture propagation in hydraulic fracturing is described as a nonlinear problem dynamic boundary. Due to the limitation of mesh refinement, it is difficult to obtain the real crack propagation path using conventional numerical methods. Meshless methods (MMs) are an effective method to eliminate the dependence on the computational grid in the simulation of fracture propagation. In this paper, a hydraulic fracture propagation model is established based on the element-free Galerkin (EFG) method by introducing jump and branch enrichment functions. Based on the proposed method, three types of fracturing technology are investigated. The results reveal that the stress interference between fractures has an important impact on the propagation path. For the codirectional fracturing simultaneously, fractures propagate in a repel direction. However, the new fracture is attracted and eventually trapped by the adjacent fracture in the sequential fracturing case. For the opposite simultaneous fracturing in multiwells, two fractures with a certain lateral spacing will deflect toward each other. The effect of stress shadow should be used rationally in the optimization of construction parameters; for the single well multistage fracturing, the stage spacing should be out of stress inversion area, while for the simultaneous fracturing of multiple wells, stress inversion zones should be used to maximize communication between natural fractures. Overall, this study establishes a novel and effective approach of using MM to simulate the propagation of hydraulic fractures, which can serve as a useful reference for understanding the mechanism of hydraulic fracture propagation under various conditions.

Numerical Simulation of Hydraulic Fracture Propagation Characteristics of Low Permeable Coal-Rock Mass

2012 ◽  
Vol 482-484 ◽  
pp. 1668-1671 ◽  
Author(s):  
Zhi Gang Yuan ◽  
Hong Tu Wang ◽  
Nian Ping Liu
Keyword(s):  
Rock Mass ◽  
Hydraulic Fracturing ◽  
Hydraulic Fracture ◽  
Fracture Propagation ◽  
Injection Pressure ◽  
Horizontal Stress ◽  
Propagation Model ◽  
Fracture Length ◽  
Coal Rock ◽  
Hydraulic Fracture Propagation

Based on the coal-rock mass deformation model, hydraulic pressure descent model in fracture, fracture propagation model and its growth criterion, the mathematical model of hydraulic fracturing of low permeable coal-rock mass is established, and the influencing factors such as injection pressure, elastic modulus of coal-rock mass and in-situ stress, which affect the characteristics of hydraulic fracture propagation, are studied using the ANSYS software. The results show that fracture length presents a linear increase and widest width increases as an exponent function with the increase of injection pressure, and the ability of making fracture width is greater than fracture length during late fracturing; besides, with the increase of Young’s modulus of coal-rock mass and least horizontal stress, fracture length and widest width decrease, which are independent of maximum horizontal stress. The obtained conclusions provide a guiding role for the optimization of operation parameters of field hydraulic fracturing of low permeable coal-rock.

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