Numerical Simulations of Fracture Propagation in Jointed Shale Reservoirs under CO2 Fracturing

Water-based hydraulic fracturing for the exploitation of shale gas reservoirs may be limited by two main factors: (1) water pollution and chemical pollution after the injection process and (2) permeability decrease due to clay mineral swelling upon contact with the injection water. Besides, shale ro...

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Main Authors: Qi Zhang, Dan Ma, Jiangfeng Liu, Jiehao Wang, Xibing Li, Zilong Zhou
Format: Article
Language:English
Published: Wiley 2019-01-01
Series:Geofluids
Online Access:http://dx.doi.org/10.1155/2019/2624716
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author Qi Zhang
Dan Ma
Jiangfeng Liu
Jiehao Wang
Xibing Li
Zilong Zhou
author_facet Qi Zhang
Dan Ma
Jiangfeng Liu
Jiehao Wang
Xibing Li
Zilong Zhou
author_sort Qi Zhang
collection DOAJ
description Water-based hydraulic fracturing for the exploitation of shale gas reservoirs may be limited by two main factors: (1) water pollution and chemical pollution after the injection process and (2) permeability decrease due to clay mineral swelling upon contact with the injection water. Besides, shale rock nearly always contains fractures and fissures due to geological processes such as deposition and folding. Based on the above, a damage-based coupled model of rock deformation and gas flow is used to simulate the fracturing process in jointed shale wells with CO2 fracturing. We validate our model by comparing the simulation results with theoretical solutions. The research results show that the continuous main fractures are formed along the direction of the maximum principal stress, whilst hydraulic fractures tend to propagate along the preexisting joints due to the lower strength of the joints. The main failure type is tensile damage destruction among these specimens. The preexisting joints can aggravate the damage of the numerical specimens; the seepage areas of the layered jointed sample, vertical jointed sample, and orthogonal jointed sample are increased by 32.5%, 29.16%, and 35.05%, respectively, at time t=39 s compared with the intact sample. The preexisting horizontal joints or vertical joints promote the propagation of hydraulic fractures in the horizontal direction or vertical direction but restrain the expansion of hydraulic fractures in the vertical or horizontal direction.
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spelling doaj-art-5a7b03e278164958a33e0a59b0ea7cea2025-02-03T05:47:43ZengWileyGeofluids1468-81151468-81232019-01-01201910.1155/2019/26247162624716Numerical Simulations of Fracture Propagation in Jointed Shale Reservoirs under CO2 FracturingQi Zhang0Dan Ma1Jiangfeng Liu2Jiehao Wang3Xibing Li4Zilong Zhou5School of Resources and Safety Engineering, Central South University, Changsha, 410083 Hunan, ChinaSchool of Resources and Safety Engineering, Central South University, Changsha, 410083 Hunan, ChinaState Key Laboratory for Geomechanics and Deep Underground Engineering, China University of Mining and Technology, Xuzhou, 221116 Jiangsu, ChinaDepartment of Energy and Mineral Engineering, EMS Energy Institute and G3 Center, Pennsylvania State University, University Park, PA 16802, USASchool of Resources and Safety Engineering, Central South University, Changsha, 410083 Hunan, ChinaSchool of Resources and Safety Engineering, Central South University, Changsha, 410083 Hunan, ChinaWater-based hydraulic fracturing for the exploitation of shale gas reservoirs may be limited by two main factors: (1) water pollution and chemical pollution after the injection process and (2) permeability decrease due to clay mineral swelling upon contact with the injection water. Besides, shale rock nearly always contains fractures and fissures due to geological processes such as deposition and folding. Based on the above, a damage-based coupled model of rock deformation and gas flow is used to simulate the fracturing process in jointed shale wells with CO2 fracturing. We validate our model by comparing the simulation results with theoretical solutions. The research results show that the continuous main fractures are formed along the direction of the maximum principal stress, whilst hydraulic fractures tend to propagate along the preexisting joints due to the lower strength of the joints. The main failure type is tensile damage destruction among these specimens. The preexisting joints can aggravate the damage of the numerical specimens; the seepage areas of the layered jointed sample, vertical jointed sample, and orthogonal jointed sample are increased by 32.5%, 29.16%, and 35.05%, respectively, at time t=39 s compared with the intact sample. The preexisting horizontal joints or vertical joints promote the propagation of hydraulic fractures in the horizontal direction or vertical direction but restrain the expansion of hydraulic fractures in the vertical or horizontal direction.http://dx.doi.org/10.1155/2019/2624716
spellingShingle Qi Zhang
Dan Ma
Jiangfeng Liu
Jiehao Wang
Xibing Li
Zilong Zhou
Numerical Simulations of Fracture Propagation in Jointed Shale Reservoirs under CO2 Fracturing
Geofluids
title Numerical Simulations of Fracture Propagation in Jointed Shale Reservoirs under CO2 Fracturing
title_full Numerical Simulations of Fracture Propagation in Jointed Shale Reservoirs under CO2 Fracturing
title_fullStr Numerical Simulations of Fracture Propagation in Jointed Shale Reservoirs under CO2 Fracturing
title_full_unstemmed Numerical Simulations of Fracture Propagation in Jointed Shale Reservoirs under CO2 Fracturing
title_short Numerical Simulations of Fracture Propagation in Jointed Shale Reservoirs under CO2 Fracturing
title_sort numerical simulations of fracture propagation in jointed shale reservoirs under co2 fracturing
url http://dx.doi.org/10.1155/2019/2624716
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