Effects of Confining Stresses, Pre-crack Inclination Angles and Injection Rates: Observations from Large-Scale True Triaxial and Hydraulic Fracturing Tests in Laboratory

Liu, Zhenghe; Ren, Xiaokai; Lin, Xiao; Lian, Haojie; Yang, Lusheng; Yang, Jianfeng

doi:10.1007/s00603-019-01995-2

Cited by 39 publications

(13 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Through studying the characteristics of tensile and shear failure induced by water pressure, the experiment combines theoretical analysis and test results to derive the calculation formula of critical water pressure for shear failure under pressure reduction closed stress state [21][22][23]. Additionally, the typical shape of an oblate ellipsoid and spatial special expansion shape of hydraulic crack are studied by using the true triaxial experimental system, the law of hydraulic crack expansion affected by principal stress difference is given, and the theory and complete technical system of hydraulic crack control of hard roof are put forward [24].…”

Section: Introductionmentioning

confidence: 99%

Investigation on Hydraulic Fracturing and Cutting Roof Pressure Relief Technology for Underground Mines: A Case Study

Chang¹,

Yao²,

Wang³

et al. 2021

Lithosphere

View full text Add to dashboard Cite

Using hydraulic fracturing for cutting roof pressure is a critical technology to protect coal pillars. In this paper, based on the engineering background of 18506 working face in the Xiqu Coal Mine, using the methods of theoretical analysis, numerical simulation, and field measurement, a reasonable coal pillar width and practical parameters of hydraulic fracturing are given. The results show that roof cutting can significantly increase the stress in goaf and relieve the advanced pressure of the working face. Taking 18506 working face as the research object, the industrial test is carried out, and the surrounding rock control scheme of hydraulic fracturing and roof cutting is put forward, the mine pressure monitoring results show that the auxiliary roadway of 18506 working face reaches a stable state within 20 days, the deformation and damage degree of roadway surrounding rock are small, and the integrity of surrounding rock is improved.

show abstract

Section: Introductionmentioning

confidence: 99%

Investigation on Hydraulic Fracturing and Cutting Roof Pressure Relief Technology for Underground Mines: A Case Study

Chang¹,

Yao²,

Wang³

et al. 2021

Lithosphere

View full text Add to dashboard Cite

show abstract

“…In recent years, relevant scholars have carried out many experiments on the interaction mechanism between hydraulic fractures and rock bedding planes [6][7][8][9]. The research results show that under the condition of different bedding plane strength [10], in situ geo stress coefficient [11], the material difference [12,13], injection pressure, and rheological and viscous characteristics of fracturing fluid [14][15][16], hydraulic fractures will form three modes: (1) expanding along the bedding plane, (2) expanding along the bedding plane and crossing the bedding plane, and (3) crossing the bedding plane.…”

Section: Introductionmentioning

confidence: 99%

Experimental and Numerical Investigation on Hydraulic Fracture Propagation Law of Composite Rock Materials considering the Disturbing Stress Effect

Zhang

2021

Geofluids

View full text Add to dashboard Cite

The stress disturbance effect will significantly affect the propagation path of hydraulic fractures in the composite rock reservoir. To reveal the influence mechanism of stress disturbance effect on the hydraulic fracture propagation, several groups of laboratory tests and simulation tests were carried out. The test results showed that the hydraulic fracture tip formed a disturbing stress field because of the pore water pressure. Before the hydraulic fracture was extended to the bedding plane, the bedding plane had been damaged under stress disturbance, and the disturbed fracture zone was formed. The propagation mode of hydraulic fracture at the bedding plane was highly sensitive to the formation of the disturbed fracture zone. The sensitivity is mainly reflected from two aspects. (1) Under the action of the hydraulic fracture tip disturbance stress, many microfractures are generated and penetrated into the disturbance fracture zone on the bedding plane. This behavior is accompanied by energy dissipation causing the bedding plane material to be significantly softened, and the energy required for hydraulic fracture propagation is reduced dramatically. (2) The formation of the disturbed fracture zone improves the degree of fragmentation of the bedding plane, and the permeability of the local area increases significantly, forming the dominant circulation path. The higher the development of the disturbed fracture zone, the greater the hydraulic fracture propagation tendency along the bedding plane. According to the formation characteristics of the bedding plane disturbed fracture zone, the author proposed a nonlinear fracture model of the bedding plane disturbed fracture zone and established the hydraulic fracture propagation path criterion. This paper further analyzed the influencing factors of the disturbed fracture zone’s formation conditions and found that the bedding plane’s cementation strength was the main factor affecting the development degree of the disturbed fracture zone.

show abstract

“…Therefore, an interactive relationship can be established to evaluate the hydraulic fracturing effect and water fracture development under different water pressures. Moreover, the strength characteristics are required by hydraulic fracturing [4][5][6][7][8][9][10][11], but it is difficult to carry out the test on-site; therefore, there is a certain engineering significance to establish a model for predicting the strength of the rock through the preliminary detection of the failure morphology of the rock so as to delimit the range of water pressure.…”

Section: Introductionmentioning

confidence: 99%

Study on the Relationship between Fracture Morphology and Splitting Strength of Granite Based on Fabric Distribution

Chen

et al. 2021

Geofluids

View full text Add to dashboard Cite

Because of the requirement of the mechanical properties of the damaged surrounding granite rock and the existence of the fracture water in hydraulic fracturing engineering, the strength of granite is related to the fabric, and the roughness of the section is also related to the liquid flow rate, a method of roughly determining the strength of the specimen by observing the failure mode of rock is needed. Considering that the physical and mechanical properties of granite are obviously affected by the fabric, the discrete element numerical simulation method was used to reconstruct the granite fabric based on the spatial correlation function to simulate the splitting experiment to investigate the failure mode of the specimen. The relationship between strength, the fractal value of cross-section, and the fabric was analyzed, which was verified through experiment. The results show that (1) the Voronoi GBM model with spatial correlation function of the discrete element can effectively simulate the controllable granite fabric and carry out micromechanical analysis. (2) The strength of the granite specimen and the fractal value of the cross-section have an obvious linear relationship with the fabric; besides, there is also a certain linear relationship between the strength of the specimen and the fractal value, which is influenced by granite fabric. (3) The predicted strength of the specimen according to the fractal value of the section is in good agreement with the actual strength with the error rate of 30%. In a word, this method can predict the strength of the specimen through the failure section and analyze the hydraulic fracture section and water pressure.

show abstract

Effects of Confining Stresses, Pre-crack Inclination Angles and Injection Rates: Observations from Large-Scale True Triaxial and Hydraulic Fracturing Tests in Laboratory

Cited by 39 publications

References 22 publications

Investigation on Hydraulic Fracturing and Cutting Roof Pressure Relief Technology for Underground Mines: A Case Study

Investigation on Hydraulic Fracturing and Cutting Roof Pressure Relief Technology for Underground Mines: A Case Study

Experimental and Numerical Investigation on Hydraulic Fracture Propagation Law of Composite Rock Materials considering the Disturbing Stress Effect

Study on the Relationship between Fracture Morphology and Splitting Strength of Granite Based on Fabric Distribution

Contact Info

Product

Resources

About