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Zhuang DD, Yin TB, Zhang ZX, Aladejare A, Wu Y, Qiao Y. An Innovative Method to Analyze the Hydraulic Fracture Reopening Pressure of Hot Dry Rock. MATERIALS (BASEL, SWITZERLAND) 2023; 16:1118. [PMID: 36770127 PMCID: PMC9919164 DOI: 10.3390/ma16031118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 01/07/2023] [Accepted: 01/14/2023] [Indexed: 06/18/2023]
Abstract
This paper focuses on a new test method and theoretical model for measuring and evaluating the reopening pressure during hot dry rock hydraulic fracturing. Firstly, rock blocks of four lithologies were collected from the hot dry rock strata. Hydraulic fracturing tests at high temperatures in real-time were conducted using drilled cubic specimens and drilled cubic specimens with a pre-crack. Breakdown pressure, reopening pressure, and fracture toughness were measured, respectively. In addition, Brazilian splitting tests at high temperatures in real-time were performed using Brazilian disc specimens to measure tensile strength. Secondly, an empirical equation for evaluating the reopening pressure during hot dry rock secondary fracturing was developed based on fracture mechanics and hydraulic fracturing theory. Third, the values calculated by the new equation, considering breakdown pressure, fracture toughness, and tensile strength, were compared to the values determined by the classical equation and to measurement results. It was found that the new equation predicted closer reopening pressure to the measurement results, regardless of the lithology of the hot dry rock. Moreover, with increasing temperature in the specimens, the error between the value calculated by the new equation and the measurement value remained low. In contrast, the difference between the classical equation predictions and the measurement results was widened. In addition, the reopening pressure was positively correlated with tensile strength and fracture toughness. Variations in lithology and temperature affected tensile strength and fracture toughness, which then changed the hot dry rock reopening pressure.
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Affiliation(s)
- Deng-Deng Zhuang
- School of Resources and Safety Engineering, Central South University, Changsha 410083, China
- Oulu Mining School, University of Oulu, 90015 Oulu, Finland
| | - Tu-Bing Yin
- School of Resources and Safety Engineering, Central South University, Changsha 410083, China
| | | | | | - You Wu
- School of Resources and Safety Engineering, Central South University, Changsha 410083, China
| | - Yang Qiao
- Oulu Mining School, University of Oulu, 90015 Oulu, Finland
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A Review of the Hydraulic Fracturing in Ductile Reservoirs: Theory, Simulation, and Experiment. Processes (Basel) 2022. [DOI: 10.3390/pr10102022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
The bottom-hole pressure of hydraulic fracturing in ductile reservoirs is much higher than that of the hydraulic fracturing simulation, and the fracture toughness inferred from the field data is 1–3 orders of magnitude higher than that measured in the laboratory. The rock apparent fracture toughness increases with the increase in the confining pressure. Excluding the influence of the fluid viscosity and the fluid lag on the apparent fracture toughness, the fracture process zone (FPZ) at the fracture tip can explain the orders of magnitude of difference in the apparent fracture toughness between the laboratory and the field. The fracture tip is passivated by plastic deformation, forming a wide and short hydraulic fracture. However, the size of the FPZ obtained in the laboratory is in the order of centimeters to decimeters, while an FPZ of 10 m magnitude is speculated in the field. The FPZ size is affected by the rock property, grain size, pore fluid, temperature, loading rate, and loading configuration. It is found that the FPZ has a size effect that tends to disappear when the rock specimen size reaches the scale of meters. However, this cannot fully explain the experience of hydraulic fracturing practice. The hydraulic fracturing behavior is also affected by the relation between the fracture toughness and the fracture length. The fracture behavior of type II and mixed type for the ductile rock is poorly understood. At present, the apparent fracture toughness model and the cohesive zone model (CZM) are the most suitable criteria for the fracture propagation in ductile reservoirs, but they cannot fully characterize the influence of the rock plastic deformation on the hydraulic fracturing. The elastic-plastic constitutive model needs to be used to characterize the stress–strain behavior in the hydraulic fracturing simulation, and the fracture propagation criteria suitable for ductile reservoirs also need to be developed.
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Investigation of Hydraulic Fracturing Crack Propagation Behavior in Multi-Layered Coal Seams. APPLIED SCIENCES-BASEL 2020. [DOI: 10.3390/app10031153] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Coalbed methane is not only a clean energy source, but also a major problem affecting the efficient production of coal mines. Hydraulic fracturing is an effective technology for enhancing the coal seam permeability to achieve the efficient extraction of methane. This study investigated the effect of a coal seam reservoir’s geological factors on the initiation pressure and fracture propagation. Through theoretical analysis, a multi-layered coal seam initiation pressure calculation model was established based on the broken failure criterion of maximum tensile stress theory. Laboratory experiments were carried out to investigate the effects of the coal seam stress and coal seam dip angle on the crack initiation pressure and fracture propagation. The results reveal that the multi-layered coal seam hydraulic fracturing initiation pressure did not change with the coal seam inclination when the burial depth was the same. When the dip angle was the same, the initiation pressure linearly increased with the reservoir depth. A three-dimensional model was established to simulate the actual hydraulic fracturing crack propagation in multi-layered coal seams. The results reveal that the hydraulic crack propagated along the direction of the maximum principal stress and opened in the direction of the minimum principal stress. As the burial depth of the reservoir increased, the width of the hydraulic crack also increased. This study can provide the theoretical foundation for the effective implementation of hydraulic fracturing in multi-layered coal seams.
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Numerical Simulation of Hydraulic Fracture Propagation in Coal Seams with Discontinuous Natural Fracture Networks. Processes (Basel) 2018. [DOI: 10.3390/pr6080113] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
To investigate the mechanism of hydraulic fracture propagation in coal seams with discontinuous natural fractures, an innovative finite element meshing scheme for modeling hydraulic fracturing was proposed. Hydraulic fracture propagation and interaction with discontinuous natural fracture networks in coal seams were modeled based on the cohesive element method. The hydraulic fracture network characteristics, the growth process of the secondary hydraulic fractures, the pore pressure distribution and the variation of bottomhole pressure were analyzed. The improved cohesive element method, which considers the leak-off and seepage behaviors of fracturing liquid, is capable of modeling hydraulic fracturing in naturally fractured formations. The results indicate that under high stress difference conditions, the hydraulic fracture network is spindle-shaped, and shows a multi-level branch structure. The ratio of secondary fracture total length to main fracture total length was 2.11~3.62, suggesting that the secondary fractures are an important part of the hydraulic fracture network in coal seams. In deep coal seams, the break pressure of discontinuous natural fractures mainly depends on the in-situ stress field and the direction of natural fractures. The mechanism of hydraulic fracture propagation in deep coal seams is significantly different from that in hard and tight rock layers.
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CH 4 CO 2 gas exchange and supercritical CO 2 based hydraulic fracturing as CBM production-accelerating techniques: A review. J CO2 UTIL 2017. [DOI: 10.1016/j.jcou.2017.10.004] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Marder M, Chen CH, Patzek T. Simple models of the hydrofracture process. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2015; 92:062408. [PMID: 26764704 DOI: 10.1103/physreve.92.062408] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Indexed: 06/05/2023]
Abstract
Hydrofracturing to recover natural gas and oil relies on the creation of a fracture network with pressurized water. We analyze the creation of the network in two ways. First, we assemble a collection of analytical estimates for pressure-driven crack motion in simple geometries, including crack speed as a function of length, energy dissipated by fluid viscosity and used to break rock, and the conditions under which a second crack will initiate while a first is running. We develop a pseudo-three-dimensional numerical model that couples fluid motion with solid mechanics and can generate branching crack structures not specified in advance. One of our main conclusions is that the typical spacing between fractures must be on the order of a meter, and this conclusion arises in two separate ways. First, it arises from analysis of gas production rates, given the diffusion constants for gas in the rock. Second, it arises from the number of fractures that should be generated given the scale of the affected region and the amounts of water pumped into the rock.
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Affiliation(s)
- M Marder
- Department of Physics, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Chih-Hung Chen
- Department of Physics, The University of Texas at Austin, Austin, Texas 78712, USA
| | - T Patzek
- Earth Sciences and Engineering Division, Upstream Petroleum Engineering Research Center, King Abdullah University of Science and Technology, Thuwal 23955-6900, Kingdom of Saudi Arabia
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Seeber L, Armbruster JG. The 1886 Charleston, South Carolina earthquake and the Appalachian Detachment. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/jb086ib09p07874] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Hickman SH, Zoback MD, Healy JH. Continuation of a deep borehole stress measurement profile near the San Andreas Fault: 1. Hydraulic fracturing stress measurements at Hi Vista, Mojave Desert, California. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/jb093ib12p15183] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Guo F, Morgenstern N, Scott J. Interpretation of hydraulic fracturing breakdown pressure. ACTA ACUST UNITED AC 1993. [DOI: 10.1016/0148-9062(93)91221-4] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Schmitt DR, Zoback MD. Diminished pore pressure in low-porosity crystalline rock under tensional failure: Apparent strengthening by dilatancy. ACTA ACUST UNITED AC 1992. [DOI: 10.1029/91jb02256] [Citation(s) in RCA: 60] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Wang Y, Dusseault M. Borehole yield and hydraulic fracture initiation in poorly consolidated rock strata—part II. permeable media. ACTA ACUST UNITED AC 1991. [DOI: 10.1016/0148-9062(91)90592-a] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Detournay E, Cheng AD, Roegiers JC, McLennan J. Poroelasticity considerations in In Situ stress determination by hydraulic fracturing. ACTA ACUST UNITED AC 1989. [DOI: 10.1016/0148-9062(89)91428-9] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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A characterization of pressure records in inelastic rock demonstrated by hydraulic fracturing measurements in salt. ACTA ACUST UNITED AC 1989. [DOI: 10.1016/0148-9062(89)91442-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Evans KF. Appalachian Stress Study: 3. Regional scale stress variations and their relation to structure and contemporary tectonics. ACTA ACUST UNITED AC 1989. [DOI: 10.1029/jb094ib12p17619] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Detournay E, Cheng AD. Poroelastic response of a borehole in a non-hydrostatic stress field. ACTA ACUST UNITED AC 1988. [DOI: 10.1016/0148-9062(88)92299-1] [Citation(s) in RCA: 229] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Plumb RA, Cox JW. Stress directions in eastern North America determined to 4.5 km from borehole elongation measurements. ACTA ACUST UNITED AC 1987. [DOI: 10.1029/jb092ib06p04805] [Citation(s) in RCA: 79] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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