Cyclic hydraulic fracturing of pocheon granite cores and its impact on breakdown pressure, acoustic emission amplitudes and injectivity

Zhuang, Łi; Kim, Kwang Yeom; Jung, Sung Gyu; Diaz, Melvin; Min, Ki‐Bok; Zang, Arno; Stephansson, Ove; Zimmermann, Günter; Yoon, Jeoung Seok; Hofmann, Hannes

doi:10.1016/j.ijrmms.2019.104065

Cited by 95 publications

(64 citation statements)

References 32 publications

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“…e developed biaxial experimental setup in the literature varies, depending on several important technical parameters. ese parameters include maximum axial pressure/load (e.g., 1000 MPa [59] and 1000 kN [44]), maximum confining pressure (e.g., 20 MPa [61], 100 MPa [62], and 137 MPa [44]), maximum pore pressure (e.g., 100 MPa [59]), maximum temperature (e.g., 100°C [60], 200°C [62], and 300°C [44]), and maximum fluid injection pressure (e.g., 35 MPa [63] and 165 MPa [44]). Similarly, a biaxial experimental setup may be also fitted out with AE sensors, deformation sensors, pressure sensors, high-speed cameras, etc.…”

Section: Biaxial Typementioning

confidence: 99%

Advances in Laboratory‐Scale Hydraulic Fracturing Experiments

Qian

Guo

Wang

et al. 2020

Advances in Civil Engineering

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Hydraulic fracturing has been widely applied to stimulate the natural gas and oil production from unconventional reservoirs. To optimize the design of hydraulic fracturing in this application, an accurate estimation of the initiation and propagation of hydraulic fractures is indispensable. However, it still remains challenging as a result of the complex stress state and geological conditions. On account of their ability to complete control some significant factors and efficient observation of fracture geometry, laboratory-scale hydraulic fracturing experiments have received abundant research attention in recent years. This paper presents a review of the state of the art of laboratory-scale hydraulic fracturing experiments, focusing on the scaling analysis, experimental setup, fracturing fluids, and sample preparation. A discussion of the directions for future research is also provided with the intention of stimulating the development of the experimental technique for investigating hydraulic fracturing.

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Section: Biaxial Typementioning

confidence: 99%

Advances in Laboratory‐Scale Hydraulic Fracturing Experiments

Qian

Guo

Wang

et al. 2020

Advances in Civil Engineering

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“…In an in-situ project, a traditional view is that the maximum induced earthquake magnitudes are only related to the volume of injected fluid [46]. Therefore, to get a good fracture network and avoid a dangerous earthquake, a small injection flow rate with a long propagation is always adopted in field-scale operation over recent years [47,48]. Whereas, this method also could cause a large earthquake, for example, hydraulic fracturing of the Pohang hydraulic fracturing project almost lasted several months over two years, a M w 5.5 earthquake was caused, this earthquake injured about 70 people and induced extensive damage to the Pohang city [49].…”

Section: Of 31mentioning

confidence: 99%

Experimental Study of Fracture Propagation: The Application in Energy Mining

Cheng

Zhang

2020

Energies

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Hydraulic fracturing has been widely used in recent years as a key technology to improve energy mining efficiency in petroleum and geothermal industries. Laboratory hydraulic fracturing experiments recently were completed in six large-scale 300 × 300 × 300 mm rock specimens to better understand this complex process of hydraulic fracturing. When injection flow rate increases from 5 to 30 mL/min. The fracture initiation pressures and breakdown pressures increase, the propagation times and post-fracturing pressures decrease. The fracture geometries are observed and analyzed, mean injection power is proposed and results show that it could be used to roughly estimate the fracture total lengths. Moreover, the fracture permeabilities based on the pressure data are calculated and linearly ascend with the increase of injection flow rates. These results can provide some reasonable advice for implementing hydraulic fracturing reservoir simulations and improving energy production efficiency on application to field-scale operation.Hydraulic fracturing usually relates complicated solid-fluid coupling processes. Due to the compactness and the low permeability of the granite, an intact large-size granite sample requires a high fracturing pressure to trigger the fracture. To better understand the characteristics of hydraulic fracturing process and fracture network after hydraulic fracturing. In this work, we carried out laboratorial hydraulic fracturing experiments with a true triaxial fracturing apparatus designed by Jilin University. Its cubic specimen fracturing capsule size is 300 × 300 × 300 mm. The granite samples were collected from the Songliao Basin petroleum reservoir field in the northeastern part of China. In order to investigate the injection flow rate on hydraulic fracturing chrematistics, we conducted hydraulic fracturing tests at different injection flow rates for six rocks. The initiation pressure, breakdown pressure, post-fracturing pressure, and propagation time were analyzed based on the fracturing pressure curves. The rock specimens were cut in half after test and the fracture geometry was observed. Based on recorded pressure data and curves, the fracture permeabilities of all specimens were calculated. Results in this study could provide some reasonable advice for implementing hydraulic fracturing reservoir simulations and improving energy production efficiency on application to field-scale operation. Laboratorial Tests BackgroundThe granite samples used in this study are taken from a place nearby YS-2 well (Figure 1) in the Songliao Basin [39]. The YS-2 well (127.25 • E, 52.36 • N) is in the Daqing Oilfield about 78 km from Daqing City, The YS-2 well is a geothermal energy exploration well, and exploration data shows that the geothermal resources here are abundant. As large size intact rock samples cannot be gotten from a wellbore. We use the outcrop rock samples as substitutes (Figure 2a). Three independent triaxial principal stresses are applied on cube-shaped samples to simulate the real field in-situ st...

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“…In an attempt to reduce seismicity during hydraulic fracturing and improve efficiency, fatigue hydraulic fracturing through cyclic injection schemes has been proposed. Hofmann et al (2018), Patel et al (2017), Zhuang et al (2020Zhuang et al ( , 2019 introduced experimental and field work on cyclic injection schemes which reduce the breakdown pressure and reduce the maximum amplitude of associated acoustic emission (AE) events released by fracture generation. The final major area of research concerning fracture propagation has been the investigation of fracture propagation with respect to anisotropic mechanical properties and pre-existing interfaces such as natural fracture networks and bedding planes.…”

Section: Introductionmentioning

confidence: 99%