Model studies of explosive well stimulation techniques

Fourney, W.L.; Barker, Donald E.; Holloway, D.C.

doi:10.1016/0148-9062(81)90737-3

Cited by 58 publications

(28 citation statements)

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“…Fourney et al (1981) observed that presence of air gap at the top causes shock wave to move up and interact with stemming base causing a pressure increase at air-stemming interface. It helps in enhanced breakage in the air-deck and stemming regions.…”

Section: Different Viewsmentioning

confidence: 95%

“…This charge structure ensures multiple impacts of a shock wave into the surrounding medium, and at the same time, it changes the nature of energy transfer to the strained rock mass that leads to an increase in the effective explosion energy for rock breakage. Fourney et al (1981) conducted a series of experiments in thick Plexiglas blocks to investigate dynamic crack propagation resulting from an airfilled bore hole. High-speed photography in conjunction with dynamic photo elasticity was used for this purpose.…”

Section: Physical Modelingmentioning

confidence: 99%

“…The shock waves oscillate in the borehole, interact mutually and also with stemming column and/or hole bottom. The repeated interactions result in the generation of reinforced secondary shock front and allow shock waves to act over the surrounding rock mass for a longer period (Mel'Nikov and Marchenko 1971;Fourney et al 1981;Moxon et al (1993). The fracture and stress profiles resulting from different charge geometries and distributions are shown in Fig.…”

Section: Introductionmentioning

confidence: 97%

“…Later on, several researchers have conducted theoretical and model studies towards further understanding of the underlying mechanism and its effects on blast performance (Fourney et al 1981;Chiappetta and Memmele 1987;Moxon et al 1993;Liu and Katsabanis 1996;Lu and Hustrulid 2003).…”

Section: Introductionmentioning

confidence: 98%

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Theory and Practice of Air-Deck Blasting in Mines and Surface Excavations: A Review

Jhanwar

2011

Geotech Geol Eng

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The mechanism by which the explosive energy is transferred to the surrounding rock mass is changed in air-deck blasting. It allows the explosive energy to act repeatedly in pulses on the surrounding rock mass rather than instantly as in the case of concentrated charge blasting. The air-deck acts as a regulator, which first stores energy and then releases it in separate pulses. The release of explosion products in the air gap causes a decrease in the initial bore hole pressure and allows oscillations of shock waves in the air gap. The performance of an air-deck blast is basically derived from the expansion of gaseous products and subsequent multiple interactions between shock waves within an air column, shock waves and stemming base and shock waves and hole bottom. This phenomenon causes repeated loading on the surrounding rock mass by secondary shock fronts for a prolonged period. The length of air column and the rock mass structure are critical to the ultimate results. Several attempts have been made in the past to study the mechanism of air-deck blasting and to investigate its effects on blast performance but a clear understanding of the underlying mechanism and the physical processes to explain its actual effects is yet to emerge. In the absence of any theoretical basis, the air-deck blast designs are invariably carried out by the rules of thumb. The field trials of this technique in different blast environments have demonstrated its effectiveness in routine production blasting, pre-splitting and controlling over break and ground vibrations etc. The air-deck length appropriate to the different rock masses and applications need to be defined more explicitly. It generally ranges between 0.10 and 0.30 times the original charge length. Mid column air-deck is preferred over the top and bottom air-decks. Top air-deck is used especially in situations, which require adequate breakage in the stemming region. The influence of air-deck location within the hole on blast performance also requires further studies. This paper reviews the status of knowledge on the theory and practice of air-deck blasting in mines and surface excavations and brings out the areas for further investigation in this technique of blasting.

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Section: Different Viewsmentioning

confidence: 95%

Section: Physical Modelingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 98%

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Theory and Practice of Air-Deck Blasting in Mines and Surface Excavations: A Review

Jhanwar

2011

Geotech Geol Eng

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“…H1YiQ1Ak [18] pointed out that the heterogeneity, isotropy, own defects, joints, and faults of the rock mass have great influence on the performance of rock blasting. Fourney et al [19] also carried out further research on eccentric decoupling charge. However, these studies assume that the surrounding rock of the borehole is homogeneous and isotropic, without considering the heterogeneity of the surrounding rock, the initial damage of the surrounding rock, and the damage of surrounding rock caused by the blasting.…”

Section: Introductionmentioning

confidence: 99%

Calculation Model and Decoupling Coefficient Sensitivity Study of Periphery Hole for Eccentric Decoupled Charge in Highway Tunnels

Wang

Liu

2018

Shock and Vibration

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On the basis of the eccentric decoupled charge form on site and borehole concentric decoupled computational theory, the calculation model of eccentric decoupling charge would be established in the present study. The calculation model takes into account the influence factors such as damage to the surrounding rock, air, and water decoupled media. Besides, based on the proposed calculation model, blasting effect of a small-diameter EJ-102 emulsion explosive is calculated by using ANSYS LS-DYNA. The influence of decoupling coefficient, different rock grade, and different RQD value on blasting effect is obtained by sensitivity analysis of the simulated parameters. Then the calculated results are compared with the empirical results. The blasting parameters of fractured rock mass are also optimized by numerical simulation.

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Influence of hydrostatic compression on crack development during an explosion

Кузнецов¹

1984

Soviet Mining Science

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Around 20 years ago, experimental investigations were conducted ob the influence of external pressure on the destructive action of an explosion.Since interest in the problem has again recently cropped up, in connection with oll and gas well stimulation this time [i, 2], it is meaningful Co analyze the experimental results obtained, and even more so, since they were not published completely in their time.We present here the results obtained i~ the Hydrodynamics Institute of the Siberian Branch of the Academy of Sciences of the USSR [3].,The tests were conducted in cylindrical Plexiglas blocks with height equal to the dlam~ eter. The specimen dimensions were 7 and 15 cm. Lead azide of 0.l-g mass for smalland 0o3-g mass for the large specimens was used as explosive.The charge was placed at the specimen center through a 6-~n-diameter axial hole, which was then filled with liquid styracryl. After polymerization, the physical properties of this latter are in agreement with the properties of organic galss. The specimens were placed in a hlgh-pressure chamber.The first series of tests (with the large specimens) were conducted in a ch-mber fabricated from an instrument shaft and having an organic glass viewing window. Water was the working fluid. The pressure varied in the 0.i (l atm) to 70-MPa range. High-speed filming of the destruction zone development (darkening) in the material was executed in the frame-by-frame mode with an SFR camera. Drawn copies of the movie frames at 32-~sec time intervals are presented in Fig. 1 for 0.i-, 9-, and 20-MPa pressures.In certain cases the development of isolated cracks could be traced.The trajectories R(t) of a conical crack developing from the bottom of a well, or more accurately, from the angular stress concentrators being formed as a result of the drilling, are shown in Fig. 2 for different pressures. Let us note that if the angular concentrators are removed after the drilling (for example, to treat the bottom of the hole wlth dichlorethane), then no conical crack is formed.Visual observations and photography of the specimens after the explosion and reduction of the pressure showed that the size of the destruction zone does not change upon diminution of the pressure from working to atmospheric. This circumstance permitted going over to a closed chamber in the research, where there was the opportunity to raise the external pressure substantially, to 400 MPa. Specimens of 8-cm dimension with a 0.l-g mass charge could here be used. A mixture of kerosene and machine oil was the working fluid o

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Model studies of explosive well stimulation techniques

Cited by 58 publications

References 1 publication

Theory and Practice of Air-Deck Blasting in Mines and Surface Excavations: A Review

Theory and Practice of Air-Deck Blasting in Mines and Surface Excavations: A Review

Calculation Model and Decoupling Coefficient Sensitivity Study of Periphery Hole for Eccentric Decoupled Charge in Highway Tunnels

Influence of hydrostatic compression on crack development during an explosion

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