Enhancing the detection of small coal structures by seismic diffraction imaging

Zhou, Binzhong; Hatherly, Peter; Sun, Weijia

doi:10.1016/j.coal.2017.04.010

Cited by 25 publications

(8 citation statements)

References 49 publications

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“…Current technology is able to detect fault throws with a resolution of 5 m at best although more sophisticated processing can perhaps improve this (Zhou et al 2015). General relationships between throw and fault length (Watterson et al 1996) and between fault length and magnitude (Zoback and Gorelick 2012) of seismic events which occur on a fault suggest that a throw of 5 m would be from a fault of a few hundred metres in length and correspond to a seismic event of the order of ML 1.5, i.e.…”

Section: Discussionmentioning

confidence: 99%

Horizontal respect distance for hydraulic fracturing in the vicinity of existing faults in deep geological reservoirs: a review and modelling study

Westwood

Toon

Styles

et al. 2017

Geomech. Geophys. Geo-energ. Geo-resour.

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Hydraulic fracturing is widely used in the petroleum industry to enhance oil and gas production, especially for the extraction of shale gas from unconventional reservoirs. A good understanding of the vertical distance which should be preserved between hydraulic stimulation and overlying aquifers (potable water) has been demonstrated as being greater than 600 m (2000 feet). However, the effective application of this technique depends on many factors; one of particular importance is the influence of the fracturing process on pre-existing fractures and faults in the reservoir, which, however, to date, has had little analysis. Specifically, the identification of the required respect distance which must be maintained between the hydraulic fracturing location and pre-existing faults is of paramount importance in minimizing the risk of felt, induced seismicity. This must be an important consideration for setting the guidelines for operational procedures by legislative authorities. We investigate the respect distance using a Monte Carlo approach, generating fifty discrete fracture networks for each of three fracture intensities, on which a hydraulic fracturing simulation is run, using FracMan Ò . The Coulomb stress change of the rock surrounding the simulated injection stage is calculated for three weighted source mechanisms combining inflation, strike-slip and reverse. The lateral respect distance is obtained using values from literature of the amount of stress required to induce movement on a pre-existing fault. We find that the lateral respect distance is dependent on fracture intensity and the failure threshold. However, the weighting of the source mechanism has limited effect on the lateral respect distance.

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Section: Discussionmentioning

confidence: 99%

Horizontal respect distance for hydraulic fracturing in the vicinity of existing faults in deep geological reservoirs: a review and modelling study

Westwood

Toon

Styles

et al. 2017

Geomech. Geophys. Geo-energ. Geo-resour.

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“…Improving the resolution of geological information will provide more realistic model scenarios, particularly important for geotechnical challenges and improving stability of underground roofs and walls. Techniques are currently being developed for example to detect faults with less than 1m throw [20,21]. Presence of minerals using remotely sensed data hyperspectral data is used widely for geological characterisation [22].…”

Section: Assessment Of Current Geological Modelling Capabilities Agaimentioning

confidence: 99%

Cousins, Siblings and Twins: A Review of the Geological Model’s Place in the Digital Mine

Hodgkinson

Elmouttie

2020

Resources

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Digital mining is a broad term describing the enhancement of the physical mining method through the use of digital models, simulations, analytics, controls and associated feedbacks. Mining optimisation will be improved through increased digitisation and real-time interactions via a “digital twin”, however digitisation of the rock mass component of this system remains problematic. While engineered systems can be digitally twinned, natural systems containing inherent uncertainties present challenges, especially where human-intensive procedures are required. This is further complicated, since the mining system is designed not only to interact with, but to substantially and continually alter its surrounding environment. Considering digital twin requirements and geological modelling capabilities, we assess the potential for a mine’s synchronised digital twin to encompass the complex, uncertain, geological domain within which it interacts. We find that current geological (and indeed hydro-geological) models and simulations would support digitisation that could be considered to provide, at best, a digitised ‘cousin’. Based on this assessment, the digital twin’s value for medium term forecasting of mining operations may be limited and we discuss technological advancements that can mitigate this.

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“…Figure 3(a) shows the raw profile, which is dominated by the direct arrival and has no indication of any reflected guided BHR waves as they are relatively weak compared to the direct waves. To enhance the reflected guided BHR waves, a 7-trace, moving average error filter (Zhou, Hatherly and Sun 2017;Huo et al 2019a) was applied to the raw data, and the filtered result was followed by the application of a 25 ns automatic gain control (AGC). The result is presented in Figure 3(b), where the reflected guided BHR waves from coal seam roof and floor can be easily observed.…”

Section: Geological Model and Corresponding Bhr Profilementioning

confidence: 99%

Coal top detection by conductively guided borehole radar wave imaging for open cut blast‐hole drilling

Zhou

Werken

Huo

2019

Geophysical Prospecting

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Damage to the top of coal seams, caused by incorrect blast stand‐off distances, results in coal losses of up to 10–15% to the Australian open cut coal mining operations. This is a serious issue to be addressed. Here we propose to use a new forward‐looking imaging technique based on the borehole radar technology to predict the coal seam top in real time while drilling blast holes. This is achieved by coupling the conventional borehole radar waves on to a steel drill rod to induce a guided wave along the axial drill rod. The drill rod ahead of the borehole radar behaves as a forward‐looking antenna for the guided waves. Both numerical modelling and field trials simulating a drill rod as an antenna are used to investigate the feasibility of the proposed technique for prediction of the coal top under typical open cut environments. Numerical modelling demonstrated that conductivity of the overburden is the most important factor affecting our ability to see coal seams ahead of the drill bit, the guided borehole radar waves could be used for top coal prediction and a theoretical prediction error less than 10 cm and a forward‐looking capability of 4–6 m can be achieved. Field trials at Australian open cut coal mines also demonstrated that guided borehole radar waves can be observed and used for prediction of coal top ahead of drill bit during blast‐hole drilling in resistive, open cut environments (the average resistivity should be higher than 75 Ωm).

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Enhancing the detection of small coal structures by seismic diffraction imaging

Cited by 25 publications

References 49 publications

Horizontal respect distance for hydraulic fracturing in the vicinity of existing faults in deep geological reservoirs: a review and modelling study

Horizontal respect distance for hydraulic fracturing in the vicinity of existing faults in deep geological reservoirs: a review and modelling study

Cousins, Siblings and Twins: A Review of the Geological Model’s Place in the Digital Mine

Coal top detection by conductively guided borehole radar wave imaging for open cut blast‐hole drilling

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