scholarly journals DEVELOPMENT OF HARD-TO-REMOVE COAL RESERVES OF STEEP AND STEEPLY INCLINED SEAMS

2021 ◽  
pp. 91-101
Author(s):  
Boris A. Anfyorov ◽  
Lyudmila V. Kuznetsova
Keyword(s):  
Coal Reserves

Assessing the mechanical stability of horizontal boreholes in coal

2007 ◽  
Vol 44 (7) ◽  
pp. 797-813 ◽  
Author(s):  
C D Hawkes
Keyword(s):  
Mechanical Stability ◽  
Petroleum Industry ◽  
Mining Industry ◽  
Sensitivity Analyses ◽  
Directional Drilling ◽  
Vertical Wells ◽  
Borehole Stability ◽  
Linear Elastic ◽  
Geophysical Logs ◽  
Coal Reserves

Horizontal wells are used in some geological settings in the petroleum industry to produce methane from coal seams. Horizontal directional drilling is used in the mining industry to enhance the effectiveness of coal degasification procedures and to aid in the delineation of coal reserves. Coals tend to be mechanically weak, hence they are prone to borehole instability related problems during drilling, completion, and production operations. This paper includes a review of the mechanical properties of selected coals and provides two empirical cross-plots that can be used for estimating coal strength from index tests and geophysical logs. Linear elastic borehole stability models are demonstrated to be appealing because they are easily implemented, require a minimum of input data, and are well suited to rapid parameter sensitivity analyses. Using experience obtained drilling vertical wells in a given setting, a methodology is described for calibrating linear elastic models to provide realistic borehole stability predictions. Furthermore, as demonstrated using a western Canadian example (a shallow well in the Ardley coal zone), relatively simple elastoplastic models can be used effectively for borehole stability analyses. The important effects of filter cake, coal depth, and rock strength anisotropy are demonstrated with two different elastoplastic models.Key words: borehole stability, coal, methane, directional drilling, strength, stress.

Numerical Study of Coal Composition Effects on the Performance of Gasification Through Computational Fluid Dynamic

2019 ◽  
Vol 17 (7) ◽  
Author(s):  
Imran Nazir Unar ◽  
Suhail Ahmed Soomro ◽  
Ghulamullah Maitlo ◽  
Shaheen Aziz ◽  
Rasool Bux Mahar ◽  
...  
Keyword(s):  
Computational Fluid Dynamic ◽  
Stokes Equations ◽  
Numerical Study ◽  
Fluid Dynamic ◽  
Great Influence ◽  
Electricity Production ◽  
Combustion Model ◽  
Heating Value ◽  
Coal Composition ◽  
Coal Reserves

Abstract Pakistan is very rich in coal reserves specifically after exploration of Thar coal reserves. At the same time country is facing energy crises due to shortage or unavailability of sustainable fuel supply at a cheaper rate. One potential solution is coal gasification which gives clean synthetic gas usually called syngas for use as an alternative fuel source for electricity production at a cheaper rate as well as a source of recovering different chemicals used as basic raw materials in other industries. Numerical simulations have been performed in this work for the gasification process of indigenous coal on a 2D computational fluid dynamic (CFD) model of downdraft entrained-flow gasifier using commercial CFD software FLUENT®6.3.26. Navier-stokes equations along with transport equations for species have been solved using eddy-dissipation combustion model. The compositions of indigenous coals (Thar, Lakhra, and Sonda) were used in simulations as gasification feedstock. Rich oxidant conditions 95 % O2 and 5 % N2 were set for gasification. The gasification performance was studied by comparing efficiencies of gasification and quality of syngas produced for three types of coal feedings. The temperature and pressure profiles inside the gasifier were also studied. From simulation results, the great influence of coal composition was observed in the performance of gasification. Lakhra coal produced syngas with a maximum heating value of 20.55 MJ/kg whereas sonda coal produced syngas with a minimum heating value of 17.96 MJ/kg.

scholarly journals Criteria for the difficulty of working out coal-bearing zones of quarry fields

2019 ◽  
Vol 134 ◽  
pp. 01018
Author(s):  
Alexei Selyukov ◽  
Nuray Demirel
Keyword(s):  
Complex Structure ◽  
Uneven Distribution ◽  
Open Pit ◽  
Coal Seams ◽  
Mining Methods ◽  
Coal Reserves ◽  
Working Out

Coal-bearing zones of open pit fields are represented by formations of coal seams from inclined to steep bedding with unstable thickness, both in dip and strike with different dip angles even within the same strata, with varying rock inter-layers and strength. In addition, most coal seams have a complex structure, including rock layers inside. In most cases, there is an uneven distribution of coal seams, and, consequently, coal reserves over the area of quarry fields. In this regard, for the analysis of quarry fields, there is a need to select criteria for assessing the complexity of coal-bearing zones for the purpose of systematizing them and choosing directions for constructing technological schemes for excavation and loading operations and mining methods.

Underground Сoal Gasification Efficiency in Areas of High Faulting Frequency

2017 ◽  
Vol 25 ◽  
pp. 118-127
Author(s):  
Vasyl Lozynskyi
Keyword(s):  
Coal Seam ◽  
Coal Gasification ◽  
Analytical Calculation ◽  
Underground Coal Gasification ◽  
Practical Application ◽  
Gasification Efficiency ◽  
Rational Order ◽  
Coal Reserves ◽  
Gasification Technology ◽  
Generator Gas

The purpose of this paper is substantiating of efficiency during application of borehole underground coal gasification technology based on target coal seam geology. Comprehensive methodology that included analytical calculation is implemented in the work. To determine the efficiency of coal seam gasification in faulting areas, an economic calculation method was developed. The obtained conditions of coal seam allow to provide rational order of mine workings. Conclusions regarding the implementation of the offered method are made on the basis of undertaken investigations. The obtained results with sufficient accuracy in practical application will allow consume coal reserves in the faulting zones using environmentally friendly conversion technology to obtain power and chemical generator gas, chemicals and heat.

Study on Strata Movement Control of Twice Strip Mining

2014 ◽  
Vol 962-965 ◽  
pp. 1085-1090 ◽  
Author(s):  
Bingnan Hu
Keyword(s):  
New Technology ◽  
Movement Control ◽  
Horizontal Layer ◽  
Additional Stress ◽  
Collapse Mechanism ◽  
Strip Mining ◽  
Karst Cave ◽  
Strata Movement ◽  
Strata Deformation ◽  
Coal Reserves

In order to further improve the recovery ratio in strip mining, this paper makes use of the law of insufficiency and sufficiency in strata movement and buildings’ additional stress release features, puts forward twice strip mining technology. The paper introduces the method and feasibility of twice strip mining. By analyzing karst cave collapse mechanism, the paper points out vertical cracks and horizontal layer separations are the direct causes of karst caves collapses and small strength mining each time can reduce karst cave collapse. The new technology has been applied in Pinghu Mine. It has totally extracted recoverable coal reserves under village buildings, effectively controlled strata deformation, and successfully avoided karst cave collapse within Yangkeng village.

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