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Reservoir simulation-based modeling for characterizing longwall methane emissions and gob gas venthole production.

Authors
Karacan-CÍ; Esterhuizen-GS; Schatzel-SJ; Diamond-WP
Source
Int J Coal Geol 2007 Jul; 71(2-3):225-245
NIOSHTIC No.
20032380
Abstract
Longwall mining alters the fluid-flow-related reservoir properties of the rocks overlying and underlying an extracted panel due to fracturing and relaxation of the strata. These mining-related disturbances create new pressure depletion zones and new flow paths for gas migration and may cause unexpected or uncontrolled migration of gas into the underground workplace. One common technique to control methane emissions in longwall mines is to drill vertical gob gas ventholes into each longwall panel to capture the methane within the overlying fractured strata before it enters the work environment. Thus, it is important to optimize the well parameters, e.g., the borehole diameter, and the length and position of the slotted casing interval relative to the fractured gas-bearing zones. This paper presents the development and results of a comprehensive, "dynamic," three-dimensional reservoir model of a typical multi-panel Pittsburgh coalbed longwall mine. The alteration of permeability fields in and above the panels as a result of the mining-induced disturbances has been estimated from mechanical modeling of the overlying rock mass. Model calibration was performed through history matching the gas production from gob gas ventholes in the study area. Results presented in this paper include a simulation of gas flow patterns from the gas-bearing zones in the overlying strata to the mine environment, as well as the influence of completion practices on optimizing gas production from gob gas ventholes.
Keywords
Gases; Mine-gases; Mine-shafts; Mine-workers; Mathematical-models; Statistical-analysis; Statistical-quality-control; Coal-gas; Coal-mining; Coal-workers; Particle-aerodynamics; Mining-industry; Underground-mining
Contact
CO Karacan, NIOSH, Pittsburgh Research Laboratory, Washington, DC 20201 USA
CODEN
IJCGDE
CAS No.
74-82-8
Publication Date
20070702
Document Type
Journal Article
Email Address
cok6@cdc.gov
Fiscal Year
2007
NTIS Accession No.
NTIS Price
Issue of Publication
2-3
ISSN
0166-5162
NIOSH Division
PRL
Source Name
International Journal of Coal Geology
State
PA
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