Increased gas recovery from the wells in coal-rock massif due to applied interval hydraulic fracturing and fracture filling with gas-conductive materials

Author(s):  
V Perepelitsa ◽  
L Shmatovskiy ◽  
A Kolomiets
Author(s):  
А. Molodetskyy ◽  
◽  
О. Gladkaya ◽  
V. Slyusarev ◽  
◽  
...  

2018 ◽  
Vol 2018 ◽  
pp. 1-16 ◽  
Author(s):  
Zhigang Yuan ◽  
Yaohua Shao

The mechanism of how hydraulic fracturing influences gas drainage in coal-rock mass is still not clear due to its complex mechanism. In this work, statistical distributions are firstly introduced to describe heterogeneity of coal-rock mass; a novel simultaneously coupled mathematical model, which can describe the fully coupled process including seepage-damage coupling during hydraulic fracturing process and subsequent gas flow during gas drainage process, is established; its numerical implementation procedure is coded into a Matlab program to calculate the damage variables, and it partly uses COMSOL solver to obtain numerical solutions of governing equations with damage-flow coupling; the mathematical model and its implementation are validated for initial damage pressure and mode of a single solid model without considering flow-damage coupling, as well as fracture initiation pressure and influence of heterogeneity on damage evolution of hydraulic fracturing considering flow-damage coupling; and finally, based on an engineering practice of hydraulic fracturing with two boreholes, the mechanism of how hydraulic fracturing influences gas drainage is investigated, numerical simulation results indicate that coal-rock mass pore-fissure structure has been improved, and there would exist a gas migration channel with characteristics of higher porosity and lower stresses, which demonstrates significant effects and mechanism of hydraulic fracturing on improving coal-rock permeability and enhancing gas drainage. The research results provide a guide for operation of hydraulic fracturing and optimal layout of gas drainage boreholes.


2014 ◽  
Vol 8 (4) ◽  
pp. 431-435
Author(s):  
V Golinko ◽  
◽  
D Saveliev ◽  
Ya Liebiediev ◽  
K Ishchenko ◽  
...  

2021 ◽  
Vol 37 (3) ◽  
pp. 28-34
Author(s):  
V. Yu. Dovhal

Purpose of work. Determine the conditions of the side rocks stability in a coal massif with different ways of support coal-rock stratum to ensure safe working conditions for miners in the excavation areas of a coal mine with steep coal seams. To achieve this goal, laboratory studies were carried out on models of optical and equivalent materials. The modeling of the stability of side rocks in a coal-rock massif was carried out with the methods of support roadways with vertical timber setsand wooden crib supports: 4-point chock.On models made of optical materials in the analysis of the static field of the distribution of shear stresses in side rocks, the regularity of the change in hazardous manifestations of rock pressure, depending on the deformability of support structures, was recorded. On equivalent models of support structures, the deformation characteristics of experimental samples were determined and their effect on the integrity of the roof under the action of static loads was established. When using rigid support structures in the form of vertical timber sets made of wooden racks to protect sliding drifts, there is a deterioration in the stability of side rocks and destruction of the roof. When using flexible support structures in the form of wooden crib supports: 4-point chock, a smooth deflection of the roof and its integrity are observed. A decrease in the size of the stress concentration zone in the model of a coal-rock massif with workings after the compaction of flexible support structures located above the haul roadway, due to a change in their rigidity, when as a result of the convergence of side rocks, a smooth deflection is provided and the movement of the roof is limited. To ensure the stability of side rocks and development workings, as well as reduce the level of injuries of miners from landslides and collapses in the excavation areas of coal mines that develop steep seams, it is advisable to use flexible support structures, when using which, a smooth deflection of side rocks and their integrity in the mined-out area is ensured coal massif.


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