scholarly journals A numerical simulation on coal seam gas recovery from high temperature reservoir

2020 ◽  
Vol 24 (6 Part B) ◽  
pp. 3971-3978
Author(s):  
Teng Teng ◽  
Xiao-Yan Zhu ◽  
Xiang-Yang Zhang ◽  
Peng-Fei Chen ◽  
Yu-Ming Wang ◽  
...  
Keyword(s):  
High Temperature ◽  
Coal Seam ◽  
Mechanical Model ◽  
Gas Flow ◽  
Gas Production ◽  
Coal Seam Gas ◽  
Production Time ◽  
Gas Recovery ◽  
Coal Deformation ◽  
Fully Coupled

The coal seam gas recovery in deep reservoirs often meets high temperature. The change of temperature can greatly influence gas sorption, and couples heat transfer with coal deformation and gas-flow. This paper modifies the conventional Langmuir adsorption equation into a non-isothermal adsorption equation with a set of experimental data. After then, a fully coupled thermo-hydro-mechanical model of coal deformation, gas-flow and heat transfer is established. By using a finite element approach of COMSOL multi-physics, a numerical simulation of coal seam gas recovery from high temperature reservoir is subsequently implemented. The results show that the gas pressure and temperature decrease with production time and increase with the distance from production well, the reservoir permeability decreases with production time due to the compaction of increasing effective stress to coal fracture network, the cumulative gas production increases with production time exponentially whereas the production efficiency decreases negative exponentially, that the gas production in earlier 10 years accounts for 80% of the total production in 30 years. Our fully coupled thermo-hydro-mechanical model can improve the current understanding of coal seam gas recovery from high temperature reservoirs.

Case study of the effects on coal seam gas well production with installation of well head compression (oil-flooded rotary screw type): early outcomes of an Australian trial of four wells in the Bowen Basin

2017 ◽  
Vol 57 (2) ◽  
pp. 629
Author(s):  
Terrance Presley ◽  
Evilia Kurnia ◽  
Basia Wronski
Keyword(s):  
Coal Seam ◽  
Gas Flow ◽  
Lower Surface ◽  
Gas Production ◽  
Coal Seam Gas ◽  
Potential Wells ◽  
Energy Field ◽  
Operational Issues ◽  
Rotary Screw

This paper discusses the early outcomes of a trial of well head compression on coal seam gas (CSG) wells to lower surface pressure at the well head. This is a case study of four Johnson Controls Frick rotary screw compressor packages that were installed on CSG wells in an Origin Energy field in the Bowen basin and the early effects of lower well pressures on increased gas production due to the installation of compression. In mid-2016 Johnson Controls installed four compressor packages on Origin Energy wells with different characteristics (age, flow pressure), with a view of determining uplift of gas flow over the remaining life of the well, as well as operational issues with having well head compression. The expected versus actual uplift is compared for the different wells, with a view of providing some guidance on future potential wells that will benefit from this type of compression. Operational issues, such as effects on water flow, effect of oil and overall design considerations for well head compression, are also discussed.

Fully coupled thermo-hydro-mechanical model for extraction of coal seam gas with slotted boreholes

2016 ◽  
Vol 31 ◽  
pp. 226-235 ◽  
Author(s):  
Feng Gao ◽  
Yi Xue ◽  
Yanan Gao ◽  
Zhizhen Zhang ◽  
Teng Teng ◽  
...  
Keyword(s):  
Coal Seam ◽  
Mechanical Model ◽  
Coal Seam Gas ◽  
Fully Coupled

scholarly journals A fully coupled thermo-hydro-mechanical model associated with inertia and slip effects

2017 ◽  
Vol 21 (suppl. 1) ◽  
pp. 259-266 ◽  
Author(s):  
Yi Xue ◽  
Zheng-Zheng Cao ◽  
Cheng-Zheng Cai ◽  
Fa-Ning Dang ◽  
Peng Hou ◽  
...  
Keyword(s):  
Coal Seam ◽  
Mechanical Model ◽  
Coalbed Methane ◽  
Gas Flow ◽  
Gas Adsorption ◽  
Coal Bed ◽  
Klinkenberg Effect ◽  
Numerical Result ◽  
Slip Effects ◽  
Fully Coupled

The inertia and slip effects have a significant impact on the coal seam gas extraction. A fully coupled thermo-hydro-mechanical model is established in this study, which takes into account the influence of non-Darcy gas flow and Klinkenberg effect on the coal seam deformation and coalbed methane migration. The numerical result shows that the coalbed methane migration and transport evolution coal bed methane reservoir is not only dependent on the coal matrix deformation, gas pressure and gas adsorption, but also closely related to inertia effect and slip effect.

scholarly journals Experimental Study on the Gas Flow Characteristics and Pressure Relief Gas Drainage Effect under Different Unloading Stress Paths

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-10 ◽  
Author(s):  
Chaolin Zhang ◽  
Jiang Xu ◽  
Enyuan Wang ◽  
Shoujian Peng
Keyword(s):  
Coal Seam ◽  
Gas Flow ◽  
Flow Characteristics ◽  
Gas Production ◽  
Gas Pressure ◽  
Coal Seam Gas ◽  
Pressure Relief ◽  
Gas Drainage ◽  
Coal Temperature ◽  
Drainage Effect

Coal seam gas is a critical substance because it can be a source of a large quantity of clean energy as well as a dangerous source of risk. A pressure relief gas drainage is an effective and widely used method for coal seam gas recovery and gas disaster control in coal mines. A series of pressure relief gas drainage experiments were conducted using large-scale coal samples under different unloading stress paths in this study to explore the unloading stress paths. From the experimental results, the dynamic evolutions of gas pressure, coal temperature, and gas production were analyzed. The trends of gas pressure and coal temperature during pressure relief gas drainage were similar: dropping rapidly first and then slowly with time. Correspondingly, gas production was fast in the early stage of pressure relief gas drainage and became stable thereafter. Meanwhile, gas flow characteristics were significantly affected by the unloading stress paths. Gas pressure and coal temperature had the maximum descent by unloading stress in three directions simultaneously, and the unloading stress of the Z direction had the minimal impact when only unloading in one direction of stress. However, the influence of unloading stress paths on gas production was complex and time dependent. The difference coefficient parameter was proposed to characterize the influence degree of unloading stress paths on the pressure relief gas drainage effect. Eventually, the selection of unloading stress path under different situations was discussed based on time, which is expected to provide the basis for pressure relief gas drainage.

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