Relation between coalbed permeability and in-situ stress magnitude for coalbed methane exploration in Jharia and Raniganj coalfields, India

2019 ◽  
Vol 38 (10) ◽  
pp. 800-807 ◽  
Author(s):  
Rima Chatterjee ◽  
Suman Paul ◽  
Prabir Kumar Pal
Keyword(s):  
Coalbed Methane ◽  
History Matching ◽  
Horizontal Stress ◽  
In Situ Stress ◽  
Gas Content ◽  
Major Influence ◽  
Reservoir Pressure ◽  
Horizontal Drilling ◽  
Cbm Production

India is among the top five countries in the world in terms of proven coal reserves and coal production. As such, significant potential exists for commercial recovery of coalbed methane (CBM). Two coalfields, Jharia and Raniganj, located in eastern India are currently under development for CBM. This paper describes work done to determine coal seam properties, ambient stress conditions, and effects of depletion at these coalfields that influence CBM production. Coalbed permeability is a parameter that has a major influence on CBM production. Other influences include in-situ stress direction, gas content, and the application of suitable stimulation techniques. A robust methodology is required to determine both initial coalbed permeability and its relation to in-situ horizontal stress magnitudes. Coalbed permeability at the Jharia and Raniganj coalfields was estimated from porosity and known cleat spacing. Initial permeability of major coalbeds was correlated with effective horizontal stress, yielding satisfactory to very good exponential fit using data from Raniganj and Jharia wells. Acoustic televiewer image-logging tool measurements in a single well in the Jharia coalfield were used to infer a maximum horizontal stress orientation between N25°W and N25°E. Reservoir-pressure-dependent permeability models are presented for coalbeds under uniaxial strain condition. The coalbed permeability is dominated by the existing effective horizontal stresses normal to the cleats. Two prospective coal seams from Jharia have been identified through assessment of the response of horizontal stress to the decline of CBM reservoir pressure. Coalbed permeability increases with the drawdown of reservoir pressure and is exponentially related to the change of effective horizontal stress during reservoir depletion. The results of this study are to be used for production history matching for wells in Jharia and to determine optimal horizontal drilling directions for increased CBM production.

Principle of Well-Net Design for Coalbed Methane Exploitation in Coal Mine Area

2014 ◽  
Vol 543-547 ◽  
pp. 3967-3973
Author(s):  
Bao Shan Han
Keyword(s):  
Coal Mining ◽  
Coal Mine ◽  
Coalbed Methane ◽  
Design Theory ◽  
Surface Condition ◽  
Coal Pillar ◽  
Negative Influence ◽  
In Situ Stress ◽  
Well Location

There are abundant CBM (Coalbed Methane) in China. These CBM has caused a remarkable problem to the coal-mining in China. In order to improve the structure of Chinese energy and eliminate the risk of coal mine gas, the relevant industries and sections have implemented many explorations in CBM enriched areas. With great achievements, there are many important problems in the actions of CBM exploitation. The disadvantageous interaction of the surface CBM well and the later coal mining has been ignored at all. There are many disadvantages and defects. To solve these problems and eliminate or weaken the disadvantageous, the scientific and reasonable design of surface CBM well location is an important step. With the thinking of surface condition, coal mining plan, the arrangement of coal mine laneway, the direction and scale of the in-situ stress, and thinking more about the negative influence to and of surface CBM well, according to the theories of mining dynamics, mining engineering, mining geomechanics, and the CBM engineering, the design theory of the surface CBM well net can be studied. Finally, the arrangement principle of CBM product well in coal field is presented. The existing or future coal pillar will be a critical location for the surface CBM well location.

Analysis of Casing Strength after Casing Wear in Ultra-Deep Rock Salt Formation

2012 ◽  
Vol 616-618 ◽  
pp. 538-542 ◽  
Author(s):  
Fu Xiang Zhang ◽  
Wei Feng Ge ◽  
Xiang Tong Yang ◽  
Wei Zhang ◽  
Jian Xin Peng
Keyword(s):  
Rock Salt ◽  
Coupling Effect ◽  
Equivalent Stress ◽  
Horizontal Stress ◽  
In Situ Stress ◽  
Attrition Rate ◽  
Salt Formation ◽  
Salt Creep ◽  
Casing Wear

To alleviate the problems of casing collapse induced by the coupling effect of rock salt creep and casing wear, the effects of salt creep, attrition rate and casing abrasive position on the equivalent stress on casings in non-uniform in-situ stress field is analyzed by finite-difference model with worn casing, cement and salt formation. It indicates that, creep reduces the yield strength of worn casing to a certain extent; Equivalent stress on casings is bigger and more non-uniform when the abrasion is more serious; Wear position obviously changes the distribution of equivalent stress on casing, and when the wear located along the direction of the minimum in-situ stress, equivalent stress on casing could be the largest that leads to the casing being failed more easily. Equivalent stress on casings increases gradually with creep time increasing and will get to balance in one year or so; In addition, new conclusions are obtained which are different from before: the maximum equivalent stress on casings is in the direction of the minimum horizontal stress, only when the attrition rate of the casing is little; otherwise, it is not. This method could help to improve the wear prediction and design of casings.

Geological and Gas-Content Features of Coalbed Methane System in Qinshui Basin, Shanxi

2012 ◽  
Vol 170-173 ◽  
pp. 1187-1191
Author(s):  
Ya Hui Jia ◽  
Xiao Ping Xie ◽  
Ai Li Lu
Keyword(s):  
Coalbed Methane ◽  
Gas Content ◽  
Structural Deformation ◽  
Shanxi Province ◽  
Qinshui Basin ◽  
The North ◽  
North Part ◽  
Coalbed Methane Reservoir ◽  
High Yields

Colabed methane system is a natural system that consists of coal seams, coalbed methane in them and surrounding rocks. As an unconventional natural gas, reservoir and conservation of coalbed methane are different from those of conventional hydrocarbon. The Qinshui Basin, covering an area about 30,000sq.km in southeastern Shanxi Province, has abundant coalbed methane resources in the carboniferous Taiyuan formation and permian Shanxi formation, with an in-situ methane resource 3.3×1012 m3.In this study, the structural deformation and tectonic evolution of coalbed methane system in Qinshui basin were reported. Relationships between structural deformation and the formation of coalbed methane reservoir in Qinshui Basin were also discussed. The results show that Yangquan-Shouyang area in the north part of the basin and Tunliu-Xiangyuan area in the east are favorable for formation coalbed methane system. In contrast, Jincheng-Qinshui area in the south part of basin and the Qinyuan area in the middle of basin are favorable for both the formation of coalbed methane reservoirs and high yields as well.

In Situ Stress Measurement and Surrounding Rock Stability Analysis of the Gaoligong Mountain Tunnel

2014 ◽  
Vol 501-504 ◽  
pp. 1766-1773
Author(s):  
Lin Hai Bao
Keyword(s):  
Large Deformation ◽  
Principal Stress ◽  
Stress Measurement ◽  
Pressure Coefficient ◽  
Horizontal Stress ◽  
Wall Rock ◽  
In Situ Stress ◽  
Rock Stability ◽  
Mountain Tunnel

Gaoligong Mountain tunnel is the key project in the Dali-Ruili Railway. In order to optimize the design and guide construction, In-situ stress has been conducted in five boreholes using hydraulic fracturing method, the current shallow crustal in-situ stress state at the project area are obtained according to the measurements results, and deep in-situ stress is predicted using lateral pressure coefficient. The test results show that at depths ranging from 299-979m, the maximum horizontal principal stress is 5.33-30.12Mpa, the minimum horizontal principal stress is 4.94-23.11Mpa, the horizontal principal stress reach 30Mpa at maximum the depth of burial, indicating that the engineering stress filed is dominated by horizontal stress. Based on the In-situ stress data and different distinguish methods, rockburst and large deformation are predicted. The results show that In-situ stress magnitude in this area is classified as high level, and the direction of the maximum horizontal stress is NEE, In-situ stress orientation is conductive to stable of the tunnel. When the tunnel passes through the deep-burial and hard rock, the wall rock may happen rockburst; and the large deformation may happen when the tunnel pass through the weak rock. In order to avoid the disadvantage conditions, reasonable excavation method and safety support method should be adopted during tunnel excavating.

scholarly journals A Dual Fractal Poroelastic Model for Characterizing Fluid Flow in Fractured Coal Masses

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-13 ◽  
Author(s):  
Guannan Liu ◽  
Dayu Ye ◽  
Feng Gao ◽  
Jishan Liu
Keyword(s):  
Fractal Dimension ◽  
Pore Structure ◽  
Coalbed Methane ◽  
Coupling Effect ◽  
In Situ Stress ◽  
Permeability Model ◽  
Fracture Length ◽  
Coal Deformation ◽  
Throat Diameter

In the process of coalbed methane exploitation, the fracture and pore structure is the key problem that affects the permeability of coalbed. At present, the coupling effect of fracture and pore structure and in situ stress is seldom considered in the study of coal seam permeability. In this paper, the fractal seepage model is coupled with coal deformation, and the adsorption expansion effect is considered. A multifield coupling model considering the influence of matrix and fracture structure is established. Then, the influence of pore structure parameters of main fracture on macropermeability is analyzed, including (1) fractal dimension of fracture length, (2) maximum fracture length, (3) fractal dimension of throat diameter, and (4) fractal dimension of throat bending. At the same time, the simulation results are compared with the results of Darcy’s uniform permeability model. The results show that the permeability calculated by the proposed model is significantly different from that calculated by the traditional cubic model. Under the action of in situ stress, when the porosity and other parameters remain unchanged, the macropermeability of coal is in direct proportion to the fractal dimension of coal fracture length, the fractal dimension of throat diameter, and the maximum fracture length and in inverse proportion to the fractal dimension of coal throat curvature.

scholarly journals The present-day in-situ stress field within coalbed methane reservoirs, Yuwang Block, Laochang Basin, south China

2019 ◽  
Vol 102 ◽  
pp. 61-73 ◽  
Author(s):  
Wei Ju ◽  
Bo Jiang ◽  
Yong Qin ◽  
Caifang Wu ◽  
Geoff Wang ◽  
...  
Keyword(s):  
Stress Field ◽  
South China ◽  
Coalbed Methane ◽  
In Situ Stress ◽  
In Situ Stress Field

scholarly journals Fracturing curve and its corresponding gas productivity of coalbed methane wells in the Zhengzhuang block, southern Qinshui Basin, North China

2020 ◽  
Vol 38 (5) ◽  
pp. 1387-1408
Author(s):  
Yang Chen ◽  
Dameng Liu ◽  
Yidong Cai ◽  
Jingjie Yao
Keyword(s):  
Hydraulic Fracturing ◽  
Coalbed Methane ◽  
Continuous Production ◽  
Fracture Morphology ◽  
Geological Structure ◽  
In Situ Stress ◽  
Gas Production ◽  
Type Curves ◽  
Stable Type

Hydraulic fracturing has been widely used in low permeability coalbed methane reservoirs to enhance gas production. To better evaluate the hydraulic fracturing curve and its effect on gas productivity, geological and engineering data of 265 development coalbed methane wells and 14 appraisal coalbed methane wells in the Zhengzhuang block were investigated. Based on the regional geologic research and statistical analysis, the microseismic monitoring results, in-situ stress parameters, and gas productivity were synthetically evaluated. The results show that hydraulic fracturing curves can be divided into four types (descending type, stable type, wavy type, and ascending type) according to the fracturing pressure and fracture morphology, and the distributions of different type curves have direct relationship with geological structure. The vertical in-situ stress is greater than the closure stress in the Zhengzhuang block, but there is anomaly in the aggregation areas of the wavy and ascending fracturing curves, which is the main reason for the development of multi-directional propagated fractures. The fracture azimuth is consistent with the regional maximum principle in-situ stress direction (NE–NEE direction). Furthermore, the 265 fracturing curves indicate that the coalbed methane wells owned descending, and stable-type fracturing curves possibly have better fracturing effect considering the propagation pressure gradient (FP) and instantaneous shut-in pressure (PISI). Two fracturing-productivity patterns are summarized according to 61 continuous production wells with different fracturing type and their plane distribution, which indicates that the fracturing effect of different fracturing curve follows the pattern: descending type > stable type > wavy type > ascending type.

scholarly journals Effect of Stress and Moisture Content on Permeability of Gas-Saturated Raw Coal

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Junhui Wang ◽  
Zhijun Wan ◽  
Yi Wang ◽  
Zhixiang Liu ◽  
Sifei Liu ◽  
...  
Keyword(s):  
Moisture Content ◽  
Coalbed Methane ◽  
Confining Pressure ◽  
Porous Matrix ◽  
In Situ Stress ◽  
Permeability Evolution ◽  
Test Range ◽  
Moisture Contents ◽  
Volumetric Stress

Hydraulic fracturing and premining gas drainage are important to safe mining and coalbed methane extraction. These technical processes cause the redistribution of in-situ stress and the regional variation of moisture contents within the affected zone. Therefore, we investigated the coupled effect of variable stresses (from 9 MPa to 27 MPa) and moisture contents (from 0.22% to 4.00%) on the permeability evolution of gas-saturated raw coal. The results show that (1) the relationship between the mean effective stress and the permeability can be described by a power function according to the permeability evolution model of the porous matrix established in this study. Besides, the influence mechanisms of moisture on fitting coefficients in the function were analyzed. (2) The permeability decreases with the increase of in-situ stress (e.g., confining pressure or volumetric stress) in a negative exponential manner. (3) The curves of permeability variations with moisture content are not always linear, and the permeability is more sensitive to the moisture content than the volumetric stress in the test range. Moreover, the sensitivity of permeability varies in different regions. These results would be beneficial for permeability prediction and surface well parameters design.

Sign in / Sign up

Export Citation Format

Share Document