Abstract: Reservoir Geology of the Hedong Coalbed Methane Prospect, Shanxi Province, China 

AAPG Bulletin ◽  
1999 ◽  
Vol 83 (1999) ◽  
Author(s):  
JENKINS, CRETIES D., and DAVID J. D
Keyword(s):  
Coalbed Methane ◽  
Shanxi Province

Modelling Methane Extraction from Stimulated Coalbed Influenced by Multidomain and Thermal Effects

2021 ◽  
Author(s):  
Wai Li ◽  
Jishan Liu ◽  
Jie Zeng ◽  
Yee-Kwong Leong ◽  
Derek Elsworth ◽  
...  
Keyword(s):  
Thermal Effects ◽  
Coalbed Methane ◽  
Thermal Strain ◽  
Fracture Network ◽  
Extraction Process ◽  
Mine Safety ◽  
Shanxi Province ◽  
Well Production ◽  
Proposed Model ◽  
Coal Deformation

Abstract The process of extracting coalbed methane (CBM) is not only of significance for unconventional energy supply but also important in mine safety. The recent advance in fracking techniques, such as carbon dioxide (CO2) fracking, intensifies the complexity of stimulated coalbeds. This work focuses on developing a fully coupled multidomain model to describe and get insight into the process of CBM extraction, particularly from those compound-fractured coalbeds. A group of partial differential equations (PDEs) are derived to characterize gas transport from matrix to fractures and borehole. A stimulated coalbed is defined as an assembly of three interacting porous media: matrix, continuous fractures (CF) and radial primary hydraulic fracture (RF). Matrix and CF constitute a dual-porosity-dual-permeability system, while RF is simplified as an 1-D cracked medium. These media further form three distinct domains: non-stimulated reservoir domain (NSRD), stimulated reservoir domain (SRD) and RF. The effects of coal deformation, heat transfer, and non-thermal sorption are coupled into the model to reflect the multiple processes in CBM extraction. The finite element method is employed to numerically solve the PDEs. The proposed model is verified by comparing its simulation results to a set of well production data from Southern Qinshui Basin in Shanxi Province, China. Great consistency is observed, showing the satisfactory accuracy of the model for CBM extraction. After that, the difference between various stimulation patterns is presented by simulating the CBM extraction process with different stimulation patterns including (1) unstimulated coalbed; (2) double-wing fracture + NSRD; (3) multiple RFs + NSRD; (4) SRD + NSRD and (5) multiple RFs + SRD + NSRD. The results suggest that Pattern (5) (often formed by CO2 fracking) boosts the efficiency of CBM extraction because it generates a complex fracture network at various scales by both increasing the number of radial fractures and activating the micro-fractures in coal blocks. Sensitivity analysis is also performed to understand the influences of key factors on gas extraction from a stimulated coalbed with multiple domains. It is found that the distinct properties of different domains originate various evolutions, which in turn influences the CBM production. Ignoring thermal effects in CBM extraction will either overestimate or underestimate the production, which is the net effect of thermal strain and non-isothermal sorption. The proposed model provides a useful approach to accurately evaluate CBM extraction by taking the complex evolutions of coalbed properties and the interactions between different components and domains into account. The importance of multidomain and thermal effects for CBM reservoir simulation is also highlighted.

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.

Multi-layer superposed coalbed methane system in southern Qinshui Basin, Shanxi Province, China

2015 ◽  
Vol 26 (3) ◽  
pp. 391-398 ◽  
Author(s):  
Zheng Zhang ◽  
Yong Qin ◽  
Xuehai Fu ◽  
Zhaobiao Yang ◽  
Chen Guo
Keyword(s):  
Coalbed Methane ◽  
Shanxi Province ◽  
Qinshui Basin ◽  
Southern Qinshui Basin

Topology Analysis and Optimization Design of Coal Bed Methane Gathering System in China

2014 ◽  
Author(s):  
Jun Zhou ◽  
XiaoPing Li ◽  
Mengya Cheng ◽  
Tao Deng ◽  
Jing Gong
Keyword(s):  
System Design ◽  
Topological Structure ◽  
Coalbed Methane ◽  
Optimization Design ◽  
Processing System ◽  
Shanxi Province ◽  
Coal Bed ◽  
Pipe Network ◽  
Gas Field ◽  
Optimal Position

China is abundant in coalbed methane (CBM) resource. The unconventional natural gas reserves has reached 36.81*1012 m3. The Qinshui Basin in Shanxi Province is the largest gas field among CBM gas fields in China which are commercially exploited since the year 2003. In order to solve some typical problems in CBM production, this article considered the geographical characteristics of the fields, introduced and analyzed the low pressure gathering and transporting process and facilities, as well as the important techniques. Respectively, this article introduced the surface gathering and transporting procedure, analyzed the characteristics and topological structure; it also proposed the optimization scheme of combining steel pipes with PE pipes in processing system. The gathering and transporting processes of remote areas should be flexible and able to solve the problems during gas recovery from both largely exploited CBM blocks and remote blocks with low production. Thus a more reasonable system design should be proposed. To carry out the scheme, it first defined the topological structure of the system with graph theory, then established the economic model of the combined scheme. The article calculated the critical length of pipeline between two methods and defined the concept of “remote” well area. With the analysis of the actual conditions in a certain block in Qinshui Shanxi, the conclusion shows that: the scheme of laying pipelines can make more profit, which is consistent with the actual field situation., At the same time, we chose a phased optimization method, which divided the optimization of entire system into several sub-problems, including well group division, nodes connection relationship, determination of plant’s optimal position, and optimization of pipe diameter. Then we established optimization model that takes the investment costs of each stage as objective functions. The example shows that compared with the artificial design result, the total length of pipeline was reduced by 4.576 km, pipeline investment by 7.35×104 US$, with the respective rates of returns of 19.57% and 4.89%. The number of valve sets in the system fell from 16 to 11 (31%). By analyzing the investment and construction scale of the existing pipe network and optimal pipe network we have proved that the method has an ideal optimization effect. These techniques and schemes can give reasonable instructions in CBM surface gathering system design, powerfully promoting the development of the Chinese CBM industry.

scholarly journals The Influence of the Injected Water on the Underground Coalbed Methane Extraction

Energies ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1151
Author(s):  
Yanbao Liu ◽  
Zhigang Zhang ◽  
Wei Xiong ◽  
Kai Shen ◽  
Quanbin Ba
Keyword(s):  
Hydraulic Fracturing ◽  
Coalbed Methane ◽  
Gas Flow ◽  
Critical Time ◽  
Shanxi Province ◽  
Coal Bed ◽  
Hydraulic Pressure ◽  
Intrinsic Permeability ◽  
Permeability Evolution ◽  
Two Phase

The increasing demand on coal production has led to the gradually increase of mining depth and more high methane mines, which bring difficulties in terms of coalbed methane (CBM) extraction. Hydraulic fracturing is widely applied to improve the production of CBM, control mine gas, and prevent gas outbursts. It improves coal bed permeability and accelerate desorption and migration of CBM. Even though the impacts of hydraulic fracturing treatment on the coal reservoirs are rare, negative effects could not be totally ignored. To defend this defect, the presented work aims to study the influence of water filtration on coal body deformation and permeability evolution. For this purpose, a simulation based finite element method was developed to build a solid-fluid coupled two-phase flow model using commercial software (COMSOL Multiphysics 5.4). The model was verified using production data from a long strike borehole from Wangpo coal mine in Shanxi Province, China. Several simulation scenarios were designed to investigate the adverse impacts of hydraulic fracturing on gas flow behaviors. The mechanisms of both relative and intrinsic permeability evolutions were analyzed, and simulation results were presented. Results show that the intrinsic permeability of the fracture system increases in the water injection process. The impacts of water imitation were addressed that a critical time was observed beyond which water cannot go further and also a critical pressure exists above which the hydraulic pressure would impair the gas flow. Sensitivity analysis also showed that a suitable time and pressure combination could be observed to maximize gas extraction. This work provides an efficient approach to guide the coal bed methane exploitation and other unconventional gas reservoirs.

Fractal Characteristics and Its Controlling Factors of Nanopore of Coal from Shanxi Province, North China

2021 ◽  
Vol 21 (1) ◽  
pp. 727-740
Author(s):  
Zhi Xu ◽  
Ming Li ◽  
Yu Xu ◽  
Luwei Sun
Keyword(s):  
Fractal Dimension ◽  
Coalbed Methane ◽  
Correlation Coefficients ◽  
Fractal Dimensions ◽  
Total Pore Volume ◽  
Nitrogen Adsorption ◽  
Fractal Model ◽  
Shanxi Province ◽  
Fractal Characteristics ◽  
Permian Coal

Much attention has been recently paid to the Carboniferous-Permian coal-bearing strata in Shanxi Province, now the largest producing coalbed methane field in China. In this study, a comprehensive approach of mercury injection, low-temperature liquid nitrogen adsorption, and permeability experiments was adopted to investigate the structure and fractal characteristics of nanopores in the Carboniferous-Permian coal (with 0.77%˜3.04% Ro,ran). Based on the fractal model, two fractal dimensions D1 and D2 corresponding to diffusion pore (<65 nm) and seepage pore (pore size ≥65 nm), respectively, were calculated, and the relationships between the fractal dimensions with the pore structure parameters and permeability are discussed here. The results indicate that the studied coal samples have good fractal characteristics and that the calculated linear correlation coefficients are higher than 0.80. The fractal dimension D1 of the diffusion pores ranges from 2.3777 to 2.4624, with an average of 2.4173, while the fractal dimension D2 of the seepage pores is between 2.5844 and 2.6256, with an average of 2.5990. The fractal dimensions D1 of the diffusion pores increases with an increase in the BET specific surface area, vitrinite content, and Ro,ran while it decreases with an increase in the permeability, and has a weak correlation with the total pore volume. The correlation coefficients R2 for the fractal dimension D2 of the seepage pores, pore parameters, permeability, and maceral composition ranges from 0.0357 to 0.2551. These results indicate that uncertain relationships exist among these parameters.

Pyrolysis characteristic of coals with different metamorphic grades and its instruction to coalbed methane development

2017 ◽  
Vol 14 (5) ◽  
pp. 423-432 ◽  
Author(s):  
Peng Xia ◽  
Kunjie Li ◽  
Fangui Zeng ◽  
Xiong Xiao ◽  
Jianliang Zhang ◽  
...  
Keyword(s):  
Pore Structure ◽  
Adsorption Capacity ◽  
Coalbed Methane ◽  
Shanxi Province ◽  
Maximum Temperature ◽  
Coal Pyrolysis ◽  
Gas Generation ◽  
Isothermal Adsorption ◽  
Content Type ◽  
Cbm Production

Purpose Pyrolysis for coal gas generation changes the composition, pore structure, permeability and adsorption capacity of coal. This work aims to discuss the utilization of coal pyrolysis on enhancing coalbed methane (CBM) production in the Gujiao area, Shanxi province, China. Design/methodology/approach This research was conducted mainly by the methods of thermogravimetry mass spectrometry (TG-MS) analysis, liquid nitrogen adsorption experiment and methane isothermal adsorption measurement. Findings The results can be concluded as that 400-700°C is the main temperature range for generating CH4. Pore volume and specific surface area increase with increasing temperature; however, the proportion of micro pore, transition pore and macro pore has no difference. The optimum temperature for enhancing CBM production should be letter than 600°C because the sedimentation of tar and other products will occupy some pores and fissures after 600°C. Originality/value Here in, to accurately recognize the suitable maximum temperature for heating development, a method enhancing CBM production, TG-MS, was adopted to analyze the products and the weight loss of coals with different ranks in the Gujiao area at temperature of 30-1,100°C. And then the pore structure, porosity, permeability, methane adsorption capacity and thermal maturity of coals during pyrolysis were investigated with increased temperature from 30°C to 750°C. On these bases, the favorable condition for enhancing CBM production and the thermal evolution of coal were recognized.

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