scholarly journals The gas content distribution of coal reservoir at the Changzhi block, south-central Qinshui Basin, North China: Influences of geologic structure and hydrogeology

2018 ◽  
Vol 37 (1) ◽  
pp. 144-165 ◽  
Author(s):  
Zhigang Du ◽  
Xiaodong Zhang ◽  
Qiang Huang ◽  
Shuo Zhang ◽  
Chenlin Wang
Keyword(s):  
Coalbed Methane ◽  
Content Distribution ◽  
Gas Content ◽  
Exploration And Exploitation ◽  
Geologic Structure ◽  
Stagnation Region ◽  
Qinshui Basin ◽  
Himalayan Orogeny ◽  
South Central ◽  
Coal Reservoir

Coalbed methane is now large-scalely explorated and exploitated in the world. The Changzhi coalbed methane block, south-central Qinshui Basin, is a new resource target zone for coalbed methane exploration and exploitation in China. However, the gas content distribution of this block and its influential factors have not yet studied. Based on the recent coalbed methane exploration and exploitation activities, the gas content distribution of coal reservoir in this block was studied. The results show that the gas content hold by the coal reservoir is 7.0 − 21.7 m3/t, which was determined by a combining control effect from geologic structure and hydrogeology. The Changzhi coalbed methane block has experienced multiple-stages geologic structure evolution, especially a tectonic-thermal event during the middle Yanshanian Orogeny improved the coal to the current R o,max 1.9 − 2.7% and meanwhile the coalbed methane was greatly generated. Subsequently, the widespreadly developed normal fault structures during the Himalayan Orogeny accelerated the coalbed methane escape through the “gas escape windows”, particularly where the location within the distance of about 1300 m to the “gas escape window” the gas content decreases significantly. Moreover, due to the action of the later Himalayan Orogeny, the slope areas of most Yanshanian fold structures were structurally cross-cut by the Himalayan normal faults, and thus an “open” syncline folds were formed. The coal reservoir was depressurized surrounding this “open” syncline structure and consequently the hydrodynamic losing effect has resulted in a comparatively lower gas content therein. By the control of geologic structure and hydrogeology, this block can be generally, compartmentalized into three hydrodynamic systems including the western groundwater stagnation region, the middle runoff region, and the north-eastern recharge region, where the hydrodynamic sealing effect at the groundwater stagnation region has made a comparatively higher gas content for the coal reservoir, but the hydrodynamic losing effect at the recharge region and runoff region has made a comparatively lower gas content of the coal reservoir.

scholarly journals A Study on the Heterogeneity Characteristics of Geological Controls on Coalbed Methane Accumulation in Gujiao Coalbed Methane Field, Xishan Coalfield, China

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-20
Author(s):  
Taotao Yan ◽  
Shan He ◽  
Yadong Bai ◽  
Zhiyong He ◽  
Dameng Liu ◽  
...  
Keyword(s):  
Coalbed Methane ◽  
Large Scale ◽  
Gas Content ◽  
Hydrocarbon Generation ◽  
Burial History ◽  
Gas Distribution ◽  
Coal Seams ◽  
Gas Generation ◽  
Himalayan Orogeny ◽  
Coal Reservoir

Commercial exploration and exploitation of coalbed methane (CBM) in Gujiao coalbed methane (CBM) field, Xishan coalfield, have rapidly increased in recent decades. The Gujiao CBM field has shown strong gas distribution heterogeneity, low gas content, and wide distribution of wells with low production. To better understand the geological controlling mechanism on gas distribution heterogeneity, the coal reservoir evolution history and CBM accumulation process have been studied on the base of numerical simulation work. The burial history of coal reservoir can be classified into six stages: shallowly buried stage; deeply buried stage; uplifting stage; short-term tectonic subsidence stage; large-scale uplifting stage; and sustaining uplifting and structural inversion stage. Mostly, coal seams have experienced two-time thermal metamorphisms with twice hydrocarbon-generation processes in this area, whereas in the southwest part, the coal seams in there suffered three-time thermal metamorphisms and hydrocarbon-generation processes. The critical tectonic events of the Indosinian, Yanshanian, and Himalayan orogenies affect different stages of the CBM reservoir accumulation evolution process. The Indosinian orogeny mainly controls the primary CBM generation. The Yanshanian orogeny dominates the second and third gas generation and migration processes. The Himalayan orogeny mainly affects the gas dissipation process and current CBM distribution heterogeneity.

scholarly journals Characterization of Coal Reservoirs in Two Major Coal Fields in Northern China: Implications for Coalbed Methane Development

2012 ◽  
Vol 2012 ◽  
pp. 1-10
Author(s):  
Junjia Fan ◽  
Yiwen Ju ◽  
Quanlin Hou ◽  
Yudong Wu ◽  
Xiaoshi Li
Keyword(s):  
Coalbed Methane ◽  
Vitrinite Reflectance ◽  
Northern China ◽  
Low Grade ◽  
High Grade ◽  
Qinshui Basin ◽  
Type Iv ◽  
South Central ◽  
Coal Reservoir

Based on the macroscopic and microscopic observation of coal structure, the vitrinite reflectance analysis, and the mercury injection testing of coal samples collected from Huaibei coalfield and Qinshui basin, the characterization of coal reservoir and its restriction on the development of coalbed methane are studied. The results indicate that coal reservoir in study area can be classified as five types according to the coal metamorphism and deformation degrees, and they are respectively high grade metamorphic and medium deformational to strongly deformation coal (I), high grade metamorphic and comparatively weakly deformational coal (II), medium grade metamorphic and comparatively strongly deformational coal (III), medium grade metamorphic and comparatively weakly deformational coal (IV), and low grade metamorphic and strongly deformational coal (V). Furthermore, the type II and type IV coal reservoirs are favorable for the development of the coalbed methane because of the well absorptive capability and good permeability. Thus, southern part of Qinshui basin and south-central of Huaibei coal field are potential areas for coalbed methane exploration and development.

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.

Microstructure of Mid and High Rank Coals from Qinshui Basin, North China and its Contribution to Coalbed Meathane

2012 ◽  
Vol 616-618 ◽  
pp. 201-207
Author(s):  
Zhi Hua Liu ◽  
Jun Gang Liu ◽  
Yi Guo Dong ◽  
Yang Chen ◽  
Li Ren Xing ◽  
...  
Keyword(s):  
Coalbed Methane ◽  
Vitrinite Reflectance ◽  
Mercury Porosimetry ◽  
Nitrogen Adsorption ◽  
Isothermal Adsorption ◽  
Qinshui Basin ◽  
Coal Macerals ◽  
Coal Reservoir ◽  
Micro Structures ◽  
Adsorption Capability

To better understand the relationship between micro-structures and coalbed methane(CBM), characterisation methods including microscopic photometer, scanning electron microscopy (SEM), mercury porosimetry, nitrogen adsorption at 77K and methane isothermal adsorption were introduced into investigating the adsorption capability of coal reservoir. The results reveal that the micropores volume has a increasing trend with increased vitrinite reflectance. The most favorable pore type is to have good connectivity, very good micro-pores porosity and good adsorption capability. Statistical analysis shows that endo-microfractures are the main type microfractures of Qinshui basin. Based on the results of coal macerals, coal lithotypes, it is found that the bright coal and telocollinites are favorable for endo-fractures formation. Obviously different from the formation of endo-microfracture, exo-microfracture strongly relates to the coal structure. A good match between the fractures and the pores is needed for a favorable CBM reservoir. Based on the evaluation of pore-fracture system, Yangquan is the second CBM commercial area of Qinshui basin.

scholarly journals Study on the Coalbed Methane Development under High In Situ Stress, Large Buried Depth, and Low Permeability Reservoir in the Libi Block, Qinshui Basin, China

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Jinkuang Huang ◽  
Shenggui Liu ◽  
Songlei Tang ◽  
Shixiong Shi ◽  
Chao Wang
Keyword(s):  
Coalbed Methane ◽  
Horizontal Wells ◽  
In Situ Stress ◽  
Low Permeability ◽  
Qinshui Basin ◽  
Hole Pressure ◽  
Bottom Hole ◽  
Single Well ◽  
Coal Reservoir

Coalbed methane (CBM) has been exploited in the deep area of the coal reservoir (>1000 m). The production of CBM vertical wells is low because of the high in situ stress, large buried depth, and low permeability of the coal reservoir. In this paper, efficient and advanced CBM development technology has been applied in the Libi Block of the Qinshui Basin. According to the characteristics of the coal reservoir in the Libi Block, the coiled tubing fracturing technology has been implemented in four cluster horizontal wells. Staged fracturing of horizontal wells can link more natural fracture networks. It could also expand the pressure drop range and control area of the single well. This fracturing technology has achieved good economic results in the Libi Block, with the maximum production of a single horizontal well being 25313 m3/d and the average single well production having increased by more than 60% from 5000 m3/d to 8000 m3/d. Based on the data regarding the bottom hole pressure, water production, and gas production, the production curves of four wells, namely, Z5P-01L, Z5P-02L, Z5P-03L, and Z5P-04L, were investigated. Furthermore, a production system with slow and stable depressurization was obtained. The bottom hole pressure drops too fast, which results in decreasing permeability and productivity. In this work, a special jet pump and an intelligent remote production control system for the CBM wells were developed; hence, a CBM production technology suitable for the Libi Block was established. The maximum release for the CBM well productivity was obtained, thus providing theoretical and technical support for CBM development with geological and engineering challenges.

Analogy Analysis of Coalbed Methane Reservoir-Forming Conditions in Jixi Basin

2015 ◽  
Vol 733 ◽  
pp. 96-99 ◽  
Author(s):  
Yu Shuang Hu ◽  
Yu Gang Hao ◽  
Hui Ting Hu
Keyword(s):  
Coalbed Methane ◽  
The United States ◽  
Gas Content ◽  
Burial Depth ◽  
Oil Drilling ◽  
Black Warrior Basin ◽  
Reservoir Conditions ◽  
Coalbed Methane Reservoir ◽  
Dip Angle ◽  
Coal Reservoir

Based on coalbed methane geology theory, make use of coal and oil drilling data, from both of the coal reservoir characteristics and conservation conditions, Through comparative analysis of a number of geological factors of coalbed thickness, burial depth, metamorphic grade, gas content, roof and floor lithology, dip angle, etc, and found that there are many similarities between Jixi Basin and Black Warrior Basin in the United States of coalbed methane reservoir conditions. Compared to Black Warrior Basin, the advantages of Jixi Basin are that the coal metamorphism degree is high, the tired and single coalbed are thick, the closeness of roof and floor are good, the fault development and coalbed gas content are similar to it; the disadvantages of Jixi Basin are that the formation dip angle is large, the pressure gradient and permeability are small.

Study on the Feasibility of SRV in Coal Reservoir

2014 ◽  
Vol 986-987 ◽  
pp. 734-737
Author(s):  
Lin Lin Cheng ◽  
Yuan Fang Cheng ◽  
Chong Chen ◽  
Dong Feng Zhu ◽  
Wen Biao Deng
Keyword(s):  
Coalbed Methane ◽  
New Technology ◽  
Gas Content ◽  
Stimulated Reservoir Volume ◽  
Reservoir Volume ◽  
Surface Development ◽  
Low Efficiency ◽  
Weak Structure ◽  
Coal Reservoir ◽  
Rock Brittleness

In our country there is plenty of CBM (coalbed methane), but the state of CBM itself, unique output mechanism and low saturation, low permeability, low reservoir pressure and high gas content, et al. determine the low efficiency of it, so in order to improve CBM recovery, combined with the successful experience of north American shale gas reservoir by SRV(stimulated reservoir volume), the writer summarizes the implementation of SRV, deeply analyzes effectiveness and limitations of this new technology in CBM development. The results of practical research and theoretical analysis show that SRV in the coal reservoir can achieve the desired effect on the condition that there are great quantity of natural fractures, joints and bedding, weak structure surface development in the reservoir, the rock brittleness index is greater than 40 and horizontal principal stress difference is relatively smaller. Finally, simulating a well’s condition by the MEYER software, the result shows that SRV is feasible in coal reservoir, which will create important guiding significance and practical value for the exploration of CBM.

Technologies extraction of coalbed methane in the Qinshui basin of China

2018 ◽  
pp. 102-108
Author(s):  
Lu Yanjun ◽  
Han Jinxuan ◽  
V. V. Shelepov ◽  
E. Yu. Makarova ◽  
Li Kai ◽  
...  
Keyword(s):  
Coalbed Methane ◽  
Electric Pulse ◽  
Gas Content ◽  
Low Permeability ◽  
Reservoir Pressure ◽  
Vertical Wells ◽  
Coal Seams ◽  
Qinshui Basin ◽  
Multi Stage ◽  
Total Resource

Coalbed methane (CBM) is a new clean and unconventional energy that has broad space for development. In Qinshui basin, CBM reserves reach 3,97·1012m3, which is 10,8% of the total resource in China. Compared to the main coal basins of USA, Australia, Canada and Russia, coal seams in Qinshui basin have the characteristics of high metamorphism, high gas content, low porosity, low permeability and low reservoir pressure. Therefore, effective stimulation treatments must be used in Qinshui basin to realize industrial exploitation of CBM. At present, vertical wells with hydraulic fracturing are dominated in Qinshui basin. In addition, injection CO2, electric pulse, multi-stage fracturing and other technologies are also applied to the CBM exploitation.

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