Structural controls on coalbed methane accumulation and high production models in the eastern margin of Ordos Basin, China

Chen, Yue; Tang, Dazhen; Xu, Hao; Li, Yong; Meng, Yanjun

doi:10.1016/j.jngse.2015.02.018

Cited by 51 publications

(32 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…4 þ 5 and No. 8 þ 9 coal seams are the primary targeted coal seams for CBM exploration and development, occurring at a depth of 300-2600 m and a thickness of 0.5-30 m. The vitrinite reflectance R o of the coals ranges from 0.44% to 2.35% in most areas, generally increasing from east to west controlled by their buried depth, except for the areas nearby the Zijin Mountain controlled by the magmatic activity (Chen et al, 2015a(Chen et al, , 2015b. Dark mud shales (for the convenience of research, carbonaceous mudstone, mudstone, and shale are collectively called mud shale in this paper) are well developed and distributed extensively and stably, both in the Shanxi and Taiyuan Formations, with a large deposition thickness.…”

Section: Geological Settingsmentioning

confidence: 99%

Characteristics of the mud shale reservoirs in coal-bearing strata and resources evaluation in the eastern margin of the Ordos Basin, China

Chen

Xia

et al. 2019

Energy Exploration & Exploitation

Self Cite

View full text Add to dashboard Cite

As the co-exploration and co-production of unconventional gas have become a new trend of the unconventional gas exploration and development in the eastern margin of the Ordos Basin, this study focuses on the distribution, pore characteristics, geochemical properties, and mineral composition of the mud shale in the coal-bearing strata. The results show that the mud shale in the coal-bearing strata is distributed relatively stably with an average cumulative thickness of 77.60 m and a buried depth of 200–2400 m, increasing from east to west. The total organic carbon content of mud shale is relatively high, ranging from 0.14% to 39.9%, and the thermal maturity ranges from 0.23% to 2.49%, affected by both buried depth and magmatic intrusion. The organic matter type of the mud shale is dominated by type III, favorable for gas generation. The mineral composition of mud shale is mainly clay minerals and quartz, with low brittle minerals content (averaging 30.34%) and high kaolinite content (averaging 59.23%). Pores and micro-fissures are relatively developed in the mud shale, dominated by intergranular pores, organic pores, and the micro-fissures developed between brittle mineral crystals, within crystals and between clay mineral particles, with a porosity of 1.05%–1.59% and a permeability of 0.001–0.142 (×10−3µm2). The specific surface area of pores in mud shale is 12.31–28.99 m2/g, and the total pore volume is 0.0146–0.0483 cm3/g. Mesopores and micropores (mainly slit shaped pores) provide the main pore volume of mud shale, and micropores contribute most of the specific surface area. The controlling factors on pore development include the total organic carbon, thermal maturity, and inorganic minerals composition. The total amount of shale gas resources is 2.49 × 1012 m3, and the Linxian-Xingxian area and Shilou-Daning area are the potential favorable zones for shale gas exploration and development.

show abstract

Section: Geological Settingsmentioning

confidence: 99%

Characteristics of the mud shale reservoirs in coal-bearing strata and resources evaluation in the eastern margin of the Ordos Basin, China

Chen

Xia

et al. 2019

Energy Exploration & Exploitation

Self Cite

View full text Add to dashboard Cite

show abstract

“…The coal-bearing basins in China experienced multi-phase tectonic movements in geologic history and developed complex geological structures [3]. Geological structure plays an important role in the process of CBM generation, occurrence, migration, and enrichment in coal seams [4][5][6][7][8][9][10][11]. Especially, the influence on CBM occurrence from the geological structure modification of the coal reservoir physical properties, such as porosity, adsorption, and permeability [12][13][14][15][16][17][18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Multi-Phase Tectonic Movements and Their Controls on Coalbed Methane: A Case Study of No. 9 Coal Seam from Eastern Yunnan, SW China

Jiang

et al. 2020

Energies

View full text Add to dashboard Cite

Multi-phase tectonic movements and complex geological structures limit the exploration and hotspot prediction of coalbed methane (CBM) in structurally complex areas. This scientific problem is still not fully understood, particularly in the Bumu region, Southwest China. The present paper analyses the occurrence characteristics and distribution of CBM based on the comprehensive analysis of CBM data. In combination with the analysis of the regional tectonics setting, geological structure features and tectonic evolution. The control action of multi-phase tectonic movements on CBM occurrence are further discussed. Results show that the Indosinian local deformation, Yanshanian intense deformation, and Himalayan secondary derived deformation formed the current tectonic framework of Enhong synclinorium. The intense tectonic compression and dextral shear action in the Yanshanian and Himalayan movements caused the complex geological structures in Bumu region, composed of the Enhong syncline, associated reverse faults and late derived normal fault. The CBM distribution is complex, which has the central and western NNE-trending high gas content zones along the syncline hinge zone and the reverse faults. The geological structure controls on CBM enrichment are definite and important. Based on geological structure features and responses of gas content, methane concentration, and gas content gradient, the gas controlling patterns of geological structure are determined and can be classified into five types: the reverse fault sealing, syncline sealing, monoclinal enrichment, normal fault dispersion, and buried floor fault dispersion types. The structural compression above the neutral surface plays an important role in the syncline sealing process, which is indicated by an increase in gas content gradient. The EW-trending tectonic intense compression and dextral shear action in the Himalayan movement avoided the negative inversion of NNE-trending Yanshanian compressive structure and its destruction of CBM reservoir. However, the chronic uplift and derived normal fault during Himalayan period caused the constant dissipation of CBM.

show abstract

“…As the source rock, coal has the ability to transport and store CBM and may be affected by stratigraphic traps and structural traps, which are developed in coal-bearing strata [18,19]. Stratigraphic traps are common in the coal-bearing strata that are mainly governed by sealing rocks, such as mudstone, siltstone, and sandstone, and their thickness controls the sealability [15], whereas structural traps are only generated from the fault-sealing strata, influenced by tectonic movement, sedimentary environment, and fault evolution [20,21]. Investigation on the geological characteristic of CBM reservoirs may contribute to the commercial potential of CBM exploration [22].…”

Section: Introductionmentioning

confidence: 99%

Influence of Overlying Caprock on Coalbed Methane Migration in the Xutuan Coal Mine, Huaibei Coalfield, China: A Conceptional Analysis on Caprock Sealability

et al. 2019

View full text Add to dashboard Cite

In order to determine the controlling factors affecting coalbed gas migration in the Xutuan coal mine, Huaibei Coalfield, China, overlying caprocks with Quaternary and Neogene formation (loose bed), Paleogene formation (Redbed), and coal-bearing strata were investigated via petrography, lithology, and physical properties according to laboratory tests, theoretical analysis, and on-site exploration. Results indicate that the basic properties of coal were not significantly changed whereas the effect of coalbed gas escape was promoted in the presence of Redbed and loose bed. The pore structure analysis shows that Redbed has well-developed pore connectivity than coal-bearing strata (main components are sandstone, siltstone, and mudstone). Also, the diffusion coefficient and permeability of Redbed and loose bed are proved to be a little different than those of sandstone but are much higher than those of mudstone and siltstone. Based on the aforementioned findings, investigation on the sealing mechanism of overlying caprocks on CBM migration was further discussed, interpreting that the thickness, permeation, and diffusion features are crucial factors for sealing capacity of the overlying caprock. Thus, with the simplification on the thickness of overlying strata, a conceptional analysis was carried out to theoretically estimate the sealability of caprocks from surface drilling holes; it appears, though, that the master factor on coalbed methane accumulation is coal-bearing strata instead of Redbed and loose bed with a poor sealability. In this case, the reliability of the evaluation method could be indirectly validated from the on-site gas content data of the actual coal seam to fundamentally reflect the effect of Redbed and loose bed on gas-escaping, and the impact of coal-bearing strata on gas accumulation in the coal seam.

show abstract

Structural controls on coalbed methane accumulation and high production models in the eastern margin of Ordos Basin, China

Cited by 51 publications

References 34 publications

Characteristics of the mud shale reservoirs in coal-bearing strata and resources evaluation in the eastern margin of the Ordos Basin, China

Characteristics of the mud shale reservoirs in coal-bearing strata and resources evaluation in the eastern margin of the Ordos Basin, China

Multi-Phase Tectonic Movements and Their Controls on Coalbed Methane: A Case Study of No. 9 Coal Seam from Eastern Yunnan, SW China

Influence of Overlying Caprock on Coalbed Methane Migration in the Xutuan Coal Mine, Huaibei Coalfield, China: A Conceptional Analysis on Caprock Sealability

Contact Info

Product

Resources

About