Application of seismic curvature attributes in the delineation of coal texture and deformation in Zhengzhuang field, southern Qinshui Basin

Cao, Lutong; Yao, Yanbin; Liu, Dameng; Yang, Yanhui; Wang, Yingjin; Cai, Yidong

doi:10.1306/12031918208

Cited by 30 publications

(24 citation statements)

References 46 publications

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“…42 , 43 Samples with particle sizes of 60–80 mesh were used for the methane isothermal adsorption isotherm experiments using an ISO-300 isothermal adsorption apparatus following the Chinese standard GB/T 19560–2008. 39 The test results including coal composition, vitrinite reflectance, proximate analysis, and adsorption isotherms are listed in Table 1 .…”

Section: Samples and Experimentsmentioning

confidence: 99%

Geological Controls on the Gas Content and Permeability of Coal Reservoirs in the Daning Block, Southern Qinshui Basin

et al. 2022

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The gas content and permeability of the coal reservoir are the key factors affecting coalbed methane (CBM) productivity. To investigate the geological controls on the permeability and gas content of coal reservoirs in the Daning block, southern Qinshui Basin, geological surveys combined with laboratory experiments, including coal petrology analysis, proximate analysis, and methane isothermal adsorption experiments, were carried out. The results show that the gas content of coals in the Daning block ranges from 5.56 to 17.57 (avg. 12.83) m 3 /t, and the coal permeability is generally above 0.1 mD, averaging 0.96 mD. The gas content of coal reservoirs shows decreasing trends with the increase in ash yield and moisture content, while tends to increase with the increase of vitrinite content; however, the correlation coefficients are all extremely low. The gas content presents a strong positive correlation with the burial depth of coal seams, but overall poorly correlates with the coal thickness. The CBM-rich areas are generally located at the hinge zones of secondary synclines, while the lower gas content areas commonly occur at the hinge zones of secondary anticlines. The normal faults are developed in the Daning block, and as expected, the gas content of coal seams that are near the normal faults is commonly lower. It was found that the well testing permeability of coal reservoirs in the Daning block decreases exponentially with the increase of the minimum horizontal stress (σ h ) and the maximum horizontal principal stress (σ H ). With the increase of the burial depth, the coal permeability also decreases exponentially. The primary and cataclastic structure coals generally have a higher hydro-fracturing permeability than the granulitic and mylonitic structure coals. This work can serve as a guide for the target area selections of CBM enrichment and high production in the Daning block.

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Section: Samples and Experimentsmentioning

confidence: 99%

Geological Controls on the Gas Content and Permeability of Coal Reservoirs in the Daning Block, Southern Qinshui Basin

et al. 2022

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“…Structural curvature that affects coal permeability is caused by the tectonic force field, which can accurately reflect the degree of crack development due to the tensile stress in curved rock layers (Liu et al 2015;Cao et al 2020). Figure 4 shows the curvature descriptions of anticline, syncline, monocline, and flat layers.…”

Section: Relationship Between Structural Curvature and Permeabilitymentioning

confidence: 99%

Influence of geological factors on coal permeability in the Sihe coal mine

Zou

Zhang

She

et al. 2022

Int J Coal Sci Technol

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Permeability of coal reservoirs influence the extraction of coal gas from coal seams. Twelve coal samples were collected at an anticline and a syncline of the No. 3 coal seam in the Sihe coal mine. Porosity, permeability, pore size, vitrinite reflectance, and liquid nitrogen adsorption of the samples were evaluated. Structural curvatures at the sample locations, and the distance between the sampling locations and the nearest faults were calculated based on seismic data. The influences of the evaluated parameters on permeability were analyzed. Major factors that influence permeability of the No. 3 coal seam were extracted using principal component analysis (PCA). Based on the porosity–permeability model derived from the Archie formula and classic Kozeny–Carman equation, we deduced that the permeability of coal increased with an increase in porosity. With an increase in average vitrinite reflectance, permeability decreases first and then increases. PCA results showed that coal permeability was regulated by three key components representing three modes. The first component included pore size, depth, and pore complexity accounting for 52.59% of the variability indicating that it was the most important in controlling permeability. The second component included specific surface area, structural curvature, and porosity, and the third component comprised of specific surface area, porosity, and average vitrinite reflectance. Overall, pore diameter and complexity had significant effects on coal permeability. The results show that researchers and stakeholders must consider the interactions among multiple factors rather than single factors to understand the influences on permeability to facilitate efficient utilization of coalbed methane resources.

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“…Zhang et al investigated the hydrodynamic conditions, folds, and collapse columns influence on CGC, and they found that folds and collapse columns distributed along the fault structures and locally developed in the northeast of the Zhengzhuang field had local influence on CGC. It is the faulting that controls the tectonic framework in the Zhengzhuang field . The focus of this study is mainly on the faulting influence on CGC.…”

Section: Introductionmentioning

confidence: 99%

Fault Development Characteristics and Their Effects on Current Gas Content and Productivity of No. 3 Coal Seam in the Zhengzhuang Field, Southern Qinshui Basin, North China

Wang

Yao

Huang³

et al. 2021

Energy Fuels

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Faulting is one of the most common geological features that impacts current gas content (CGC) of coal seams, which is an important parameter for coalbed methane (CBM/gas) production. However, the detailed faulting effects on CGC and productivity have not been thoroughly investigated, because of inadequate methods for quantitative evaluation of the effects. In this study, we carry out comprehensive analysis of diverse geological coring data and experimental results and production data of exploration wells as well as the three-dimensional fault interpretation in the Zhengzhuang field. We introduce a parameter fault scale (F) to quantify the scale of faults, which is described by fault length, fault throw, and the investigated area. Then we propose a horizontal grid method to determine the faulting influence on CGC. The relationships between the CGC and the fracture density of coal core, the mechanical properties of the roof and floor of coal seam, the average gas production in a faulting system (including the upthrown side, downthrown side, and fault plain) are analyzed. In the study area, the well-developed normal faults have significant influence on CGC, but the locally developed thrust faults have negligible influence. The square grid with length of 1.5 km is probably the most effective grids for analyzing faulting effected distance on CGC. Thus, the normal faults can be divided into small- (F 1.5 < 0.05), moderate- (0.05 < F 1.5 < 0.15), and large-scale (F 1.5 > 0.15). The evident effect of faulting on CGC can be observed up to ∼1.5 km away from the normal fault. When the coal seam is further away from the normal faults (i.e., >1.5 km), the CGC is higher or closer to 20.7 m3/t. In contrast, when the coal seam is <1.5 km from the normal faults, the CGC decreases with increasing value of F. In general, the CGC is higher on the downthrown side, with better gas preservation conditions than the upthrown side. Relatively high CGC (>20 m3/t) is necessary for good gas production of CBM wells. The CBM wells with low ADGP (<500 m3/d) and low CTGP (<105 m3) are commonly located on the fault plane and upthrown side of normal faults. In general, the places far away (>1.5 km) from the normal faults is the most favorable productivity area, and only the small-scale normal faults developed is the secondary favorable productivity area. These places have the average gas production as high as 1000 m3/d and cumulative total gas production as high as 4 × 105 m3.

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Application of seismic curvature attributes in the delineation of coal texture and deformation in Zhengzhuang field, southern Qinshui Basin

Cited by 30 publications

References 46 publications

Geological Controls on the Gas Content and Permeability of Coal Reservoirs in the Daning Block, Southern Qinshui Basin

Geological Controls on the Gas Content and Permeability of Coal Reservoirs in the Daning Block, Southern Qinshui Basin

Influence of geological factors on coal permeability in the Sihe coal mine

Fault Development Characteristics and Their Effects on Current Gas Content and Productivity of No. 3 Coal Seam in the Zhengzhuang Field, Southern Qinshui Basin, North China

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