Indication of origin and distribution of coalbed gas from stable isotopes of gas and coproduced water in Fukang area of Junggar Basin, China

Wang, Qiong; Tang, Dazhen; Yang, Shenglai; Wang, Gang; Ren, Pengfei; Dong, Wenyang; Guo, Jingzhen

doi:10.1306/09152120028

Cited by 9 publications

(8 citation statements)

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“…Interestingly, there are two erratic dots at depth of around 250 m in Figure 10B, which exhibit extremely high gas contents (14.21 and 13.00 m 3 /t, respectively). Concerning the high gas content at such a shallow burial depth, late-stage biogenic gases might occur in these positions which have been confirmed in literature in the southern Junggar Basin (Hu et al, 2010;Zhi et al, 2013;Wang et al, 2022), and will be discussed in the following section. As a result, late-stage biogenic gases might also contribute to the scatter correlation between gas content and burial depths.…”

Section: Tectonic Structure and Burial Depthsupporting

confidence: 67%

“…Recently, carbon isotopic analyses were conducted in the southern Junggar Basin by several researchers. The isotopic composition of methane from the southern Junggar Basin indicated that methane δ 13 C value ranges between −41.9‰ and −64.6‰ (Figure 12B) (Hu et al, 2010;Zhi et al, 2013;Wang et al, 2022). In general, thermogenic methane has δ 13 C values higher than −55‰ and biogenic methane has values lower than −60‰ because of preferential depleted carbon consumption by methanogens (Whiticar, 1996(Whiticar, , 1999Rice et al, 2008).…”

Section: Origins Of Coalbed Methanementioning

confidence: 99%

“…Regional structures and basin hydrodynamics can significantly affect the gas generation and accumulation in coal reservoirs (Bustin and Clarkson, 1998;Pashin, 2010;Gentzis, 2013;Li et al, 2022;Wang et al, 2022). In the Fukang area, groundwater recharges are dominated by glacial melt-water runoff from the Bogda Mountain perennial snow areas, and burnt rock hydrops in the burnt rock zones (Li et al, 2018).…”

Section: Hydrogeology and Burnt Rocksmentioning

confidence: 99%

“…In general, thermogenic methane has δ 13 C values higher than −55‰ and biogenic methane has values lower than −60‰ because of preferential depleted carbon consumption by methanogens (Whiticar, 1996(Whiticar, , 1999Rice et al, 2008). The Intermediate carbon isotopic value has been interpreted to be a mixture of coexisting biogenic and thermogenic gases (Hu et al, 2010;Fu et al, 2021;Zhang B et al, 2021;Wang et al, 2022). Biogenic gases in the study area have been demonstrated to be dominated by second-stage biogenic gases and a combined microbial pathway of methane generation via both CO 2 reduction and acetate fermentation was proposed by Wang et al (2022).…”

Section: Origins Of Coalbed Methanementioning

confidence: 99%

“…In terms of gas enrichment and origin, Fu et al (2016), Ou et al (2018), and Yu and Wang (2020) evaluated the CBM potential of the southern Junggar Basin. Zhi et al (2013), Fu et al (2019), Fu et al (2021) and Wang et al (2022) investigated the origin and distribution of coalbed gas in the Jurassic coal reservoirs from different parts of the southern Junggar Basin by isotopic and compositional analysis. Several enrichment patterns were further proposed by Li et al (2018) and Hou et al (2021).…”

Section: Introductionmentioning

confidence: 99%

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Coalbed methane accumulation, in-situ stress, and permeability of coal reservoirs in a complex structural region (Fukang area) of the southern Junggar Basin, China

Li²,

Pan³

et al. 2023

Front. Earth Sci.

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The enrichment of coalbed methane (CBM), in-situ stress field, and permeability are three key factors that are decisive to effective CBM exploration. The southern Junggar Basin is the third large CBM basin in China but is also known for the occurrence of complex geological structures. In this study, we take the Fukang area of the southern Junggar Basin as an example, coalbed methane accumulation and permeability, and their geological controls were analyzed based on the determination of geological structures, in-situ stress, gas content, permeability, hydrology and coal properties. The results indicate that gas contents of the Fukang coal reservoirs are controlled by structural framework and burial depth, and high-to-ultra-high thickness of coals has a slightly positive effect on gas contents. Perennial water flow (e.g., the Baiyanghe River) favors gas accumulation by forming a hydraulic stagnant zone in deep reservoirs, but can also draw down gas contents by persistent transportation of dissolved gases to ground surfaces. Widely developed burnt rocks and sufficient groundwater recharge make microbial gases an important gas source in addition to thermogenic gases. The in-situ stress field of the Fukang area (700–1,500 m) is dominated by a normal stress regime, characterized by vertical stress > maximum horizontal stress > minor horizontal stress. Stress ratios, including lateral stress coefficient, natural stress ratios, and horizontal principal stress ratio are all included in the stress envelopes of China. Permeability in the Fukang area is prominently partitioned into two distinct groups, one group of low permeability (0.001–0.350 mD) and the other group of high permeability (0.988–16.640 mD). The low group of permeability is significantly formulated by depth-dependent stress variations, and the high group of permeability is controlled by the relatively high structural curvatures in the core parts of synclines and the distance to the syncline core. Meanwhile, coal deformation and varying dip angles intensify the heterogeneity and anisotropy of permeability in the Fukang area. These findings will promote the CBM recovery process in China and improve our understanding of the interaction between geological conditions and reservoir parameters and in complex structural regions.

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Section: Tectonic Structure and Burial Depthsupporting

confidence: 67%