Accumulation conditions and target area evaluation of coalbed methane in eastern uplift of Junggar Basin
The eastern uplift of the Junggar Basin has great coalbed methane (CBM) exploration potential. CBM selection and evaluation will provide scientific guidance and direction for CBM exploration in the region. Utilizing well logging data, core analysis test results, and seismic data, well-seismic calibr...
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| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | zho |
| Published: |
Editorial Office of Petroleum Geology and Experiment
2025-01-01
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| Series: | Shiyou shiyan dizhi |
| Subjects: | |
| Online Access: | https://www.sysydz.net/cn/article/doi/10.11781/sysydz2025010117 |
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| Summary: | The eastern uplift of the Junggar Basin has great coalbed methane (CBM) exploration potential. CBM selection and evaluation will provide scientific guidance and direction for CBM exploration in the region. Utilizing well logging data, core analysis test results, and seismic data, well-seismic calibration and seismic profile interpretation were carried out. Connecting-well profiles and thickness distribution maps for coal seams in the Jurassic Xishanyao and Badaowan formations were compiled. The study analyzed main accumulation factors, including gas source, basic characteristics of coal rocks, reservoir physical properties, gas content, and preservation conditions. The results show that: ① Coal seams of the Xishanyao Formation are distributed continuously in the Wucaiwan-Wutongwozi sags to the north of the Shaqi Uplift, while to the south of the Shaqi Uplift, the seams are mainly distributed in the Jimusaer-Jinan sags. Coal seams of the Badaowan Formation are strongly segmented and mainly distributed in parts of the sags. ② This region contains self-sourced biogenic gas from coal seams, low-maturity thermogenic gas, and high-maturity deep-seated exogenous gas. ③ The organic components in coal rocks are mainly inertinite, followed by vitrinite with small amounts of exinite. The vitrinite reflectance (Ro) in coal rocks is low (0.39%-0.47%), indicating low-rank coal. CBM mainly consists of N2, CO2, and CH4, with N2 being the dominant component. The combustible gas (CH4) content is low relative to the total gas content in coal rocks. ④ CBM enrichment and accumulation models include piedmont fault depression, deep depression, and open slope gas escape models. ⑤ Evaluation parameters and classification standards were established. The Wucaiwan, Wutongwozi, Jimusaer, and Jinan sags are favorable areas for CBM exploration. The Shazhang fault-fold belt and the Shiqiantan Sag are moderately favorable areas. The Shishugou and Gucheng sags are unfavorable areas. |
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| ISSN: | 1001-6112 |