| 云南恩洪煤层气区块单井多煤层合采方式探讨 |
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| 引用本文： | 姜杉钰,康永尚,杨通保,王金,张兵,顾娇杨,孙晗森.云南恩洪煤层气区块单井多煤层合采方式探讨[J].煤田地质与勘探,2018,46(2):80-89. |
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| 作者姓名： | 姜杉钰 康永尚 杨通保 王金 张兵 顾娇杨 孙晗森 |
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| 作者单位： | 中国石油大学(北京)地球科学学院;油气资源与探测国家重点实验室;贵州省煤层气页岩气工程技术研究中心;中海石油(中国)有限公司非常规油气分公司;中联煤层气有限责任公司 |
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| 基金项目： | 国家科技重大专项课题（2016ZX05044-005） |
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| 摘 要： | 云南恩洪区块属于多薄煤层发育区，煤层气资源丰富，但勘探开发程度较低。以恩洪区块煤层气井资料为基础，分析了前期单井产气量低的原因，探讨了多煤层合采的必要性及开发层系划分方式和单井开发潜力，进而结合流体可动性和国外煤层气开发经验，提出适合恩洪区块的煤层气开发方式。研究表明:恩洪区块单煤层资源丰度较低，前期煤层气井动用的资源不足是产气量低的重要原因；恩洪区块单井多煤层合采动用储量多，单井合采尽可能多的厚度大于0.5 m的原生-碎裂结构煤层是提高单井产气量的有效方式；恩洪区块煤层气吸附时间短，扩散能力强，但受地应力强度大、非均质性强和煤体结构复杂影响，渗透率较低且空间变化剧烈；分段压裂适合恩洪区块多薄煤层和弱含水的煤系地层特点，多煤层合采可依据煤层垂向上分布特点合理划分开发层系进行分段压裂合层排采，进行排水阶段缓降液面-见套压后憋压-稳产期稳压，之后缓慢降压的排采措施，最后形成各组整体降压提高产量。
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| 关 键 词： | 煤层气 恩洪区块 多煤层合采 流体可动性 开发方式 |
| 收稿时间： | 2017-07-10 |
Combined CBM drainage of multiple seams by single well in Enhong block,Yunnan Province |
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| Abstract: | With abundant coalbed methane (CBM) resources, Enhong block in Yunnan Province has trouble in developing CBM due to the multiple-thin coal seams. Based on CBM wells data, this paper focused on the necessity of multi-seam drainage through analyzing the resource abundance and EUR(estimated ultimate recovery), and then came up with some advice for development of Enhong block by referring the fluid mobility of coal seams and CBM development experience in the US. The study shows that the resource is not efficient enough trough drainage of only one seam by single well, which is also the reason of unsatisfactory gas production. On the other hand, the ultimate recovery resources of multiple coal seams are sufficient in Enhong CBM block, paving the way for necessity of multi-seams drainage in every single well. It is wise to drain all coal seams whose thickness are more than 0.5 m with native structure or cataclastic structure. Besides, the low desorption time is beneficial to drainage but the low permeability with intense variety will produce a negative effect on CBM development, which need to be overwhelmed through proper fracturing and drainage methods. Staged fracturing technology is appropriate in Enhong Block which is specialized by its multiple-thin coal seams and weak aquifer between coal-bearing formations, so much more CBM resources can be recovered. In addition, it is important to divide lots of coal seams into groups and drain each group from top to bottom when single vertical well drains multiple coal seams. Moreover, it is necessary to lower liquid level with a slow process when draining water from the coal seams and a high gas production could appear after a long time each coal seam had a reduction of formation pressure. |
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