阜康白杨河矿区高倾角煤层气成藏主控因素分析

Analysis on Main Controlling Factors of High-Dip Coalbed Methane in Baiyanghe Mining Area of Fukang, NW China

摘要: 针对阜康白杨河矿区特殊的高倾角、厚煤层、高含气量、高产气量特征，通过构造演化、煤层气成因、沉积环境、水动力条件及煤层自燃的多因素综合分析，探讨了阜康白杨河矿区高倾角煤层成藏主控因素。研究表明：白杨河矿区煤层气为生物成因和热成因的叠加作用，均在燕山运动I幕沉降阶段形成；燕山运动II幕、III幕及喜山期运动，煤层气进入保存阶段，最终形成现今的高倾角煤层气藏；稳定的成煤环境沉积形成巨厚煤层，为煤层气成藏提供了丰富的资源基础；上倾方向水动力封堵作用和下倾方向水动力封闭作用，两者有效的保存了煤层气的富集。本文对高倾角煤层气成藏富集机制的分析认为，下倾部位、较大埋深、高水势区、水体滞留处易富集成藏，是勘探的有利目标区。

Abstract: In view of the special features in Baiyanghe mining area of Fukang, including of high-dip, thick coal seam, high air content, and high volume of coal seam, this paper discusses the main controlling factors of high-dip coalbed methane accumulation through comprehensive analysis of tectonic evolution, CBM formation, sedimentary environment, hydrodynamic conditions and spontaneous combustion of coal seam. The results show that the genetic type of coalbed methane is the primary biogenic gases and thermogenic gas, they are formed in the Yanshan movement I curtain falling stage. Under the effect of the II Yanshan movement, III curtain and Himalayan tectonic movement, the high-dip coalbed methane reservoir was formed finally. The thick coal seam was sedimentary in stable sedimentary environment, and it provides the rich material basis. In the effect of sealing of up-dip direction hydrodynamic and hydraulic seal of down dip direction, the coalbed methane was effectively preserved. According to the enrichment of high-dip coalbed methane, the paper discovers that the CBM was enriched in buried depth of down dip area and water retention area. There will be a useful exploration target zone.