六盘水煤田土城向斜煤储层现今地应力分布特征及其效应

Present Ground Stress Distribution Features and Effects in Tucheng Syncline,Liupanshui Coalfield

近期勘探实践显示,六盘水煤田土城向斜内煤层气资源丰富,如何实现高效开发是关键,而现今地应力在煤层气开发过程中具有重要作用。本次研究基于研究区注入/压降地应力实测数据,分析土城向斜煤储层现今地应力分布特征及其效应,结果表明:煤储层现今地应力随埋藏深度的增加而逐渐增大,呈明显的线性关系。水平最大主应力和最小主应力均随着煤储层压力的增大而增大,表明现今地应力对于煤储层能量有所贡献,影响独立叠置含煤层气系统的形成。现今地应力影响煤层渗透性,进而控制煤层气开发。土城向斜内煤储层渗透率随有效地应力增大呈指数减小。本次研究成果期望可以在六盘水煤田土城向斜煤层气开发中提供新的地质参考与科学依据。

The recent exploration practices have shown that CBM resources are abundant in the Tucheng syncline,Liupanshui coalfield.How to realize efficient exploitation is the key,while present ground stress will play an important role during CBM exploitation process.The study is based on study area injection/pressure fall experiment measured ground stress data have analyzed present ground stress distribution features and effects of coal reservoir in Tucheng syncline.The result has shown that coal reservoir present ground stress is gradually increasing with buried depth inreasing and presented obvious linear relationship.Horizontal maximum and minimum principal stresses are all increasing with coal reservoir pressure increasing.It indicates present ground stress has some contributions to coal reservoir energy,and impacted the formation of independent superimposed CBM-bearing system.Present ground stress will impact coal seam permeability,and then control CBM exploitation.Coal reservoir permeability in Tucheng syncline will present exponential decreasing with effective ground stress increasing.The studied result can be expected to provide new geological references and scientific basis for CBM exploitation in Tucheng syncline,Liupanshui coalfield.