宁武盆地煤岩静态力学特征研究

The static mechanics characteristics in Ningwu basin

井壁失稳是目前制约煤层气规模化开发的关键问题之一。由岩石力学理论可知,煤岩的力学强度是井壁稳定性的决定因素之一。通过对宁武盆地煤岩进行系统力学研究,利用应力摩尔圆法求出宁武盆地主力煤岩的内摩擦角、内聚力等强度参数;建立横波与纵波幂律关系曲线,动态弹性模量与静态弹性模量间线性关系曲线及动静态泊松比间线性关系曲线,得出煤岩静态弹性参数以直接反应地层力学性质,解决了勘探开发中声波测井所得动态弹性参数无法真实反映地层力学特点的技术问题。

How to develop the rich CBM resource now becomes an important project in China. The wellbore instabilityis a key factor restricting CBM economical development. According to rock mechanics the mechanical characteristicsof coal bed is critical factor for CBM wellbore stability, the study of the static mechanical characteristics hasonly developed in a limited level in China recently, this paper makes the systematic study on the mechanics of coalbed in Ningwu basin, got the extension and compressive strength, calculated the internal friction angle and thecohesion, built the power law relationship for longitudinal wave and transverse wave and also found out the linearrelation between dynamic elastic parameters and static elastic parameters. It gives a technical method on how to getmechanics characteristics of formation on the basis of dynamic elastic parameters obtained from acoustic logging.