地层压力条件下沁水盆地煤岩动静态弹性参数同步超声实验研究

静态弹性参数对储层压裂改造、应力场及裂缝预测具有重要意义,开展地层压力条件下煤岩动、静态弹性参数实验研究,获得动、静态弹性参数之间的关系,为利用动态弹性参数预测静态弹性参数提供了岩石物理依据.本次研究应用MTS岩石物理参数测试系统完成沁水盆地和顺地区的煤岩样在地层压力条件下的动静态弹性参数同步测试.结果表明:动态杨氏模量随压力的增加而增加,而动态泊松比随压力的变化较为复杂;动、静态杨氏模量之间呈线性关系,且动态杨氏模量大于静态杨氏模量;动、静态泊松比之间的相关性较差,大部分煤样的动态泊松比小于静态泊松比.获得的这些关系为动静弹性参数转换提供了基础,进而为利用地震资料进行静弹性参数预测,获得岩石力学性能参数提供了一种途径.

Simultaneous ultrasonic experiment of dynamic and static elastic parameters of coal under formation pressure conditions in Qinshui Basin

The static elastic parameters play a very important role in reservoir fracturing, and prediction of fracture and stress field. In order to obtain the relationship between dynamic and static elastic parameters, the dynamic and elastic parameters were tested under formation pressure conditions, which supply rock physics basis for transforming dynamic parameters into static parameters. Using MTS (a rock mechanics test system) we measure simultaneously the dynamic and static elastic parameters of coal samples in HS region of Qinshui Basin under formation pressure conditions in this study. Experimental results show that:dynamic Young's modulus increases with pressure, while dynamic Poisson's ratio varies relatively complicated with pressure; dynamic and static Young's modulus show a good liner relation, and dynamic Young's modulus is higher than static Young's modulus; dynamic and static Poisson's ratio have poor correlation, and dynamic Poisson's ratio is lower than static Poisson's ratio for most coal samples. These relations provide basic data for transforming dynamic parameters into static parameters, providing a new method for forecasting static elastic parameters and obtaining mechanical property of coal rock using seismic data.