孔隙流体类型对地层声波速度的影响

The Impact of Pore Fluid Types on Formations Acoustic Velocity

根据实际井的岩心资料,对砂岩样品的纵、横波速度与孔隙度及所含流体类型间的关系进行了实验研究,回归出了饱和气、水和油岩样的纵、横波速度与孔隙度的关系式。结果表明,饱和不同流体岩石的声波速度不同,岩石饱和气时的纵波速度明显低于饱和油、水时的纵波速度,并且孔隙度相同时岩石饱和油时的纵波速度略大于饱和水时的纵波速度,孔隙流体类型对横波速度的影响较小。含不同流体类型的岩样,其纵、横波波速比具有明显差异,利用纵、横波波速比和纵波时差的交绘图可识别地层流体的类型。为了解气体的声波特性,识别气层和气-液界面位置,对天然气的声波速度随温度和压力的变化情况进行了实验研究,从实验结果可以看出,不同压力环境下天然气随温度的变化规律不同。

Based on actual core data, the experimental studies were conducted to investigate the relationships of compressional wave velocity and shear wave velocity （P-wave and S wave） with porosity and fluid types using sandstone core samples. The relationship of the porosity with respect to P-wave and Swave in the rock saturated with gas, oil or water was regressed. The results indicate that the acoustic ve locities of rock saturated with different fluid are different. The P wave velocity of rock saturated with gas is lower than that of rock saturated with oil or water. The P-wave velocity of rock saturated with oil is higher than that of rock saturated with water. The type of fluid has little impacts on the S-wave. The rock saturated with different fluid, the P-wave velocity and S-wave velocity has obvious difference. The type of fluid in the formation can be identified using the ratio of P wave velocity to S-wave velocity and the P-wave slowness-time map. In order to understand the characteristic of acoustic wave and to identify the gas formation and gas liquid contact depth, the experimental studies of the relation of the acoustic wave velocity with the change of pressure and temperature were conducted. The results indicate that change of gas with the change of temperature is different under different pressure.