摘要
用有限差分数值方法研究了由分层均匀流体（地层的声波方程近似）和弹性固体地层包围的流体井孔体系声波和弹性波的传播规律．用声压描述井中流体，使奇异点源处理简单，使流体与流体、流体与弹性固体内边界连接条件的差分格式稳定．在Ｆｏｕｒｉｅｒ变换方法与半解析方法适用的简单地层条件下，将有限差分数值模拟结果与Ｆｏｕｒｉｅｒ变换及半解析方法计算结果进行比较，检验了方法的精确性．从模拟井外有薄层介质存在时的全波曲线看，层速度显示正确，并可以定性判断薄层出现的位置．
The propagation of acoustic and elastic waves in the fluid-filled borehole surrounded by the layered-homogeneous fluid (approximation of acoustic equations in the formation) and the elastic solid formation is investigated by the finite-difference method. Selecting pressure as the field quantity in the borehole fluid has some advantages. The singular point source is simplified and the difference formulation cases between fluid and fluid, fluid and elastic solid are stable. In the simple formation cases where Fourier transform and semi-analytical method are respectively applicable the numerical results from the finite-difference schemes are respectively compared with that of Fourier transform and semi-analytical methods. The correctness of the finite-difference method is verified. Observing the full waveforms with layered formation outside the borehole, one can obtain correctly the velocities in the layer and determine quantitatively the layer location. One can utilize the method and schemes given in this paper to investigate the effect thin-layer on full waveforms and to observe the distinguishing-layer ability along longitudinal direction and probling depth in the acoustic logging with thin-layer formation outside. the borehole.
出处
《地球物理学报》
SCIE
EI
CSCD
北大核心
1995年第A01期205-215,共11页
Chinese Journal of Geophysics
基金
国家自然科学基金大庆石油管理局联合资助
关键词
声波测井
有限差分
流体声压
弹性波
地层
井孔
Acoustic wave logging, Finite-difference, Fluid pressure, Thin-layer.
