井间地震定向接收的物理模型实验

1998年 37卷 第No. 1期
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Physical model experiment for cross-well seismic oriented receiving
中国新星石油公司石油物探研究所, 南京 210014
Research Institute of Geophysical Prospecting for Petroleum, CNSPC, Nanjing 210014
本文利用超声物理模型实验技术,对一个二维双层各向同性的水平层物理模型,进行了野外井间地震模拟。利用接收换能器的方向特性,有目的地作定向接收井间波场实验,研究检波器定向和其方向特性对井间地震数据采集的影响。实验资料表明,不同定向接收的井间波场有明显的差异。通过对井间地震波场的简单剖析和实验结果对比分析,得出了定向接收到的井间地震波具有明显滤波效应不能完全反映井间波场特性,以及震源位置也会对定向接收到的波场产生影响的结论。因此,要设计出最佳井间地震观测系统,必须同时考虑射线有限视角与检波器的方向角,同时还应注意,检波器的安放也会严重影响井间地震层析成像的质量。
A field cross-well seismic modeling is performed for a 2-D two-layered isotropic physical model by using the ultrosonic physical model technique. The directivity characteristic of receiving transducer is used to experiment on the orientationally-received cross-well wavefield so as to study the effect of geophone orientation and directivity characteristic on cross-well seismic data acquisition. Real data show that the cross-well wavefields by different oriented receiving have an evident difference. Through the simple dissection of cross-well seismic wavefields and the comparative analysis of experimental result, we conclude that orientationally-received cross-well seismic wave has obvious filtering effects, is not able to reflect the cross-well wavefield characteristic completely, and the source position can also influence the orientationally-received wavefield. Therefore, in order to design the optimal cross-well observation systern,both the ray finite visual angle and the geophone directional angle must be taken into account. Furthermore it should be noted that the position of geophone can also seriously influence the quality of cross-well seimic tomography.
井间地震; 物理模型; 定向接收; 方向特性;
cross-well seismic; phsical model; oriented receiving; directivity characteristic;