井间地震物理模拟研究

井间地震资料具有极高的分辨率,但是,其波场十分复杂,特别是有效一次反射波场能量较弱,且往往被管波等强相干干扰淹没,波场的识别与分离难度较大.地震物理模拟技术是认识复杂地震波场的有效手段.我们通过单一地质体模型、复杂地质体模型和真实井间模拟模型等多种逼真地质模型的物理模拟,揭示了井间地震观测下直达波、透射波、反射波、折射波,多次波和导波等各类波型的特征.物理模拟试验表明,在炮检域平面上分析直达波的信噪比与能量分布,可以使处理人员对旅行时的误差有更直观的认识.所以识别初至与拾取旅行时间时,不仅要在共震源点道集(CSG)上分析拾取,而且还要在共炮检距道集(COG)上分析拾取,这样就提高了直达波识别的可靠性与拾取时间的精度.

Study of crosswell seismic physical modeling

Crosswell seismic data are of very high resolution and complex wavefield. Primaries are usually weak and are tend to be smeared by strong coherent interference such as guide waves, which poses challenges for identification and decomposition of wavefield. In this paper, the author studied the characteristics of different wave modes in crosswell seismic data such as direct wave, transmitted wave, reflected wave, refracted wave, multiples, and guide wave through single geological body models, combined geological body models, and real crosswell seismic physical model. Results show that it provides more reliable estimation of traveltime on shot-receiver domain. First arrivals should be picked and verified on both common shot gathers and common offset gathers to ensure the reliability of direct wave identification and accuracy of travetime picking.