石油地震纵横波速度层析成像

Velocity Tomography of Petroleum by P and S Seismic Waves

本文以分层均匀"多层介质模型"为依据,正演模拟多炮人工地面地震记录。其观测方式为:三炮位置分别在1500m,2500m,3500m处;道检距25m,140道(或道检距5m,700道),偏移距1000m。为提高地震反射层析成像的精度,运用"走时最小纵横波速度层析成像"与"波形基本解纵横波速度层析成像"相结合的方法,反演各层界面形状及各层纵波、横波速度,这是本文的特点。反演结果图与"多层介质模型"基本一致,相对误差小于5%,达到实际部门的要求。我们在数学上发展了"层析成像"的内容,如探索出求二维场强公式用一维基本解表示,因此大大提高了数值计算速度,具有一定的实用与理论价值。用"ProMAX软件"分析实际地震数据,获得地下11层垂直剖面图与纵横波速度层析成像结果。"项目程序系统"可供相关部门实际参考使用。

This paper study simulates artificial surface seismic record of multiple-shot on the base of ＂uniform-layer multi-medium model＂（as shown in Figure 10）.The observation method is：three shot positions at 1 500 m,2 500 m,3 500 m;road distance 25 m,140 road（or road distance 5 m,700 road）,offset 1 000 m.Combining the method of＂P and S seismic wave＇s velocity tomography of minimum travel time＂with＂P and S seismic waves velocity tomography of wave fundamental solution＂to invert the interface shape and the velocity of P and S seismic wave of each layer.With the principle of＂The simpler the better＂,we only put three shots to the ＂multi-medium model＂,then using the＂minimization of travel time＂and＂boundary conditions＂to replace the conventional multi-shots,so we can reduce the computation greatly.After then,supposing the shot and receiver points are known,we programming to compute the reflected wave＇s travel time from the shot points to receiver points.We developed the content of CT,and explored one-dimensional fundamental solution＇s important role in expressing the field intensity,which could highlight the characteristics of our work.Finally,analyzing the actual seismic data with＂Pro MAX software＂to revise the process above,then getting the vertical sectional drawing of 11 ground floors and also the result of petroleum P and S seismic wave＇s velocity tomography.