垂直地震剖面的采集、处理与应用

在进行 VSP 测量时，为了减少电缆波、保证激发的重复性，我们采用电火花震源在井中潜水面以下5米处以不同的能量激发，井下检波器要保持和井壁紧密接触，深度间隔为20-50米之间，电缆要处于松弛状态。资料处理的关键在于根据地震测井资料建立的速度模型，求出校正量。然后利用 VSP 测量的各道时间减去其对应的校正量，得到一条类似于地面地震观测中的自激自收时间剖面。最后通过二维滤波处理，消除了低视速度的电缆波和套管波。应用 VSP 资料可以测定地震波频率随深度变化的曲线，进而求得吸收系数，它还可用于烃类检测，了解井孔附近的地质构造和岩性特征。

The caquisition,processing and application of VSP data

In order to reduce cable wave and ensure repeatable shooting in vertical seismic profile survey, we use the following field method: electric sparker fires repeatedly with different energy levels at a depth of 5m below water table in a shot hole, well geophones are kept in close contact with hole wall, geophone interval is 20-50m and the cable is relaxed while shooting. The key to data processing lies in accurate time corrections which are computed from velocity model made by well shooting data, After the time corrections are applied to the time measurements of corresponding VSP traces, a zero-offset time section similar to that got in surface seismic survey is obtained, Finally,2D filtering is used to eliminate low velocity cable wave and tube wave. Seismic frequency-depth curve can be plotted from VSP data. This curve is then used to estimate absorption coefficients.VSP data can also be used in studies of HCI, geologic structures and lithology nearby a bore hole.