多点激发小排列层析反演时深曲线

Time-Depth Curve from Tomographic Inversion of Small Spread with Multiple Sources

在地震勘探中,当近地表呈现连续介质特征时,通常是利用微测井进行表层调查得到时深曲线,用于建立近地表模型和计算静校正量,但是大范围布设微测井会增加野外施工成本。利用多点激发、小排列接收的方法进行野外采集,在确保近炮检距内有充足的初至个数的情况下,可通过小网格层析反演出近地表速度模型,最后根据层析反演的速度模型建立时深曲线。理论模型和实际资料测试结果表明,该方法反演的模型精度高,可以用于建立时深曲线。上述方法为类似近地表区域表层调查提供了有益借鉴。

In seismic exploration,the first breaks of upholes will be used to achieve the time-depth curves and then the near surface model and static corrections for continuous medium areas.However,large-scale layout of upholes will increase the cost in the field.By collecting data using small spread with multiple sources in the field,the number of first breaks in the near offset can be ensured,and the near surface model can be inverted by using tomographic inversion with small grid cell.Finally,the desired time-depth curve can be achieved from the near surface velocity model.Both theoretical and actual data show that the accuracy of the inverted near surface model using this method is high,and can be used to create the time-depth curve.The method provides a useful reference for near surface investigation of similar situation.