电阻率法在复杂地区近地表速度建模中的应用

Application of electromagnetic method for near surface velocity modeling in complex area

（1.中国石油化工股份有限公司石油勘探开发研究院南京石油物探研究所，江苏南京210014；2.中国石油化工股份有限公司石油勘探开发研究院，北京100083）

Nanjing Institute of Geophysical Prospecting,Petroleum Exploration & Production Research Institute,SINOPEC,Nanjing 210014,China

针对南方复杂地表特点，分析了电阻率法近地表速度建模方法中存在的问题，提出了实用化的速度反演方法。首先对勘探区的岩性进行分析，获得不同岩性的速度与电阻率和深度之间的关系；然后进行自适应加权广义逆反演，在充分考虑复杂地表特点的情况下，通过对参数的自适应加权将对复杂表层岩性变化的约束加入反演过程；最后通过与微测井资料的对比，对反演的速度进行精度分析。该反演方法在勘探区的试验结果表明，无论是稳定性还是精度都得到了很大的提高，取得了较好的结果。

Aiming at the complex surface conditions in southern area,we analyzed the existing problems of near surface velocity modeling by electromagnetic method and proposed a practical velocity inversion method.Firstly,the lithology in exploration area was analyzed to obtain the relation between velocity and resistivity and depth with different lithology;then,the self-adaptable weighted generalized inverse is carried out;by sufficiently considering the complex surface conditions and through self-adaptable weighting of parameters,the restraints for complex surface lithologic changes were put into the inversion process;finally,through compared with uphole data,the precision of inversion velocity was analyzed.The method was applied to the exploration area,and the precision and stability were improved greatly.