利用多偏移距VSP资料实现井间层析成像

Crosshole seismic tomography using multi-offset VSP data

地矿部石油物探研究所, 南京210014

Geophysical Prospecting for Petroleum, MGMR, Nanjing 210014

本文提出了利用多偏移距井中VSP资料进行井间区域的层析成像方法。通过在不同初始速度模型的情况下对不同地点数的两井中VSP记录进行了层析成像试验。试验结果表明,随着VSP资料道数的增加,层析反演的质量得到了明显的提高；在道数较少的情况下,反演结果对初始速度模型的依赖性变大。只要观测方式设计合理,数据量达到一定的要求,利用多偏移距VSP资料实现目标区的高质量层析成像是完全可行的。最后,将本方法用于吉林地区采集到的三个炮点的两井中VSP资料的层析反演,取得了初步应用效果。

This paper presents a method for crossholc tomographic imaging using multi-offset borehole VSP data. Tests of tomographic imaging with VSP data are carried out under the condition of different initial velocity models. The results show that with the increase of VSP data track the quality of tomographic pictures will be improved obviously .and at the situation of less VSP data.tomographic results will depend large]y on the initial velocity model The way to obtain high quality tomographic results from multi-offset VSP data is practicable if the acquisition gcometry is designed reasonably and the data amount reach the certain degree. The method is used in the tomographic inversion of field VSP data from the Jilin area. And a preliminary result is achieved.