井间地震反射波POSTMAP偏移成像方法研究

The research and application of crosswell seismic reflection POSTMAP migration imaging

VSP-CDP成像是常用的井间地震反射波成像方法,因其成像不能使绕射波很好收敛,降低了资料的横向分辨率。为此,我们提出了对反射波进行两步成像的策略——POSTMAP偏移成像。其先利用改进的VSP-CDP成像方法得到CDP道集,再将VSP-CDP成像后的数据作为输入并提取偏移算子进行偏移。合成记录和实际资料应用表明,该方法能使绕射波很好收敛,可提高井间地震资料的横向分辨率。

Vertical seismic profiling-common depth point （VSP-CDP） mapping is a common crosswell seismic reflection migration. The lateral resolution of reflection events is reduced as it can not collapse the diffractions very well. We present a two-step migration, called as POSTMAP migration mapping： Firstly, the CDP trace gathers are acquired by improved VSP-CDP mapping. Then using the migration operator, obtained by VSP-CDP mapping, to collapse the diffractions essentially. The result showed that the diffractions can be collapsed very well with the POSTMAP migration, and the lateral resolution of crosswell seismic is also improved.