Subsurface Imaging of 2D Seismic Data Using Kirchhoff Time Migration Method, Central Iraq

Fadhil A Obaid,Ali M Al-Rahim,Hassan Zaid Ali

doi:10.24996/ijs.2020.61.12.19

Abstract

Kirchhoff Time Migration method was applied in pre-and post-Stack Time Migration for post-processing of images collected from Balad-Samarra (BS-92) survey line that is sited across Ajeel anticline oilfield. The results showed that Ajeel anticline structure was relocated at the correct position in the migrated stacked section. The two methods (Pre and Post) of migration processing showed enhanced subsurface images and increased horizontal resolution, which was clear after the broadening the syncline and narrowing or compressing the anticline. However, each of these methods was associated with migration noise. Thus, a Post-Stack process was applied using Dip-Removal (DDMED) and Band-Pass filters to eliminate the artifact noise. The time-frequency and signal to noise spectrum analyses as well as the ISO-velocity distribution analysis confirmed that the Pre-Stack Time Migration method outperformed the Post-Stack method as a result of structural complexity.

Highlights

Seismic processing is a method that aims to produce a subsurface image that characterizes the subsurface geological structure from the acquired seismic data
Kirchhoff migration is one of the most common and simplest methods of migration used in the seismic processing
Dip- Dependent Median Filter (DDMED) was used as a quality control (QC) of the migration process; it is clear that the Pre-Stack Time Migration (Pre-STM) image (Figure-12A) is improved as compared to that of the Post-STM (Figure-12B)

Summary

Introduction

Seismic processing is a method that aims to produce a subsurface image that characterizes the subsurface geological structure from the acquired seismic data. The result is the reflector imaged by the seismic data with an apparent dip of ( ) that is less than the true dip ( ) (Figure-1) [4]. For the quality control (QC) of the migration process, the Time-Frequency distribution slice (Figure-7) illustrates a clear difference between the image of residual stack (Figure-7A) and that of Post-Migrated stack section (Figure-7B).

Results

Conclusion