Comparison of seismic processing and interpretation tradeoffs between Kirchoff and finite-difference migrations, using poststack migrated data in the west Niger Delta, Nigeria

The Kirchoff and Finite-Difference migrations were carried out on seismic data from the western part of the Niger Delta of Nigeria. The survey for the acquisition of the data was oriented southwest-north-east, at an angle of 45.4490 o . The KIRCH and FXMIG seismic migration programs were used to process and display the seismic sections. The sections were interpreted for diffractions, faults, and structures. It was observed that the dipping structures were incorrectly positioned downdip from the true reflection point. Prior to migration, the dipping structures were steeper and longer. For both Kirchoff and Finite-Difference migrations, there was proper imaging of the dipping structures. The structures were accurately moved updip and diffractions collapsed. The faulting pattern is a growth fault system as is generally the case in the Niger Delta basin. The reflectors became shorter, anticlines more clearly defined, and reflection events terminating at fault planes. Finite-Difference migration is preferred because it is faster, handles velocity variation and noise better, and events appearance is sufficiently distinctive for the interpreter to find traps, seals and reservoirs.