OPTIMIZING SEISMIC DATA ACQUISITION FOR SUBSURFACE EXPLORATION: A CASE STUDY OF NIGER DELTA

Abstract

The seismic reflection method has played a crucial role in geological exploration, spanning from petroleum
to engineering investigations. This study aims to enhance seismic acquisition in the demanding Niger Delta terrain, particularly in the OML 28 block, considering environmental and urban complexities. A
comprehensive 3D reshoot seismic survey was conducted, involving systematic partitioning of the field into 7 swaths, while ensuring quality control measures. Shot points that fell on non-seismic objects were
strategically relocated to ensure full-fold coverage and adequate subsurface sampling without having any
negative environmental implications, utilizing techniques like point shift, smooth curve and laminar flow.
Fold coverage analysis delineated distinct ranges across various offsets, including near, mid, far, and full
offsets. Notably, the nominal full-fold coverage for OML 28 was 312, with observable improvements in mid offset ranges compared to near-offset and far-offset. Merging offset ranges facilitated achieving the required fold through swath overlap, ensuring thorough subsurface sampling. Additional analyses encompassed bin statistics, offset/azimuth rose diagrams, and surface topography examination, shedding light on trace distribution and elevation variations. Drilling operations were essential, revealing disparities between drilled and loaded depths, indicating potential signal attenuation concerns. Arrival time analysis
emphasized drilling past weathered layers to mitigate signal attenuation. This study enhances seismic
acquisition optimization, providing insights into fold coverage variations across offsets and emphasizing
comprehensive drilling practices for signal enhancement. These findings are crucial for refining subsurface
imaging and geological comprehension, particularly in challenging terrains like the Niger Delta.