Subsurface Imaging of the Niger Delta Shallow Gas Zones Using Seismic Reflection Data

Shallow gas accumulations within the Niger Delta continental shelf pose significant drilling hazards to offshore oil and gas operations, with rapid pressure build-up and gas kicks capable of causing well blowouts and platform incidents. This study applies seismic reflection data interpretation to image and characterise shallow gas zones in a selected block of the offshore Niger Delta, evaluating the distribution and seismic expression of shallow gas anomalies within the upper five hundred metres of the subsurface. A two-dimensional time migrated seismic dataset was loaded into a standard interpretation workstation and the shallow section processed with enhanced colour displays to identify acoustic anomalies. Seismic attributes including amplitude, instantaneous frequency, and acoustic impedance were computed along targeted horizons to delineate gas-charged intervals distinguished by high amplitude anomalies, frequency shadows, and bright spots. Time slices and horizon extractions were produced to map the lateral extent of identified anomalies. The study evaluates the stratigraphic context of anomalies, assessing whether they are hosted within shallow channel sands, mass transport complexes, or fault-related structures. Shallow gas maps produced are intended to support pre-drilling hazard assessments and well trajectory planning for future development wells in the study block. This study provides undergraduate students with practical seismic interpretation training applicable to the Nigerian deepwater frontier. Keywords: shallow gas, seismic reflection, Niger Delta, drilling hazard, amplitude anomalies.