Frequency Attribute Analysis at Euchis Field, Niger Delta, South-Southern Nigeria for Structural and Hydrocarbon Delineation

Aimed at enhancing hydrocarbon exploration in the Niger Delta, Nigeria; structural interpretation of at Euchis field was undertaken by analysing the frequency attribute of the reservoirs therein. Schlumberger’s Petrel 2017 software was used for data processing and interpretation of the field’s Well logs. In order to facilitate the lithostratigraphic interpretation of the field, seismic-to-well tie was carried out using three dimensional 3D seismic data provided. Seismic attribute analysis and prospects identification were carried out for structural analysis. Lithostratigraphic interpretation shows that the Euchis field is predominantly characterized by sand-shale interbeddings. The frequency attributes map analysis indicated three distinct reservoirs with frequency ranges of ≈ -9 to 48 Hz, ≈ -9 to 51 Hz and ≈ -6 – 54 Hz respectively. Based on the inverse proportionality between the thicknesses of rock layers in the subsurface and peak frequencies of the seismic reflection, the lower frequency were delineated as indicators of hydrocarbon occurrence at the field. Lithologic correlation at the field showed that the occurrence of the Basin within the Euchis field fall within the depth range of 2500 m and 3360 m and the presence of intra-reservoir seals. The structural analysis revealed occurrences of normal, listric, regional and minor faults at various depths. The regional faults were observed to have cut across the three reservoirs, forming a conduit for hydrocarbon migration; whereas the minor faults serve as traps within the second and third reservoirs. The other faults were observed to have a predominant trend in northnorth-west south-south east direction