Application of Spectral Decomposition to 3-D Visualization of thin Sandstone Reservoir in “X Field” Niger Delta, Nigeria

A.O. Aderoju¹, O.G. Bayowa¹, and O.A. Alao²

Abstract

Technology has been predicted as the last card in combating the ever increasing demand of our commodity; oil and gas. Modern approach to Seismic acquisitions and interpretation is of prime essence. A powerful Interpretation tool; Spectral decomposition, has been used to visualize a thin sandstone reservoir in “X – Field” Niger Delta. The study aimed at mapping thin sandstone beds which have been considered sub seismic. Well log data were acquired. Two thin sandstone bed TB 01T and TB 03T were mapped and qualitatively and quantitatively interpreted using RocDok software and correlated across four wells; Tmb 01, 02, 04 and 05. The interpreted well logs were presented in tables. Seismic data were also acquired. Thin sandstone bed markers were identified from well logs and consequently mapped on the seismic data. The data were interpreted using the OpendTect software for sandstone frequency analysis which was presented in form of maps. The frequency analysis was carried out both on the plan view and the section view. Two thin sandstone beds were delineated from the well log. TB 01T had an average thickness of 4.16m. The sandstone unit cuts across three wells (Tmb 01, 04 and 05) but could not be delineated in Tmb 02. TB 03T was extremely thin. Its average thickness could not be estimated but it cuts through the four considered wells. Frequency analysis from seismic sectional view revealed the portion of the thin pay sandstone as the markers were perfectly engulfed by high amplitude. The plan view seismic analysis also showed high amplitude across the region of the thin sandstone. The study concluded that the high amplitude represented on the seismic views characterize the thin sandstone pay. Other regions on the seismic views represented by high amplitude were identified to be new prospects. Further exploration work is suggested for the identified prospects.

AAPG Search and Discovery Article #90188 ©GEO-2014, 11th Middle East Geosciences Conference and Exhibition, 10-12 March 2014, Manama, Bahrain