Prediction of Thin Bed Reservoirs Below ¼ Wavelength Tuning Thickness Using Full Bandwidth Inverted Seismic Impedance

Abstract

Although conventional 3D reflection seismic data has been invaluable in the exploration and development of oil and gas fields worldwide, the stand-alone technology fundamentally lacks the resolution required to adequately characterize complex, thin-bedded hydrocarbon reservoirs. Limited vertical seismic resolution, implicitly defined at ¼ wavelength tuning thickness, can become particularly problematic when predicting reservoir dimensions, and ultimately for risk and reserve evaluation. Widess (1973) observed that thickness estimation of a “thin-bed”, below ¼ wavelength tuning, can be detected (or is encoded) within the amplitude of the composite amplitude, which results from the increasing constructive interference of the top and base reflections as the bed thins. Herein, a methodology is introduced whereby aggregate reservoir sandstone thickness is successfully predicted away from well control via full bandwidth (0 to 25 Hz) inverted seismic impedance.