Abstract
Quantitative geophysical study of seismic stratigraphy technique was examined through a case study of the prediction of sandstone reservoir distribution on the Minenobu structure in the Ishikari Plains, Hokkaido.
This geophysical study was performed by the integrated interpretation consisting of seismic modeling, VSP, model-based inversion and conventional 2D seismic sections. As the result of this study, the distributions of two target sandstones are clearly delineated as described below.
1100m-layer sandstone reservoir in Atsuta Formation is distributed covering Minenobu structure with the width of 1km-1.5km, trending north-south direction and extending irregularly and discontinuously in east to west directions. This sandstone is estimated to deposit along the turbidity current with north to south direction in consideration of well data information.
1600m-layer sandstone reservoir in Ponsubetsu Formation is distributed only in the limited area with the width of about 500m almost along the line 84 V-1 on the higher part of the acoustic basement, trending north west to south east direction. Paleo depositional environment of this sandstone is estimated to be bar sand or channel sand in shallow waters according to the dipmeter and geological information.
Model-based inversion is rather reliable and powerful technique for the lithological interpretation on the condition that original seismic data quality is good.
VSP in a deviated well is useful technique for the lateral prediction of reservoirs.
Recently the seismic stratigraphy technique has been remarkably advanced. Seismic stratigraphy has become a fully integrated working discipline, integrating the purely geological and geophysical approaches to exploration.
