Seismic trace attributes for thickness and fluid discrimination

Our goal is to understand how different trace attributes can help identify the pore fluid and how these attributes vary with the thickness of the reservoir. The study is based on a synthetic earth model where a quartz-rich rectangular reservoir is surrounded by clay-rich shale. The novel feature of this work is that we build an earth model based on rock physics modeling. Specifically, we use rock physics to simulate various degrees of cementation of the rock. Once the pseudo-well is constructed, we produce a normal incidence and offset traces and compute various attributes. It appears that one powerful fluid identifier is the minimum of the relative Poisson's ratio as well as the definite integral of the envelope of the relative Poisson's ratio. This study lays a foundation for rock physics based trace attribute analysis. The fact that relative Poisson's ratio and, to a lesser degree, relative acoustic impedance, are powerful reservoir and pore fluid identifiers is confirmed by applying our methodology to real data, including wellbore data and synthetic seismic traces generated based on these data, as well as real seismic traces. This is confirmed in our two case studies conducted on offshore oil and gas fields.