Petrophysics/Rock Physics Projects

Preparing Well Data for Inverison

For most geoscientists, well logs represent the “ground truth” since they, along with cores, are the only direct measurements of rock properties at the reservoir. Yet well log data frequently come with their own sets of problems.

In order to properly obtain rock property information from the seismic data through inversion, we must have a very accurate estimation of the seismic wavelet. The wavelet estimation in turn is based on the acoustic reflectivity from the sonic and density logs. Therefore, in order to do a proper job of seismic inversion, we must have high-quality well log data.

Traditional petrophysics cares only what is going on in the reservoir zone itself. However, seismic reflections are driven by the acoustic contrasts between the zone above the reservoir and the reservoir itself, and between the reservoir and the zone below the reservoir. Therefore in a Fugro-Jason reservoir characterization project, we are concerned with a much longer interval of the well logs than in a typical petrophysical analysis.

Further, Petrophysics is concerned with Porosity, Sw, and Vclay. Seismic works in elastic rock properties Vp, Vs, and density. Rock Physics is the link between the petrophysical properties and the elastic properties needed for successful seismic inversion.

We use PowerLog® and RPM in our reservoir consultancy projects to integrate the Petrophysics and Rock Physics workflows to provide the best quality well logs to support the model building and inversion processes.