Stage 2: The Petrophysical Workflow

• Clay Volume

  What clay volume is, how the gamma ray, SP, neutron and density-based methods differ, and how to choose and combine them.

• TOC Analysis

  What total organic carbon is, how the Passey, density-based and sonic methods differ, and how to choose, calibrate and combine them.

• Porosity

  How porosity is computed from the density, neutron and sonic logs, how kerogen, gas and clay are handled, and when mineral inversion should be used, given clay volume and kerogen volume as inputs.

• Water Saturation

  What water saturation is, how clean-sand and shaly-sand models differ, how clay and salinity change the answer, and how to choose, calibrate and check a model, with shared inputs for water resistivity, exponents and the flushed zone.

• Irreducible Water Saturation (Swirr)

  What irreducible water saturation is, how the Buckles, Foil, permeability, RQI, Lucia and NMR estimates differ, and how to choose and calibrate one.

• Permeability

  How permeability is estimated from logs with the Wyllie-Rose, Coates, Timur, Tixier and Heslop equations and with porosity-permeability transforms, and how to calibrate, choose and combine them.

• Cutoffs Analysis

  How gross reservoir, net reservoir and net pay are defined and flagged, how to choose and defend the cutoff curves and values, and how a minimum bed thickness changes net-to-gross.