SPWLA Monthly Luncheon Meeting  

Thursday – October 18 2018

PanAm Building- Suite 1600

601 Poydras St, New Orleans, LA 70130

11:30 – 1:00 pm

or
email Elizabeth Tanis ([email protected]) with RSVP



GEOCHEMICAL PHOTOELECTRIC (PE) LOGGING

Presented By: Jim Galford
Formation Scientific Advisor, Haliburton

ABSTRACT

Photoelectric logs from lithodensity tools have become a mainstay of modern logging and are valuable to petrophysical interpretation and mineralogy identification. Like most measurement techniques, they are not without limitations. Reliable lithodensity photoelectric (PE) logs can only be obtained in wells drilled with modest mud densities because the additives used to achieve high-density muds contain high Z materials that compromise the PE measurement. In addition, because they are often obtained with pad devices, lithodensity PE logs can be compromised by loss of contact between the pad and the borehole wall. Mudcake between the pad and the formation can also adversely affect lithodensity PE measurements. A useful substitute can be obtained from neutron-induced gamma ray spectroscopy logs when borehole conditions are not suitable for lithodensity PE tools.

The process to obtain PE logs from geochemical data that are compatible with lithodensity PE logs is described. Example logs from wells drilled with low-density muds demonstrate and validate the technique. Additional examples illustrate how geochemical PE logs can identify lithodensity logs that have been affected by borehole rugosity and how they be used to replace compromised or missing lithodensity PE logs in wells drilled with heavy muds.