J. S. Gardner and J. L. Dumanoir
Schlumberger Well Services, Houston, Texas
ABSTRACT
The Litho-Density log has now come of age. Successfully run in a wide variety of lithologic
environments, it has been most helpful in analyzing hydrocarbon-bearing formations with variable
lithology. For this reason it has proved invaluable in determining whether changes in Density-Neutron log response are due to light hydrocarbons or lithology. Thus the log computational process becomes more accurate, requires less detailed parameter decisions, and allows the analyst to concentrate on the broader aspects of the log interpretation problem.
A brief review of the physical basis and dimensions of the Pe (apparent photoelectric absorption
cross section) measurement is made. Some guidelines to quick-look field log interpretation are
provided, and several field log suites analyzed.