Technical advances in pulsed-neutron interpretation for cased-hole logging; physics, interpretation, and log examples
Technical advances in pulsed-neutron interpretation for cased-hole logging; physics, interpretation, and log examples (in Geologic, geophysical, and petrophysical interpretation of core data and well logs, Chicheng Xu (prefacer), Carlos Torres-Verdin (prefacer) and Thaimar Spikes (prefacer))
Interpretation (Tulsa) (February 2015) 3 (1): SA159-SA166
Recently developed multidetector pulsed-neutron tools (MDPNTs--a term describing a pulsed-neutron tool with at least three detectors) can provide three-phase formation fluid analysis in cased wells. These tools are 43 mm (1 11/16 in.) or 54 mm (2 1/8 in.) in diameter and can be logged in or below most tubing sizes. We reviewed traditional oil- and water-saturation techniques as well as indirect gas-saturation techniques, and we compared them with recently developed direct gas-saturation techniques, now available from MDPNTs. A log example developed the data verification and interpretation process. The interpretation process was divided into two parts: First, we verified the log data quality and second, we applied a newly developed gas model to the log data providing gas saturation without any reliance on the previously determined oil and water saturation.