Correction-free Interpretation in Nuclear Geophysics

With due regard of a poor state of interpretation systems of nuclear logging tools and nonreliable<br>correction-based methodology we have devised and proposed a method for chart-free interpretation<br>of nuclear logs CFINL. A related computing technology includes as follows: a). fast vector modeling of<br>nuclear logs for a dense grid with about 105 points covering the space of geological and technological<br>parameters; b). synthesis of a multidimensional system of theoretical-and-experimental charts TEP; c).<br>generation of TEP strictly relating to actual measurement conditions; d). determination of a sought parameter<br>of formation and its accuracy from TEP without introducing any corrections. Method and software for<br>CFINL have been devised and can be applied to all the types of to nuclear logs for vertical, horizontal and<br>deviated wells. By way of testing we generated a complete system of TEP’s for interpretation of dual<br>neutron-neutron, neutron gamma, pulsed neutron-neutron, formation density, and pulsed gamma-gamma<br>spectral logs. It took from 1 week to 2 months to generate the TEP system for a single logging tool.