ABSTRACT

In mineralized igneous rocks, the structural (bound) water present in the form of alteration minerals contributes significantly to the response of the neutron log. This paper shows two examples in low porosity rock where the bound water actually dominates the log response. The neutron response equation must be modified to account for this effect and as a result the cross-plot relationships are also modified. For the neutron-sonic and the neutron-density cross plots, the bound water term is conveniently incorporated in newly-defined expressions for an apparent matrix transit time and an apparent grain density.

Keywords:
log analysis, cross plot, transit time, coefficient, neutron response, well logging, correlation, contribution, grain density, Symposium
Subjects:
Formation Evaluation & Management, Open hole/cased hole log analysis
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1975. Society of Petrophysicists & Well Log Analysts
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