The writer has developed a new indicator which allows major local tectonic features to be determined from a single well. Only 1 measurement is required (in addition to Rw and temperature)--the SP log. The information which can be determined from this indicator includes locations of (1) fault zones, (2) compaction stress changes, (3) high pressure, and (4) permeable sandstone beds of significant extent.

The method is simple and may be cross-checked with the density or travel-time log. It involves several simple principles: (A) [water salinity] [shale porosity] = constant, and (B) [shale porosity] ~ [overburden-hydraulic pressure]. Water salinity may be determined accurately from clean sandstones, but a complete well profile is needed to make an analysis. Several offshore analyses have been made, and, in those analyses, the various stresses have been confirmed.

End_of_Article - Last_Page 863------------