Abstract

This study presents the clay mineral diagenesis observed in a hydrocarbon exploration well located offshore southeast Korean peninsula. An occurrence of dioctahedral chlorite-smectite (C-S) mixed layer mineral (Li-tosudite) is, in particular, documented by mineralogical and chemical analysis. The clay mineral diagenesis in sandstones is quite different from that in the associated mudstones, indicating that the clay mineral diagenesis has been affected by a hydrothermal episode.