- © 2014 by The Society of Exploration Geophysicists
The elastic and petrophysical properties of the fluvial rocks of the Miocene in the western basin of the Gulf of Thailand display typical signatures of dispersed-clay sandstones and dispersed-quartz shales. That is, the relationships between various properties exhibit two strong trends associated with a grain-supported domain and a matrix-supported domain. The minimum porosity and maximum P-velocity occur at the transition between these domains at a clay volume of approximately 40–50%. This means that the hardest rocks occur at this transition. A simple rock-physics model has been developed that quantifies the elastic properties over a large depth range but does not explicitly account for the dispersed nature of the clay and quartz. It employs a single aspect ratio at each depth within an inclusion-based modeling scheme. The required aspect ratio at each depth can be estimated from the depth, the porosity, and the clay volume of the rock.