"Tidal Signal Analysis"
The Earth is subjected to the gravitational attraction of the solar-system bodies; primarily the Moon and the Sun. Because the solid Earth is an elastic body, it undergoes elastic deformation induced by the three kinds of tidal dilatations; Earth, oceanic, and barometric.
The Earth tide leads to a pore-volume change, resulting in the decrease and increase of the pore pressure respectively corresponding to the expansion and contraction of the pore volume. The ocean tide yields periodic pressure variations on the seafloor, which are transmitted through the overlying layers to the reservoir of interest. The mechanism of the barometric tidal dilatation is similar to that of the oceanic tidal dilatation in the sense that the dilatation is induced by a periodic variation of the compressive force of the overburden.
The diurnal and semi-diurnal features of the pressure fluctuations can be retrieved from pressure transients due to tides and be utilized to understand the physical properties of the Earth.
■ Estimation of Petrophysical Properties
in situ Pore Compressibility
Saturation Changes
in situ Permeability
■ Foresight of Fluid Migration
Investigation Radius of Tidal-signal Analysis
■ Estimation of Discrete Heterogeneity
Fracture Orientarion
Seepage through Fault
