EVALUATION OF NATURAL AND PRESENT SUBSIDENCE IN THE NORTHEASTERN COAST OF THE CASPIAN SEA

The main goal of the study is to test different methodologies helpful for the definition of natural and present subsidence along coastal area. Specifically, tests were carried out on the Kazakh coastal area (northeastern part of the Caspian Sea coast). Specific objectives include: • the reconstruction of the geological assets of the projects area; • the definition of processes that influence the subsidence under specific geological conditions; • the calculation, through numerical models application (both 1D – NATUB and 2D - BASIN), of natural subsidence; • the detection of present ground vertical movements through Synthetic Aperture Radar Interferometry (InSAR), from 2003 to 2009. Collected data was derived from international literature (especially for the basin-scale) and from O&G companies reports and surveys, and considering several geological disciplines (stratigraphy, geodynamics, hydrogeology etc.). Integration of data and the reconstruction of the geological framework of the area have been developed at different scales: basin-scale: regional geology and geodynamic evolution of the Precaspian Basin and the North Ustyurt Basin; local scale: four subareas of the northern part of the Caspian Sea have been identified. For each subarea, when data is available the study focuses on the complexity and variability of the area; the stratigraphic complexity is determined by several kilometres of clastic and carbonatic sediments interrupted by 4 km salt layer, a distribution of soil features (with geotechnical properties) linked to the interaction of fluvial and marine dynamics, prevalence of saline waters in a multistage aquifer system, and the presence of oil and gas reservoirs