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Velocity-porosity Evolution of Mechanically Compacted Brine-saturated Sand-clay Mixtures
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 77th EAGE Conference and Exhibition 2015, Jun 2015, Volume 2015, cp-451-00398
Abstract
In this study, four brine-saturated specimens of unconsolidated sands and sand-clay mixtures are tested to infer velocity-porosity trends of sand-dominated facies when a full control on mineralogy is applied on the tested samples. The current results show consistency with the published experimentally derived compaction trends of natural sands. The iso-stress curves connecting the data points with the same effective stress in the velocity-porosity plot are comparable to the friable sand model curves proposed to estimate the rock properties of sands within the mechanical compaction domain. As expected, the achieved iso-stress curves for mechanically compacted samples are too far away from the empirical lines suggested estimating rock properties of sandstones within the chemical compaction domain. To check creditability of the rock physics models in both mechanical and chemical compaction domains, the log-derived petrophysical properties acquired from the North Sea are compared to the derived experimental compaction trends. The shallow unconsolidated sands follow closely the experimentally derived iso-stress curves and friable sand model but, the consolidated sandstones show a wide range of physical properties and may sometimes follow different trends compared to suggested rock physics models.