Anomalous velocity and porosity are often indicators of abnormal pore pressure. It is important, therefore, to be able to link velocity to porosity and rock texture in a rational, firstprinciple-based manner. The critical porosity concept allows for building such rock physics models. Critical porosity is the porosity above which the rock can exist only as a suspension. In sandstones the critica...

We have examined the nature and origin of smectites in glaciomarine sediments of the AND-2A drill core (McMurdo Sound, Antarctica) by means of X-ray diffraction (XRD) analyses on the clay fraction, field emission scanning electron microscopy (FESEM), scanning electron microscopy (SEM) observations and SEM-EDS microanalyses on smectite particles. Relying on the smectite variation throughout the ...

The fracture of sandstone is closely related to the condition internal microcracks and fabric micrograin. macroscopic mechanical property depends on its microscopic structures. However, it difficult obtain law microcrack growth under loading by experiments. A series models were established with particle flow code 3D (PFC3D) based triaxial experiment results sandstones. experimental numerical si...

Adam Kraft, Albrecht Dürer’s contemporary in Nuremberg, worked the material of sandstone to provide a comparable experience carved relief about Passion Christ. Both artists began their work Nuremberg around same time, 1490, although older Kraft actually predeceased Dürer by two full decades (1508/1528). But both shared religious sentiment late-medieval art as having goal evoke pious emotions th...

Overpressure is widespread in the southern margin of the Junggar Basin, northwestern China. Pressure measurements in drillstem tests and repeated formation tests and estimates from wire-line logs indicate contrasting overpressure values between permeable sandstones and adjacent low-permeability mudrocks. In addition, excess pressure differs among anticlines with similar depth, lithologies, and ...

ABSTRACT Estuaries provide an excellent depositional environment to study the interaction between minerals (clays, quartz sands…) and biofilms. The estuary bottom is largely covered by biofilms that impact sediment stability, mud clay-coat content in sands, sedimentary-structure thus influencing sandstone properties during burial. Although numerous oil, gas, geothermal reservoirs are exploited ...

Liquid permeability of sedimentary rocks is relevant in several contexts, but gas easier to measure, so liquid typically estimated from via empirical or semiempirical correction procedures. A frequently used and trusted procedure the well-known Klinkenberg correction, which based on pressure dependence permeability. However, gaseous flow-through experiments a series Fontainebleau, Castlegate, B...

Sedimentary rocks are one component of the modern threefold classification of rocks. They derive from the lithification of sediments, which are produced in basically two ways: by the mechanical deposition of grains derived from the alteration of other rocks (detrital or clastic rocks), or as chemical precipitates or grains formed organically or inorganically from an aqueous solution. The whole ...