Giant clastic intrusions primed by silica diagenesis

Development and flow structures of sand injectites: The Hind Sandstone Member injectite complex, Carboniferous, UK

“…Mechanisms of overpressure generation may include disequilibrium compaction, hydrocarbon and basinal fluid expulsion from surrounding sediments, seismicity, and diagenetic alteration (e.g., Osborne and Swarbrick, 1997;Jolly and Lonergan, 2002;Davies et al, 2006). In mud-rich systems, pore fluids from less permeable sediments, such as mudstones, may drain into higher permeability sandstones during compaction, increasing the poreefluid pressure of the porous body (Dott, 1966;Hiscott, 1979;Magara, 1981).…”

“…In mud-rich systems, pore fluids from less permeable sediments, such as mudstones, may drain into higher permeability sandstones during compaction, increasing the poreefluid pressure of the porous body (Dott, 1966;Hiscott, 1979;Magara, 1981). These fluids may include hydrocarbons and early diagenetic fluids (Davies et al, 2006). Additionally, tectonic forces may add to the generation of overpressure by applying additional horizontal stresses to the compacting sediment (Berry, 1973).…”

Deep-seated faults and hydrocarbon leakage in the Snøhvit Gas Field, Hammerfest Basin, Southwestern Barents Sea

“…uplift (Jolly and Lonergan, 2002); lateral pressure transfer during fault interaction and reactivation (Andresen et al, 2009); overpressure caused by influx of fluids from the source and the reservoir (Huuse et al, 2010;Osborne and Swarbrick, 1997); tilting of the reservoir; diagenetic transformations (Davies et al, 2008(Davies et al, , 2006; and seal failure are other mechanisms that could enhance hydrocarbon migration and plumbing systems in the study area. Migration is possible through vertical transmission of fluid through the faults and laterally along the margins of the gas chimneys ( Figure 5.1).…”

Large-scale conical sandstone intrusions and polygonal fault systems in Tranche 6, Faroe-Shetland Basin

“…It is thus possible that inversion triggered widespread fluid migration at this time. Fluids may have been sourced from the topseal leakage of deep overpressured sandstones, or possibly from fault pumping during seismic events (Muir Wood, 1994), and even silica diagenesis (Davies et al, 2006) cannot be ruled out. Fluid migrating upwards along faults (e.g., Holmes et al, 1999) may have encountered sand bodies at different levels in the section, fluidising them and transporting sand within the migrating fluid.…”