This article does not cite any sources. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. Find sources: "Geologic overpressure" – news · newspapers · books · scholar · JSTOR(September 2016) (Learn how and when to remove this message)
Geologic overpressure in stratigraphic layers is caused by the inability of connate pore fluids to escape as the surrounding mineral matrix compacts under the lithostatic pressure caused by overlying layers. Fluid escape may be impeded by sealing of the compacting rock by surrounding impermeable layers (such as evaporites, chalk and cemented sandstones). Alternatively, the rate of burial of the stratigraphic layer may be so great that the efflux of fluid is not sufficiently rapid to maintain hydrostatic pressure.
Common situations where overpressure may occur: in a buried river channel filled with coarse sand that is sealed on all sides by impermeable shales, or when there is an explosion within a confined space.
It is extremely important to be able to diagnose overpressured units when drilling through them, as the drilling mud weight (density) must be adjusted to compensate. If it is not, there is a risk that the pressure difference down-well will cause a dramatic decompression of the overpressured layer and result in a blowout at the well-head with possibly disastrous consequences.
Because overpressured sediments tend to exhibit better porosity than would be predicted from their depth, they often make attractive hydrocarbon reservoirs and are therefore of important economic interest.
and 26 Related for: Geologic overpressure information
Geologicoverpressure in stratigraphic layers is caused by the inability of connate pore fluids to escape as the surrounding mineral matrix compacts under...
A geologic hazard or geohazard is an adverse geologic condition capable of causing widespread damage or loss of property and life. These hazards are geological...
that can occur, depending on the degree of overpressure. Capillary failure can occur in moderate overpressure conditions, resulting in widespread but low...
mechanism for overpressure release through piercement structures. Implications for the Lusi mud volcano, Indonesia". Marine and Petroleum Geology. 26 (9):...
Common causes of landslides include: i) presence of weak geological layers, ii) overpressure due to rapid accumulation of sedimentary deposits, iii) earthquakes...
fluids is blocked, the pore fluid pressure can build up, leading to overpressure. An understanding of the geochemistry of connate fluids is important...
beneath the wedge can produce a large steady supply of such highly overpressured fluid. Dilatant fracturing will create escape routes, so the fluid pressure...
island arc. A passive margin built out over a weaker layer, such as an overpressured mudstone or salt, tends to spread laterally under its own weight. The...
combination of regional extension, which lowers the maximum attainable overpressure on the chamber roof, and a large magma chamber with warm walls, which...
The most important factor of this field is the overpressure of the central horst. This overpressure has been created by what is thought to be an uplift...
quartz-bearing rocks have been severely shocked by an instantaneous overpressure. Shocked quartz cannot be created by volcanic action; the only known...
responsible for the bumps or 'knees' in the above overpressure range graph. For each goal overpressure, there is a certain optimum burst height at which...
the shallower strata they get pushed into.[clarification needed] Such overpressured "floaters" pose a significant risk when trying to drill through them...
(breccia pipes), or even some synsedimentary diatremes formed solely by the overpressure of pore fluid within sedimentary basins. Hydrothermal breccias are usually...
toe-thrusts. Examples include the outboard part of the Niger delta (with an overpressured mudstone detachment) and the Angola margin (with a salt detachment)...
which significantly reduces the frictional resistance, is the fluid overpressure, which acts against the normal pressure, thereby reducing high lithostatic...
when the local pressure is less than the hydrostatic pressure, and in overpressure when the local pressure is greater than the hydrostatic pressure. Effective...
Group can be significantly overpressured. Further south in UKCS quadrant 30 and Norwegian quadrants 1 and 2, this overpressure helps preserve porosity and...
been named 'Pythia's Oasis', and may play a role in the regulation of overpressures. Some other subduction zones have major earthquakes every 100 to 200...
shelter, in that its main purpose is to protect from shock waves and overpressure instead of from radioactive precipitation, as a fallout shelter does...
directly above it is the epicenter. Earthquakes are primarily caused by geological faults, but also by volcanic activity, landslides, and other seismic events...
scale ignimbrite sheets. Aguas Calientes caldera is considered to be an overpressure caldera, where eruption is triggered by intrusions from the volcano sill...
geologically active since the Paleogene epoch. The basin started to become overpressured during the Oligo-Miocene period. Some of the overpressured mud...
decompression chamber specially made to measure by the OMV was not needed, as no overpressure existed in the survival chamber in which Georg Hainzl found himself,...
portions of the island of Öland emerge from the Baltic Sea, after the overpressure of the last glaciers was relieved by melting. Over the next several thousand...
helium quickly flooded the tank, eventually causing it to burst from overpressure. NASA's independent accident investigation into the loss of SpaceX CRS-7...