Overpressure can mean:
- In geology: the pressure regime in a stratigraphic unit that exhibits higher-than-hydrostatic pressure in its pore structure. Geology (from Greek γη gê, "earth" and λόγος Logos, "speech" lit Pressure (symbol 'p' is the force per unit Area applied to an object in a direction perpendicular to the surface Stratigraphy, a branch of Geology, studies rock layers and layering ( stratification) Fluid statics (also called hydrostatics) is the Science of Fluids at rest and is a sub-field within Fluid mechanics. Porosity is a measure of the void spaces in a material and is measured as a fraction between 0–1 or as a Percentage between 0–100% This phenomenon is the primary cause of "oil gushers". This is described below.
- In military terminology, the pressure caused by an explosion over and above normal atmospheric pressure, especially when measuring the effects of nuclear weapons or thermobaric bombs. A military is an Organization authorized by its Nation to use force usually including use of Weapons in defending its Country (or by attacking An explosion is a sudden increase in Volume and release of Energy in an extreme manner usually with the generation of high Temperatures and the release A nuclear weapon is an explosive device that derives its destructive force from Nuclear reactions either fission or a combination of fission and fusion. Thermobaric weapons distinguish themselves from conventional Explosive weapons by using atmospheric Oxygen, instead of carrying an Oxidizer in their
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Causes of overpressure
Overpressure in stratigraphic layers is fundamentally caused by the inability of connate pore fluids to escape as the surrounding mineral matrix compacts under the lithostatic pressure caused by overlying layers. The term connate fluids in the context of Geology, and of Sedimentology in particular refers to the liquids that were trapped in the pores of Sedimentary rocks Overburden pressure, lithostatic pressure, and vertical stress are terms that denote the Pressure or stress imposed on a layer of Soil Fluid escape may be impeded by sealing of the compacting rock by surrounding impermeable layers (such as evaporites, chalk and cemented sandstones). Evaporites (iˈvæpəraɪt are water-soluble Mineral sediments that result from the Evaporation of bodies of surficial Water. Chalk (ʧɔːk is a soft white porous Sedimentary rock, a form of Limestone composed of the Mineral Calcite. Sandstone is a Sedimentary rock composed mainly of Sand -size Mineral or rock grains. 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. Fluid statics (also called hydrostatics) is the Science of Fluids at rest and is a sub-field within Fluid mechanics.
A common type of situation where overpressure may occur is in a buried river channel filled with coarse sand that is sealed on all sides by impermeable shales.
Implications
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. In Geotechnical engineering, drilling mud, also known as spud mud (when beginning the drilling process is a Drilling fluid used to drill Boreholes 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. Porosity is a measure of the void spaces in a material and is measured as a fraction between 0–1 or as a Percentage between 0–100% In Organic chemistry, a hydrocarbon is an Organic compound consisting entirely of Hydrogen and Carbon.
Explosives effects
| Compound | Pressure | Effects[1] |
|---|---|---|
| RDX/C4 | 10 Psi | *Reinforced concrete buildings severely damaged
|
| ANFO | 4 Psi | *Most buildings collapse except concrete buildings
|
| KClO3 | 2 Psi | *Residential structures collapse
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References
- ^ Fool Me Twice (documentary film). Cyclotrimethylenetrinitramine, also known as RDX, cyclonite, hexogen, and T4, is an Explosive Nitroamine widely used C-4 or Composition C-4 is a common variety of military Plastic explosive. The pound per square inch or more accurately pound-force per square inch (symbol psi or lbf/in² or lbf/in²) is a unit of ANFO (or AN/FO, for ammonium nitrate / fuel oil) is a widely used Explosive mixture The pound per square inch or more accurately pound-force per square inch (symbol psi or lbf/in² or lbf/in²) is a unit of Potassium chlorate is a compound containing Potassium, Chlorine and Oxygen, with the chemical formula KClO3 The pound per square inch or more accurately pound-force per square inch (symbol psi or lbf/in² or lbf/in²) is a unit of Documentary film is a broad category of visual expression that is based on the attempt in one fashion or another to " Document " reality Retrieved on 2007-12-26. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 1481 - Battle of Westbrook - Holland defeats troops of Utrecht. Event occurs at 1h 6m.
See also
- Underpressure
- Lithification
- petroleum geology
Dictionary
overpressure
-noun
- excess or markedly elevated pressure, especially a transient high pressure due to a shock wave
-verb
- To subject to a high pressure
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