Oil and gas glossary
97 petroleum, reservoir, drilling, completions, production and geoscience terms, with short definitions written for working engineers.
8 of 97 terms match Geomechanics. Clear filters
F
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Fracture gradient
frac gradient
The wellbore pressure, per unit of true vertical depth, at which the formation fractures and starts to take drilling fluid.
H
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Hydraulic fracture
frac, hydraulic fracturing
A fracture opened by pumping fluid into a zone faster than the rock can accept it, then kept open so the well can flow.
M
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Minimum horizontal stress
Shmin
The smaller of the two horizontal principal stresses in the earth at a depth.
O
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Overburden stress
Sv, vertical stress
The vertical stress from the weight of the rocks and their fluids above a depth.
P
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Poisson’s ratio
Poisson ratio
The ratio of sideways strain to lengthwise strain when a rock is loaded along one axis.
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Pore pressure
formation pore pressure
The pressure of the fluid in the pore space of the rock.
W
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Wellbore stability
borehole stability
Whether the hole stays close to bit size while it is drilled, instead of caving in or fracturing.
Y
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Young’s modulus
Young modulus
Stiffness: the axial stress needed to produce a given axial strain while the rock is still elastic.