Triaxial compression and extension test accompanied by ultrasonic and permeability measurements

The highly porous and permeable Castlegate Sandstone (k: 350 mD, φ: 25%) was exposed to a confining pressure of 34 MPa and subjected to axial extension and also axial compression up to failure at 150 MPa (see green stress-strain curve in the graph below.). The porous Castlegate Sandstone compacts strongly during compression. Thus the loss of porosity leads to a decrease in permeability (blue curve) and superimposes the effect of microcrack formation which is recorded by the deceleration of both compression wave velocity (pink triangles) and shear wave velocity (red crosses). Micro crack orientation is parallel to the largest stress component. In the extension test (left part of the diagram) the behaviour of the sonic velocities are exactly opposite to the compression test: here the velocity reduction begins immediately, whereby the effect is stronger on the P wave (for details see (Braun & Jahns 1998).



21.02.2018 10:12

AAPG ACE 2018 in Salt Lake City (19.-23.05.2018)

Gesteinslabor will present brandnew results from the frontline of research at one of the key events for petroleum geologists.

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21.02.2018 08:45

TSK 2018 in in Jena (21.-23.03.2018)

Gesteinslabor will take part at the distinguished conference dealing with tectonics, structural geology and crystalline rocks.

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31.01.2018 12:06

Spring meeting 2018 in Celle

Following a well established tradition, also in 2018 DGMK and ÖGEW will host their annual conference in the Congress Union Celle.

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