Manual Page for Command >> COMPRESSIBILITY

Syntax
>> COMPRESSIBILITY

Parent Command
> PARAMETER

Subcommand
>>> MATERIAL

Description
This command selects as a parameter the pore space compressibility c (TOUGH2 variable COM(NMAT)) of a certain rock type. It is suggested to estimate the logarithm of c. Under fully liquid-saturated conditions, pore space compressibility estimates c can be converted to a specific storage coefficient S [1/m] as follows:

Ss = phi*rho*g*(cl + c)

where phi is porosity, rho is density of water, g is gravitational acceleration, and cl = 4.4E-10 [1/Pa] is water compressibility. Similarly, estimation of c for grid blocks representing a well or borehole is useful for the determination of a dimensionless wellbore storage coefficient Cbh :

Cbh = phibh *rho*g*Vbh*(Sl* cl + Sg * cg + c)

where phibh and Vbh are the porosity and volume of the grid block representing the well, Sl and Sg are the liquid and gas saturation, and cg is gas compressibility which is approximately 1/p.

Example
> PARAMETER
>> pore space COMPRESSIBILITY
>>> MATERIAL: BOREH
>>>> ANNOTATION: Wellbore storage
>>>> LOGARITHM
>>>> RANGE : -10.00 -7.0
<<<<
>>> MATERIAL: SKIN_ ROCK_ BOUND
>>>> ANNOTATION: Storativity
>>>> LOGARITHM
<<<
<<

See Also
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Page updated: July 29, 1997