| dc.description |
This work presents the validation and enhancement of existing correlations for estimating and predicting
the permeability in low permeability gas sands . The "original" problem of predicting the corrected or
"liquid equivalent" permeability has been under investigation since the early 1940s â  in particular , using
the application of "gas slippage" theory to petrophysics by Klinkenberg .
In the first part of this work , the viability of the Jones -Owens and Sampath -Keighin correlations for
estimating the Klinkenberg -corrected (absolute ) permeability from single -point , steady -state measurements
were investigated . We also provide an update to these correlations using modern petrophysical
data .
In the second part of this work we proposed and validated a new "microflow" model for the evaluation of
an equivalent liquid permeability from gas flow measurements . This work was based on a more detailed
application of similar concepts employed by Klinkenberg . In fact , we obtained the Klinkenberg result as
an approximate form of this result . A theoretical "microflow" result was given as a rational polynomial
(i .e . , a polynomial divided by a polynomial ) in terms of the Knudsen number (ratio of the mean free path
of the gas molecules to the characteristic flow length (typically the radius of the capillary ) ) , and this result
can be applied as an explicit correlation device , or as an implicit prediction model (presuming the model is
tuned to a particular data set ) .
The following contributions are derived from this work :
â  Validation and extension of the correlations proposed by Jones -Owens and Sampath -Keighin for low
permeability samples .
â  Development and validation of a new "microflow" model which correctly represents the flow of gases
in low permeability core samples . This model is also applied as a correlation for prediction of the
equivalent liquid permeability in much the same fashion as the Klinkenberg model , although the new
model is substantially more theoretical (and robust ) as compared to the Klinkenberg correction model . |
|