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Formation Factor vs. Porosity

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core-formation-factor

F=a/PHIm
Series 1 Input Data
PHI v/v
F
Series 2 Input Data
PHI v/v
F
Series 3 Input Data
PHI v/v
F
Paste Series Data

Paste series data below (using CTRL-V). Each line should contain a pair of values for PHI and F separated by whitespace. This will overwrite any existing values for the series.

Instructions

This crossplot is used to graphically determine a cementaion exponent (m) value for a set of core data representing a particular rock type.

Formation factor (F) is measured in the lab and is equal to the resistivity ratio of the 100% brine saturated rock (Ro) to the resistivity of the brine with which it is saturated (Rw). Formation factor (F=Ro/Rw) can also be determined with the equation F=a/PHI^m, where the slope equals cementation exponent (m) and the intercept at PHI=1.00 is equal to the tortuosity factor (a).

Start by inputting porosity-F data series, (green, blue and orange cells). Each data series allows an unlimited number of rows, and cut and paste functionality is available. Next, adjust the cementation exponent value until the line fits the desired data series.  The tortuosity factor input is often pinned at 1.00 for core work.

Reference

Archie, G. E., “The Electrical Resistivity Log As An Aid In Determining Some Reservoir Characteristics.” Transactions of the AIME Volume 146, Issue 1, December 1942: 54-62.

Aptian Technical

 

Client Comments

“We are going to run with your model Dorian. I think your average perms over the intervals are in line with publications for the area. Great work on this set!”

B.L., Principal Geologist

“It’s nice to see your work around the office – always a solid place to start from.”

G.G., President & Principal Geoscientist

“Great work on the last round of data. I threw a few new technical tasks your way and you did a great job integrating them.”

B.L., Principal Geologist

“The merged compressional sonic log that you created now ties the seismic from surface to TD. Great job.”

N. K., Senior Geophysicist

“Thanks Dorian, this is why we keep coming back to you. Hassle free, no BS service, very refreshing.”

Z.J., Senior Geologist

“Many thanks Dorian, excellent work.”

J.C., Lead Geoscientist

“Thanks again Dorian.  And BTW, your analysis helped us enormously with our reserves evaluations. Your company does hold authority.”

P.T., Vice President Exploration

“Thanks Dorian, I knew you would come through. This is one of the reasons we keep coming back to you…you always deliver.”

Z.J., Vice President Exploration

“Hi Dorian, I was just going through the mapping and it looks great so far! Very happy with what I’m seeing.”

J.G., Senior Geologist

“Thanks Dorian for the quick turnaround. Your proposal for petrophysical services looks very good (impressive) and I will be approving.”

A.B., Vice President Geosciences

“Your petrophysical model matches core very closely.”

B.E., Senior Engineer

“Hi Dorian, Thanks for solving those problems. You have a black belt in petrophysics.”

S.R., Senior Geophysicist

“Excellent work! Thank you for the speed!!!”

R. R., Senior Engineer

“Thank you for your petrophysical evaluation. We appreciate that it is ahead of schedule.”

J.M., Vice President Exploration & Production

“Your work is consistently good and your results are very credible.”

R.C., Senior Engineer

“You come highly recommended. We would like you to complete a project for us.”

T.G., Geologist

“We took your advice and had some cuttings analyzed in a few wells. The results support your interpretation. Thanks for pointing us in the right direction.”

D.M., Senior Geophysicist

“We have found your petrophysical evaluations extremely useful and have had good success integrating the work into Petrel.”

A.B., Vice President Geosciences
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