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# Excel Worksheet to Calculate the Permeability in Shale Gas Fields ## Excel Worksheet to Calculate the Permeability in Shale Gas Fields

In this article I will leave them and I'll explain the file (worksheet) of Excel with which I did the calculations and graphs of the paper "Flow Mechanics in Shale Gas". With this we can calculate and view in a fast, simple and immediate as varies the Knudsen number and the apparent permeabilities  for the models presented in the previous post through the introduction of petrophysical parameters of our field. The calculations are carried out and plotted for a range of pressures comprised between 1psi to 15000psi.

### The Worksheet is Formed by:

#### 1-Main Worksheet (Input data):

Here it's the console where we have to introduce the field variables  and the four graphs presented in the previous post, these are: ka/kD vs pressure; ka/kD vs Knudsen number; Q vs pressure and Ka vs Knudsen number. Console: In the console, we’ll enter the following information in order to make the calculations and obtain the graphs:

•     Field temperature
•     Molecular mass of the gas or gas mixture
•     Viscosity of the gas or gas mixture
•     Pipe length of radius r (for plotting the flow rate).
•     Pressure drop across the length of the pipe
•     Porosity
•     Slip factor of Klinkenberg (bk)
•     Collision diameter of gas molecule
•     Tangential momentun accommodation
•     Boltzmann constant
•     Universal gas constant.

#### 2-Worksheets Secondary:

In them we find the graphs one by one in a bigger size for their analysis. In the worksheet  “K vs Knudsen” we get additional data, such as the slopes of the straight taken by each model when these are plotted on a graph of apparent permeability against the Knudsen number: Also we can interact in the following Worksheet  (Kn vs P and radius) where we get  the flow regimes present quickly and all values that reaches the Knudsen number in our field for the parameters entered and multiple pore radius  to be chosen by the user. Finally we have the Worksheet “Equations” where are all the equations and calculations made. In it we can see the values that take the variables to different pressures, and Knudsen numbers for each method. Also it's open to possible modification by the user as the introduction of a new model, the addition of graphics and/or analysis of other variables. ## Conclusion:

1-This Excel file is useful and practical to analyze the variation of apparent permeability in a particular shale field, to see the Knudsen numbers who we can find during the field exploitation and the flow regimes present in the same.

2-Its use is extremely simple as much as introduce a group of variables. The only possible complication that can occur is have to adjust the axes of graphs to obtain a good visualization of the same. This problem is something characteristic of Microsoft Excel, where its graphics by default always leave much to be desired.

3-The file is open to possible modification by the user or also can be requested. The theoretical foundation of the same is explained in my previous post: "Flow Mechanics in Shale Gas"

4-This Excel is focused to students, engineers and researchers of Shale gas as a practical tool to display and classify the flow regimes and the Knudsen number present in a shale gas play.

### Getting the Excel File:

To get it you have to request it by Linkedin message or email to [email protected] and pay 7 US\$ by PayPal.

#### Written by the author:

Emanuel Martin
Emanuel Martin is a Petroleum Engineer graduate from the Faculty of Engineering and a musician educate in the Arts Faculty at National University of Cuyo. In an independent way he’s researching about shale gas & tight oil and building this website to spread the scientist knowledge of the shale industry.