Well head pressures to bottom hole pressure.. please!!
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Brainmolester
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- Joined: Wed Aug 01, 2007 12:48 am
Well head pressures to bottom hole pressure.. please!!
Hi there, I need urgently an excel sheet that can help me out to calculate the bottom hole pressure from well head pressure.... I guess i need something with a macro in it...or anything else equivalent!! your help is much appreciated!! 
Hi my friend
I think the equition for this used only for Gas well when the density of the Gas are the same for the wide range of depth.
I think it wrong for Oil well
We always used the Digital downhole pressure recorders for this kind of calculation , when the gauges lowered to the specified depth of interest.
I hope this is benfit for you.
I have the equiation for this calc. ....... I mean the gas well
I think the equition for this used only for Gas well when the density of the Gas are the same for the wide range of depth.
I think it wrong for Oil well
We always used the Digital downhole pressure recorders for this kind of calculation , when the gauges lowered to the specified depth of interest.
I hope this is benfit for you.
I have the equiation for this calc. ....... I mean the gas well
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Brainmolester
- Junior member
- Posts: 55
- Joined: Wed Aug 01, 2007 12:48 am
Dear Friend
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The calculation of the BHP of Gas well from the following equation developed by Pierce and Rawlines
Pws = (Pwh)^e(0.0000347*y*D)
Pws=Static Bottom hole pressure ,psia.
Pwh = Well head pressure , psia.
e = natural logarithms .
y=Specific pressure of gas (air=1)
D= Depth of well , ft.
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This equation is based on an average temperature of the column of gas ( 60 F) .While the temperature gradient in a producing well is rarely a straight line , the average temperature at a depth below seasonal effect (20 to 30 ft) and at a depth of the pressure is sufficiently accurate for practical purpose. The equation can be then written as follows:-
Pws = (Pwh)^ey^(D/53.34*T)
Or
Log Pws = Log Pwh + (y^D /122.82*T )
Where T is the average temperature in the borehole ,( F+460 ).
Deviation of a gas from Boyle's law will affect the calculated BHP enough to be considered only in high pressure deep wells , USBM Monograph (7) presents the following equation .
(Pwh / (1+Pws^z) = (Pwh /(1+Pwh^z))^ey^(D/(53.34*T))
Where (z) is the deviation coefficient , deviation per psi expressed as a decimal.
((The above description directly copied from the book titled "Petroleum Engineering Handbook".
---------------------------------------------------------
The calculation of the BHP of Gas well from the following equation developed by Pierce and Rawlines
Pws = (Pwh)^e(0.0000347*y*D)
Pws=Static Bottom hole pressure ,psia.
Pwh = Well head pressure , psia.
e = natural logarithms .
y=Specific pressure of gas (air=1)
D= Depth of well , ft.
-----------------------------------------------------------------------------------------------------------------------------------------------------------
This equation is based on an average temperature of the column of gas ( 60 F) .While the temperature gradient in a producing well is rarely a straight line , the average temperature at a depth below seasonal effect (20 to 30 ft) and at a depth of the pressure is sufficiently accurate for practical purpose. The equation can be then written as follows:-
Pws = (Pwh)^ey^(D/53.34*T)
Or
Log Pws = Log Pwh + (y^D /122.82*T )
Where T is the average temperature in the borehole ,( F+460 ).
Deviation of a gas from Boyle's law will affect the calculated BHP enough to be considered only in high pressure deep wells , USBM Monograph (7) presents the following equation .
(Pwh / (1+Pws^z) = (Pwh /(1+Pwh^z))^ey^(D/(53.34*T))
Where (z) is the deviation coefficient , deviation per psi expressed as a decimal.
((The above description directly copied from the book titled "Petroleum Engineering Handbook".
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Brainmolester
- Junior member
- Posts: 55
- Joined: Wed Aug 01, 2007 12:48 am
Thanks a lot Jabbar and Reservoir for the precious info!
@ Reservoir, The file BHP gas that you mentioned i could not download it?! there is a problem or something wrong with it?! That site is pretty cool... do you have any more like that where there are several excel sheets to try for different jobs?!
@ Jabbar, Thanks for the equation. I have already used the Cullender and smith method that I have made from scratch on Excel. it gave me a good result compared to the derived BHP from my gradient. I have a wet gas well. I the books it mentioned that Cullender and Smith is trhe most accurate....but this is important to compare different methods...
We have also performed a small build up test too.... do you think it will help me out to plot the horner graph and get my BHP like that?!
@ Reservoir, The file BHP gas that you mentioned i could not download it?! there is a problem or something wrong with it?! That site is pretty cool... do you have any more like that where there are several excel sheets to try for different jobs?!
@ Jabbar, Thanks for the equation. I have already used the Cullender and smith method that I have made from scratch on Excel. it gave me a good result compared to the derived BHP from my gradient. I have a wet gas well. I the books it mentioned that Cullender and Smith is trhe most accurate....but this is important to compare different methods...
We have also performed a small build up test too.... do you think it will help me out to plot the horner graph and get my BHP like that?!
