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onemorecoonass
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lag

can someone please hook me up with a`lag calculation formula

02-11-2008 09:53 PM
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samplerock
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RE: lag


Go here, This has worked great for most all holes I have done. Just un zip it and it opens with excel, hope this helps.

http://mudlogging.createmybb.com/showthread.php?tid=9


What does not kill us, makes us stronger.....


http://www.myspace.com/painter22

02-13-2008 08:08 PM
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brad74
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RE: lag

For paper calculations:

(Pipe OD)^2 / 1029.4 = Displacement/Ft * Depth = Total pipe displacement

(Hole Dia)^2 /1029.4 = Capacity/Ft * Depth = Total Hole capacity

Hole Cap - Pipe Disp = Annular Volume / Pump output = Bottoms UP


After you do this for a while, you'll memorize capacities and displacements per foot when using different sizes, and it will be a lot faster. You can layer this as many times as necessary for BHA, cased sections, etc. to improve accuracy. I know the programs are a lot easier, but everyone should be able to do it by hand...it can save your ass.

If anybody notices a mistake, let me know. Been a long time since I actually wrote it out....

02-15-2008 01:21 PM
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samplerock
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RE: lag

brad74 Wrote:

For paper calculations:

(Pipe OD)^2 / 1029.4 = Displacement/Ft * Depth = Total pipe displacement

(Hole Dia)^2 /1029.4 = Capacity/Ft * Depth = Total Hole capacity

Hole Cap - Pipe Disp = Annular Volume / Pump output = Bottoms UP


After you do this for a while, you'll memorize capacities and displacements per foot when using different sizes, and it will be a lot faster.  You can layer this as many times as necessary for BHA, cased sections, etc.  to improve accuracy.  I know the programs are a lot easier, but everyone should be able to do it by hand...it can save your ass.

If anybody notices a mistake, let me know.  Been a long time since I actually wrote it out....


Your right, everyone should know how to do this. I was never very good at math. Can you give us an "easier" calculation example? For me it just about has to be spelled out.
Welcome to the Forum, Troy.


What does not kill us, makes us stronger.....


http://www.myspace.com/painter22

02-15-2008 04:51 PM
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BeeHay
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RE: lag

isn't this - "depth / 160" the lazy mans lag formula?

:)

03-03-2008 05:01 AM
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BeeHay
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RE: lag

Here is our Excel Uptime calc...

Enter the appropriate values in the cell and the Uptime changes at the bottom...

Th efficiency value must be scaled if you are using a double or triple pump...

:)

edit - can't upload the .xls file...?

This post was last modified: 03-06-2008 12:07 AM by BeeHay.

03-06-2008 12:04 AM
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alizarin who?
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RE:  lag

samplerock Wrote:

brad74 Wrote:

For paper calculations:

(Pipe OD)^2 / 1029.4 = Displacement/Ft * Depth = Total pipe displacement

(Hole Dia)^2 /1029.4 = Capacity/Ft * Depth = Total Hole capacity

Hole Cap - Pipe Disp = Annular Volume / Pump output = Bottoms UP


After you do this for a while, you'll memorize capacities and displacements per foot when using different sizes, and it will be a lot faster.  You can layer this as many times as necessary for BHA, cased sections, etc.  to improve accuracy.  I know the programs are a lot easier, but everyone should be able to do it by hand...it can save your ass.

If anybody notices a mistake, let me know.  Been a long time since I actually wrote it out....


Your right, everyone should know how to do this. I was never very good at math. Can you give us an "easier" calculation example? For me it just about has to be spelled out.
Welcome to the Forum, Troy.


[(outer pipe diamer x outer pipe diamer) / 1029.4] x Depth = Barrels to subtract

[(Bit Diameter x Bit Diameter)/ 1029.4] x Depth = Open Hole Volume in Barrels

the 1029.4 is the conversion factor if you are using inches and you want barrels.

(Open Hole volume - Barrels to subtract)= Annular Volume

Annular Volume (bbl) / Pump Output (bbl/stroke) = stroke to B/U

you do a similar dimensional analysis for the Pipe ID if you want surface to bit, or surface to surface. You have to do it for different sections of the drill string if you have more than one size pipe, or if you have a lot of heavy weight pipe on the BHA. You also have to do the annular volume of the inside of the casing as seperate section from the annular volume of the open hole. You calculate the annular volume's for each of the sections that need to be considered, add them up to get a total annular voulme before you can do the final calculation for B/U. Or, if you are in a huury and ou don't trust the pump efficiency or think there's so much wash out, you do a quick and dirty estimate of the annular volume and the pump output and BS it until you can get a good connection gas or a carbde drop.

But at some point durring your shift you really should know your theoretical lag. The comparison between your theoretical lag and your actual lag are pretty important if you are paying attention to the hole. It could get you run off the location if you can't do this.

I usually use a spreadsheet because I can never remember te constant and because I can play with the pump output to see if I suspect the rig pump is the bad lag culprit. Sometimes you can get bad pipe figures, or a pipe could be washed out, or a number of other things could be going on.

You ave to also be able to trust your stroke counters.. another unnpleasant topic..

man, I'm kinda glad I laid off.

05-13-2009 12:41 AM
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dboschmann
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RE: lag

Tired of using crappy lag sheets and too much time on my hands so I put this together.  Works well in most situations...accomodates up to 2 casing sizes plus open hole, full BHA volume, gives you bottoms up, surface to surface strokes, lag time and some other useful information.

uses 0.0009714 x D^2 for in-bbl conversion

1/1029.4 = 0.0009714

Unzip and enjoy.  If you find any mistakes or have suggestions let me know.

Drilling Kilauea...but mudlogging in paradise is still mudlogging.



Attached File(s)
.zip File  MyLag_v1.1.zip (Size: 11.46 KB / Downloads: 48)
08-19-2009 03:55 AM
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wellsight data
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RE: lag

Try this simple to use program

Any questions call 713 757 2218

06-21-2012 11:42 PM
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Tima11
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RE: lag

Hey buddy could you please find an easy way to solve losses while drilling formulas or excel files????

cheers

09-10-2015 05:57 AM
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