Depletion "Type Curves" from company websites show a dramatic drop in production after one year

The "Type Curves" from many of the company presentations seem to indicate that the gas/NGL output from horozontal wells will fall by ~75% within one year, and oil by ~50%.   Page 36 from the Antero presentation is one example.  Am I intrepeting this accurately?  Any comments will be appreciated.

 

http://www.anteroresources.com/wp-content/uploads/Company%20Website...

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Permalink Reply by Dan on February 22, 2013 at 3:30pm

Is a Barnett well dead in four years even with restimulation, or do they not ever try to do that?

Permalink Reply by Joseph-Ohio on February 22, 2013 at 7:32am

Thanks for the Spreadsheet Tool.

Pretty slick.

Permalink Reply by Bluflame on February 22, 2013 at 7:43am

Thanks Jay,

   This is an interesting calculation. I wish the authors would have selected a well with an oil component. Of the GPOR wells reported to date, the Stutzman well is the only one reporting no oil production. Really, it wouldn't be that difficult to factor in an oil component....think I will fiddle with the spreadsheet an see if I can make the modification.

   We must start somewhere and at this point the Barnett decline curve is as good as any. Actually seems a bit more optimistic than Antero's posted decline curve for the Marcellus.

BluFlame

Permalink Reply by Bluflame on February 22, 2013 at 8:20am

Jay,

 You forgot to attach the link

Bluflame

Permalink Reply by Bluflame on February 22, 2013 at 8:23am

Jay,

  For what it's worth, I've heard the high well pressures found so far in the southern Utica play have the effect of reducing the decline curve. How much? Still up in the air.

BluFlame

Permalink Reply by Joseph-Ohio on February 22, 2013 at 8:43am

Blu,

Hearing much about lower geo pressures north and higher geo pressures south.

Due to what ?

Mountainous terrain rendering more geo pressure due to more (earth) cover (does the elevation above sea level / depth of the Utica Point Pleasant factor in) ?

J-O

 

Permalink Reply by Bluflame on February 22, 2013 at 8:49am

J-O,

  Wish I was smart enough to know!  However, I'd speculate it may have something to do with the massive amounts of gas coming out of wells from CHK's Buell well and wells further south.

  BluFlame

Permalink Reply by Area Man on February 22, 2013 at 12:04pm

There are obviously a whole mess of things that can contribute to higher pressures, but two big ones are confining layers and depth.  If you have something to trap the generated gas (ie a limestone) above the source rock that will cause higher pressures.  One thing to remember is these shales have low permiability, but it is still non-zero so over geologic timescales the hydrocarbons can migrate.

And as mentioned, having a greater overburden (greater depth) will also cause higher pressures.

You can have other factors as well, but usually a combination of these two will be the reason.

Hope that helps!

Cheers,

-AreaMan

Permalink Reply by LERRET on February 22, 2013 at 2:57pm

Hearing much about lower geo pressures north and higher geo pressures south.

Due to what ?

 

Two things affect pressure - Over burden which can be calculated as "Normal" which would be 0,465± psi per foot depth.  10,000 = 4,650 psi at bottom hole

More pressure moves more gas.  But formations can be overpressured or underpressured. Basins with confined shales that have been compressed can be overpressured. The Barnett was slightly over pressured which helped a lot.in increasing production.  In the Gulf Coast it was that severe over-pressuring that created the high pressure conditions that resulted in the Macondo accident.

Permalink Reply by Joseph-Ohio on February 22, 2013 at 8:28am

Bluflame,

Seems to me that you could at least satisfy your curiosity about the oil component by plugging in the $ figure for oil production.

You could save that to a file called Natural Gas + Oil.

You could do another for NGLs by entering zero production for Natural Gas and the $ figure for NGL production.

You could save that to a separate file called NGLs.

Between the two saved spreadsheets you would have the complete picture !

Combine them longhand if you want or develop a few more cells below for the 3rd production.

Just sayin'.

J-O

 

Permalink Reply by Bluflame on February 22, 2013 at 8:54am

J-O & Jay,

   I'll fiddle with the spreadsheet tonight and see what I can come up with. Jay, I noticed that Dr. Chase's spreadsheet also didn't include oil. May be that the spreadsheet dates back to 2011, before anyone realized there would be a significant oil component. Also, I notice his spreadsheet assumes 6 wells/ pad. Probably not a bad assumption going forward, but I don't think any Utica well pads have 6 laterals yet.

BluFlame

   

Permalink Reply by Bluflame on February 22, 2013 at 10:31am

Yes, but not yet. Several other GPOR pads likely will also be expanded to six laterals. Likely, GPOR's short term objective is to first HBP all their acreage.

BluFlame

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