Replies to This Discussion

Permalink Reply by Skip Peel - Mineral Consultant on December 14, 2010 at 9:30

Yes,  the orifice is measured in sixty fourths of an inch.    16/64 = one quarter inch.   32/64 = one half inch.

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Permalink Reply by HMI on December 14, 2010 at 9:49

So Skip, on this well where it uses the number 78 in the choke column, are they saying they're running that at 78/64 = 1 and 14/64 inches? Wouldn't that be a gaping choke compared to what we're seeing in the way of these other wells?

WELL TESTS

RPT TYP	TEST DATE	RPT DATE	OIL POT	COND	GAS DEL	WATER	BSW%	FLOW PRES	SHUTIN PRES	CHOKE	UPPER PERF	LOWER PERF	BOT HOLE PRES
DT-1	09/19/2010	11/01/2010			4107	90		2902	304	78	10858	14696
DT-1	04/06/2010	05/01/2010							157	15	10858	14693
SDM2G	01/15/2010	01/15/2010			6502	12				12	10858	14977

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Permalink Reply by Skip Peel - Mineral Consultant on December 14, 2010 at 10:10

I don't know how you define gaping, HMI, but you can look at the Flowing Pressure and Shutin Pressure and see the reason for the open choke setting.  I suggest that you compare those pressure readings with those of wells that are on choke settings a fraction of an inch.

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Permalink Reply by Skip Peel - Mineral Consultant on December 14, 2010 at 11:45

Here is a link to a previous discussion of a choke greater than 64 that may help answer some questions.

 

http://www.gohaynesvilleshale.com/forum/topics/80-choke

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Permalink Reply by Robert Duke on December 14, 2010 at 11:59

The replies in this discussion contradicted each other.  The general feeling seems to be it is just a 64ths inch reading, and going above 64 implies a pipe over 1 inch in diameter, but Brad, a well-tester said:

"Some of the auto chokes the producers are using show percentages when first installed until they have updated the software to show 64ths. There is no such thing as an 80/64 choke. I know this because I deal with these wells on a daily basis. Well tester here!".

 

Of course, I don't know if that implies that the chokes for the wells shown that went to 80 were  always calibrated in %, or what...

 

So I used to think that everything was in 64ths myself, but am now confused...

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Permalink Reply by Skip Peel - Mineral Consultant on December 14, 2010 at 12:06

Yes, you can pick and choose who to believe or just believe the choke numbers over 64 are a typo.  I see a lot of old wells with very low pressures that are reported as producing on an "open choke".  I guess we could then go into coiled tubing diameters.

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Permalink Reply by HMI on December 14, 2010 at 12:11

Gaping may be a strong adjective. Relatively speaking ... 78/64 would be a far cry larger opening than the 10/64th the well meter technician told me it was at when we talked on the site of this well. On those numbers above, it looks to me like the shut in pressure increased when the choke number increased - which strikes me as being opposite of what it should be. Am I missing something Skip? Talk to me about the Flow pressure and Shut in pressure and what you see there. Translate please. Are you basically saying that they needed to open it up because if they hadn't the production would be nill?

 

I did read the other thread and LesB's comment about the "Choke body" possibly being an answer to the question.

 

In the meantime I'll go compare some numbers on other wells.   

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Permalink Reply by Skip Peel - Mineral Consultant on December 14, 2010 at 12:24

  I think a tighter choke should equate to an increase in flowing pressure.  And I think that shut in pressure should not be affected by choke settings.  But there are better members to ask.  LOL!  I suggest Les B.

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Permalink Reply by Jack Blake on December 15, 2010 at 4:14

Your statement is correct Skip Peel.

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Permalink Reply by Les Bamburg on December 15, 2010 at 4:34

HMI, the shut-in pressures shown above look to be questionable.  What is the well serial number?

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Permalink Reply by Les Bamburg on December 14, 2010 at 18:00

HMI, as someone mentioned I believe a reading greater than 64 like 78 would be a reference to a percentage opening (ie 78%) rather than to a fraction.

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Permalink Reply by Jack Blake on December 15, 2010 at 4:07

Jack Blake don't know much, but he knows all types of chokes inside, outside and upside down............

They are measured in 64ths of an inch.

a 78 is 78/64"- yes- it is over an inch.

If they put "open choke" it means the choke is fully opened. They would put "open choke" if the well has an adjustable choke and it is fully opened. I have worked with adjustable chokes in the past that full open is 128/64". That is a 2" opening. I have also worked with adjustable chokes where full open is 64/64, 72/64", 128/64" and 196/64".  It just depends on the application and the manufacturer. 

If it is a "positive" or "bean type" choke you have to install the choke in the "choke box" which is on the wellhead. If you get to where you need a full open choke on these type chokes you install a "72/64" or a "thread protector" which is a 96/64".

Sometimes if the well flows cool and is under high pressure you will have a choke on the well head and another choke downstream in the flowline about 10' from the first one.  In this way you take two pressure drops to eliminate freezing.

Sometimes you install a "downhole choke" in the tubing so you take your first pressure drop downhole and your second pressure drop at the surface.

I have seen and operated positive chokes that were 4" choke boxes and you could go up to 196/64" choke beans.

I went to look at the well in my section (It is a SWEPI well so I think this is probably a standerd SWEPI configuration for HS wells) and it has a " 2" ABB Vetco Gray Type 80" positive choke box on the well. You can put from a 6/64" choke bean up to a 72" choke bean in the well normally.  ABB Vetco does not manufacture them, but you can have a machine shop make a 96/64" thread protector to go in this choke box.

 

Some of my statements may contradict each other, but there are misc. nuances and this is how it is.

Jack Blake

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