LP separator (~250 psig) PSV relieving to flare line vs. venting to air 3

[aegis4048]

Hi, I'm seeing two kinds of P&IDs for primary separators from wellhead:

1) PSV venting to air
----> Safer, because it's always guaranteed to work (almost always). But its "dirtier"
2) PSV relieving to flare line
----> Cleaner, but if something goes wrong with flare line, HP shutdown will have to be triggered, resulting in downtime.

I see well sites, some with option 1, and some with option 2. I asked this question to my supervisor and he just told me to go with option 1 because its safer, and that "it's only the big companies that have that one nerd guy that only does these P&ID things that choose to implement these fancy-pants things."

What are yall's thoughts on this? If I am to be tasked with PSV design in the future, what should I implement?

 

[LittleInch]

I'm seeing two kinds of companies.

One who actually cares for the environment and the safety of their workers and one....

And your PSV must always have a route to low pressure to relive the high pressure event.

what goes wrong with flare lines?

Anyway, you get a choice as to who you want to work for and with.

PSVs should hopefully never go off if the system is operated properly. If they are going off regularly you are normalising failure and I would run away if I was you and then report them to whoever the AHJ is in your neck of the woods.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[1503-44]

The choice may depend on how big his cheque book is, or how much he values the skin on his ass..

LI, you forgot the third kind of company: Don't know wtf they're doin'.

Some wells HAVE APPROVED EXCEPTIONS to air quality emission requirements, others DO NOT.
Being on the wrong side of your applicable emissions regulations will net you a hefty fine plus get your wells shut in. (Yup. Downtime! And it will be awhile before you get them up again.)
You may not even be permitted to flare at all.
Even the Texas RRC is relenting (seeing the handwriting on the wall) and is now flying helicopters armed with methane emission sensors. Plus, if there is money to be had, they want it.
You might want to give your regulatory compliance department a call.
You say you don't have such a department?
Revert to line no. 1 above.

--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[georgeverghese]

Follow Company written practice. Your supervisor may deny any non compliant verbal instructions he may have given you at an Audit.

 

[hacksaw]

Don't forget flare stacks are tall and dangerous for several reasons.

Failure to use one, invites a disaster, and crininal punishment.

 

[1503-44]

And using one without a permit may result in same.

Yes, both venting to air, or flaring, without a permit can end you up in hot water. Unless your well is exempt from meeting emission regulations, better to plan on flaring and then not using it outside of your permitted circumstances.

Summary of Venting and Flaring Regulations
The TRRC generally prohibits the routine venting and flaring of natural gas from oil and gas wells. Operators must capture and use or market the gas produced, except under specific circumstances where venting or flaring is allowed.

Permitted Situations: During initial production, limited venting or flaring is allowed during well completion, re-completion, or testing of a well for up to 10 days.

Emergency Situations: Venting or flaring is permitted during emergencies, such as equipment failure, to ensure safety. The RRC must be notified of such events.

Unavailability of Market: If there is no feasible way to capture, use, or market the gas, operators can apply for a permit to flare gas.

Permit Requirements: Operators must obtain a permit (Statewide Rule 32 exception) from the TRRC to legally vent or flare gas beyond the initial testing period. The application must demonstrate the necessity for flaring and the inability to market the gas.

Volume Reporting: Operators are required to report the volumes of gas vented or flared monthly. Accurate record-keeping and reporting are critical to ensure compliance with TRRC regulations.
Environmental and Safety Considerations:

Venting is generally discouraged due to its direct release of methane, a potent greenhouse gas. Flaring, which burns off the gas, is preferred over venting for safety and environmental reasons, as it converts methane to carbon dioxide, which is less impactful on the environment.
Technology and Best Practices:

Operators are encouraged to use best practices and technologies to minimize the need for venting and flaring, such as vapor recovery units and improved gas capture systems.


--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[georgeverghese]

Based on @1503 post, emergency local venting from PSVs' is permitted. Continuous vents on the other hand must be flared or recovered. Check your Company standards and/or project specific regulatory compliance statements.

 

[aegis4048]

@1503-44
Thanks for the very detailed answer. I've always heard that such regulations exist, but this is my first time actually checking the details.

On the other hand, is there any website or publications that list the detailed upstream wellsite regulations when it comes to venting and flaring? I work on some wells on Oklahoma and Colorado as well, would like to know if there's any good sources that summarize these rules (the goal is not to struggle having to read +100pg PDF legal document)

 

[1503-44]

Okla. Admin. Code § 165:10-3-15
Current through Vol. 41, No. 17, May 15, 2024

Section 165:10-3-15 - Venting and flaring
(a)Conditioning a producing well without a permit. An operator may blow down a producing well without a permit for a period not to exceed 72 hours if:
(1) Blowing down the well is necessary for efficient operation of the well or unexpected circumstances are encountered;
(2) Blowing down the well will not damage any producing formation in the well; and
(3) The operator complies with the H 2 S requirements of 165:10-3-16.
(b)Gas volumes less than or equal to 50 mcf/d. An operator may vent or flare up to 50 mcf/d without a permit if:
(1) It is not economically feasible to market the gas;
(2) A suitable stand, line, or stack is used to prevent a hazard to people, and such stand, line or stack has a properly installed and operating stack arrestor;
(3) H 2 S content of gas exceeds 100 ppm, then the gas must be flared; and
(4) The operator shall notify the appropriate Conservation Division District Office or Field Inspector within 24 hours of initiating the flaring of gas with an H 2 S content exceeding 100 ppm.
(c)Permit to vent or flare gas volumes in excess of 50 mcf/d.
(1) The Conservation Division may administratively grant a permit to vent or flare on a daily basis gas volumes in excess of 50 mcf/d, if:
(A) The operator applies for the permit on Form 1022;
(B) The application lists the location of the well and the maximum daily volume of gas to be vented or flared;
(C) It is not economically feasible to market the gas; and
(D) A suitable stack, stand, or line will be used to prevent a hazard to people or property, and such stand, line or stack has a properly installed and operating stack arrestor.
(2) The operator shall file an amended application in the event that the amount of gas to be vented or flared exceeds the permitted volume.
(d)Temporary permit exemption for gas vented or flared during initial flowback from a newly completed or recompleted well. Gas vented or flared during initial flowback from a newly completed or recompleted well shall be exempt from the permit requirements of subsection (c) for a period not to exceed 21 days, commencing with the first date gas flow is in excess of 50 mcf/d, if:
(1) Combustible gas flow greater than 50 mcf/d is flared;
(2) Gas with H2S content in excess of 100 ppm is flared;
(3) The operator gives at least 48 hours notice by electronic mail or facsimile to the appropriate Conservation Division District Office or Field Inspector regarding the time when the venting or flaring of gas pursuant to this subsection will begin;
(4) It is not economically feasible to market the gas; and
(5) A suitable stack, stand, or line will be used to prevent a hazard to people or property, and such stand, line or stack has a properly installed and operating stack arrestor.
(e)Gas flared after initial flowback from a newly completed or recompleted well. Subsequent to the 21 day initial flowback period addressed in subsection (d), gas flared during flowback from a newly completed or recompleted well shall be exempt from the permit requirements in subsection (c) for an additional period not to exceed 45 days if:
(1) Gas volumes flared from the well are less than or equal to an average rate of 300 mcf/d over the 45 day period, and one or more of the following conditions applies:
(A) No appropriate takeaway structure exists;
(B) The well is an exploration well; or
(C) The quality of the gas to be flared is not pipeline acceptable.
(2) Gas with H 2 S content in excess of 100 ppm must be flared.
(3) A suitable stack, stand, or line must be used to prevent a hazard to people or property, and such stand, line or stack has a properly installed and operating stack arrestor.
(4) The well operator is required to maintain a daily log of gas volumes flared from the well during the 45 day period. The daily log must be preserved for 3 years subsequent to the conclusion of the 45 day period. The log shall be produced upon request by an authorized representative of the Commission.
(5) If gas volumes greater than 300 mcf/d are to be flared during flowback from a newly completed or recompleted well subsequent to the initial 21 day period addressed in subsection (d), then the operator is required to obtain a permit as provided in subsection (c).
(f)Application for an order permitting venting or flaring.
(1) If the Conservation Division denies a Form 1022 application for a well, the operator of a well may apply for an order permitting venting or flaring of gas.
(2) The application and notice shall be in accordance with OAC 165:5-7.
(3) Upon application, notice, and hearing, the Commission may grant or deny an application made pursuant to OAC 165:5-7.
Okla. Admin. Code § 165:10-3-15

By following the links on this page,
Download the state profile of interest
Clink the link as given in the profile to the state regulation
you should be able to find the rules of other states.

https://www.energy.gov/fecm/findyou...ing-and-venting-regulations-fact-sheets-state

COLORADO

https://files.engineering.com/getfi...a5-377ae0ad957f&file=Colorado_2_CCR_404-1.pdf

TEXAS

https://rrc.texas.gov/media/i14nezuo/statewide-rule-32-venting-and-flaring.pdf

--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[aegis4048]

@1503-44
wow you are awesome, literally saved 4~6 hrs of struggle that I would've had if I were to look these up on my own with no experience on regulations. Very informative, thank you!

 

[LittleInch]

He's pretty good isn't he?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[1503-44]

State of flux is currently high with new regulatory proposals and court cases.
Changes are probably on the way,
so tuned in stay.


--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[1503-44]

The flux

https://www.epa.gov/newsreleases/bi...nal-rule-cut-methane-emissions-strengthen-and

https://www.federalregister.gov/doc...esource-conservation#sectno-reference-3179.90

--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[Heaviside1925]

44,
For my own curiosity and lack of upstream oil extraction experience, does the PSV used in this service have a standard controlling case or does it vary wellsite to wellsite?
I apologize if that is stated in one of links you posted but my brain can only handle so much regulation reading for one day.

 

[1503-44]

It's going to usually be a very low psig. One or 2, couple of psi.
Somewhat higher with a high condensate crude that boils at 70°F.

https://www.epa.gov/sites/default/files/2017-07/documents/06_vrus_vernal_2010.pdf

https://corporate.exxonmobil.com/-/...hash=FB210119349131FDD386A8E58D1B830C1BC6CD71

https://www.emerson.com/en-us/automation/valves/vent-valves

Although now a bit dated (2015), many Dept Justice resolutions were agreed with producers in 2015

https://search.justice.gov/search?a...ery=Noble+energy+settlement+methane+emissions

https://cimarron.com/malfunctioning-stuck-separator-dump-valves-the-fugitive-emissions-impact/

--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[aegis4048]

All of the atmospheric tanks I've seen at wellsite are rated at 16oz = 1 psig. Usually they have one safety valve and a thief hatch. PSV opens at 8~12oz. Enardo950 PRV is the most common that I've seen. This valve has both over-pressure and vacuum safety features. The tanks also have a thief hatch that lifts open at 12~14 oz. But these thief hatches don't always open for so many unthinkable reasons, which includes birds nest & bird poops.

Some operators are moving onto installing 3 psig tanks to give more operating margin for flare & VRU operations, but almost all of the wellsite tanks are rated at 16oz. Not sure if the manufacturers actually make MAWP 16oz tanks, but when it comes to operations, production engineers assume the max operating P to be 16 oz.

And @1503-44, I don't understand the concept of crude that boils at 70F, because there's usually a heater treater that usually operate hotter than minimum 100F. Any crude that boils at 70F will have already been cooked off at the heater.

 

[1503-44]

Right. Its straight out of the well, or entering the high pressure tank or separator.

Yes 950. There is a link error on one Emerson page to the 950. The other worked
Then I found a working 950 link

https://www.emerson.com/en-us/catalog/enardo-series-950

--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[GD2]

OP,
Time to fire your Supervisor. He can cost the company thousands of dollars for his governance.

GDD
Canada