Dear Pradeep,
In the near past I had a chance to visit one of the
world's largest oil field in Kazakhstan. As of now
Karachaganak field has more than 40 wells and average
well depth is around 3000 â 5000m. The pressure of the
oil gas mixer is so high that it comes out without any
pump and that too with a pressure of 150-200bar. So
the pressure in the well is somewhere as high as
700bar. Normally from each well one 6â flow line comes
out which passes the oil gas mixture to RMS (Remote
Manifold Station, in Karachaganak there are 8 RMS).
Each RMS takes feed from 3-8 wells. From each RMS 1 or
2 10â Trunk Line/s is/are sent to processing unit.
Each flow line coming out from the well has to be
corrosion protected. So outer corrosion is protected
by cathodic protection and for internal corrosion
protection we feed an inhibitor to each well by a 1â
line.
Output from each well is mixer of Oil, Gas and Water
so before putting any well into use quality of the
output has to be tested if the same is within
acceptable range. For this purpose each RMS is having
one test line (normally 6â) which can be connected to
any of the well connected to same RMS which needs to
be tested. If the output is not of acceptable quality
then the oil well is abandoned.
The mixture of Oil, Gas & Water, which is fed to the
processing unit, is separated at 70bar. So Gases and
water coming out from this separation is fed back to
the oilfield using re-injection wells. This
re-injection is done to keep maintained the life and
pressure of the field and to dump the separated gas &
water which is not being used presently. Some of the
gas is being sweetened means processed to use it in
the gas turbine & for other usage.
Re injection of gas is done at a pressure of 500 bar
where as re-injection of water is done at 90 bar. This
is because it has to go 3000-5000m down and water head
is higher than gas head. So the effective pressure at
the discharge point which is 3000-5000m down will be
almost same in both the cases.
I hope this will satisfy you.
Regards,
Mukesh Chugh
- pradeeep mahajan <pra1_mahajan@yahoo.com> wrote:
> can enybody tell me about offshore piping and
> removing oil from well
>
>
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>
> There are 2 messages in this issue.
>
> Topics in this digest:
>
> 1. RE: stress corrosion cracking
> From: "Steve McKenzie"
> 2. Re: stress corrosion cracking
> From: Narendra Roy
>
>
>
>
>
> Message: 1
> Date: Mon, 8 Dec 2003 11:05:08 +1300
> From: "Steve McKenzie"
> Subject: RE: stress corrosion cracking
>
> Hi LAKSHMI NARAYANA
>
> havent had this problem. The following link and the
> bibliography within may
> be of some help to you.
>
> http://www.ncedaust.org/peter3.htm
>
> The passivation by water addition sounds
> interesting.
>
> Cheers
>
> Steve McKenzie
>
> -----Original Message-----
> From: Lakshmi V. Narayana
> [mailto:LNarayana@safco.net]
> Sent: Sunday, December 07, 2003 11:34 PM
> To: 'PipingDesign@yahoogroups.com'
> Subject: [PipingDesign] stress corrosion cracking
>
>
> Dear friends,
>
> We are facing SCC problem since long time. The
> service is anhydrous liquid
> ammonia and material of construction is LTCS. We
> observed leaks in weldments
> due to SCC as Liquid NH3 is contaminated with CO2.
> SS material can be
> replaced.however cost will be more. Can SCC be
> mitigated by doing stress
> relieving of all joints. What about small bore
> lines. My suggestion is to
> replace all small bore line SS304L and all bog bore
> lines shall be stress
> relieved. Can any body share his experience in this
> regard.
>
> Regards
> LAKSHMI NARAYANA
> MECHANICAL ENGINEER(FERTILIZERS)
>
>
>
>
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> helpful advice, nonsense,
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> of the above. The intent
> is to spark discussion and encourage
> knowledge-sharing amongst
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> info gleaned from reading this list, you are an
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>
> Message: 2
> Date: Sun, 7 Dec 2003 18:23:09 -0800 (PST)
> From: Narendra Roy
> Subject: Re: stress corrosion cracking
>
> Dear Lakshmi V Narayana
> CSLT is the most popular selection. Yes anhydrous
> ammonia cause SCC in Carbon steels, but the
> precautions like inhibition using distilled water
> added upto 0.2 % makes CS SCC resistant to Ammonia
> service. Another precaution is to reduce the
> residual
> stress by PWHT of welds and the cold formed
> components
> of the handling system. Slight over design (reduced
> component stress) may give you relief from stress
> cracking.
> Hope it solves the problem faced by you.
> Narendra K Roy
> Gramya Research
>
> --- "Lakshmi V. Narayana" wrote:
> > Dear friends,
> >
> > We are facing SCC problem since long time. The
> > service is anhydrous liquid
> > ammonia and material of construction is LTCS. We
> > observed leaks in weldments
> > due to SCC as Liquid NH3 is contaminated with CO2.
> > SS material can be
> > replaced.however cost will be more. Can SCC be
> > mitigated by doing stress
> > relieving of all joints. What about small bore
> > lines. My suggestion is to
> > replace all small bore line SS304L and all bog
> bore
> > lines shall be stress
> > relieved. Can any body share his experience in
> this
> > regard.
> >
> > Regards
> > LAKSHMI NARAYANA
> > MECHANICAL ENGINEER(FERTILIZERS)
> >
> >
> >
> > ------------------------ Yahoo! Groups Sponsor
> >
> > ========================================
> > Discussion List sponsor: The fluid flow
> calculations
> > website - www.LMNOeng.com - LMNO Engineering,
> > Research, and Software, Ltd.
> > =======================================
> > Information presented on this list is given as
> > helpful advice, nonsense, carefully-considered
> > calulation or any combination of the above. The
> > intent is to spark discussion and encourage
> > knowledge-sharing amongst professionals. If you
> blow
> > yourself up by doing stuff remotely described by
> > info gleaned from reading this list, you are an
> > idiot.
> >
> > Your use of Yahoo! Groups is subject to
> > http://docs.yahoo.com/info/terms/
> >
> >
>
>
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Received on Sat Dec 13 09:23:00 2003