Well Integrity Technical Section

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  • 1.  MAWP v. MOWP?

    Posted 06-04-2014 10:24 AM
    (sorry if this posts twice - SPE Connect seems to be hanging today...)
    Can anyone out there explain if there is a difference between MAWP and MOWP (and if so, what they are)? I seem to be in acronym confusion land.

    Thanks,
    Christi
    Expro


  • 2.  RE: MAWP v. MOWP?

    Posted 06-05-2014 10:02 AM

    These are different. MAWP Maximum Allowable Working Pressure is the maximum pressure permissible per design  in normal operating position and temperature, in corroded condition and while under the effects of other loadings. It depends on allowable stress of material and temperature.
    MOWP Maximum Operating Working Pressure can be equal or lower than MAWP and is the pressure at which normally operates and depends on additional safety factor that the operator considers for safely operation. Usually MAWP=MOWP*SF (Safety factor)
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    Pablo Cardenas
    Petroleum Engineer
    Newfield Exploration Company
    TulsaOK
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  • 3.  RE: MAWP v. MOWP?

    Posted 06-06-2014 05:45 AM
    Christianne,

    Hello again. 
    I would like to add to Pablo's reply;

    There are many other similar acronyms including MAWOP (Maximum Allowable Wellhead Operating Pressure) , MAASP (Maximum Allowable Annulus Surface Pressure), MATP (Maximum Allowable Tubing Pressure), etc. In practice the Control system will/may actually have two additional points including an alarm point and an 'action point' so the Operators get a signal before any limits are reached.

    In practice the different numbers were used by different people for different things.  I might have a Design MAASP, a Tested MAASP, a Functional MOASP (Maximum Operating Annulus Surface Pressure), and Alarm Pressure for each annulus.  The Operators would only ever see the MOASP and Alarm points. This allowed the Controls personnel to set up an alarm point sufficiently below the 'limit' so that we gave the operators a chance to respond before taking an extreme action such as shutting in the well as they approached MOASP.  This methodology was for each annulus and the tubing.

    What is required is that you define clearly the acronym that you are using. You also have to apply a consistent methodology to determine the different pressure limits. Finally, that you recognize that each of these acronyms apply to each annulus and the tubing.

    I hope this helps,

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    Dan Gibson
    TheWellDoctor
    Completion / Well Integrity Advisor
    Gibson Petroleum Consultants
    FulshearTX
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  • 4.  RE: MAWP v. MOWP?

    Posted 06-06-2014 03:06 AM

    Christi,

    If you are mentioning this in context of Well Integrity, then the acronym used is MAWOP - Maximum Allowable Wellhead Operating Pressure. API RP 90 (Annular Casing Pressure Management for Offshore Wells) defines it as "the maximum allowable operating pressure for a particular annulus, measured at the wellhead relative to ambient pressure."

    If you have come across MAWP or MOWP somewhere relating to Well Integrity, it is most likely some company's way of describing MAWOP.

    In surface operations, MAWP refers to Maximum Allowable Working Pressure. This is however used for pipings, pipelines, pressure vessels etc. API 570 (Piping Inspection Code: In-service Inspection, Rating, Repair, and Alteration of Piping Systems) defines it as "the maximum internal pressure permitted in the piping system for continued operation at the most severe condition of coincident internal or external pressure and temperature (minimum or maximum) expected during service."


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    Sudeep Roy
    Functional Head of Production
    Addax Petroleum
    Geneve
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