M&W Annulus Pressure Relief System.

    Overpressure Protection for Oil & Gas Well Stimulation and Intervention since 1995

    An advanced – yet simple to install and use – system utilizing burst disc technology adapted from the nuclear power industry.

    Mark & Wedell invented the Annulus Pressure Relief System (APRS) together with Maersk Oil & Gas (Total) as a trusted overpressure protection system for oil and gas well stimulation treatments and intervention up to 10,000 psi (690bar).

    Accurate
    Precise
    Reliable
    Safe

    Zero incidents on more than 1,000 well stimulation jobs over 30 years.

    The APRS has been used world-wide by 10+ oil and gas companies and service companies such as Shell, BP, Equinor, Aker BP, Maersk Oil & Gas (now Total), Hess, Itacha Energy, Halliburton, Schlumberger and Stimwell Services.

    Used in over 1,000 jobs, APRS supports safe and controlled pressure management during oil & gas well treatment in locations including the North Sea, Middle East, Kazakhstan, and the South China Sea.

     

    • Can be used for live or closed annulus operations onshore and offshore
    • For acid stimulation in limestone formations and propant stimulation in sandstone reservoirs

     

    RigAdvanced – yet simple: The M&W Annulus Pressure Relief System (APRS) is a compact, easy-to-install solution for well stimulation treatments and interventions based on burst disc technology adapted from the nuclear power industry
    RigProven globally: Used in over 1,000 well stimulation jobs by
    more than 10 oil and gas companies and service providers:

    • Shell, BP, Equinor, Aker BP, Maersk Oil & Gas (now Total),
      Hess, Ithaca Energy, Crescent Petroleum, Halliburton,
      Schlumberger and Stimwell Services.

    Field-tested in harsh environments across the North Sea,
    Middle East, Kazakhstan, and the South China Sea.

    Rig
    • Can be used for live or closed annulus operations onshore and offshore
    • Effective for both acid stimulation in limestone and; propant stimulation in sandstone
    DNV GL CertifiedCertified Safety & Performance

    • Accuracy: +/- 2%
    • Proven Reliability Over Traditional Systems:
      Unlike spring-loaded or nitrogen operated valves, the APRS offers higher reliability, fewer premature shut-in, non-productive time (NPT) and job cancellations
    • Type approved by DNV
      System: ASME B31.3 (6,000 psi) / API 6A (10,000 psi)
      Burst Discs: PED 2014/68/EU Cat. IV, EN/ISO 4126-2 for quality and safety compliance
    PrecisionPressure range customized to your needs:

    (± 10 psi from 1,500 – 10,000 psi/ 103 – 690 bar)

    RigContinuous Operation – Without Downtime

    • Enables parallel rig-up with two or more units
    • If the active line bursts, switch to the backup in under a minute minimizing downtime and ensuring uninterrupted operation
    • Avoids off-set reset issues tied to spring/ N2 valve
      systems
    24 7 SupportMark & Wedell offers 24/7 service and fast global delivery for critical oil & gas safety system needs

    • Any unused burst discs can be returned to Mark & Wedell and warehoused free of charge
    • Ready for the next stimulation job

    Testimonials

     

    “It is a good and reliable system. It has never let us down and it is easy to use.”

    – Jakob Monberg, Total

     

    Erik Jakobsen, Senior Well Stimulation Engineer (ex-Hess)

    Jakob Monberg, Global Well Stimulation Specialist (Total)

    APRS-Presentation-2025

    Presentation

    The M&W Annulus Pressure Relief System is a compact, easy-to-install solution for well stimulation treatments and interventions based on burst disc technology adapted from the nuclear power industry.

    Read the presentation to understand what roles the APRS has in well stimulation jobs, how it is installed and where and by who it is used.

    Download now

    Brochure

    Download the brochure for the M&W Annulus Pressure Relief System. Overpressure protection for oil and gas well stimulation and intervention based on burst disc technology adapted from the nuclear power sector.

    Download now

    APRS-Brochure-2025

    More information

     

    To find out more about our Annulus Pressure Relief System (APRS) please feel free to to contact Bjarke Pålsson.

     

    •   APRS Type Approval Certificate
    •   APRS Data Sheet

    Bjarke Pålsson

    Bjarke Pålsson

    Co-CEO and Owner