Expro Well Services (EWS) provides services to ensure that a client’s annulus well integrity is maintained in both new and existing wells. For any annulus, the MAASP (Maximum Allowable Annulus Surface Pressure) is the highest surface pressure that can safely be applied to that annulus without the danger of exceeding the safe operating pressure of any component within the well. In order to achieve this, a number of load cases have to be taken in to account.
These will include some of the following, although not all of the cases listed below will be applicable in every annulus.
Inner tubular collapse
Outer tubular burst
Formation leak-off
Wellhead pressure rating
Packer pressure rating
Previous test pressures
In order to account for changes in the well condition over time it may be necessary to de-rate the tubular burst and collapse pressure ratings to account for corrosion and wear. These de-ratings can come from either inspection logs or models. In addition, changes to the fluid pressure gradients may also have to be taken into account.
The approach used for MAASP calculation within Expro Well Services was developed in conjunction with Mike Murray, head of well integrity at ExxonMobil.
MAASPs and acceptable leak rates for valve testing need to be periodically reviewed based upon changing well conditions.
MAASP review
Expro Well Services (EWS) provides services to ensure that a client’s annulus well integrity is maintained in both new and existing wells. For any annulus, the MAASP (Maximum Allowable Annulus Surface Pressure) is the highest surface pressure that can safely be applied to that annulus without the danger of exceeding the safe operating pressure of any component within the well. In order to achieve this, a number of load cases have to be taken in to account.
These will include some of the following, although not all of the cases listed below will be applicable in every annulus.
In order to account for changes in the well condition over time it may be necessary to de-rate the tubular burst and collapse pressure ratings to account for corrosion and wear. These de-ratings can come from either inspection logs or models. In addition, changes to the fluid pressure gradients may also have to be taken into account.
The approach used for MAASP calculation within Expro Well Services was developed in conjunction with Mike Murray, head of well integrity at ExxonMobil.
MAASPs and acceptable leak rates for valve testing need to be periodically reviewed based upon changing well conditions.