Sealing system

摘要

The present invention relates to sealing method for sealing a zone of a casing in a well, the zone comprising several leaks, perforations and/or weakened casing parts, or other irregularities having a casing characteristic which, when measured, is found to be outside a predetermined interval. The sealing method comprises the steps of measuring the characteristics of the casing, determining a position of the zone, determining an extent of the zone in a longitudinal direction of the casing, determining a part of the zone and an extent of the part whose casing characteristic when measured is within the predetermined interval, the part extending in the longitudinal direction of the casing, positioning a first liner overlapping the first area of the part of the casing, positioning a second liner overlapping the second area of the part of the casing, expanding the first liner, and expanding the second liner.

主权项

1. A sealing method for sealing an imperfect zone of a casing in a well, comprising:
measuring a characteristic of the casing, the characteristic being related to structural damage or weakening of the casing at a particular location; evaluating the characteristic and classifying the characteristic as acceptable or imperfect along a plurality of locations in a longitudinal section of the casing relative to a predetermined value; locating a first damaged or weakened zone randomly located in the casing, the first damaged or weakened zone comprising two discrete damaged or weakened sections of the casing, the first damaged or weakened section of the casing being separated longitudinally from the second damaged or weakened section of the casing by an acceptable region; positioning a first liner overlapping the first damaged or weakened section and a first portion of the acceptable region; positioning a second liner overlapping the second damaged or weakened section and a second portion of the acceptable region different from the first portion; ensuring a third portion of the acceptable region exists between the first portion and second portion and dimensioning the third portion to have a minimum predetermined extent based on the locating of the first and second damaged or weakened zones such that no liner overlaps the third portion; expanding the first liner; and expanding the second liner.