Well Integrity - the basics
Well Integrity is a generic term which can mean different things to different people. However, a good definition is 'the monitoring, maintenance, testing and remediation of the well envelope to ensure the system remains 'fit for purpose'.
The well envelope may be defined as 'from well bore to wing valve (or choke) including all inner and outer casing strings both part and whole'. To successfully manage well integrity through the field life or indeed platform life requires technical resources, a planned work programme or schedule plus a budget allocation year on year.
For a typical organisation responsible for well integrity the following minimum standards should apply:
- Well Integrity Management Scheme identifying:
- Performance standards
- Technical Authorities / Accountable person
- Planned Maintenance Routines
- Operational procedures
- Legislation Compliance
The operational side of Well Integrity is split into two main areas:
- Maintenance & Testing
Failure to manage Well Integrity risks:, these include but are not limited to:
- Loss of containment - failed casing strings
- Tubing collapse/ burst
- Casing collapse / burst
- Tubing /annulus leaks
- Loss of well / loss of production
- Environmental spill
Equipment to conduct well integrity operations will vary dependant on the scale and complexity of the actual programme. For maintenance activities only hand tools and injection pumps may be required, however should a well entry be required to restore well integrity then any of the intervention services may be required to solve the problem and may include Wire-line, Coil tubing or Hydraulic Workover (HWO).