First of all apologies for those who read a similar post on LinkedIn.
While cement is setting, overpressured formation fluids can migrate through it and leave behind a pathway, sometimes called a chimney. The fluid can be gas, resulting in early gas migration (later gas migration is caused by microannuli), or brine, resulting in shallow water flow.
A new model predicts when and how fast fluids migrate through the setting cement sheath, indicating whether the upward movement will stop before reaching the wellhead or an intermediate permeable formations.
This model, as all its peers, now needs two types of validations: are its predictions correct? Is it useful in taking non-obvious design and remediation decisions?
The model has so far been successful in its application to two wells, but of course more are needed. Would you have a cement job where you suspect fluid migration took place, or you thought it should have happened but it didn't?
If you do and are interested in understanding why and how, please get in touch.
------------------------------
Matteo Loizzo
Wel integrity consultant
Berlin
------------------------------