Casing repair in CSS wells
CSS casing repair with Saltel extreme high-temperature casing patch. This single-well method injects steam at high pressure and high temperature in the reservoir during the first phase.
Operators complete a soaking (or shut-in) phase to let the reservoir heat up evenly by convection. Then they can pump out the heated oil from the same producing well. Once the oil production rate decreases when cooling the reservoir, they can engage another cycle.
Challenges
- Withstand working temperature conditions up to 335°C
- The aggressive environment due to H2S concentration and high temperature
- Up to 10 thermal cycling
- Seals equally well at both high and low temperatures
- Minimum impact on production rate to keep well profitable by leaving a maximum inside diameter.
Solution
The High-Temperature patch (335 degC/635 degF) is a life-of-the-well solution. This permanent inner-lining comes up with a custom design for cyclic steam stimulation casing repair. If CSS means ‘thermal well,’ then ‘thermal well’ involves high-temperature conditions.
The technology and the setting procedure are similar to standard patches. The technology bears a few changes on the material to fit harsh conditions. For example, the CSS Patch does not use elastomer. The product is successfully qualified through CSS conditions. The qualification involves ten thermal cycles. The CSS patch design allows for repairing the “out of zone” parts of the well.