Stage Cementing Tools
Multiple-stage cementing tools allow for selected intervals around the casing string to be cemented at separate times or in stages. Two-stage cementing is the most common of the multiple-stage cementing techniques, but a three-stage method can be used. New technologies and techniques have led to the use of lightweight cement solutions in some situations that would conventionally call for multiple-stage cementing.
Multiple-stage cementing tools are recommended for the following circumstances:
- Wells where the hydrostatic head of the cement is greater than the formation pressure in some intervals but not other intervals
- Lighter-weight cement would be required in the low-pressure formation section) in order to avoid breakdown of the formation and reduce the potential for lost circulation
- Heavier-weight cement would be required in the high-pressure formation sections in order to maintain control of the well
- In deep, hot holes where time to pump the desired quality and quantity of cement is limited and thus slurry pumpability is best maintained by reducing the total volume to be placed in an interval during any particular pumping operation
- When only certain portions of the wellbore require zonal isolation
- In downhole conditions that require different slurry blends to address unique challenges to each segment and achieve the intended zonal-isolation integrity
- In horizontal wells where the bend radius of the well requires cementing
Two types of multiple-stage cementing tools are available: plug-opened (free fall) or hydraulically-opened (pump down). All of Halliburton's stage cementing tools are rated for continuous service up to 275°F (135°C).
