In cementing operations, precision and sequence are everything. The cement head (or cementing head) plays a critical role in managing fluids and isolating stages during the primary cementing process.
Here is a concise breakdown of the standard operational sequence for a Double Plug Cement Head as shown in the animation:
1️⃣ Preparation & Loading: * Loading the Bottom Plug (non-solid/hollow) into the lower chamber, secured by the bottom pull pin.
- Loading the Top Plug (solid) into the upper chamber, secured by the top pull pin.
- Installing the cement head cap securely.
2️⃣ Circulation: Initial mud circulation, followed by pumping conditioning spacers and washes to clean the wellbore.
3️⃣ Dropping the Bottom Plug: The middle Hamer valve is adjusted to equalize pressure, and the bottom pin is pulled to release the plug. This plug separates the drilling mud from the oncoming cement slurry.
4️⃣ Pumping the Slurry: The designed volume of cement slurry is pumped down into the casing.
5️⃣ Dropping the Top Plug: The top Hamer valve is equalized, and the top pin is pulled to release the solid top plug. This plug acts as a barrier behind the cement.
6️⃣ Displacement: Displacement fluid (mud or water) is pumped behind the top plug until it bumps, ensuring the cement is properly displaced into the annulus.
7️⃣ Line Clearing: Opening all valves after 40-50 bbls into displacement to clean internal lines.
Mastering these steps ensures fluid separation, prevents contamination, and ultimately secures zonal isolation.