Two-stage cementing device is a cementing tool often used in deep wells, exploratory wells and complex wells. It can change the conventional one-stage cementing into two-stage cementing, so as to solve the problem of cementing in the case of leakage, large cement volume and large temperature difference. question. Mainly used for cementing and cementing operations in the following occasions.

1. The amount of cement injected at one time is too large;
2. The formation cannot withstand excessive liquid column pressure;
3. Seal off special layers;
4. Prevent the annular air from channeling after cementing;
5. The temperature difference between the upper and lower parts of the sealing section is large, and the performance of the cement slurry is not easy to adjust;
6. Two-stage cementing for inclined wells and horizontal wells.
Features:
1. The closing sleeve is designed with an anti-rotation device, which can prevent the closing sleeve from rotating synchronously with the drill bit when drilling and removing accessories;
2. A special mechanism is designed to prevent the closure sleeve from closing in advance;
3. After the closing sleeve closes the circulation hole, the locking mechanism on the closing sleeve prevents the closing sleeve from going backwards and realizes permanent closing;
4. All accessories are made of rubber/aluminum materials with good drillability, and have a good anti-rotation mechanism, which is convenient for drilling and removal;
5. Gravity type opening plug or displacement type opening plug can be used for mechanical opening;
6. The inner diameter of the lower joint is the same as the inner diameter of the casing, but smaller than the inner diameter of the closing sleeve, which can effectively protect the closing sleeve from damage during tripping and drilling operations.