Two stage cementing Flashcards
1
Q
What is Multistage Cementing?
A
A cement job performed in two or more stages is called Multistage cementing.
2
Q
Three standard multistage techniques are commonly employed.
A
- Regular two-stage cementing
- Continuous two-stage cementing
- Three-stage cementing
3
Q
The execution time of stage cementing increases the rig time.?
A
true
4
Q
Reasons for Multistage Cementing
A
- Upper zone to be cemented with special cement system Salt or Gas zone
- Cost Reduction
- Avoid long cementing intervals
- Logistic
- Temperature difference
- Leave some zones not cemented
- Cost Reduction
- Injection of formation Cuttings
5
Q
Hardware for two-stage jobs
A
Stage collar (First stage plug/wiper plug, opening bomp, closing plug)
6
Q
Double stage operation
A
1st Stage
- Start 1st-stage cementing
- Release 1st-stage plug and start displacement
- 1st-stage plug passes through stage collar and lands at float collar (displacement is completed)
- Opening bomb is dropped
- Wait for ~5 minutes per 1000 ft to to reach the stage collar
2nd Stage
- Opening Bomb lands on stage collar
- Pressure up and open the stage collar
- Now circulation starts through ports at stage collar
- Start 2nd-stage cementing
- Release closing plug and start displacement
7
Q
Stage Collar Does Not Open !
A
Possible Solutions
- Wait: Bomb may not have arrived yet.
- Increase Pump Pressure.
- Run Drill Pipes in the hole and try to open mechanically
- Perforate above collar and cement
8
Q
Where to place Stage Collar
A
Weak Formation
- Above the LC zone, it will reduces the hydrostatic above the problem zone
Gas or Salt zone
- Below 200 to 500 ft
9
Q
A stage collar is considered to be a “weak” point in the casing by many clients and so avoid using them.?
A
yes
10
Q
Alternatives to 2 stage cementing
A
- Reduce hydrostatic column
- Use of lightweight slurries
- Foam Cement
- High performance lightweight systems
- This leads to:
- Complex designs
- Logistical problems
- Expensive slurries
