The are several kill methods in common use today. This techniques are similar in principle, and differ only in respect of when kill mud is pumped down.
In the driller’s method, the kick is circulated out of the hole using the existing mud weight. The mud weight is then raised to the required level and circulated around the well.
For the first is to pump the kick out of the well using existing mud weight, then pump the kill weight around the well.
Advantages of Driller’s Method:
- Minimum arithmetic
- Minimum waiting around time
- Minimum information required
Disadvantages of Driller’s Method :
- Highest annular pressure
- Maximum well under pressure time
- Longest “on choke” time
Wait and Weight Method (also known as the “engineer method”)
This method achieves both operations simultaneously. Kill mud is prepared before starting the kill, and the kick fluids is circulated out while this mud is circulated to the well. In this theory, kill the well in one circulation.
Advantages of Wait and Weight Method :
- Lowest wellbore pressure and lowest surface pressure, it mean the stress of pressure control can reduced.
- Minimum “on choke” circulating time
Disadvantages of Wait and Weight Method:
- Considerable waiting time – gas migration
- large increases in mud weight required, this is difficult to do uniformly in one stage
In This method, a compromise is adopted between this two methods. The kick fluid is circulated out while the mud being circulated in, is weighted up in stages, toward the kill weight.
The volumetric method is mostly used in production and workover operation. It is a mean of allowing the gas to migrate to surface under control.
When to use volumetric well control?
- A gas kick is taken and is migrating and the drill string is plugged and only casing pressure can be read
- No drill string in the well, packer leaking
In this method, the kick fluid is circulated out by kill weight mud.