We’ve learned so many topics regarding wait and weight well control method and I would like to share what advantages and disadvantages of wait and weight method are.
Advantages of Wait and Weight Method
• When compared to driller’s method, the wait and weight will generate lower pressure at casing shoe while circulating.
• It will generate the lowest pressure on surface equipment.
• It requires less circulation than driller’s method therefore time of equipment exposed to pressure is less.
Transocean demonstrates an excellent animated video of the Deepwater Horizon incident. This video will show you what was happened to the Deepwater Horizon rig’s BOP and there are a lot of things that you can learn from this VDO as sequence of the incident, deep water BOP stack configuration, why the BOP elements were failed, force of high flow velocity, etc.
Please click at the image below to see the full VDO.
Please give me your thought about this VDO.
Many topics of driller’s method have been taught on the drillingformulas.com and I would like to summarize about advantages and disadvantages of driller’s method.
• Circulation can be established right away so the bottom hole pressure will not increase much due to gas migration.
• Influx can be removed out of the well even though the rig does not have sufficient amount of weighting agent.
• Gas migration is minimized.
• Operation is quite simple when compared to weight and weight method.
• Calculation is simple and drill pipe pressure schedule is not required.
This topic will explain you how wait and weight well control controls bottom pressure constant. There are 2 steps that must be took into consideration separately. The first one is when kill weight mud is displaced to the bit and the second one is when the kill weight mud from bit to surface.
1) Displace kill weight mud to the bit
Once kill weight mud is mixed and displaced into drill pipe, drill pipe pressure will be decreased due to increasing in hydrostatic pressure. In order to control bottom hole pressure, a drill pipe pressure schedule must be developed and followed until kill mud weight to the bit.
There are some well control formulas that you need to know for wait and weight method.
1. Kill Weight Mud
KWM = OMW + [SIDPP ÷ (0.052 x TVD)]
Where;
KWM is kill weight mud in ppg.
OMW is original mud weight in ppg.
SIDPP is shut in drill pipe pressure in psi.
TVD is true vertical depth of the well in ft.
Note: Read more about it>> Kill Weight Mud
