Riser margin in the mud weight increase below mud line to compensate bottom hole pressure in case of an accident disconnect or a failure marine riser close to the BOP stack at sea bed.

Riser margin in the mud weight increase below mud line to compensate bottom hole pressure in case of an accident disconnect or a failure marine riser close to the BOP stack at sea bed.

A drill pipe float valve is a check valve installed in the drill stem that allows mud to be pumped down but prevents flow back up. There are two types of float valves which are flapper type and plunger type.

The following VDO will demonstrate you the mechanism of each type of drilling float valve.
These are some footage showing some oil drilling rigs were blown out and got fired. I would like to share these VDO clips to raise awareness of well control.
Oil Rig Blowout
Chesapeake Energy Nomac Rig 17 Blowout Fire
Kick tolerance is the maximum gas volume for a given degree of underbalance which the circulation can be performed without exceeding the weakest formation in the wellbore. This article is the extended version of Kick Tolerance Calculation which will explain more on this topic. It is very critical that drilling personnel understand its importance to well design and drilling operation.

There are two important factors used for determining the kick tolerance
• Kick Intensity – It is the different between the maximum anticipated formation pressure and planned mud weight. For example, the planned mud weight is 13.0 ppg and the possible kick pressure is 13.5 ppg. Therefore, the kick intensity is 0.5 ppg (13.5 – 13.0).
A zero kick intensity (swabbed kick scenario) should be used for a know area where you have less uncertainty about an overpressure zone.
• Kick Volume – It is a gas influx entering into the wellbore from the formation. Gas kick is always used for well control calculation because it is the worst case scenario. The kick volume should be realistic figure which personal can detect the influx on the rig. In a larger hole, it allows bigger influx volume than a small hole.
I would like to share these 3 VDO’s demonstrating how Pipe Rams, Variable Bore Rams and Shear Rams work.

This eliminate confusion when the new people in the oilfield read and try to understand about these rams.
Pipe Rams – You will see that the pipe rams will work only on size of the drill string.