Mud leg provides hydrostatic pressure in order to prevent mud going through the separator into the rig. If the pressure in the mud gas separator exceeds hydrostatic pressure provided by mud leg, gas blowing through situation will be happened. Once blow-through occurs with a mud gas separator, it is very difficult to stop this situation until the mud leg column is re-established.
Figure 1 illustrates mud-blow through. The pressure that will create blow-through can be calculated by determining hydrostatic pressure of mud leg. Continue reading →
4-way valves in the accumulator (Koomey) unit are used to control the position of Blow Out Preventer (BOP). Today we will go into the detail of 3 positions of 4-way vales in order to see how each position affects to the BOP.
When the valve is turned into the open position, it directs hydraulic pressure from the manifold into the BOP openning port therefore the BOP is in the open position. The hydraulic fluid in the ram closing chamber will return back to the reservoir tank. Figure 1 illustrates how the hydraulic pressure is lined up to open the BOP.
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.
In the previous topic, we discuss about the annular preventer and today we would like to give you more details regarding ram preventers. The ram preventers were invented by James Smither Abercrombie and Harry S. Cameron in 1922.
This preventer consists of two rams which extend into the center of the wellbore in order to shut the well in (see the image below). The ram preventers can be hydraulically or manually operated. When people would like to shut the well in using the ram preventer, they will go to the hydraulic option first. If the hydraulic is not properly operated, the manual system will be utilized.
In order to provide the wellbore sealing, the rams must compose of top seals and packers which are made of the special elastomer. For more understanding, please take a look at the diagram of Cameron BOP below.
(Courtesy of Cameron)
When the well is shut in, the packer will seal around drillstring or tubular and the top seal will be pushed against the BOP body. With both top seals and packer, the well is securely shut in when
In the drilling industry, there are four types of rams preventers which are Pipe Rams, Variable Bore Rams (VBR), blind rams and blind-shear rams.