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Well control is the technique used in oil and gas operations such as drilling, well workover and well completion for maintaining the hydrostatic pressure and formation pressure to prevent the influx of formation fluids into the wellbore.
Secondary oil well control is done after the Primary oil well control has failed to prevent formation fluids from entering the wellbore. This process uses "blow out preventer", a BOP, to prevent the escape of wellbore fluids from the well. As the rams and choke of the BOP remain closed, a pressure built up test is carried out and a kill mud ...
“Kill” the well (prevent the flow of formation fluid, influx, from the reservoir into the wellbore); Seal the wellhead (close off the wellbore); Sever the casing or drill pipe (in case of emergencies). In drilling a typical high-pressure well, drill strings are routed through a blowout preventer stack toward the reservoir of oil and gas
Should the balance of the drilling mud pressure be incorrect (i.e., the mud pressure gradient is less than the formation pore pressure gradient), then formation fluids (oil, natural gas, and/or water) can begin to flow into the wellbore and up the annulus (the space between the outside of the drill string and the wall of the open hole or the ...
Diagram showing the MWD Negative pulse Negative pulse tools briefly open and close the valve to release mud from inside the drillpipe out to the annulus. This produces a decrease in pressure that can be seen at surface. The digital information can be encoded in the pressure signal using line codes or pulse-position modulation. [9] Continuous wave
The full name for this most common type of downhole safety valve is a Tubing Retrievable Surface Controlled Sub-Surface Valve, shortened in completion diagrams to TRSCSSV. If a tubing retrievable valve fails, rather than go to the expense of a workover, a "wireline retrievable" valve may be used instead.
The oil and gas industry uses wireline logging to obtain a continuous record of a formation's rock properties. Wireline logging can be defined as being "The acquisition and analysis of geophysical data performed as a function of well bore depth, together with the provision of related services."
A diagram showing forces at work during differential sticking. The small black arrows represent pressure exerted on the drill pipe from the wellbore, the red arrows represent pressure exerted on the pipe from the formation (smaller than in the wellbore) and the large black arrow represents the net force on the pipe, which is pushing it into the wall.