Shutting and killing a well in phases

[wati]

Hi,

I don't understand how a well is shutted and killed. What is the "kill phase" diagram and can anyone explain to me?.

Any information lecture notes, graphs,material attached are appreciated.

Thanks

 

[mountainbrewhaus]

I suppose you are talking about a producing well. Gas wells you dont want to kill. I assume you are looking to do some downhole work on a producing well. Maybe a hole full of heavy fluid,like a brine.

 

[wati]

Its about a producing well. If for instance a well has to be shutted due to e.g maintenance operations in the wellhead or failure downhole how the shutting and killing process will take place. I understand that a heavy mud is used.

 

[DrillerNic]

You have to have a hydrostatic column of fluid that exerts a higher pressure on the reservoir formation than the pore pressure in the reservoir. So, for example, in the depleted reservoir I'm working on, with a pressure of approx. 3500psi at 8300ft TVD, the mud weight needed to be greater than the pore pressure is about 8.1ppg:- 3500/ 8300 = 0.4217psi/ft; 0.4217 /0.052 = 8.1ppg. So seawater, at 8.7ppg will kill the well, if you can stop it flowing away into the reservoir. In order to do this we use a perflo pill, (which is a trade name for sized CaCO3), to block the pores in the reservoir formation, similar to how a mud filter cake works, which can be easily removed when we want to bring the well back on.

You wouldn't used mud to kill a well you want to bring back on, as you will proabaly have problems getting the well to flow again- you'd use the various solids-free brines that are available at variuos weights up to 16ppg: NaCl, bromides, formates, whatever, with a pill to stop the brines flowing away into the reservoir.

If you're killing the well before plugging & abandoning it, you'd use mud, probably the mud you've been using to drill the well.