Well control contingencies when running drilled or slotted liners

16 May 2013 Normal practice in projects I have been involved in has been to run an inner string in drilled or slotted liners if the reservoir pressure is normal or higher, in order to always have a means of circulating from the bottom of the string for well control. For the last few years the reservoirs concerned have been partially depleted and we dispensed with the inner string as it was never needed to help get the liner in by circulating, and it is operationally time-consuming and unnecessary.

Now we have a case where TVD of the reservoir happens to be only a little more than the drilled liner length but the inner string is not practical due to the type of hanger, and the issue of well control contingency has come up. The reservoir pressure is slightly below hydrostatic and GOR low. A bushing will be available to make up to drill pipe at any point,long flow check beforehand, and procedure of off-bottom kill will be reviewed.

Are there any other contingent procedures or equipment that people have been using? Are many people running without inner strings these days? The service companies tell me not many inner strings are run now.

Thanks.

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