[QUOTE=New Orleans Lady;43863]Definition of a LINER A casing string that does not extend to the top of the wellbore, but instead is anchored or suspended from inside the bottom of the previous casing string. There is no difference between the casing joints themselves. The advantage to the well designer of a liner is a substantial savings in steel, and therefore capital costs. To save casing, however, additional tools and risk are involved. The well designer must trade off the additional tools, complexities and risks against the potential capital savings when deciding whether to design for a liner or a casing string that goes all the way to the top of the well (a “long string”). The liner can be fitted with special components so that it can be connected to the surface at a later time if need be.http://www.glossary.oilfield.slb.com/DisplayImage.cfm?ID=510[/QUOTE]
Adding a bit of additional info to New Orleans Lady’s post…
If I understand the procedure for running a liner versus a long string, a Halliburton Versaflex Liner hanger would have been run in the hole on drill pipe with the 7" liner assembly attached to the bottom.
I think this video is a good simulation of the procedure although there are several Versaflex options and other vendors offering similar solutions.
http://www.halliburton.com/public/cps/contents/Multimedia/web/VersaFlex_Flapper.wmv
Keep in mind that there are two Versaflex liner hangers located on larger casing strings up the hole so this concept was not foreign to the design engineeers…
Funny thing is Weatherford provided the casing and the flapper valve assembly and there were problems getting the flapper valve to operate properly (required several atempts and about 7 times the normal pressure to convert) however Weatherford is rarely mentioned as having any liability for this event.