Earl Tim Morris

US Patent:

42574838, Mar 24, 1981

Filed:

Jan 11, 1979

Appl. No.:

6/002772

Inventors:

Earl F. Morris - Wagoner OK
Dustin L. Free - Midland TX
Roland L. Root - Tulsa OK
Thomas J. Griffin - Sand Springs OK

Assignee:

The Dow Chemical Company - Midland MI

International Classification:

E21B 3314

US Classification:

166292

Abstract:

A method of well completion is provided which enables much of the well casing to be later recovered from the well in the event the well is later abandoned, or where intermediate casing must be run during drilling of the well but may later be removed when the liner is in place. The well is completed by any of several embodiments of manipulative steps, leaving the lower portion of the annulus filled with a conventional cementitious material and the upper portion of the annulus filled with an aqueous gel comprising effective quantities of water, a water soluble alkali metal silicate, and a water soluble metal compound capable of releasing a multivalent metal cation to react with the water soluble silicate. An economically significant portion of the casing can thereafter be recovered if necessary after first severing the casing above that portion adjacent the set cementitious material. Where an intermediate string of casing is employed only to facilitate drilling the remainder of the well, the cement may be omitted with respect to the intermediate string as is known in the art.