The Dow Chemical Company

Earl F Morris

Oliver W Crinkelmeyer

Thomas J Griffin, Jr

Dustin L Free

Roland L Root

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.

Method of well completion with casing gel

An aqueous hydraulic cement slurry is provided which has low fluid loss properties at elevated temperatures. In addition to water and a hydraulic cement the hydraulic cement slurry contains a polyamine compound; a lignoamine and/or lignosulfonate; a borate ion releasing compound; and a carbonate and/or bicarbonate.

Aqueous hydraulic cement slurry

Method of cementing a high temperature borehole

A high-alumina cement composition is disclosed which has thermal stability over a wide temperature range and which develops strength at an early age. The cement composition comprises a high-alumina cement, a halide salt and calcium sulfate. This composition when added to water provides a hydraulic cement composition which can be employed in environments subject to wide temperature fluctuations below and above freezing (e.g. 32.degree. F).

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Wagoner, OK, United States of America

Earl F Morris