Use of cellulose mixed ethers as additives for earth pressure shields
AssigneeWolff Walsrode AG
InventorsKlaus Szablikowski, Werner Lange, Jorn-Bernd Pannek, Rene Kiesewetter
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Abstract
The present invention relates to water-soluble, particularly ternary, preferably ionic, cellulose mixed ethers, more particularly to anionic water-soluble cellulose mixed ethers, as additives for drilling fluid applications.
Claims9
In a drilling fluid comprising water and a cellulose ether, the improvement wherein the cellulose ether is a water-soluble ternary ionic cellulose mixed ether selected from the group consisting of methyl-hydroxy-ethylcarboxymethyl cellulose;
- methyl-hydroxyethyl-dicarboxymethyl cellulose;
- methyl-hydroxyethyl-sulphoethyl cellulose;
- and methyl-hydroxypropyl-carboxymethyl cellulose.
In the drilling into earth with removal of earth to form a substantially earth-free hole, wherein during drilling there is added a drilling fluid comprising water and a cellulose ether, the improvement wherein the cellulose ether is a water-soluble ternary ionic cellulose mixed ether selected from the group consisting of methyl-hydroxy-ethyl-carboxymethyl cellulose;
- methyl-hydroxyethyl-dicarboxymethyl cellulose;
- methyl-hydroxyethyl-sulphoethyl cellulose;
- and methyl-hydroxypropyl-carboxymethyl cellulose.
Dependencies are inferred from the claim text.