Eniricerche S.p.a.

Agip S.p.a.

Stefano Carminati

Giovanni Burrafato

Thomas Paul Lockhart

Fausto Miano

Antonello Pittalis

Pretreated clays, their preparation and use in formulation drilling muds

Aqueous drilling muds are disclosed which contain, as fluidifier agent, one or more complexes, which may be either pre-formed or produced in situ, selected from: tetravalent zirconium and one or more organic acids, or their salts, having the general formula (I) ##STR1## wherein R.sub.1 and R.sub.2, which may be the same or different from each other, represent --H, --COOH, --CH.sub.3, --CH.sub.2 COOH, --CH(OH)COOH; aluminum citrate.

Aqueous drilling muds fluidified by means of zirconium and aluminum

Aqueous drilling muds effective at high temperature containing complexes, preformed or formed in situ, of tetravalent zirconium with one or more organic acids, or relative salts, of general formula (I) ##STR1## where R.sub.1 and R.sub.2, which can be the same or different, represent --H, --COOH, --CH.sub.3, --CH.sub.2 COOH or --CH(OH)COOH, or R.sub.1 and R.sub.2 jointly represent an oxo group (.dbd.O).

Drilling muds effective at high temperature

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Bergamo, Italy

Stefano Carminati