Schlumberger Technology Corporation

Rhodia Chimie

Cnrs

Françoise Lafuma

Julien Hernandez

Pierre Maroy

Lionel Ventelon

Coralie Simonet

Christophe Chassenieux

Christelle Perreur

The invention concerns a method for preparing anisotropic silica aggregates comprising the following steps: a) contacting at least one polymer with non-aggregated silica particles and/or highly dispersed in an aqueous medium, with a ratio R, polymer weight to silica particle surface, ranging between 0.03 and 2 mg/m; 2; and whereof the electrostatic value of the silica particle surface is not less than the value of the charge of the silica particle surface measured in an aqueous phase without added salts at a pH not less than 7; b) consolidating the aggregates obtained at step a) either by heat treatment, or by precipitation of a mineral compound. The invention also concerns a silica aggregate comprising a chaining of elementary particles whereof the number of particles ranges between 5 and 15, whereof 80% of elementary particles are in contact with not more than 2 particles and whereof the greatest distance measurable between 2 points of the aggregate is not more than 5 times the average size of one elementary particle.

Method for preparing anisotropic silica aggregates

The present invention provides a water-based fluid, in particular for drilling, completion or for any other intervention in a well such as a hydrocarbon well, in which the viscosity is controlled by a system constituted by precipitated silica nanoparticles (A) associated with a water-soluble copolymer (B) comprising one or more water-soluble co-monomers (I) having little or no affinity for silica and one or more co-monomers (II) which absorb onto the silica. The invention is of particular application to the secondary recovery of hydrocarbons.

Liquid compositions which reversibly viscosify or gel under the effect of shear

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Sceaux, France

Françoise Lafuma