Liquid compositions which reversibly viscosify or gel under the effect of shear
AssigneeSchlumberger Technology Corporation
InventorsPierre Maroy, Francoise Lafuma, Coralie Simonet
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Abstract
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.
Claims21
A water-based fluid with a viscosity which is controlled by a system constituted by precipitated silica nanoparticles having a diameter less than 70 nanometers associated with a water-soluble copolymer of the type monomer I(I−x) monomer II(x) with a molecular mass of over 700,000 g/mol wherein monomer I is acrylamide, monomer II is selected from the group consisting of vinylpyrrolidone and vinylimidazole, and x is in the range 0.05 to 0.2.
A water-based fluid with a viscosity which is controlled by a system constituted by precipitated silica nanoparticles having a diameter less than 70 nanometers associated with
- i) a water-soluble copolymer with a molecular mass of over 700,000 g/mol formed by at least 50% of at least one water-soluble comonomer (I) selected from the group consisting of
- acrylamide,
- acrylic acid,
- methacrylic acid,
- acrylic acid derivatives with an alkyl group in the β position,
- 2-acrylamido-2-methylpropanesulphonate, and
- sulphonated styrene;
- and the remainder being formed by at least one water-soluble co-monomer (II) selected from the group consisting of
- vinylpyrrolidone,
- vinylimidazole (pH>6),
- vinylpyridine,
- alkylvinylethers,
- N-vinylacetamide,
- hydroxyethylmethacrylate and
- alkyl derivatives of these compounds;
- and
- ii) at least one competing agent selected from the group consisting of
- fatty alcohol non ionic surfactants;
- polyethers;
- N-substituted amides;
- and
- dispersing agents.
Dependencies are inferred from the claim text.