Patent EA-001879-B1 (EA)
Title: Coated products and use therefor in oil fields
Inventor: COLLINS IAN RALPH
IPC: C09K8/92
Filed: 1997-05-29
Abstract: 1. Particles comprising an oil field production chemical and a casing partially coating the chemical and including a dispersing agent. 2. Particles as claimed in claim 1 wherein the relative weight of the coating to the particle is less than 10g coating dry weight per 100g of dry weight particle. 3. Particles as claimed in claims 1 or 2 wherein the coating is selected from the group comprising (a) a comb type polymer, (b) a polymer of an oligomeric polyacid polyester or amine derivative thereof, (c) a surfactant and (d) a polymer having a hydrocarbon backbone with at least one pendant oxygen and/or nitrogen containing polar group. 4. Particles as claimed in claim 3 wherein the surfactant is a polymeric or monomeric alkoxylated alcohol or phenol. 5. Particles as claimed in claim 3 wherein the surfactant is a polymeric ether. 6. Particles as claimed in claim 3 wherein the polymer having a hydrocarbon backbone with at least one pendant oxygen and/or nitrogen containing polar group is an aliphatic(N-heterocyclic)carbonyl polymer. 7. Particles as claimed in claim 6 wherein the aliphatic(N-heterocyclic)carbonyl polymer is an alkylated derivative of polyvinylpyrrolidone. 8. Particles as claimed in claim 3 wherein the coating includes a fatty acid polyamine condensate. 9. Particles as claimed in any one of the preceding claims wherein the oil field production chemical is a scale inhibitor, a corrosion inhibitor, an asphaltene inhibitor, a wax inhibitor or a demulsifier. 10. Particles as claimed in claim 9 wherein the scale inhibitor is a polymeric compound. 11. Particles as claimed in claim 11 wherein the polymeric compound is a polyvinyl sulphonic acid, a poly(meth)acrylic acid or a copolymer of a vinylsulphonic acid and a (meth)acrylic acid or an alkali metal salt thereof. 12. Particles as claimed in any one of the preceding claims wherein the average size of the particles is 1-10 microns. 13. A process for the manufacture of particles as claimed in any one of the preceding claims, the process including comminuting a solid particulate oil field production chemical in the presence of a dispersion of a polymer or dispersing agent in an inert oil to cause the polymer or dispersing agent to adhere to at least part of the surface of the solid particulate oil field production chemical. 14. A suspension including an inert oil and particles as claimed in any one of claims 1-12. 15. A suspension as claimed in claim 14 wherein the inert oil is diesel oil or kerosene. 16. A suspension as claimed in claim 15 or claim 16 further including an organophilic thickening agent or viscosifier. 17. A method of reducing the formation of a separate phase from a liquid phase in a subterranean environment producing oil, or removing said separate phase, the method including injecting particles as claimed in any one of claims 1-12 or a suspension as claimed in any one of claims 14-15 into said environment. 18. A method as claimed in claim 17 wherein the particles are particles of an inhibitor of solid growth formation. 19. A method as claimed in claim 18 wherein the particles are particles of scale inhibitor and the scale inhibitor is released into the liquid phase.