Coated products and use thereof in oil fields

• US 6,380,136 B1
• Filed: 11/30/1998
• Issued: 04/30/2002
• Est. Priority Date: 05/31/1996
• Status: Expired due to Term

• Current Assignee: BP Exploration Operating Company Limited (BP PLC)
• Original Assignee: BP Exploration Operating Company Limited (BP PLC), Collag Limited
• Inventors: Ravenscroft, Paul Derek, Collins, Ian Ralph, Bates, Christopher Ian
• Primary Examiner(s): TUCKER, PHILIP C
• Application Number:
  US09/201,723
• Time in Patent Office: 1,247 Days
• Field of Search: 507/902, 507/244, 507/131, 507/219, 507/261, 507/229, 507/224, 507/227, 507/90, 507/939
• US Class Current: 507/90
• CPC Class Codes: C09K 8/536 characterised by their form or by the form of their components, e.g. encapsulated material
• CPC Class Codes: C09K 8/54 Compositions for in situ inhibition of corrosion in boreholes or wells
• CPC Class Codes: C09K 8/92 characterised by their form or by the form of their components, e.g. encapsulated material C09K8/70 takes precedence
• CPC Class Codes: Y10S 507/901 Organically modified inorganic solid
• CPC Class Codes: Y10S 507/902 Controlled release agent
• CPC Class Codes: Y10S 507/906 Solid inorganic additive in defined physical form
• CPC Class Codes: Y10S 507/939 Corrosion inhibitor

Abstract

An oil field production chemical, especially a scale inhibitor, is in the form of particles thereof carrying a coating e.g. of a dispersing agent. The coating may be polymeric such as an oligomeric polyacid polyester, a polymeric alkoxylated alcohol or a fatty acid polyamine condensate or it may also be a surfactant and may be used in the form of a suspension in an inert oil, such as diesel oil or kerosene which may be injected into a subterranean formation to inhibit the formation of deposits, e.g. scale in oil wells over a longer period than compounds free of the coating.

Claims

1. Particles of a solid comprising an oil field production chemical, wherein said solid carries a discontinuous coating comprising a dispersing agent, said particles having an average particle size of less than 20 microns.

2. Particles according to claim 1 wherein the weight of said coating is 0.1-10 g coating per 100 g of the particles.

3. Particles according to claim 1 wherein the coating is selected from

a) a comb type polymer;

b) a polymer of an oligomeric polyacid polyester or amine derivative thereof;

c) a surfactant; and

d) a polymer comprising 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 comprising 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 comprises a fatty acid polyamine condensate.

9. Particles as claimed in claim 1 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 10 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 claim 1 having an average particle size of between 0.4 and 10 microns.

13. Particles as claimed in claim 12 having an average particle size of between 1 and 10 microns.

14. Particles as claimed in claim 13 having an average particle size of between 1 and 3 microns.

15. Particles as claimed in claim 1 wherein the particles have a particle size of 100% less than 10 microns.

16. Particles as claimed in claim 15 wherein the particles have a particle size of 100% less than 5 microns.