Microencapsulated oil field chemicals

• US 5,922,652 A
• Filed: 05/05/1992
• Issued: 07/13/1999
• Est. Priority Date: 05/05/1992
• Status: Expired due to Term

• Current Assignee: Corsicana Technologies, Inc. (Ecolab, Inc.)
• Original Assignee: Corsicana Technologies, Inc. (Ecolab, Inc.)
• Inventors: Pike, Robert Wayne, Kowalski, Thomas Charles
• Primary Examiner(s): TUCKER, PHILIP C
• Application Number:
  US07/878,940
• Time in Patent Office: 2,625 Days
• Field of Search: 252/8.552, 252/8.555, 264/4.3, 428/402.2, 507/129, 507/902, 507/939, 507/131, 507/132
• US Class Current: 507/129
• 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 507/902 Controlled release agent
• CPC Class Codes: Y10S 507/939 Corrosion inhibitor
• CPC Class Codes: Y10T 428/2984 Microcapsule with fluid core [includes liposome]

Abstract

Gelatin capsules containing oil field chemicals, preferably weighted with a heavy metal compound, are made more stable under certain conditions by the incorporation of a strong chelating agent. The microcapsules can provide an extended treatment period since many materials that would damage the microcapsules are controlled by the chelating agent.

Claims

1. Microcapsule containing from about 5% to about 80% of oil field chemical, wherein said oil field chemical is selected from the group consisting of:

(A) scale inhibitor;

(B) corrosion inhibitor;

(C) biocide;

(D) chemicals to limit the presence of solid hydrocarbons;

(E) scavenger for H₂ S;

(F) scavenger for O₂ ;

(G) demulsifier;

(H) clay stabilizer;

(I) surfactant;

(J) acidizing agent; and

(K) mixtures thereof;

said microcapsules having a wall being formed by coacervation at a pH of rom about 3.5 to about 6, and said microcapsules being stabilized in brine solution containing about 20,000 mg/l chloride ion by incorporation of from about 3% to about 12% of a strong chelating agent selected from the acids and salts of the group consisting of;

material having the formula;

##STR5## and mixtures thereof, and wherein said microcapsule also comprise a weighting agent at a level of from about 5% to about 75%.