Wax deposit removal using aqueous surfactant

Patent metadata

Field	Value
Publication number	US-11427749-B2
Application number	US-202016921100-A
Country	US
Kind code	B2
Filing date	Jul 6, 2020
Priority date	Jul 4, 2019
Publication date	Aug 30, 2022
Grant date	Aug 30, 2022

Abstract

A method and system for removing wax deposits from a wellbore and other oil production and processing equipment using a wax removal surfactant having at least 1% alkyl polyglycoside (APG), at least 0.5% ethoxylated alcohol (AE) or alcohol ethoxysulfates (AES), and at least 1% saturated alcohol, and optionally comprising D-Limonene, wherein the wax removal surfactant solution forms a Winsor Type III or Type IV microemulsion with water and wax.

First claim

The invention claimed is:

1. A method of removing wax deposits from oil production or processing equipment (OPPE), said method comprising:
a. determining that efficiency is reduced in OPPE as a result of wax deposits;
b. adding a wax removal surfactant having a temperature of at least 50° C. into said OPPE in an amount sufficient to dissolve said wax deposits, said wax removal surfactant consisting essentially of an aqueous solution having at least 1% alkyl polyglycoside (APG), at least 0.5% ethoxylated alcohol (AE) or alcohol ethoxysulfates (AES), at least 1% linear alcohol, and about 20% D-limonene, wherein said wax removal surfactant solution forms a microemulsion with water and wax and/or oil; and
c. recovering or removing said wax removal surfactant plus dissolved wax deposits, thus leaving said OPPE with reduced or no wax deposits,
wherein said wax removal surfactant with about 20% D-limonene removes more wax and prevents more wax re-solidification on cooling than a control wax removal surfactant with 0%, 2% or 5% D-limonene.

2. The method of claim 1 , wherein said wax removal surfactant is used at ≥60°.

3. The method of claim 1 , wherein said APG are C8-C16, said AE or AES are C8-C15 with an average of about 2-14 ethylene oxide groups, and said alcohols are about C4-C15.

4. The method of claim 1 , wherein said APG are C10-C14 alkyl polyglucosides, said ethoxylated alcohols are C9-C15 with an average of about 12 ethylene oxide groups, and said alcohols are about C6-C12.

5. The method of claim 1 , wherein said wax removal surfactant further comprises wax dispersants, wax solvents, wax crystal modifiers, or combinations thereof.

6. A method of removing wax deposits from crude oil production and processing equipment (OPPE), said method comprising:
a. obtaining a sample of a wax deposit in an OPPE;
b. testing said sample to optimize a wax removal surfactant for dissolving said sample, said wax removal surfactant being used at a temperature of at least 50° C. and consisting essentially of an aqueous solution having at least 1% alkyl polyglycoside (APG), at least 0.5% ethoxylated alcohol (AE) or alcohol ethoxysulfates (AES), at least 1% linear alcohol, and about 20% D-limonene, wherein said wax removal surfactant solution forms a Winsor Type III or Type IV microemulsion with water and wax;
c. adding said optimized wax removal surfactant having a temperature of least 50° C. into said OPPE in an amount sufficient to dissolve said wax deposits; and
d. recovering or removing said wax removal surfactant plus dissolved wax deposits, thus leaving said OPPE with reduced or no wax deposits,
wherein said wax removal surfactant with about 20% D-limonene removes more wax and prevents more wax re-solidification on cooling than a control wax removal surfactant with 0%, 2%, or 5% D-limonene.

7. The method of claim 6 , wherein said optimized wax removal surfactant is used at a temperature of at least 60° C.

8. The method of claim 6 , wherein said APG are C8-C16, said AE or AES are C8-C15 with an average of about 2-14 ethylene oxide groups, and said alcohols are about C4-C15.

9. The method of claim 7 , wherein said APG are C10-C14 alkyl polyglucosides, said ethoxylated alcohols are C9-C15 with an average of about 12 ethylene oxide groups, and said alcohols are about C6-C12.

10. The method of claim 6 , wherein said optimized wax removal surfactant is left to soak said OPPE for a period of at least 2 hours.

11. The method of claim 6 , wherein said optimized wax removal surfactant is circulated though said OPPE for a period of at least 2 hours.

12. The method of claim 6 , said wax removal surfactant further comprising wax dispersants, wax solvents, wax crystal modifiers, or combinations thereof.

13. The method of claim 6 , wherein said method is repeated at periodic intervals to keep wax deposits at a minimum.

14. The method of claim 6 , wherein said OPPE is an oil well, and wherein said well is shut-in after said adding step c for a period of at least 12 hours.

15. The method of claim 14 , wherein said well is opened after said period and an initial flow back is sent to a truck or tank for disposal or reuse until insignificant amounts of optimized wax removal surfactant are in said flow back, and thereafter said flow back is routed to a central processing facility (“CPF”) for producing oil.

Assignees

• Conocophillips Co

Inventors

• Wu Yaqin
• Xu Ying
• Blumer David

Classifications

• C09K8/524 Primary

  organic depositions, e.g. paraffins or asphaltenes · CPC title