# US 2021/0230472 A1 · Encapsulated filtercake removal treatment

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- Number: US 2021/0230472 A1
- Document ID: US20210230472A1
- Status: Published application
- Kind: A1
- Application number: 16/644,422
- Filed: 2019-04-18
- Published: 2021-07-29
- Earliest claimed: 2019-04-18
- Assignees: Halliburton Energy Services, Inc.
- Applicants: Halliburton Energy Services, Inc.
- Inventors: Alexandra Clare Morrison
- Web page: https://patentgrep.com/patent/US20210230472A1

## CPC

- C09K 8/52: Compositions for preventing, limiting or eliminating depositions, e.g. for cleaning
- C09K 8/536: characterised by their form or by the form of their components, e.g. encapsulated material
- E21B 37/00: Methods or apparatus for cleaning boreholes or wells (E21B21/00 takes precedence)
- C09K 2208/24: Bacteria or enzyme containing gel breakers
- C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- E21B: EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS

## Abstract

Systems and methods for treating a subterranean formation with particulate additives that may be useful in removing filtercake and/or mitigating premature fluid loss from the subterranean formation are provided. In some embodiments, the methods include providing a treatment fluid that includes a base fluid and a particulate additive, wherein particulates of the particulate additive each include an enzyme core and a degradable coating that at least partially encapsulates an outer surface of the enzyme core; and introducing the treatment fluid into at least a portion of a subterranean formation.

## Claims

### Claim 1

A method comprising:
providing a treatment fluid that comprises a base fluid and a particulate additive, wherein particulates of the particulate additive each comprise an enzyme core and a degradable coating that at least partially encapsulates an outer surface of the enzyme core; and
introducing the treatment fluid into at least a portion of a subterranean formation.

### Claim 2 (depends on 1)

The method of claim 1 wherein the degradable coating comprises calcium carbonate.

### Claim 3 (depends on 1)

The method of claim 1 wherein the enzyme core comprises a starch enzyme.

### Claim 4 (depends on 1)

The method of claim 1 wherein the enzyme core comprises an α-amylase.

### Claim 5 (depends on 1)

The method of claim 1 wherein the treatment fluid further comprises an additive selected from the group consisting of an organic acid, a chelating agent, any derivative thereof, and any combination thereof.

### Claim 6 (depends on 1)

The method of claim 1 wherein the treatment fluid further comprises a chelating agent selected from a group consisting of ethylenediaminetetraacetic acid (EDTA), glutamic acid diacetic acid (GLDA), and diethylene triamine penta-acetic acid (DTPA), novel polyacidic chelate (NPC), any derivative thereof, and any combination thereof.

### Claim 7 (depends on 1)

The method of claim 1 wherein the particulate additive is mixed, slurrified, or mixed and slurrified, with the base fluid.

### Claim 8 (depends on 1)

The method of claim 1 wherein the treatment fluid is a treatment pill having a volume of about 1000 lbs/bbl or less.

### Claim 9 (depends on 1)

The method of claim 1 wherein the particulates have a particle size (d50) of from about 20 am to about 100 am in diameter.

### Claim 10 (depends on 1)

The method of claim 1 wherein the degradable coating comprises a thickness of from about 0.01 am to about 10 am.

### Claim 11 (depends on 1)

The method of claim 1 wherein a filtercake is present in at least the portion of the subterranean formation.

### Claim 12

A method comprising:
providing a treatment fluid that comprises a base fluid and a particulate additive, wherein particulates of the particulate additive each comprise an enzyme core and a degradable coating, wherein the degradable coating at least partially encapsulates an outer surface of the enzyme core; and
contacting a filtercake in at least a portion of a well bore penetrating a subterranean formation with the treatment fluid.

### Claim 13 (depends on 12)

The method of claim 12 wherein the degradable coating comprises calcium carbonate.

### Claim 14

A filtercake removal agent comprising:
a base fluid; and
a plurality of particulates, wherein each of the particulates comprises
an enzyme core, and
a degradable coating that encapsulates an outer surface of the enzyme core.

### Claim 15 (depends on 14)

The filtercake removal agent of claim 14 wherein the degradable coating comprises calcium carbonate.

### Claim 16 (depends on 14)

The filtercake removal agent of claim 14 wherein the enzyme core comprises a starch enzyme.

### Claim 17 (depends on 14)

The filtercake removal agent of claim 14 wherein the enzyme core comprises an α-amylase.

### Claim 18 (depends on 14)

The filtercake removal agent of claim 14 further comprising an additive selected from the group consisting of an organic acid, a chelating agent, any derivative thereof, and any combination thereof.

### Claim 19 (depends on 14)

The filtercake removal agent of claim 14 further comprising a chelating agent selected from a group consisting of ethylenediaminetetraacetic acid (EDTA), glutamic acid diacetic acid (GLDA), and diethylene triamine penta-acetic acid (DTPA), novel polyacidic chelate (NPC), any derivative thereof and any combination thereof.

### Claim 20 (depends on 14)

The filtercake removal agent of claim 14 wherein the particulates have a particle size (d50) of from about 20 μm to about 100 μm in diameter.