# US 2023/0147740 A1 · Diverting agent and method of filling fracture in well using the same

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 2023/0147740 A1
- Document ID: US20230147740A1
- Status: Published application
- Kind: A1
- Application number: 18/090,917
- Filed: 2022-12-29
- Published: 2023-05-11
- Earliest claimed: 2017-08-10
- Assignees: Mitsubishi Chemical Corporation
- Applicants: Mitsubishi Chemical Corporation
- Inventors: Kazutoshi TSUJI; Norihito SAKAI; Tomoya FUJITA; Takahiro SAKA; Chizuko FURO
- Web page: https://patentgrep.com/patent/US20230147740A1

## CPC

- C09K 8/508: macromolecular compounds {(C09K8/512 takes precedence)}
- C09K 8/725: {Compositions containing polymers}
- C08F 8/00: Chemical modification by after-treatment (graft polymers, block polymers, crosslinking with unsaturated monomers or with polymers C08F251/00 - C08F299/00; of conjugated diene rubbers C08C)
- C08F 8/12: Hydrolysis
- C08F 16/06: Polyvinyl alcohol {; Vinyl alcohol}
- C09K 8/68: containing organic compounds
- C09K 8/88: macromolecular compounds
- E21B 43/26: by forming crevices or fractures
- E21B 43/261: {Separate steps of (1) cementing, plugging or consolidating and (2) fracturing or attacking the formation}
- E21B 43/267: reinforcing fractures by propping
- C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C08F: MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- E21B: EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS

## Abstract

A problem to be solved of the present invention is to provide a diverting agent which gradually dissolves in water. The present invention relates to a diverting agent containing a polyvinyl alcohol-based resin and a method of filling a fracture using the diverting agent.

## Claims

### Claim 1

A diverting agent comprising:
a polyvinyl alcohol-based resin, wherein
an average degree of polymerization of the polyvinyl alcohol-based resin is from 150 to 4000.

### Claim 2 (depends on 1)

The diverting agent according to claim 1,
wherein the polyvinyl alcohol-based resin has a degree of saponification of 90 mol % or more.

### Claim 3 (depends on 1)

The diverting agent according to claim 1,
wherein the polyvinyl alcohol-based resin has a dissolution rate of 0.1 mass % to 30 mass %, when 4 g of the polyvinyl alcohol-based resin is charged into 96 g of water and is stirred for 180 minutes at 40° C.

### Claim 4 (depends on 1)

The diverting agent according to claim 1,
wherein a degree of crystallinity of the polyvinyl alcohol-based resin is 25% to 60%.

### Claim 5 (depends on 1)

The diverting agent according to claim 1,
wherein when 1 g of the polyvinyl alcohol-based resin is immersed in 100 g of water at 40° C., a ratio of a dissolution rate after 24 hours with respect to a dissolution rate after 1 hour of the polyvinyl alcohol-based resin is 2.8 or more.

### Claim 6 (depends on 5)

The diverting agent according to claim 5,
wherein when 1 g of the polyvinyl alcohol-based resin is immersed in 100 g of water at 40° C., the dissolution rate after 1 hour is less than 30 mass %.

### Claim 7 (depends on 5)

The diverting agent according to claim 5,
wherein when 1 g of the polyvinyl alcohol-based resin is immersed in 100 g of water at 40° C., the dissolution rate after 24 hours is 30 mass % or more.

### Claim 8 (depends on 5)

The diverting agent according to claim 5,
wherein the polyvinyl alcohol-based resin is a modified polyvinyl alcohol-based resin.

### Claim 9 (depends on 8)

The diverting agent according to claim 8,
wherein a modification rate of the modified polyvinyl alcohol-based resin is 0.5 mol % to mol %.

### Claim 10 (depends on 1)

The diverting agent according to claim 1,
wherein the polyvinyl alcohol-based resin satisfies formula (A):
degree of swelling×elution rate (mass %)≤500 (A)
wherein the degree of swelling is a value determined according to formula (B):
Degree
⁢
of
⁢
swelling
=
Mass
⁢
(
g
)
⁢
of
⁢
polyvinyl
⁢
alcohol
⁢
‐
⁢
based
⁢
resin
⁢
after
⁢
swelling
-
mass
⁢
(
g
)
⁢
of
⁢
polyvinyl
⁢
alcohol
⁢
‐
⁢
based
⁢
resin
⁢
dried
⁢
after
⁢
swelling
mass
⁢
(
g
)
⁢
of
⁢
polyvinyl
⁢
alcohol
⁢
‐
⁢
based
⁢
resin
⁢
dried
⁢
after
⁢
swelling
(
B
)
wherein a mass in grams of the polyvinyl alcohol-based resin after swelling is the mass of a residual polyvinyl alcohol-based resin obtained by charging 1 g of a polyvinyl alcohol-based resin into 100 g of water, leaving it to stand for 1 day in a thermostatic chamber at 23° C., collecting a filtrate by filtration, and drying the filtrate at 140° C. for 3 hours, and
wherein the elution rate, in mass %, is a value determined according to formula (C):
Elution
⁢
rate
⁢
(
mass
⁢
%
)
=
{
1
⁢
(
g
)
-
1
⁢
(
g
)
⨯
⁢
M
⁢
ass
⁢
(
g
)
⁢
of
⁢
polyvinyl
⁢
alcohol
⁢
‐
⁢
based
⁢
resin
⁢
dried
⁢
after
⁢
swelling
Solid
⁢
fraction
⁢
(
mass
⁢
%
)
⁢
of
⁢
polyvinyl
alcohol
⁢
‐
⁢
based
⁢
resin
100
}
⨯
100
(
C
)
wherein the mass of the polyvinyl alcohol-based resin dried after swelling is the same as defined for formula (B).

### Claim 11 (depends on 10)

The diverting agent according to claim 10,
wherein the elution rate of the polyvinyl alcohol-based resin is 50 mass % or less.

### Claim 12 (depends on 10)

The diverting agent according to claim 10,
wherein the degree of swelling of the polyvinyl alcohol-based resin is 30 or less.

### Claim 13 (depends on 1)

A method of filling a fracture which is a method of temporarily filling the fracture generated in a well, comprising:
allowing the diverting agent according to claim 1 to flow into a fracture to be filled with a flow of fluid in the well.