# US 10,767,103 B2 · Method of obtaining mineral oil using a silica fluid

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- Number: US 10,767,103 B2
- Document ID: US10767103B2
- Status: Granted
- Kind: B2
- Application number: 15/770,786
- Filed: 2016-10-18
- Published: 2018-11-01
- Granted: 2020-09-08
- Earliest claimed: 2015-10-26
- Assignees: Evonik Operations GmbH
- Applicants: Evonik Degussa GmbH
- Inventors: Wolfgang Lortz; Ulrich Fischer; Gabriele Bergmann; Ole Torsaeter; Katherine Rose Aurand
- Web page: https://patentgrep.com/patent/US10767103B2

## CPC

- C09K 8/584: characterised by the use of specific surfactants
- E21B 43/16: Enhanced recovery methods for obtaining hydrocarbons
- C09K 2208/10: Nanoparticle-containing well treatment fluids
- 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

Method of obtaining mineral oil, comprising the steps of: providing a fluid comprising surface-modified silica particles, introducing this fluid into a mineral oil deposit via a first well in contact with this mineral oil deposit, recycling a mixture comprising the fluid and mineral oil via the first well or a further well and separating the mineral oil from the mixture, wherein the fluid comprises surface-modified nanostructured silica particles in an aqueous phase, A) the surface modified silica particles a) being mixed aluminium-silicon oxide, where the mixed oxide component is also part of the particle surface, and b) the surface modification comprises a hydrocarbon radical which is interrupted by one or more heteroatoms and comprises a silicon atom is bonded to a carbon atom of the hydrocarbon radical, the surface modification being selected from the group consisting of Si—(CH2)n—Ym—R, where Si is the Si atom which is bonded via a C atom to a hydrocarbon radical, and n=1, 2 or 3 and m=0 or 1 R is a radical which does not impart hydrophobic properties, and if m=1, is —H, —CH3, —C2H5, —OH, —OCH3, —OC2H5, —C(═O)OCH3, —C(═O)OC2H5, —O—C(═O)CH3, —O—C(═O)CH3, —O—C(═O)CH═CH2, —O—C(═O)CH═CH(CH3), —C(═O)CH3, —CH(O)CH2 and hydrolysates of —CH(O)CH2, and, if m=0, the aforementioned R radicals without —H, —CH3, —C2H5, Y=—(OCH2CH2)o—, o=5-15 or a mixture of the aforementioned R and Y radicals. c) having c1) a ratio of the proportions by weight of Al2O3/SiO2 of 0.1:99.9-5:95 c2) an average particle diameter d50 of 40-200 nm and c3) a carbon content of 3%-25% by weight and B) the fluid having d) a content of 0.01%-5% by weight of the surface modified silica particles, and e) a pH of the aqueous phase being 7≤pH≤8.5.

## Claims

### Claim 1

A method of obtaining mineral oil, comprising the steps of:
a) providing a fluid comprising surface-modified silica particles;
b) introducing this fluid into a mineral oil deposit via a first well in contact with this mineral oil deposit;
c) recycling a mixture comprising the fluid and mineral oil via the first well or a further well; and
d) separating the mineral oil from the mixture;
wherein the fluid comprises surface-modified nanostructured silica particles in an aqueous phase,
A) the surface modified silica particles:
a) being mixed aluminium-silicon oxide, wherein the mixed oxide component is also part of the particle surface, and
b) the surface modification comprises a hydrocarbon radical which is interrupted by one or more heteroatoms and comprises a silicon atom bonded to a carbon atom of the hydrocarbon radical, the surface modification being selected from the group consisting of Si—(CH2)n—Ym—R, where Si is the Si atom which is bonded via a C atom to a hydrocarbon radical, and
n=1, 2 or 3 and m=0 or 1
R is a radical which does not impart hydrophobic properties, and
if m=1, is: —H, —CH3, —C2H5, —OH, —OCH3, —OC2H5, —C(═O)OCH3, —C(═O)OC2H5, —O—C(═O)CH3, —O—C(═O)CH3, —O—C(═O)CH═CH2, —O—C(═O)CH═CH(CH3), —C(═O)CH3, —CH(O)CH2 and hydrolysates of —CH(O)CH2; and,
if m=0, the aforementioned R radicals without —H, —CH3, —C2H5;
Y=—(OCH2CH2)o—, o=5-15;
or a mixture of the aforementioned R and Y radicals;
c) having:
c1) a ratio of the proportions by weight of Al2O3/SiO2 of 0.1:99.9-5:95;
c2) an average particle diameter d50 of 40-200 nm; and
c3) a carbon content of 3%-25% by weight; and
B) the fluid having:
d) a content of 0.01%-5% by weight of the surface modified silica particles; and
e) a pH of the aqueous phase being 7≤pH≤8.5.

### Claim 2 (depends on 1)

The method of claim 1, wherein the surface modification comprises an aluminium atom which is bonded via an oxygen atom to a silicon atom of the particle surface.

### Claim 3 (depends on 1)

The method of claim 1, wherein the mixed silicon-aluminium oxide is a fumed mixed silicon-aluminium oxide having a BET surface area of 140-200 m2/g and an aluminium oxide content of 0.3%-1.3% by weight.

### Claim 4 (depends on 1)

The method of claim 1, wherein (Al2O3/SiO2)surface/(Al2O3/SiO2)ttl is 0.1-10.

### Claim 5 (depends on 1)

The method of claim 1, wherein the surface modification further comprises Al.

### Claim 6 (depends on 5)

The method of claim 5, wherein the proportion of Al in the surface modification is ≤0.15 mg Al/m2 of BET surface area.

### Claim 7 (depends on 1)

The method of claim 1, wherein the surface modification is selected from the group consisting of: Si(CH2)3—(OCH2CH2)6-9—OCH3, Si(CH2)3—(OCH2CH2)9-12—OCH3, Si(CH2)3—(OCH2CH2)21-24—OCH3, Si(CH2)3—(OCH2CH2)8-12OH and Si—(CH2)3—CH(O)CH2.

### Claim 8 (depends on 2)

The method of claim 2, wherein the mixed silicon-aluminium oxide is a fumed mixed silicon-aluminium oxide having a BET surface area of 140-200 m2/g and an aluminium oxide content of 0.3%-1.3% by weight.

### Claim 9 (depends on 8)

The method of claim 8, wherein (Al2O3/SiO2)surface/(Al2O3/SiO2)ttl is 0.1-10.

### Claim 10 (depends on 9)

The method of claim 9, wherein the surface modification further comprises Al.

### Claim 11 (depends on 10)

The method of claim 10, wherein (Al2O3/SiO2)surface/(Al2O3/SiO2)ttl is 0.1-10.

### Claim 12 (depends on 1)

The method of claim 1, wherein the surface modification further comprises Al.

### Claim 13 (depends on 3)

The method of claim 3, wherein the silane is mixed with at least one metal compound selected from the group consisting of the metal alkoxides and metal acetylacetonates of aluminium, titanium and zirconium, and also sodium aluminate wherein the molar metal/Si ratio of the surface modification is 1:2-1:20 before it is added to the predispersion.

### Claim 14 (depends on 1)

The method of claim 1, wherein the fluid is introduced into a mineral oil deposit having a temperature of 10-200° C.

### Claim 15

A method of obtaining mineral oil, comprising the steps of:
a) providing a dispersion comprising more than 5 wt.-% of surface-modified silica particles by:
a1) dispersing a mixed aluminium-silicon oxide powder having a ratio of the proportions by weight of Al2O3/SiO2 of 0.1:99.9-5:95 and Si atoms and Al atoms each bearing hydroxyl groups on the surface of the particles in an aqueous solution to an average particle diameter d50 40-200 nm and subsequently;
a2) adding the agent for surface modification;
a3) causing the mixture to react to obtain the dispersion comprising of surface-modified silica;
a4) optionally removing the hydrolysis product; and
a5) optionally adjusting the pH;
wherein the agent for surface modification is added in such an amount as to obtain a carbon content of 3-25% by weight, taking account of the hydroxyl groups, alkoxy groups or chloride groups detached in the hydrolysis, and
wherein the agent for surface modification is a silane selected from the group consisting of:
X4-a[Si—(CH2)n—Y—R]a with a=1, 2 or 3; preferably a=1; n=1, 2 or 3;
X=OH, OCH3, OC2H5, Cl; Y=—(OCH2—CH2)o−, o=5-15,
R=—H, —CH3,—C2H5, —OH, —OCH3, —OC2H5, —C(═O)OCH3, —C(═O)OC2H5, —O—C(═O)CH3, —O—C(═O)CH3, —CH(O)CH2 or a hydrolysate of —CH(O)CH2;
b) diluting the dispersion to obtain a fluid having a content of 0.01%-5% by weight of the surface modified mixed aluminium-silicon oxide particles, and having a pH of the aqueous phase of 7≤pH≤8.5 or adjusting the pH to this range;
c) introducing this fluid into a mineral oil deposit via a first well in contact with this mineral oil deposit;
d) recycling a mixture comprising the fluid and mineral oil via the first well or a further well; and
e) separating the mineral oil from the mixture.

### Claim 16 (depends on 15)

The method of claim 15, wherein the fluid is introduced into a mineral oil deposit having a temperature of 10-200° C.