# US 10,815,416 B2 · Multi-functional surfactant solution for improving hydrocarbon recovery

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- Number: US 10,815,416 B2
- Document ID: US10815416B2
- Status: Granted
- Kind: B2
- Application number: 16/379,367
- Filed: 2019-04-09
- Published: 2019-10-10
- Granted: 2020-10-27
- Earliest claimed: 2018-04-09
- Assignees: Alchemy Sciences, Inc.
- Applicants: Alchemy Sciences, Inc.
- Inventors: Luchao Jin; James Russum
- Web page: https://patentgrep.com/patent/US10815416B2

## CPC

- C09K 8/602: {containing surfactants}
- C09K 8/665: {containing inorganic compounds (proppants C09K8/80)}
- C09K 8/68: containing organic compounds
- C09K 8/80: Compositions for reinforcing fractures, e.g. compositions of proppants used to keep the fractures open
- C09K 8/88: macromolecular compounds
- E21B 43/16: Enhanced recovery methods for obtaining hydrocarbons
- E21B 43/26: by forming crevices or fractures
- E21B 43/267: reinforcing fractures by propping
- G01N 33/2823: {Raw oil, drilling fluid or polyphasic mixtures}
- 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
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)

## Abstract

A fluid injection process includes removing a core sample from a low permeability reservoir. The process also includes performing an imbibition test on a plurality of stage one surfactants, each stage one surfactant mixed with a first treatment fluid, using a portion of the core sample to obtain a wettability index or measurement of capillary pressure for each stage one surfactant. In addition, the process includes selecting a stage one surfactant by determining which of the plurality of stage one surfactants has the highest wettability index or lowest capillary pressure and performing an oil recovery test on a plurality of stage two surfactants, each stage two surfactant mixed with a second treatment fluid. Further, the process includes selecting a stage two surfactant by determining which of the plurality of stage two surfactants has the highest oil recovery test result and injecting the selected stage one surfactant into a matrix of the low permeability reservoir. In addition, the method includes injecting the selected stage two surfactant into a fracture network of the low permeability reservoir.

## Claims

### Claim 1

A fluid injection process comprising:
removing a core sample from a low permeability reservoir;
performing an imbibition test on a plurality of stage one surfactants, each stage one surfactant mixed with a first treatment fluid, using a portion of the core sample to obtain a wettability index or measurement of capillary pressure for each stage one surfactant;
selecting a stage one surfactant by determining which of the plurality of stage one surfactants has the highest wettability index or lowest capillary pressure;
performing an oil recovery test on a plurality of stage two surfactants, each stage two surfactant mixed with a second treatment fluid;
selecting a stage two surfactant by determining which of the plurality of stage two surfactants has the highest oil recovery test result;
injecting the selected stage one surfactant into a matrix of the low permeability reservoir; and
injecting the selected stage two surfactant into a fracture network of the low permeability reservoir.

### Claim 2 (depends on 1)

The process of claim 1, wherein the stage one surfactant is different than the stage two surfactant.

### Claim 3 (depends on 1)

The process of claim 1, wherein the stage two surfactant is retained within the fracture network.

### Claim 4 (depends on 1)

The process of claim 1 further comprising after the step of injecting the selected stage one surfactant into a matrix of the low permeability reservoir:
increasing oil flow from the matrix.

### Claim 5 (depends on 4)

The method of claim 4, further comprising after the step of injecting the selected stage two surfactant into a fracture network of the low permeability reservoir:
increasing oil flow from the fracture network.

### Claim 6 (depends on 5)

The method of claim 5 further comprising after the step of selected stage two surfactant into a fracture network of the low permeability reservoir:
displacing oil through a borehole drilled within the low permeability reservoir.

### Claim 7 (depends on 1)

The method of claim 1, wherein the stage one surfactant is nonionic, cationic, anionic, zwitterionic, or a combinations thereof.

### Claim 8 (depends on 1)

The method of claim 1, wherein the stage two surfactant is nonionic, cationic, anionic, zwitterionic, or a combinations thereof.

### Claim 9 (depends on 1)

The method of claim 1, wherein the imbibition test is the Amott cell test.

### Claim 10 (depends on 1)

The method of claim 1, wherein the step of performing the oil recovery test comprises:
saturating the cores sample that has been crushed with crude oil from the low permeability reservoir;
passing the second treatment fluid containing one of the stage two surfactant through the core sample;
collecting the effluent; and
quantifying the amount of crude oil in the effluent.

### Claim 11 (depends on 1)

The method of claim 1, wherein the first stage surfactant or the second stage surfactant is a nonionic surfactant, wherein the nonionic surfactant is an alcohol oxylalkylate, an alkyl phenol oxylalkylate, a nonionic esters, a castor oil alkoxylate, a fatty acid alkoxylate, a lauryl alcohol alkoxylates, a nonylphenol alkoxylate, a octylphenol alkoxylate, a tridecyl alcohol alkoxylate, or a combination thereof.

### Claim 12 (depends on 1)

The method of claim 1, wherein the first stage surfactant or the second stage surfactant is a cationic surfactant, wherein the cationic surfactant is an alkyl amine, an alkyl amine salt, aquaternary ammonium salt, an amine oxide, an alkyltrimethyl amine, a triethyl amine, an alkyldimethylbenzylamine, cetyltrimethylammonium bromide, an alkyl dimethyl benzyl-ammonium chloride, trimethylcocoammonium chloride, or combinations thereof.

### Claim 13 (depends on 1)

The method of claim 1, wherein the first stage surfactant or the second stage surfactant is an anionic surfactant, wherein the anionic surfactant is an alkyl carboxylate, an alkylether carboxylate, a N-acylaminoacid, a N-acylglutamates, a N-acyl-polypeptides, an alkylbenzenesulfonate, a paraffinic sulfonate, an α-olefinsulfonate, a lignosulfate, a derivative of a sulfosuccinate, a polynapthylmethylsulfonate, an alkyl sulfate, an alkylethersulfate, a C8 to C22 alkylethoxylate sulfate, an alkylphenol ethoxylate sulfate or a salt thereof, a monoalkylphosphate, a polyalkylphosphate, a fatty acid, an alkali salt of a fatty acid, a glyceride sulfate, a sodium salt of a fatty acid, a soap or a combinations thereof.

### Claim 14 (depends on 1)

The method of claim 1, wherein the first stage surfactant or the second stage surfactant is an amphoteric or zwitterionic surfactant selected from the group consisting of dihydroxyl alkyl glycinate, alkyl ampho acetate or propionate, alkyl betaine, alkyl amidopropyl betaine, alkylimino mono- or di-propionates, and combinations thereof.